a. Pioneers
b. A.G. Tansley
b. Trophic level
a. Climax communities
a. R does not explains A
In this scenario, the pyramid of numbers would likely be inverted or spindle-shaped. The base consists of a small number of large-sized trees (producers). The next trophic level, herbivores like deer and elephants (primary consumers), would be more numerous than the trees they feed on. Following this, the number of secondary consumers like foxes and snakes would be less than the primary consumers. Finally, the tertiary consumers, such as lions, would be at the apex, with the fewest individuals. This structure, where the number of organisms decreases at successively higher trophic levels but the base is narrow, leads to an inverted or spindle-shaped pyramid.
d. Anthropogenic activities
a) Carbon sequestration
a. Amount of energy in the tissues of consumer (or) heterotrophs
a. Only 2 – 10% of solar energy is used by green plants for photo synthesis
d. A, B and D
a. A and R are correct
d. R is the correct explanation of A
b. Grey carbon – Green carbon
d. (i) – D; (ii) – C; (iii) – B; (iv) – A
a. Gradual, fairly changes and pH development of a given area
Ecological succession occurs in areas that have been disturbed or altered, leading to the colonization of new or previously inhabited sites by different communities of organisms over time. This can happen in areas that have experienced natural disturbances such as floods, which alter soil conditions and remove existing vegetation, or earthquakes, which can cause significant physical changes to the landscape. Succession also takes place in areas affected by anthropogenic activities, including deforestation, agriculture, or pollution, where the original ecosystem has been damaged or destroyed, creating opportunities for new species to establish and develop.
Halosere
Allogenic succession.
Secondary succession takes less time compared to the time taken for primary succession. Secondary succession occurs in areas where soil is already present and some pioneer species may remain, allowing faster recolonization and community development. Primary succession, on the other hand, must begin on bare substrate with no soil or existing vegetation, making it a much slower process.
a. Heterotrophic
a. A – iv), B – iii), C – ii), D-i)
Phytoplankton stage
The submerged free floating stage is characterized by the presence of rooted floating plants such as Nelumbo, Nymphaea, and Trapa, as well as free floating plants like Wolffia and Lemna. These plants are adapted to aquatic environments where they remain partially or fully submerged in water. This stage represents an early phase of aquatic succession where floating vegetation begins to colonize freshwater bodies such as ponds and lakes, gradually modifying the environment for subsequent stages of ecological development.
Submerged plant.
Marsh meadow.
The marsh meadow stage is characterized by the colonization of species belonging to the families Cyperaceae and Poaceae, including genera such as Carex, Juncus, Cyperus, and Eleocharis. These plants are herbaceous species adapted to wet, marshy conditions with waterlogged soils. This stage represents a transitional phase in aquatic succession where the water level decreases and the substrate becomes increasingly terrestrial, allowing grasses and sedges to establish dominance and gradually convert the aquatic environment toward a more terrestrial ecosystem.
Shrub stage
True
Urban ecosystem restoration model.
Lithosere
d. Xerosere
b. Hydrosere
d. Ecosystem
d. 46% reaches earth surface
a. Blue and red
a. Fixation of radiant energy
c. Fallen leaves → Earthworm → Black bird → Hawk. This is the correct representation of a detritus food chain because it begins with dead organic matter (fallen leaves) rather than living plants. In a detritus food chain, energy flow starts from decomposing organic material and dead organisms, which are consumed by detritivores such as earthworms, followed by primary carnivores like black birds, and finally secondary carnivores such as hawks. This chain demonstrates how energy stored in dead biomass is transferred through the ecosystem, contrasting with grazing food chains that begin with living producers.
b. 170
a. 55
c. Ten percent law
a. Lichens
a. Ocean
d. The part of the earth with life. The biosphere refers specifically to the regions of the Earth where life exists, including the atmosphere, hydrosphere, and lithosphere where organisms are found. It encompasses all living organisms and their interactions with the physical environment, extending from the upper atmosphere to the depths of the ocean and the soil. The biosphere is the global ecosystem that supports all life forms and represents the zone of life on Earth.
b. Cycling of nutrients with ecosystem
d. Respiration
b. Natural
a. Upright pyramid of biomass
Omnivores
b. Secondary consumer
a. Inverted pyramid of number
a. Pond and lake
c. Phytoplanktons → Zooplanktons → Fishes → snakes. This food chain represents an inverted pyramid because the biomass of phytoplanktons (producers) is much smaller than the biomass of zooplanktons (primary consumers), which in turn is smaller than the biomass of fishes (secondary consumers). This inverted relationship occurs in aquatic ecosystems where producers have a small biomass but high productivity and rapid reproduction rates, supporting a larger biomass of consumers. The inverted pyramid demonstrates that energy flow and biomass relationships can vary depending on the ecosystem type and the characteristics of the organisms involved.
b. First law of thermodynamics. The statement that the quantity of energy present in the universe is constant relates to the first law of thermodynamics, also known as the law of conservation of energy. This law states that energy cannot be created or destroyed but can only be transformed from one form to another. In the context of ecosystems, this principle explains how light energy from the sun is converted into chemical energy through photosynthesis and subsequently transferred through food chains, with the total energy remaining constant throughout these transformations.
d. Forest ecosystem
a. Unidirectional
c. Goat is a primary consumer, herbivore, second trophic level
d. Food web is used for the construction of ecological pyramid. This is the incorrect statement. Ecological pyramids are constructed using data from food chains, not food webs. A food chain represents a linear sequence of energy transfer from one trophic level to the next, making it suitable for pyramid construction. A food web, which shows multiple interconnected food chains in an ecosystem, is too complex to directly construct pyramids. The other statements are correct: pyramids of energy are always upright, pyramids of biomass are typically upright in grassland and forest ecosystems, and pyramids of number can display three different shapes including upright, spindle, and inverted forms depending on the ecosystem type.
d. Inorganic compounds
b. Rice field
d. fresh water ecosystem
d. self sufficient and self regulating
b. no effective light penetration
d. Forest ecosystem
d. all of the above
c. Tertiary consumers → Secondary consumers → Primary consumers → Producers. This represents the correct descending order of a food chain, showing the sequence from the highest trophic level to the lowest. Tