The incorrect pair is d. July 06 is Van Mahostav day. The other statements are correct: Hollard is the total soil water content, Echard is the water not available to plants, and the visible part of light spectrum is composed of wavelengths ranging from 400 nm to 700 nm. Van Mahotsav is celebrated on July 05, not July 06, making this statement factually incorrect.
Mukia is the odd man out. Isoetes, Hydrilla, Potamogeton, and Ranunculus are all aquatic plants adapted to live in water environments, whereas Mukia is a terrestrial plant that grows on land. Mukia is a creeping or climbing herb belonging to the Cucurbitaceae family and does not share the aquatic habitat characteristic of the other four plants listed.
Bryophyllum is the odd man out. Argemone, Mollugo, and Tribulus are all xerophytic plants adapted to survive in dry, arid environments with reduced water availability. These plants possess various xeromorphic features such as reduced leaf surface area, thick cuticles, and efficient water conservation mechanisms. Bryophyllum, however, is a succulent plant that stores water in its fleshy leaves and stems, making it a different type of drought-resistant plant with a distinct adaptation strategy compared to the typical xerophytes listed.
The correct answer is c. Community → Ecosystem → Landscape → Biome. This represents the proper sequence of ecological hierarchy from lower to higher levels of organization. A community consists of all the different populations of species living and interacting in a particular area. An ecosystem includes the community along with the abiotic environment and all the interactions between biotic and abiotic components. A landscape is a larger geographical area comprising multiple ecosystems with similar characteristics. A biome is an even larger unit representing a major regional or global biotic community characterized by distinctive climate, vegetation, and fauna. This hierarchical arrangement correctly progresses from smaller, more localized ecological units to progressively larger and more inclusive organizational levels.
d. ii and iii only
b. niche
b. ii, iii and iv correct answer
a. Calotropis
d. ii and iii only
b. Statement A is correct but statement
c. capillary water
a) i – Holard, ii-Echard, iii-Chresard
The correct answer is c) I (iii), II (ii), III (i), IV (iv). Soil particles are classified by size into different categories. Sandy soil particles range from 0.2 to 2.00 mm in diameter, making option I correspond to iii. Clayey soil particles are the finest, measuring less than 0.002 mm, so option II matches with ii. Silt soil particles fall between 0.002 to 0.02 mm in size, corresponding option III to i. Loamy soil is a mixture of sand, silt, and clay particles with sizes ranging from 0.002 to 0.2 mm, making option IV match with iv. This classification is based on the Wentworth scale used in soil science to determine soil texture and properties.
The correct answer is d. A – (2), B – (4), C – (1), D – (3). Stenobathic refers to organisms that can tolerate only a narrow range of depth of water or habitat, so it matches with (2). Stenoecious organisms are restricted to a particular habitat or show habitat selection, corresponding to (4). Stenohaline organisms can tolerate only a narrow range of salinity variations in their environment, matching with (1). Stenophagic organisms have a narrow range of food preferences and can consume only specific types of food, corresponding to (3). These terms all begin with 'steno-' meaning narrow, and each describes an organism's limited tolerance to a specific environmental factor.
In ecology, organisms are classified based on their tolerance to environmental factors. Eurythermal organisms can tolerate and thrive in a wide range of temperatures, while stenothermal organisms are restricted to a narrow temperature range. Similarly, euryhaline organisms can withstand significant variations in salinity, whereas stenohaline organisms are adapted to a limited range of salt concentrations. Considering these definitions, Eurythermal (A) relates to a wide range of temperature tolerance, which is not directly listed but is analogous to the concept of tolerance. Stenothermal (B) is the opposite, indicating a narrow temperature range. Euryhaline (C) refers to tolerance to a wide range of salinity. Stenohaline (D) refers to tolerance to a narrow range of salinity. Given the options, the best match for Euryhaline (C) is 'Wide range of salinity' (4), and for Stenohaline (D) is 'Narrow range of salinity' (not explicitly listed but implied by contrast). However, looking at the provided options and typical ecological pairings, the question likely intends to match tolerance ranges. If we interpret the options as general tolerance, then Eurythermal and Euryhaline imply wide ranges, and Stenothermal and Stenohaline imply narrow ranges. Let's re-evaluate the options provided in the question's answer. The provided answer is 'b. A – (3), B – (1), C – (4), D – (2)'. This suggests A (Eurythermal) is matched with 3 (Food), B (Stenothermal) with 1 (Salinity), C (Euryhaline) with 4 (Wide range of salinity), and D (Stenohaline) with 2 (Depth of water/habitat). This mapping seems incorrect based on standard ecological definitions. Let's assume there's a typo in the provided options or the intended question. If we strictly follow the definitions: Eurythermal means wide temperature range, Stenothermal means narrow temperature range, Euryhaline means wide salinity range, Stenohaline means narrow salinity range. Option C (Euryhaline) correctly matches with 4 (Wide range of salinity). Option D (Stenohaline) should match with a narrow salinity range. Option A (Eurythermal) should match with a wide temperature range, and B (Stenothermal) with a narrow temperature range. None of the options directly provide temperature ranges. However, if we assume the question intends to test the concept of 'wide' vs 'narrow' tolerance, and that 'Salinity' (1) and 'Depth of water/habitat' (2) are factors, and 'Food' (3) is a resource, then the provided answer 'b' implies A-3, B-1, C-4, D-2. This is still problematic. Let's reconsider the possibility that the question or options are flawed. If we assume the question meant to ask about tolerance to factors, and option 4 is 'Wide range of salinity', then C (Euryhaline) is correctly matched. If we assume there's a corresponding 'Narrow range of salinity' for D (Stenohaline), it's missing. The provided answer 'b' suggests A-3, B-1, C-4, D-2. This means Eurythermal is linked to Food, Stenothermal to Salinity, Euryhaline to Wide range of salinity, and Stenohaline to Depth of water/habitat. This is ecologically inconsistent. Given the constraint to use the provided answer, the correct choice according to the provided key is 'b', despite the apparent discrepancies in ecological definitions.
The correct answer is c. A – (3), B – (4), C – (1), D – (2). Sclerophyllous vegetation is characterized by hard, thick, waxy leaves adapted to past climates with heavy rainfall during winter, matching with (3). Timberline marks the level or altitude above which trees cannot grow due to harsh environmental conditions, corresponding to (4). Paleoclimatology is the study of past climates and climate patterns, matching with (1). Evergreen forests are characterized by heavy rainfall throughout the year, which supports continuous growth and foliage, corresponding to (2). These terms represent different ecological and climatic concepts related to vegetation patterns and environmental history.
The correct answer is d. A – (3), B – (4), C – (1), D – (2). Altitude refers to the height or elevation of a place above sea level, matching with (3). Hypolimnion is the colder, deeper water layer in a stratified lake that remains isolated from the surface, corresponding to (4). Maximum temperature is the highest temperature at which physiological activities of an organism stop or cease, matching with (1). Optimum temperature is the temperature at which physiological activities of an organism are most efficient and occur at maximum rate, corresponding to (2). These terms describe important ecological and environmental parameters that affect organism distribution and function.
b. A- (iii),B- (ii),C- (iv),D- (i)
d. D alone
d. C alone
d. Halophytes
In the given table illustrating ecological interactions, species X and Y are affected by different types of relationships. Mutualism is an interaction where both species benefit, denoted by (+) for both species X and Y. Therefore, A represents the effect on species Y in a mutualistic relationship, which is beneficial (+). Competition occurs when two or more species require the same limited resource, resulting in negative effects on both. Thus, C represents the effect on species X in a competitive interaction, which is detrimental (-). Parasitism is an interaction where one species (the parasite) benefits at the expense of the other (the host). In this case, the parasite benefits (+) while the host is harmed (-). Therefore, B represents the effect on species Y in a parasitic relationship, which is detrimental (-). Amensalism is an interaction where one species is harmed, and the other is unaffected (0). Therefore, D represents the effect on species Y in an amensalistic relationship, which is unaffected (0). Based on this analysis, A is (+), B is (-), C is (-), and D is (0). The provided answer 'a) A (+) B – Parasitism, C (-), D – Amensalism' seems to be interpreting the labels differently or is incomplete. Let's re-examine the table structure. The table shows 'Interaction', 'Effects on species X', and 'Effects on species Y'. For Mutualism, X is (+), Y is (+). So A should be (+). For Competition, X is (-), Y is (-). So C should be (-). For Parasitism, the interaction is listed, and the effects on X and Y are given as (-) and (+). This implies X is the host (harmed, -) and Y is the parasite (benefited, +). So, B represents the effect on species Y, which is (+). For Amensalism, the effects on X and Y are given as (-) and (0). So D represents the effect on species Y, which is (0). Therefore, A=(+), B=(+), C=(-), D=(0). The provided answer 'a) A (+) B – Parasitism, C (-), D – Amensalism' is still confusing as it seems to be mixing effects with interaction types and not providing complete values for B and D. However, if we interpret 'B – Parasitism' as indicating that the effect on species Y in the context of parasitism is (+), and 'D – Amensalism' indicates the effect on species Y is (0), and A is (+) and C is (-), then the answer seems to be trying to identify the effects. Let's assume the question asks to identify the effects A, B, C, D. From the table: Mutualism: X (+), Y (+). So A = (+). Parasitism: X (-), Y (+). So B = (+). Competition: X (-), Y (-). So C = (-). Amensalism: X (-), Y (0). So D = (0). Thus, A=(+), B=(+), C=(-), D=(0). The provided answer 'a) A (+) B – Parasitism, C (-), D – Amensalism' lists A as (+), C as (-), and then mentions Parasitism and Amensalism without specifying the effects clearly. If we assume the option intends to say A is (+), B's interaction is Parasitism (implying B is + for Y), C is (-), and D's interaction is Amensalism (implying D is 0 for Y), then it's partially correct but poorly formatted. Given the provided answer format, it's likely that the question expects identification of the effects and possibly the interaction types. If we strictly follow the table: A is the effect on Y in Mutualism, which is (+). B is the effect on Y in Parasitism, which is (+). C is the effect on X in Competition, which is (-). D is the effect on Y in Amensalism, which is (0). The provided answer format is problematic. However, if we interpret the answer 'a) A (+) B – Parasitism, C (-), D – Amensalism' as identifying the effects: A is (+), C is (-), and implicitly B is (+) (from parasitism where Y benefits) and D is (0) (from amensalism where Y is unaffected), then it aligns partially. The most plausible interpretation of the provided answer 'a' is that it correctly identifies A as (+), C as (-), and implies B is (+) and D is (0) by mentioning the interactions. Without a clearer set of options or a better-formatted answer, it's difficult to be definitive, but based on the provided answer, 'a' is the intended choice.
c. Mimicry
b. Anabaena
d. Soil
b. Absorbing inorganic ions from soil
c. Nerium
a. Nymphaea and typha
d (I) iv, (II) iii, (III) ii, (IV) v, (V) i
a. Argemone
b. Zoochory
Ecology is the branch of biology that studies the reciprocal relationship and interactions between living organisms and their physical environment. It examines how organisms adapt to their surroundings, how they interact with each other within communities, and how energy and nutrients flow through ecosystems. Ecology encompasses the study of populations, communities, ecosystems, and the biosphere, investigating factors such as habitat, food chains, competition, predation, and environmental influences on biodiversity and ecosystem functioning.
Ecological hierarchy refers to the different levels of biological organization that result from the interaction of organisms with their environment and with each other. The establishment of these groupings creates distinct levels of ecological organization. The levels of ecological hierarchy, arranged from the smallest to the largest unit of organization, are as follows: organism, which is an individual living being; population, consisting of all individuals of the same species living in a particular area; community, comprising all different populations of various species living and interacting in a specific area; ecosystem, which includes the community along with all the abiotic factors and their interactions; landscape, representing a larger geographical area composed of multiple ecosystems; biome, which is a major regional or global biotic community with characteristic climate and vegetation; and finally biosphere, the largest level encompassing all living organisms and their environments on Earth. Each level exhibits emergent properties and functions that are not present at lower levels of organization.
Ecological equivalents are taxonomically unrelated species that occupy similar ecological niches in different geographical regions. These species have evolved independently but have adapted to similar environmental conditions and perform similar roles within their respective ecosystems. For instance, the epiphytic orchids found in the Western Ghats of India and those found in South America are ecological equivalents. Although they belong to different genera and species, they share the characteristic of growing on other plants (epiphytism) and occupy a similar niche as aerial plants dependent on host trees for support, obtaining moisture and nutrients from the atmosphere and debris. This convergence in form and function despite distinct evolutionary origins highlights the power of similar environmental pressures to shape life.
A habitat refers to the specific physical location or environment where an organism or a species lives. It encompasses the abiotic factors such as temperature, rainfall, sunlight, and soil type, as well as the biotic components like other organisms present in that area. A single habitat can be occupied by numerous different species. For example, a pond is a habitat that supports fish, amphibians, aquatic plants, and various microorganisms. In contrast, a niche describes the functional role and position of a species within an ecosystem. It includes not only the physical space it occupies but also its interactions with other species, its food sources, its predators, and its impact on the environment. A unique niche is typically occupied by a single species, defining its specific way of life and resource utilization. For instance, the niche of a dragonfly in a pond includes its feeding habits, its breeding grounds, and its role as both predator and prey. Organisms may also exhibit niche plasticity, adapting their niche over time or seasonally to changing conditions.
Organisms are classified as eurythermal or stenothermal based on their tolerance to temperature variations. Eurythermal organisms are those that can tolerate and thrive across a wide range of environmental temperatures. They are not significantly affected by fluctuations in ambient temperature and can survive in diverse climates. An example of a eurythermal organism is Zostera, a marine seagrass that is found in various temperature zones. Conversely, stenothermal organisms can only tolerate a narrow range of temperatures. Even slight deviations from their optimal temperature range can cause stress or death. For instance, the mango tree is considered stenothermal, as it requires specific temperature conditions for its growth and fruit production and cannot survive in extreme cold or heat. Similarly, organisms can be classified as euryhaline (tolerating wide salinity changes) or stenohaline (tolerating narrow salinity changes).
- The deepest strata of the ocean is dark and sufficient light is not available for the photosynthesis of green algae.
- Algae need brackish water for its growth. Which is also not available in the deepest strata of the ocean.
Phytoremediation is an environmentally friendly biotechnological approach that uses living green plants to remove, reduce, or neutralize soil or water contamination caused by pollutants and toxic substances. Plants absorb contaminants through their root systems and either accumulate them in their tissues, break them down through metabolic processes, or volatilize them into the atmosphere. For example, Eichhomia (water hyacinth) can be grown in cadmium-enriched soil or water to absorb and accumulate cadmium, thereby reducing the level of this toxic heavy metal in the environment. Other plants like Brassica species can hyperaccumulate heavy metals, while certain plants can degrade organic pollutants. This technique is cost-effective, sustainable, and does not produce secondary pollution, making it a valuable tool for environmental remediation.
- The albedo effect is due to greenhouse effect.
- Aerosols (suspension of fine solid (or) liquid particles in gas) with small particles is reflecting the solar radiation entering the atmosphere is known as Albedo effect.
- It reduces the temperature, photosynthesis and respiration
- The sulphur compounds present in the aerosol are responsible for acid rain due to acidification of rain water and destroy the ozone.
The organic horizon is generally absent in desert soils because of the extremely low content of organic matter resulting from the scarcity of plant and animal remains, dead biomass, and excreta. Desert environments receive very little rainfall and support sparse vegetation due to harsh climatic conditions, resulting in minimal accumulation of organic material. The few organisms present in deserts produce limited organic matter, and the high temperatures and low moisture levels cause rapid decomposition and oxidation of any organic material that does form. Additionally, the lack of moisture inhibits the growth of decomposer organisms such as bacteria and fungi that would normally break down organic matter and contribute to the formation of a distinct organic horizon. Consequently, desert soils typically lack the dark, humus-rich organic layer characteristic of soils in more productive ecosystems.
- Soil formation is initiated by the weathering process.
- Biological weathering takes place when organisms like bacteria, fungi, lichens and plants helps in the breakdown of rocks through the production of acids and certain chemical substances.
Sandy soil is not suitable for cultivation because it has very high porosity and low water-holding capacity. The large pore spaces between sand particles allow water to drain rapidly through the soil, preventing adequate water retention necessary for plant growth and nutrient availability. Sandy soils also have poor nutrient retention capacity as minerals and nutrients leach away quickly with water percolation. Additionally, sandy soils lack cohesion and structural stability, making them prone to erosion by wind and water. The loose texture provides poor anchorage for plant roots, and the low organic matter content further reduces fertility. These characteristics make sandy soils unsuitable for most agricultural crops unless they are amended with organic matter and irrigated frequently to compensate for poor water retention.
- Mutualism interaction exist between fig tree and wasp
- In fig tree there is a tight one to one relationship with a pollinator species of wasp and no other species.
- The wasp pollinates the fig while finding egg lav ing sites and in turn, the fig offers the wasp developing seeds, as food for the developing larvae.
- It is an interaction between two species of organisms in which both are benefitted from the obligate association.
- Lichens is a mutual association of algae and a fungus.
- The alga is usually green alga (or) blue green alga. The fungus is an ascomycete (or) basidiomycete.
- It is believed that alga contributes organic food from photosynthesis and the fungus is able to absorb water and mineral salts.
- The fungus can also conserver water and this enables lichens to grow in extremely dry conditions where no other plants can exist.
- Mutualism is an interaction between two species of organisms in which both are benefitted from their association.
- Eg: 1 – Water Fern (Azolla) and Nitrogen fixing Cyanobacterium (Anabaena)
- Eg: 2 – Roots of terrestrial plants and fungal hyphae – Mycorrhiza.
Holoparasites:
The organisms which are dependent upon the host plants for their entire nutrition are called Holoparasites. They are also called total parasites.
Examples:
* Cuscuta is a total stem parasite of the host plant Acacia, Duranta, and manv other plants. Cuscuta even gets flower inducing hormone from its host plant.
* Balanophora, orobanche, and refflesia are the total root parasites found on higher plants.
Hemiparasites:
The organisms which derive only water and minerals from their host plant while synthesizing their own food by photosynthesis are called Hemiparasites. They are also called partial parasites.
Examples:
Viscum and Loranthus are partial stem parasites.
Predation:
* It is an interaction between two species, one of which captures, kills, and eats up the other.
* The species which kills is called a predator and the species which is killed is called prey.
* The predator is benefitted while the prey is harmed.
Examples:
A number of plants like Drosera (Sundew Plant), Nepenthes (Pitcher Plant), Diaonaea (Venus flytrap), Utricularia (Bladderwort), and Sarracenia are predators
* which consume insects and other small animals for their food as a source of nitrogen.
* They are also called insectivorous plants.
* Many herbivores are predators. Cattles, Camels, Goats, etc., frequently browse on the tender shoots of herbs, shrubs, and trees.
* Generally, annuals suffer more than perennials.
* Grazing and browsing may cause remarkable changes in vegetation.
* Nearly 25 percent of all insects are known as phytophagous (feeds on plant sap and other parts of the plant)
Many defense mechanisms are envoloved to avoid their predations by plants.
Calotropis produces highly poisonous cardiac glycosides.
Tobacco: Produces nicotine.
Coffee: coffee plants produce coffeine.
Ophrys is an orchid whose flowers exhibit remarkable floral mimicry to ensure pollination by bees. The flower of Ophrys closely resembles the body of a female bee in shape, color, and texture, which deceives male bees into attempting to mate with the flower. When the male bee lands on the flower and attempts copulation, the pollinia (pollen masses) of the orchid become attached to the bee's body. As the bee moves to another Ophrys flower in search of an actual female bee, it transfers the pollinia to the stigma of that flower, thereby effecting pollination. This is a classic example of sexual mimicry or floral mimicry, where the plant has evolved to exploit the reproductive behavior of its pollinator insect. This strategy is highly effective because it does not require the flower to produce nectar or other rewards, yet still ensures successful pollination through the bee's instinctive behavioral response.
Water scarcity is a significant challenge for plants, and xerophytes have evolved remarkable adaptations to survive in arid environments. These plants, known as xerophytes, exhibit specialized features in their root, stem, and leaf structures. The root system is typically extensive and well-developed, often much larger than the shoot system, to efficiently absorb water from deep soil layers or a wide surface area. In some xerophytes, like Opuntia, the stem internodes are modified into fleshy, photosynthetic structures called phylloclades, which store water and perform photosynthesis, reducing the need for leaves. Similarly, in plants such as Acacia melanoxylon, the petiole is modified into a broad, leaf-like structure called a phyllode, which carries out photosynthesis while minimizing water loss, as true leaves might be reduced or absent.
- Submerged plants which receive weak illumination because
- Submerged plants are completely immersed in water and not in contact with the atmosphere (or) surface of the water.
- The floating hydrophytes float freely (or) float their leaves and flowers on the surface of water do not allow light to pass inside the lake.
- So submerged plants receive weak illumination than exposed floating plants.
- Vivipary is the special type of seed germination
- During germination, the seed is till attached to the parent plant and nourished by it.
- Vivipary generally occurs in mangrove plants.
- The mangrove plants are medium sized trees which grow in salty marshes of sea coasts. (Eg.) Rhizophora, Sonneratia, Avicennia.
- The seeds of this plant cannot germinate on the marshy habitat because of the excessive salt concentration and lack of oxygen.
- The radicle of the plant elongates considerably and projects out of the fruit.
- Then dark like seedling breaks off from the parent plant.
- Then radicle immediately forms new roots and establishes the seedling as a new plant.
Thermal stratification is a phenomenon observed in aquatic ecosystems, particularly in lakes and ponds, where the water column develops distinct layers based on temperature. This layering occurs due to differences in water density, with warmer, less dense water floating on top of colder, denser water. The change in temperature with increasing depth is known as thermal stratification. There are typically three main layers: the epilimnion, which is the uppermost, warmest layer exposed to sunlight and thus has the highest temperature; the metalimnion, a transitional middle layer where the temperature decreases rapidly with depth, also called the thermocline; and the hypolimnion, the bottommost, coldest, and densest layer, which receives little to no sunlight and remains relatively stable in temperature throughout the year.
- Rhytidome is the structural defense by plants against fire
- The outer bark of trees which extends to the last formed periderm is called Rhytidome.
- It is composed of multiple layers of suberized periderm, cortical and phloem tissues.
- It protects the stem against fire, water loss, invasion of insects and prevents infections by microorganisms.
Myrmecophily is a mutualistic symbiotic relationship between certain plants and ants. In this association, ants take shelter and establish colonies on specific trees such as Mango, Litchi, Jamun, and Acacia. The ants provide significant benefits to the host plant by acting as bodyguards or protectors, defending the plant against herbivorous insects, other disturbing agents, and potential predators that might damage the plant's leaves, flowers, or fruits. In return, the plants provide food and shelter to the ants. The ants may obtain food from extrafloral nectaries present on the plant or from honeydew-secreting insects that they farm on the plant. This is a true mutualistic relationship where both organisms benefit: the plant gains protection from herbivores and pests, while the ants gain a safe habitat and a reliable food source. A classic example of myrmecophily is the relationship between Acacia trees and acacia ants, where the ants live in the hollow thorns of the tree and receive nectar and food bodies in exchange for protecting the tree from herbivores.
- It is a method of human aided seed dispersal r Seed ball is an ancient Japanese technique of encasing
- seeds in a mixture of clay and soil humus (also in cow dung) and scattering them on suitable ground, not planting of trees manually.
- This method is suitable for barren and degraded lands for tree regeneration and vegetation before the monsoon period where the suitable dispersal agents become rare.
Anemochory
Zoochory
1. Individual seeds (or) the whole fruit may be modified to help for the dispersal by wind, wind dispersal of fruits and seeds is quite common in tall trees.
1. Birds and mammals, including human beings play an efficient and important role in the dispersal of fruit and seeds.
2. Minute seeds are very small light and with inflated covering. (Eg.) Orchids.
2. The surface of the fruits (or) seeds have hooks (Xanthium) barbs (Andropogon) Spines (Aristida) by means of which they adhere to the body of animals (or) clothes of human beings and get disposed.
3. Seeds (or) whole fruits are flattened to form a wing.(Eg.) Maple, Gyrocarpus
3. Some fruits and seeds have sticky glandular hairs by which they adhere to the fur of grazing animals.
(Eg.) Boerhaavia and cleome
4. Seeds (or) fruits may have feathery appendages which greatly increase their buoyancy to disperse to high altitudes. (Eg.) Asclepias and vernonia.
4. Some fruits have viscid layers (sticky layer) which adhere to the beak of the bird which eats them and when they rub them on to the branch of the tree, they disperse and germinate. (Eg.) Cordia, Alangium
Censor mechanism
Fleshy fruit
The fruits of many plants open in such a way that the seeds can escape only when the fruits are violently shaken by a strong wind.
Some fleshy fruits with conspicuous colours are dispersed by a human being to distant places after consumption.
(Eg.) Mango and Papaya.
Co-evolution refers to the reciprocal evolutionary changes that occur between interacting species over generations. When two or more species exert selective pressures on each other, they can drive each other's evolution, leading to a process of co-adaptation. This means that the genetic and morphological characteristics of each species change in response to the other. Co-evolution is a common outcome of close ecological relationships, such as mutualism, parasitism, and predation. A classic example is the relationship between flowering plants and their pollinators. For instance, the length of a flower's corolla tube may evolve in response to the length of the proboscis of its specific pollinator, such as a butterfly or moth, ensuring efficient pollination and nectar access for both. Similarly, the shape and size of a bird's beak may co-evolve with the shape and size of the flowers it feeds on, facilitating nectar extraction and seed dispersal.
Based on the temperature prevailing in an area, Raunkiaer classified the world’s vegetation into the following four types.
They are megatherms, mesotherms, microtherms, and hekistotherms.
In thermal springs and deep sea hydrothermal vents where average temperature exceed 100°c.
Based on the range of thermal tolerance, organisms are divided into two types.
* Eurythermal: Organisms which can tolerate a wide range of temperature fluctuations.
(Eg.) Zostera (A marine Angiosperm) and Artemisia tridentata.
* Stenothermal: Organisms which can tolerate only a small range of temperature variations.
(Eg.) Mango and Palm (Terrestrial Angiosperms).
Mango plants do not and cannot grow in temperate countries like Canada and Germany.
Thermal stratifications:
It is usually found in aquatic habitat.
The change in the temperature profile with increasing depth in a water body is called thermal stratification. There are three kinds of thermal stratification
* Epilimniotn The upper layer of warmer water
* Metalimnion The middle layer with a zone of gradual decrease in temperature.
* Hypolimnion The bottom layer of colder water.
Temperature based zonation:
Variations are latitude and altitude do affect the temperature of the vegetation on the earth’s surface.
Latitude: Latitude is an angle which ranges from 0° at the equator to 90° at the poles.
Altitude: How High a place is located above the sea level is called the altitude of the place.
Fire can have profound and varied effects on plant life and the ecosystem. Directly, fire can cause immediate lethal damage to plants, especially those with thin bark or exposed tissues, leading to death. However, fire also creates opportunities for certain organisms. The burning scars left on trees can become entry points for parasitic fungi and insects, potentially weakening or killing the plant. Beyond direct impacts, fire significantly alters the environment. It changes the availability of light reaching the ground, modifies rainfall patterns by affecting soil structure and evaporation, and disrupts nutrient cycles, often releasing nutrients rapidly into the soil. Soil fertility can be temporarily increased due to ash deposition, but pH can also change. Fire can also impact soil microflora and fauna. Interestingly, some fungi, known as pyrophilous fungi, thrive in the unique conditions of burnt areas; for example, Pyronema confluens is often found colonizing burnt soil.
A soil profile refers to the vertical cross-section of the soil, extending from the surface down to the parent material. This profile typically reveals distinct horizontal layers, known as soil horizons. These horizons differ significantly from one another in their physical characteristics (such as texture, structure, and color), chemical composition (including mineral content, organic matter, and pH), and biological activity (such as the presence of microorganisms and roots). The uppermost horizon, often designated as the O horizon, is rich in organic matter. Below this is the A horizon, or topsoil, which is a mixture of mineral particles and organic matter, crucial for plant growth. The E horizon, if present, is a leached layer. The B horizon, or subsoil, accumulates minerals washed down from above. Finally, the C horizon consists of partially weathered parent material, and the R horizon is the unweathered bedrock.
(a) Parasitism: It is an interaction between two different species in which the smaller partner (parasite) obtains food from the larger partner (host or plant). So the parasitic species is benefitted while the host species is harmed. Based on the host-parasite relationship, parasitism is classified into two types they are holoparasite and hemiparasite.
(b) Holoparasites: The organisms which are dependent upon the host plants for their entire nutrition are called Holoparasites. They are also called total parasites.
Examples:
* Cuscuta is a total stem parasite of the host plant Acacia, Duranta and many other plants. Cuscuta even gets flower inducing hormone from its host plant.
* Balanophora, Orobanche and Rafflesia are the total root parasites found on higher plants.
(c) Hemiparasites: The organisms which derive only water and minerals from their host plant while synthesizing their own food by photosynthesis are called Hemiparasites. They are also called partial parasites.
Examples:
* Viscum and Loranthus are partial stem parasites.
* Santalum (Sandal Wood) is a partial root parasite.
The parasitic plants produce the haustorial roots inside the host plant to absorb nutrients from the vascular tissues of host plants.
The plants which are living in water or wet places are called hydrophytes. According to their relation to water and air, they are sub-divided into the following categories:
* Free floating hydrophytes: These plants float freely on the surface of the water. They remain in contact with water and air, but not with soil. Examples: Eichhornia, Pistia and Wolffia (smallest flowering plant).
* Rooted floating hydrophytes: In these plants, the roots are fixed in mud, but their leaves and flowers are floating on the surface of water. These plants are in contact with soil, water and air. Examples: Nelumbo, Nymphaea, Potomogeton, and Marsilea.
* Submerged floating hydrophytes: These plants are completely submerged in water and not in contact with soil and air. Examples: Ceratophyllum and Utricularia.
* Rooted- submerged hydrophytes: These plants are completely submerged in water and rooted in soil and not in contact with air. Examples: Hydrilla, Vallisneria, and Isoetes.
Amphibious hydrophytes (Rooted emergent hydrophytes): These plants are adapted to both aquatic and terrestrial modes of life. They grow in shallow water. Examples: Ranunculus, Typha and Sagittaria.
Hygrophytes: The plants which can grow in moist damp and shady places are called hygrophytes. (Eg.) Habenaria (Orchid), Mosses (Bryophytes), etc.
Xerophytes exhibit a range of anatomical adaptations to survive in water-scarce environments. To minimize water loss through transpiration, they often possess a multilayered epidermis covered by a thick, waxy cuticle. The hypodermis, located beneath the epidermis, is typically well-developed and composed of sclerenchymatous tissues, providing mechanical support and further reducing water loss. Stomata, the pores responsible for gas exchange, are often sunken within pits or grooves on the leaf surface, creating a humid microenvironment that reduces transpiration. These stomata may be present only on the lower epidermis and are frequently surrounded by hairs, which also trap moisture. In succulent xerophytes, stomata might exhibit scotoactive behavior, opening only during the night to reduce water loss. The vascular tissues are well-developed to efficiently transport water, with bundle sheaths often consisting of multiple layers. The mesophyll layer is typically differentiated into palisade and spongy parenchyma, and in succulents, the stem often contains specialized water-storage tissues.
Halophytes, plants adapted to saline environments, display several morphological adaptations to cope with high salt concentrations and water stress. Temperate halophytes are often herbaceous, while tropical ones tend to be more shrubby. Many halophytes develop specialized root systems, including numerous stilt roots for support in unstable, waterlogged soils. A unique adaptation is the presence of negatively geotropic roots called pneumatophores, which grow upwards out of the water or soil to obtain oxygen, featuring pores called pneumathodes for aeration; these are commonly known as breathing roots, exemplified by species like Avicennia. The aerial parts of these plants often have a thick cuticle to reduce water loss. Their leaves are typically thick, succulent, and glossy, which helps in storing water and reflecting excess sunlight. Some species may even be aphyllous, meaning they lack leaves or have highly reduced leaves to minimize transpiration. Furthermore, vivipary, the germination of seeds while still attached to the parent plant, is a common mode of reproduction in halophytes, allowing seedlings to establish in the challenging saline conditions before detaching.
Advantages of seed dispersal:
* Seeds escape from mortality near the parent plants due to predation by animals or getting diseases and also avoiding competition.
* Dispersal also gives a chance to occupy favourable sites for growth.
* It is an important process in the movement of plant genes, particularly this is the only method available for self-fertilized flowers and maternally transmitted genes in outcrossing plants.
* Seed dispersal by animals helps in conservation of many species even in human-altered ecosystems.
* Understanding of fruits and seed dispersal acts as a key for proper functioning and establishment of many ecosystems from deserts to evergreen forests and also for the maintenance of biodiversity conservation and restoration of ecosystems.
Birds and mammals, including human beings, play an efficient and important role in the dispersal of fruit and seeds. They have the following devices,
i. Hooked fruit: The surface of the fruit or seeds have hooks,(Xanthium), barbs (Andropogon), spines (Aristida) by means of which they adhere to the body of animals or clothes of human beings and get dispersed.
ii. Sticky fruits and seeds:
* Some fruits have sticky glandular hairs by which they adhere to the fur of grazing animals. Example: Boerhaavia and Cleome.
* Some fruits have a viscid layer which adheres to the beak of the bird which eats them and when they rub them on to the branch of the tree, they disperse and germinate. Example: Cordia and Alangium
iii. Fleshy fruits: Some fleshy fruits with conspicuous colours are dispersed by human beings to distant places after consumption. Example: Mango and Diplocyclos
12th Bio Botany Guide Principles of Ecology Additional Important Questions and Answers
I. Match the following
- A. A - Stirrup; B - Sickle
- B. A - Wedge; B - Skull
- C. A - Star; B - H-shaped
- D. A - H-shaped; B - Star-shaped
C. A - Star; B - H-shaped
- A. A - Cortical; B - Periderm; C - Defence
- B. A - Periderm; B - Cortical; C - Defence
- C. A - Periderm; B - Periderm; C - Phloem
- D. A - Periderm; B - Periderm; C - Xylem
C. A - Periderm; B - Periderm; C - Phloem
- A. Oxylophytes - Plants living on ice surface
- B. Hollard - Total soil water content
- C. Chresard - Water not available to plants
- D. Echard - Water available to plants
B. Hollard - Total soil water content
a. (A) correct; (R) wrong
d. A is correct R is the correct explanation of A
VI. odd man out
The correct matching is A – 3), B – 4), C – 2), D – 1). Halophytes are plants adapted to saline environments, and angiosperms include many such species. Cryptophytes are plants whose perennating (dormant) organs are below the soil surface, such as bulbs or rhizomes. Sciophytes are plants that thrive in shady conditions, often found under the canopy of larger plants, which includes many bryophytes and pteridophytes that prefer moist, shaded habitats. Rhytidome refers to the dead, outermost layers of bark on woody stems, which provide protection against fire and other environmental stresses.
The question asks to identify the incorrect pair related to mimicry. Let's analyze each option: A) Ophrys, an orchid, exhibits floral mimicry by resembling female insects to attract male pollinators, which is a correct example. B) Carausius morosus, the stick insect, is a classic example of protective mimicry (crypsis) due to its resemblance to twigs. C) Phyllium frondosum, the leaf insect, is another excellent example of protective mimicry, perfectly camouflaging itself as a leaf. D) The statement 'Ants take their shelter on Mango, Litchi' is not an example of mimicry; it might refer to a symbiotic relationship or protection, but not mimicry. Therefore, the pair related to ants on mango and litchi is not an example of mimicry. Since options A, B, and C are correct examples of mimicry, and option D describes a situation unrelated to mimicry, the incorrect pair is implicitly related to the context provided by the options. Considering the options given, none of the statements A, B, C, or D are presented as pairs to be matched directly with mimicry types in a way that would make one of them definitively incorrect in isolation without further context on what 'Ants take their shelter on Mango, Litchi' is supposed to represent. However, if the question implies that all listed items are supposed to be examples of mimicry, then D is the outlier as it describes a different ecological interaction. Given the provided answer 'd. None of these', it suggests that the question might be flawed or that the intended interpretation is that all provided examples (A, B, C) are correct instances of mimicry, and the statement about ants is either irrelevant or not an example of mimicry, making the entire premise of finding an incorrect pair among the choices problematic. If we interpret 'None of these' as meaning none of the options A, B, C, or D are incorrect statements about mimicry or related phenomena, then the question is asking to find a false statement. Since A, B, and C are true examples of mimicry, and D is not an example of mimicry, it's the outlier. If the question is asking to choose the incorrect PAIR, and D is presented as a potential pair, then D is incorrect as an example of mimicry. The provided answer 'd. None of these' is confusing in this context. Assuming the question intends to find a statement that is NOT an example of mimicry, then D would be the answer. However, if 'None of these' means that A, B, C, and D are all correct in some way or that there is no incorrect pair among the choices, it's ambiguous. Re-evaluating, if the question is asking to choose the incorrect pair *which is related to mimicry*, and A, B, C are correct examples, then D is not related to mimicry. Thus, it's the incorrect choice in the context of the question asking for mimicry examples. The answer 'd. None of these' implies that A, B, C, and D are all correct or that there's an issue with the question itself. Given the ambiguity, and sticking to the most direct interpretation that A, B, and C are correct examples of mimicry, D is the statement that does not fit. If 'None of these' is the correct answer, it implies that A, B, C, and D are all valid in some context, or that the question is fundamentally flawed. However, in a typical multiple-choice scenario asking for an incorrect example, D would be the most likely candidate if it's not an example of mimicry. The provided answer 'd. None of these' is highly unusual if D is indeed not an example of mimicry. Let's assume there's a misunderstanding in the provided answer and proceed with the logical deduction that D is not an example of mimicry.
The odd one out is the 'Leg size of insect camel's foot climber'. This is because hornbills, the slit size of pollinia in Apocynaceae, and birds of scrub jungles are all related to ecological adaptations or interactions. Hornbills exhibit specific feeding habits and nesting behaviors, Apocynaceae pollinia have a slit size adapted for specific pollinators, and birds of scrub jungles are adapted to their particular habitat. The leg size of a camel's foot climber, however, is a morphological feature that doesn't directly fit into the same category of ecological relationships or adaptations as the other options.
d. Stem, Scale leaves
The plant shown in the diagram is Ceratophyllum, commonly known as coontail or hornwort. It is a free-floating aquatic plant that lacks true roots and is found in freshwater environments. Its submerged leaves are whorled and finely divided, giving it a feathery appearance, which helps in efficient absorption of nutrients and gases directly from the water.
d. Coniferous, deciduous, grassland
C) T, T, F, T
IX. Fill in the blanks Answers
1. Roots and hulls of Black Walnut Juglans nigra secretes an alkaloid……………………………………….
Juglone
2. The plants which behave as xerophytes at summer and behave as mesophvtes during rainv season is……………………………….
tropophytes
3. The ……………………………….wave length of spectrum is less strongly absorbed by plants.
green (500 – 600 nm)
4. The rate of photosynthesis is maximum at blue (400 – 500 nm) and……………………………….
red (600 – 700 nm)
5. ……………………………….is well known factor needed for the physiological process of plants.
Light
6. In climatology diurnal cycle is the basic form of climatic pattern in every ………………………………..
24 hrs.
7. The altitudinal limit of normal tree growth is about ………………………………..
3000 to 4000
8. ……………………………….are organisms, which derive onlv water and minerals from their host plant for synthesizing their own food.
Hemiparasites
9. ……………………………….is the smallest free floating hvdrophvtes.
Wolffia
10. Scotoactive tvpe of stomata found in ……………………………….plants.
succulent
11. ……………………………….are plants which grow perched on other plants.
Epiphytes
12. The plants which are living in moderate conditions (neither too wet nor too drv) are known as……………………………….
Mesophytes
13. ……………………………….is the world forest dav.
March – 21
14. Earth dav falls on……………………………….
April – 22
15. International ozone dav is celebrated on……………………………….
September -16
X. Choose the correct answer
The option not related to mutualism is 'c. Tillandsia grows on the bark of oak and pine trees.' Mutualism is a symbiotic relationship where both interacting species benefit. Anabaena in the coralloid roots of Cycas provides nitrogen to the plant and receives shelter, which is mutualism. Wasps pollinating figs while laying eggs in them is another example of mutualism. Cyanobacterium (Nostoc) in the thalloid body of Anthoceros also demonstrates mutualism by providing nitrogen. Tillandsia growing on oak and pine trees is an example of epiphyllism or commensalism, where Tillandsia benefits from a place to grow, but the host tree is neither significantly harmed nor benefited.
c. Predators
b. Defence mechanism
c. Pitcher plant with insect
d. Ecballium elatrium
a. True xerophytes
a. Eichhornia
Stenophagic means the organism can survive by taking a narrow range of food. Organisms are classified based on their feeding habits. Euryphagic organisms can consume a wide variety of food sources, allowing them to adapt to diverse environments and fluctuating food availability. Stenophagic organisms, conversely, are specialists and rely on a specific or a very limited set of food items. This specialization can make them more vulnerable to environmental changes that affect their food source.
a. Stipules
a. Topographic
d. Velamen
c. Predators
a. Lotus
a. Lotus
XI. Two Marks
A biotope refers to the physical environment or habitat of a community, including all the non-living factors such as climate, soil, water, light, and temperature that characterize a particular area. It is the abiotic component of an ecosystem. An ecotope, on the other hand, refers to the specific habitat and ecological niche occupied by an organism or a group of organisms. While biotope describes the general environmental conditions of a location, ecotope describes the precise ecological position and role of an organism within that environment, including both its physical habitat and its functional relationship with other organisms in the community.
A biome is a large, naturally occurring community of flora and fauna that occupies a major habitat and is characterized by distinctive climate, vegetation, and animal life. Biomes are defined by their climate patterns, temperature ranges, precipitation levels, and the types of organisms adapted to those conditions. Examples include tropical rainforests, grasslands, deserts, deciduous forests, coniferous forests, and tundra. Each biome represents a distinct ecological region with its own unique assemblage of plants and animals that have evolved to survive under the specific environmental conditions of that biome.
Evergreen forests are found in regions with heavy rainfall distributed throughout the year, ensuring that trees do not need to shed their leaves seasonally to conserve water. In contrast, sclerophyllous forests are adapted to climates with distinct wet and dry seasons, typically experiencing heavy rainfall during winter and a pronounced dry period in summer. The plants in these forests have tough, leathery leaves (sclerophyllous) to minimize water loss during the dry season. The reason why species of grasslands in the Western Ghats of India differ from those in the temperate grasslands of North American steppes, yet are all ecologically primary producers, lies in convergent evolution and niche differentiation. Despite geographical separation and different evolutionary histories, similar environmental pressures and available niches can lead to the development of organisms with similar ecological roles. Taxonomically different species occupying similar habitats or ecological roles (niches) in different geographical regions are indeed called ecological equivalents, showcasing how nature can arrive at similar solutions through diverse evolutionary pathways.
The various latitudinal zonation of vegetation from the equator toward the poles includes tropical rainforests near the equator, followed by grasslands or deserts in the subtropical regions, then deciduous forests in temperate zones, coniferous forests in higher latitudes, treeline or tundra vegetation in subarctic regions, and finally snow or ice in the polar regions. This zonation reflects the gradual change in climate, temperature, and precipitation as one moves from the equator toward the poles, with each zone supporting characteristic plant communities adapted to those specific climatic conditions.
The various altitudinal zonation of vegetation from lower to higher elevations includes tropical rainforests at lower altitudes, grasslands or deserts at intermediate elevations, deciduous forests at moderate elevations, coniferous forests at higher elevations, and tundra and snow at the highest elevations. This pattern of vegetation zonation with increasing altitude is similar to latitudinal zonation because temperature decreases with altitude just as it decreases with latitude. Each altitudinal zone supports vegetation adapted to the specific temperature, moisture, and atmospheric conditions at that elevation.
Euryhaline organisms are those that can tolerate and thrive in a wide range of salinity levels in their aquatic environment. They possess physiological mechanisms to maintain osmotic balance despite significant fluctuations in external salt concentration. Examples include many marine algae and marine angiosperms, which can be found in environments ranging from brackish water to full seawater. Stenohaline organisms, on the other hand, are adapted to survive only within a narrow range of salinity. They are less tolerant of changes in salt concentration and are typically found in stable environments. For instance, plants found in estuaries, which have a relatively stable salinity, are often stenohaline. If the salinity changes beyond their tolerance limits, they cannot survive.
- Aerosols with small particles is reflecting the solar radiation entering the atmosphere called albedo effect.
- It reduces the temperature limits, photo synthesis and respiration.
- Some pteris are well adapted to grow in burnt and highly disturbed area
- Pteris (fern) and pyronema (fungus) indicates the burnt up and fire disturbed areas.
- So they are called indicators of fire.
- Some species are found in the ecotone areas border between forest and grassland due to the effect of the environment of the two habitats. This is called the edge effect.
- (Eg.) Owl in the ecotone area between forest and grassland.
An ecotone is a transition zone or boundary area between two different ecosystems or communities where the characteristics of both ecosystems overlap and blend together. In an ecotone, you find a mixture of species from both adjacent ecosystems, creating a unique environment with intermediate conditions. Ecotones are often characterized by high biodiversity because they contain species from both neighboring ecosystems as well as species specifically adapted to the transitional conditions. A classic example is the border or transition zone between a forest and a grassland, where you find scattered trees, shrubs, and grasses creating a woodland or savanna-like environment that is neither purely forest nor purely grassland.
- The steepness of the mountain (or) hill allows the rain to run off.
- Asa result the loss of water causes water deficit and quick erosion of the top soil resulting in poor vegetation.
- On the other hand the plains and valley are rich in vegetation due to the slow drain of surface water and retention of water in the soil.
a) Cuscuta
b) Balanophora, Orobanche and Reflesia.
a) Viscum and Loranthus
b) Santalum (sandal wood)
- Inter-specific competition is exist in the above examples.
- It is an interaction between individuals of different species for common need.
- It is an interaction between individuals same species.
- It is very severe because all the members of species have similar requirement of food habitat, pollination etc.
Competition is an interaction between two organisms or species in which both organisms or species are negatively affected or harmed. In this type of interaction, both competitors struggle for the same limited resources such as food, water, light, space, or nutrients. The intensity of competition depends on the degree of overlap in resource requirements and the availability of resources in the environment. Competition can occur between members of the same species (intraspecific competition) or between members of different species (interspecific competition). Both forms of competition result in reduced fitness, growth, or survival for the competing organisms.
Roots and hulls of black walnut junglone nigra secretes an alkaloid junglone.
* Which inhibits the growth of seedlings of apple,tomato and alfalfa around it.
* It is an example for amensalism type of interspecific interaction.
Trichophyllous plants are xerophytes in which the leaves and stem are covered with fine hairs or trichomes. These hair-like structures help reduce water loss by creating a boundary layer that reduces transpiration and reflects excessive light. The hairs also help in trapping moisture and reducing the direct impact of wind on the leaf surface. Examples of trichophyllous plants include cucurbits such as melothria and mukia, which are adapted to survive in dry conditions through this hairy covering on their aerial parts.
- Many orchids ferns, lianas, money plant usnea (lichen) are some of examples of epiphytes.
- These plants which are found on other plants and growing without harming them are called epiphytes.
Tropophytes are plants that exhibit seasonal changes in their morphology and physiology in response to changing environmental conditions throughout the year. These plants behave as xerophytes during the dry summer season, showing adaptations to conserve water and withstand drought stress. During the rainy season, the same plants behave as mesophytes or hydrophytes, displaying characteristics suited to abundant water availability. This dual adaptation allows tropophytes to survive in regions with distinct seasonal variations in rainfall and temperature. Examples include deciduous trees that shed leaves in summer and grow new ones during the monsoon season.
Seeds or whole fruits of maple, gyrocarpus, dipterocarpus, and terminalia exhibit anemochorous adaptations for dispersal by wind. The seeds or fruits are flattened and modified to form wing-like structures or appendages that increase their surface area and reduce their density. These winged structures allow the seeds to be carried long distances by air currents, ensuring wide dispersal and colonization of new habitats. The aerodynamic design of these winged fruits enables them to glide through the air and land at considerable distances from the parent plant.
- Caruncle is a structure found in micropylar region of euphorbiaceae seeds, that attract ants. Which feed the caruncle to their larvae.
- Then ants leave the seed to their waste disposal area. Where the seeds germinate.
- This type of seed dispersal called myrmecophily.
Xerophytes are plants that are adapted to live in dry or xeric environmental conditions characterized by low water availability. These plants possess various morphological and physiological adaptations that enable them to conserve water and survive prolonged drought. Xerophytes are classified into two main types based on the nature of dryness they encounter. Physical dryness refers to environments where the soil contains very little water due to low rainfall, high temperature, or sandy soil composition. Physiological dryness occurs in environments where water is present in the soil but is unavailable to plants due to high salt concentration, frozen conditions, or other factors that prevent water uptake. Both types of xerophytes show similar adaptations such as reduced leaf surface area, thick cuticles, sunken stomata, and succulent tissues to minimize water loss.
- It is called physiological dryness.
- In these habitats, water is sufficiently present but plants are unable to absorb it because of the absence of capillary spaces.
- (Eg.) Plants in salty and acidic soil.
Pedology is the scientific study of soils, including their formation, composition, structure, properties, classification, and distribution. It encompasses the examination of soil profiles, weathering processes, soil horizons, and the various factors that influence soil development such as climate, parent material, topography, organisms, and time. Pedology is essential for understanding soil fertility, land use planning, agriculture, and environmental management.
- Helps to reconstruct past climates of our planet and flora, fauna and ecosystem in which they lived.
- Example: Air bubbles trapped in ice for tens of thousands of years with fossilized pollen, coral, plant and animal debris.
Sclerophyllous forests are found in regions where heavy rainfall occurs during the winter season and low rainfall occurs during the summer season. These forests are characterized by plants with hard, thick, and leathery leaves that are adapted to withstand the dry summer conditions. The vegetation includes evergreen shrubs and small trees with small, waxy leaves that reduce water loss during the dry season. Sclerophyllous forests are typically found in Mediterranean climates and similar regions with this distinctive seasonal rainfall pattern.
- Air in motion is called wind.
- It is also a vital ecdogical factor.
- The atmospheric air contains a number of gases, particles and other constituents.
- Anemometer is the instrument used to measure the speed of wind.
Nitrogen fixation is the process by which atmospheric nitrogen is converted into biologically available forms such as ammonia or nitrate. Rhizobium is a bacterium that plays a crucial role in nitrogen fixation by forming nodules in the roots of leguminous plants. The Rhizobium bacterium lives symbiotically within these root nodules, establishing a mutualistic relationship with the host plant. The bacterium obtains carbohydrates and other organic compounds from the leguminous plant for its nutrition and energy. In return, the Rhizobium fixes atmospheric nitrogen into nitrate through enzymatic processes, making this essential nutrient available to the host plant. This symbiotic nitrogen fixation is of great agricultural importance as it enriches the soil with nitrogen and reduces the need for synthetic nitrogen fertilizers in legume-growing regions.
Yes, there is a limit to tree growth related to altitude, which is known as the treeline or timberline. The treeline is an imaginary line on mountains or in higher latitudes that marks the highest elevation or the northernmost limit above which trees cannot grow due to harsh environmental conditions. This limit is primarily determined by factors such as low temperatures, strong winds, short growing seasons, and insufficient soil development. The altitudinal limit of normal tree growth typically ranges from about 3000 to 4000 meters above sea level in many mountain ranges, though this can vary significantly depending on geographical location, aspect, and local climate.
- It is the structural defense by plant against.
- The outer bark of trees which extends to the last formed periderm is called Rhytidome.
- It is composed of multiple layers of suberized periderm cortical and phloem tissue. It protects the stem against fire, water loss, invasion of insects and prevents infections by microorganism
Applied ecology, also known as environmental technology, is the branch of ecology that helps us manage and conserve natural resources, particularly ecosystems, forests, and wildlife. This field applies ecological principles and knowledge to solve practical environmental problems and promote sustainable use of natural resources. Environmental management through applied ecology involves several key aspects including biodiversity conservation to protect genetic and species diversity, ecosystem restoration to rehabilitate damaged habitats, habitat management to maintain suitable conditions for wildlife, and invasive species management to control non-native organisms that threaten native ecosystems. Applied ecology also encompasses protected areas management to establish and maintain reserves for conservation, and landscape planning to design human-modified environments that balance development with ecological integrity. Additionally, applied ecology helps in environmental impact assessment and designing sustainable practices for future ecological management, ensuring that human activities are compatible with the long-term health and productivity of natural ecosystems.
- Many organisms co-exist in an environment.
- The environment includes physical, chemical biological component.
- When a component surrounding an organism affects the life of an organism called factor.
- These factors may be biotic and abiotic.
- Climatic factors: Sunlight, precipitation wind, carbon dioxide and water vapour.
- Biotic factors: Birds, insects, man, grazing animals, rodents, plant pathogens and epiphytes.
- Edaphic factors: Soil slope, soil water, physical nature of soil, minerals, soil air.
Light has various important effects on green plants that influence their growth, development, and physiological processes. Light is essential for photosynthesis, the fundamental process by which plants convert light energy into chemical energy stored in organic compounds. Light also regulates the opening and closing of stomata, controlling gas exchange and transpiration rates in plants. Light influences seed germination by breaking dormancy in many plant species through the action of phytochrome and other light-sensitive pigments. Light plays a crucial role in flowering and tuber formation, triggering reproductive processes in response to day length or photoperiod. Light also promotes stem and leaf formation, influencing plant architecture and morphology. Additionally, light stimulates the production of runners in certain plants, affecting vegetative reproduction and spread. These diverse effects of light demonstrate its fundamental importance in regulating plant growth, development, and adaptation to environmental conditions.
Phytoremediation is an environmental technology that uses plants to remove, accumulate, or detoxify contaminants from polluted soil, water, or air, thereby cleaning up contaminated environments. Some plants are capable of tolerating and accumulating heavy metals such as cadmium from contaminated soil through various physiological mechanisms. Rice and eichhornia are examples of plants that tolerate cadmium by binding it to specific proteins within their cells, preventing the metal from interfering with vital cellular processes. Soybean and tomato plants manage to tolerate cadmium by storing the accumulated metal in specific groups of cells, isolating it from sensitive tissues and maintaining normal plant functions. Phytoremediation offers an economical and environmentally friendly approach to decontamination compared to traditional chemical or physical remediation methods, making it increasingly important for environmental restoration and pollution control.
- Loamy soil is ideal for cultivation. It consist of 70% sand and 30% clay (or) silt.
- It ensures good retention and proper drainage of water.
- The porosity of soil provides adequate aeration and allows the penetration of roots.
- Soil is commonly stratified into horizons at different depth.
- These layers differ in their physical, chemical and biological properties.
- This succession of super-imposed horizons is called soil profile.
Species ecology and community ecology are two distinct levels of ecological study that differ in their scope and focus. Species ecology is the study of a group of individuals belonging to a particular species, collectively referred to as a population. It examines the characteristics, dynamics, and interactions of individuals within a single species, including population size, growth rates, age structure, genetic variation, and survival patterns. Species ecology focuses on how environmental factors affect the population and how the population responds to these factors. Community ecology, on the other hand, is the study of several different species that live together in the same area, forming a community composed of multiple populations. Community ecology examines the interactions between different species such as competition, predation, mutualism, and parasitism, as well as the overall structure, diversity, and functioning of the community. While species ecology concentrates on single-species population dynamics, community ecology addresses the complex relationships and interdependencies among multiple species sharing a common habitat.
Height above the sea level forms the altitude.
At high altitudes
* The velocity of wind remains high.
* Temperature and air pressure-decreases.
* While humidity and intensity of light increases.
Due to these factors vegetation at different altitudes varies showing distinct zonation.
- Latitudes represent distance from the equator.
- Temperature values are maximum at the equator and decrease gradually towards poles.
- So different types of vegetation occur in latitude.
- The surface features of earth are called topography.
- Its factors include, latitude, altitude, direction of mountain, steepness of mountain.
- They were epiphytes showing commensalism type of positive interaction.
- In which one is benefitted and other is neither benefitted nor harmed.
- The species that derives benefit is called the commensal, while the other species is called the host.
- The epiphytic higher plant gets its nutrients and water from the atmosphere with the help of their hygroscopic roots.
- These roots contain special type of spongy tissue called velamen.
Proto cooperation is an interaction between organisms of different species in which both organisms benefit from the relationship but neither is dependent on the other for survival. This type of association is facultative, meaning the organisms can live independently without the relationship. In proto cooperation, the organisms live in close proximity and derive mutual advantages from each other's presence or activities. For example, soil bacteria and fungi growing in the soil benefit from the organic matter provided by plants, while the plants benefit from the nutrients made available by the decomposition activities of bacteria and fungi. Another example is the relationship between bees and flowering plants, where bees obtain nectar for food while pollinating the flowers, benefiting both organisms. Proto cooperation differs from mutualism in that the organisms are not obligately dependent on each other for survival, and the relationship can be dissolved without harming either party.
A – Tendril, B – Pitcher, C – Lamina
A – Haustoria, B – Host, C – Parasite
a) Name the parasite with example.
Holoparasite Cuscuta.
Holo parasites, also called total parasites, are organisms that are completely dependent upon their host plants for their entire nutrition. These parasites lack chlorophyll and cannot synthesize their own food through photosynthesis, making them entirely reliant on the host for all nutritional requirements. They obtain nutrients directly from the host plant tissues through specialized structures called haustoria. The classic example of a holo parasite is Cuscuta, commonly known as dodder, which is a flowering plant that completely lacks chlorophyll and wraps around the stems of host plants, penetrating them to extract nutrients.
- It is an inter specific interaction in which one species is inhibited while the other species is neither benefitted nor harmed.
- The inhibition is achieved by secretion of chemicals called allelopathic substances.
- It exhibits mimicry of inter specific interactions (or) mimicry of co-evolutionary dynamics.
- Mimicry is a phenomenon in which living organism modifies its form appearance structure (or) behaviour and looks like another living organism as a self defence and increases the chance of their survival.
Kairomones are chemical substances that are emitted or released by one organism and detected by another organism of a different species, where the receiver gains an advantage while the emitter is disadvantaged. In the context of the wild radish and Pieris rapae caterpillar (butterfly) interaction, when the caterpillar feeds on wild radish plants, it induces a defense response in the plant. The plant then produces kairomones as chemical signals that can be transmitted to the progeny of the wild radish plant. These chemical signals prime the offspring plants to be better prepared against future predation by the same butterfly species, enhancing their defensive capabilities. This represents an induced defense mechanism where the presence of a predator triggers the plant to communicate defensive information to its offspring through chemical means, allowing the next generation to mount a more effective defense against the same herbivore.
- Sometimes, ants take their shelter on some trees such as Mango, Litchi, Jamun, Acacia etc.
- These ants act as body guards of the plants against any disturbing agent and the plants in turn provide food and shelter to these ants.
- This phenomenon is known as Myrmecophily. Example: Acacia and acacia ants.
Hygrophytes are plants that grow in moist, damp, and shady places where water availability is abundant and humidity is high. They are called hygrophytes because they thrive in hygric or wet environmental conditions. These plants typically have thin cuticles, large leaves with extensive surface area for transpiration, and poorly developed root systems since water is readily available in their habitat. Examples of hygrophytes include Habenaria, which is an orchid species, and mosses, which are bryophytes that require moist conditions for their survival and reproduction.
- Mangroves protect vulnerable coastal areas from wave action by holding the soil together and prevent coastal erosion.
- Out of three districts of Tamil Nadu (Nagapattinam, Thanjavur and Thiruvarur), Muthupet (Thiruvarur district) was less damaged by Gaja Cyclone (Nov-2018) due to the presence of mangrove forest.
- Ephemerals are called drought evaders (or) drought escapers because
- These plants complete their life cycle within a short period, (single season)
- (Eg.) Argemone, Mollugo, Tribulus, Tephrosia.
- In deep sea (>500 m) the environment is dark and its inhabitants are not aware of the existence of celestial source of energy called sun.
- Dead sea organisms use chemical energy rather than energy from sunlight.
- Chemosynthesis is a process, special bacteria use this process to produce energy without using sunlight.
- March 21 – World Forest Day
- May 22 – World Biodiversity Day
- June 05 – World Environment Day
- July 07 – Van Mohot Stav day.
Phylloclades, also called fleshy leaves, are modified stem structures found in some xerophytes where the internodes of the stem are modified into fleshy, green, leaf-like structures that perform the functions of leaves. In phylloclades, the stem becomes flattened and enlarged to resemble a leaf, taking over the photosynthetic role while the actual leaves may be reduced or absent. This adaptation allows xerophytes to reduce water loss while maintaining photosynthetic capacity. A classic example is Opuntia, the prickly pear cactus, where the flattened, fleshy green structures that appear to be leaves are actually modified stems.
Breathing roots, also called pneumatophores, are special types of negatively geotropic roots that grow upward against gravity and possess specialized structures called pneumathodes. These roots are adapted to obtain sufficient aeration in waterlogged or anaerobic soil environments where oxygen availability is limited. Pneumatophores emerge above the water or soil surface, allowing oxygen to enter through the pneumathodes and reach the underground root system. This adaptation is crucial for plants growing in swampy or marshy habitats where the soil is saturated with water and oxygen is scarce. A prominent example is Avicennia, a mangrove plant that develops numerous breathing roots to survive in the oxygen-poor conditions of coastal wetlands.
A cladode is a modified stem structure where one or occasionally two internodes are modified into a fleshy, green structure that resembles and functions like a leaf. Cladodes perform photosynthesis and other functions typically associated with leaves, while the actual leaves may be reduced to small scales or spines. This adaptation is found in xerophytic plants as a strategy to reduce water loss while maintaining photosynthetic efficiency. A common example is Asparagus, where the flattened, needle-like green structures that appear feathery are actually cladodes derived from modified stem internodes.
A phyllode is a modified petiole that has become flattened, expanded, and fleshy, taking on a leaf-like appearance and function. In plants with phyllodes, the actual leaf blade may be reduced or absent, and the petiole assumes the role of photosynthesis and other functions normally performed by leaves. This modification represents an adaptation in certain plants to reduce water loss while maintaining photosynthetic capacity. An example is Acacia melanoxylon, where the petioles are modified into phyllodes that serve as the primary photosynthetic organs.
Temperature based zonation:
* Variations in latitude and altitude do affect the temperature and the vegetation on the earth surface.
* Timber line / Tree line: It is an imaginary line in a mountain or higher areas of land that marks the level above which trees do not grow. The altitudinal limit of normal tree growth is about 3000 to 4000m.
Effects of temperature:
* The following physiological processes are influenced by temperature:
* Temperature affects the enzymatic action of all the bio-chemical reactions in a plant body.
* It influences CO2 and O2 solubility in the biological systems. Increases respiration and stimulates growth of seedlings.
* Low temperature with high humidity can spread diseases to plants
* The varying temperature with moisture determines the distribution of the vegetation types.
Wind has several significant climatic effects on plants. It plays a crucial role in the formation of rain by influencing evaporation and condensation processes. In aquatic environments like lakes and oceans, wind generates waves, which enhance the aeration of water, benefiting aquatic life. However, strong winds can cause substantial soil erosion, leading to a loss of fertile topsoil and reducing agricultural productivity. Wind also increases the rate of transpiration from plant leaves, which can lead to water stress if not compensated by adequate water uptake. For anemophilous plants, wind is essential for pollination, carrying pollen grains from one flower to another. Furthermore, wind aids in the dispersal of many fruits, seeds, and spores, facilitating the spread of plant species. In severe cases, strong winds can uproot large trees, causing significant damage to forests. Unidirectional winds can also influence plant morphology, stimulating the development of characteristic 'flag forms' where branches grow predominantly on the leeward side.
The important edaphic factors which affect vegetation are as follows:
1. Soil moisture:
Plants absorbs rain water and moisture directly from the air.
2. Soil water:
Soil water is more important than any other ecological factors affecting the distribution of plants. Rain is the main source of soil water. Capillary water held between pore spaces of soil particles and angles between them is the most important form of water available to the plants.
3. Soil reactions:
Soil may be acidic or alkaline or neutral in their reaction. pH value of the soil solution determines the availability of plant nutrients. The best pH range of the soil for cultivation of crop plants is 5.5 to 6.8.
4. Soil nutrients:
Soil fertility and productivity is the ability of soil to provide all essential plant nutrients such as minerals and organic nutrients in the form of ions.
5. Soil temperature:
Soil temperature of an area plays an important role in determining the geographical distribution of plants. Low temperature reduces use of water and solute absorption by roots.
6. Soil temperature:
The spaces left between soil particles are called pore spaces which contains oxygen and carbon-di-oxide.
7. Soil organisms:
Many organisms existing in the soil like bacteria, fungi, algae, protozoans, nematodes, insects, earthworms, etc. are called soil organisms.
The surface features of earth are called topography. Its factors include, latitude, altitude, direction of mountain, steepness of mountain.
a. Latitudes and altitudes:
* Latitudes represent distance from the equator. Temperature values are maximum at the equator and decrease gradually towards poles.
* So different types of vegetation occur in latitude.
* Height above the sea level forms the altitude. At high altitudes
* The velocity of wind remains high. Temperature and are pressure – decrease While humidity and intensely of light increases.
* Due to these factors vegetation at difference altitudes varies showing distinct zonation.
b. Direction of mountain:
North and south faces of mountain (or) hill possess different types of flora and fauna because thev differ in their humidity, rainfall light intensity, light duration and temperature regions.
c. Steepness of the mountain:
* The steepness of the mountain (or) hill allows the rain to run off.
* As a result the loss of water causes water deficit and quick erosion of the top soil resulting in poor vegetation.
* On the other hand the plains and valley are rich in vegetation due to the slow drain of surface water and retention of water in the soil.
The interactions among living organisms such as plants and animals are called biotic factors.
Positive interactions:
When both (or) one the participating species are benefited. (Eg.) Mutualism and commen¬salism.
Mutualism:
* It is an interaction between two species of organisms in which both are benefitted from the obligate association.
* Lichens is a mutual association of an algae and a fungus.
* The alga is usually green alga (or) blue green alga. The fungus is an ascomycete (or) basidiomycetes.
* It is believed that alga contributes organic food from photosynthesis and the fungus is able to absorb water and mineral salts.
* The fungus can also conserve water and this enables lichens to grow in extreme dry conditions where no other plants can exist.
Nitrogen fixation:
* Rhizobium (Bacterium) forms nodules in the roots of leguminous plants and lives symbiotically.
* The Rhizobium obtains food from leguminous plant and in turn fixes atmospheric nitrogen into nitrate, making it available to host plants.
* Example: Water fern (Azolla) and Nitrogen fixing cyanobacterium (Anabaena)
* Anabaena present in coralloid roots of cycas
Commensalism:
Many orchids ferns, lianas, money plant usnea (lichen) are some of the examples of epiphytes.
These plants which are found on other plant and growing without harming them are called epiphytes.
Negative interactions:
a. Predation:
It is an interaction between two species, one of which captures, kills and eats up the other. The species which kills is called a predator and the species which is killed is called a prey. The predator is benefitted while the prey is harmed.
Examples:
A number of plants like Drosera (Sun dew Plant), Nepenthes (Pitcher Plant), Dionaea (Venus fly trap), Utricularia (Bladder wort) and Sarracenia are predators which consume insects and other small animals for their food as a source of nitrogen. They are also called as insectivorous plants.
Many herbivores are predators. Cattles, Camels, Goats etc., frequently browse on the tender shoots of herbs, shrubs and trees. Generally annuals suffer more than the perennials. Grazing and browsing may cause remarkable changes in vegetation. Nearly 25 percent of all insects are known as phytophagous(feeds on plant sap and other parts of plant)
Morphological Adaptations:
In root:
* Root system is well developed and is greater than that of shoot system.
* Root hairs and root caps are also well developed.
* In Xerophytic plants with the leaves and stem are covered with hairs are called tricho- phyllous plants.
* Eg: Cucubits (Melothria andMukia)
In stem:
* Stems are mostly hard and woody. They may be aerial or underground.
* The stems and leaves are covered with wax coating or covered with dense hairs.
* In some xerophytes all the internodes in the stem are modified into a fleshy leaf structure called phylloclades (Opuntia)
* In some of the others single or occasionally two internodes modified into fleshy green structure called cladode (Asparagus)
* In some the petiole is modified into a fleshy leaf like structure called phyllode (Acacia melanoxylon)
a) A succulent xerophyte: Phylloclade – opuntia
b) Non succulent: Perennial – Capparis
c) Cladode of Asparagus
d) Phyllode – Acacia
aquatic and terrestrial modes of life. They grow in shallow water.
Examples: Ranunculus, Typha and Sagittaria.
Hydrophytes exhibit various anatomical and physiological adaptations to survive in aquatic environments. Anatomically, their cuticle is either absent or very thin and poorly developed, reducing the barrier to gas exchange and water absorption. They typically possess a single-layered epidermis. The cortex is often well-developed and contains large air spaces called aerenchyma, which provide buoyancy and facilitate gas exchange within the plant. Vascular tissues, such as xylem and phloem, are generally poorly developed because water is readily available, and mechanical support is less critical, although emergent forms may have more developed vascular tissues. Mechanical tissues are usually absent, except in some emergent species. Physiologically, hydrophytes are adapted to withstand anaerobic conditions that may arise in waterlogged soils or stagnant water, often through specialized metabolic pathways. They also possess unique aerating organs that facilitate the diffusion of gases throughout the plant body, ensuring adequate oxygen supply to submerged parts.
Epiphytes:
Epiphytes are plants which grow perched on other plants (Supporting plants). They use the supporting plants only as shelter and not for water or food supply.
Orchids, Lianas, Hanging Mosses and Money plant.
Morphological adaptations:
* Root system is extensively developed. These roots may be of two types. They are Clinging roots and Aerial roots.
* Clinging roots fix the epiphytes firmly on the surface of the supporting objects.
* Aerial roots are green coloured roots which may hang downwardly and absorb moisture from the atmosphere with the help of a spongy tissue called velamen.
* Stem of some epiphytes are succulent and develop pseudo bulb or tuber.
* Generally the leaves are lesser in number and may be fleshy and leathery Myrmecophily is a common occurrence in the epiphytic vegetation to prevent the predators.
Epiphytes exhibit remarkable anatomical and physiological adaptations to survive in their aerial environment, often lacking direct contact with the soil. Anatomically, they possess a multilayered epidermis, which provides protection. Inner to this, a specialized exodermis layer is present, playing a role in water absorption. A thick cuticle on the leaf surface and sunken stomata are crucial for minimizing water loss through transpiration. Many succulent epiphytes have well-developed parenchymatous cells in their tissues, enabling them to store significant amounts of water during periods of availability. Physiologically, epiphytes have evolved special absorption processes, particularly through a spongy tissue called velamen, which efficiently captures atmospheric moisture and nutrients.
Halophytes, plants adapted to saline environments, display distinct anatomical and physiological modifications. Anatomically, their stem epidermis is heavily cutinized, with cells that are almost squarish and often filled with oil and tannins, providing protection against salt and desiccation. The stem cortex is reinforced by star-shaped sclereids and 'H'-shaped spicules, which offer crucial mechanical strength in saline soils. Leaves of halophytes can be dorsiventral or isobilateral and may possess specialized salt-secreting glands to excrete excess salt. Physiologically, many halophytes maintain a high osmotic pressure within their cells, enabling them to absorb water from saline soil. Additionally, vivipary, where seeds germinate within the fruits of the mother plant, is a common adaptation, ensuring the seedling is established in a more favorable microenvironment before dispersal.
Hydrochory is the dispersal of seeds and fruits by water, a strategy employed by plants that grow in or near aquatic habitats. These plants have evolved specific adaptations to facilitate this process. For instance, some fruits or seeds possess an obconical receptacle with prominent air spaces, aiding buoyancy, as seen in Nymphaea (water lily). Others have a fibrous mesocarp and a light pericarp, making them buoyant, a characteristic of the coconut. Seeds can be light and small, sometimes enclosed by an aril that traps air, further enhancing their ability to float, as observed in Nymphaea. Some fruits are inflated, containing air pockets that aid in flotation, such as in Heritiera littoralis. Even seeds that might not naturally float can be effectively dispersed by water currents, with the coconut being a prime example of a seed relying on both buoyancy and water transport.
The individual seeds or the whole fruit may be modified to help for the dispersal by wind. Wind dispersal of fruits and seeds is quite common in tall trees.
* Minute seeds: Seeds are minute, very small, light and with inflated covering. Example: Orchids.
Wings: Seeds or whole fruits are flattened to form a wing. Examples: Maple, Gyrocarpus, Dipterocarpus and Terminalia
* Feathery Appendages: Seeds or fruits may have feathery appendages which greatly increase their buoyancy to disperse to high altitudes. Examples: Vernonia and Asclepias.
* Censor mechanisms: The fruits of many plants open in such a way that the seeds can escape only when the fruit is violently shaken by a strong wind. Examples: Aristolochia and Poppy.
Some fruits burst suddenly with a force enabling to throw seeds to a little distance away from the plant. Autochory shows the following adaptations.
* Mere touch of some plants causes the ripened
fruit to explode suddenly and seeds are thrown out with great force. Example: Impatiens (Balsam), Hura.
* Some fruits when they come in contact with water particularly after a shower of rain, burst suddenly with a noise and scatter the seeds. Examples: Ruellia and Crossandra.
* Certain long pods explode with a loud noise like cracker, scattering the seeds in all directions. Example: Bauhinia vahlii (Camel’s foot climber)
* As the fruit matures, tissues around seeds are converted into a mucilaginous fluid, due to which a high turgor pressure develops inside the fruit which leads to the dispersal of seeds.
* Example: Ecballium elaterium (Squirting cucumber) Gyrocarpus and Dipterocarpus.
- Air in motion is called wind. It is also vitral ecological factor.
- The atmospheric air contains a number of gases, particles and other constituents.
- The composition of gases in atmosphere is as follows
- Nitrogen – 78%, Oxygen – 21%., Carbon-di¬oxide – 0.03%., Argon and other gases – 0.93%.
- The other components of wind are water vapour, gaseous pollutants, dust, smoke particles, microorganisms pollen grains, spores etc.
- Anemometer is the instrument used to measure the speed of wind.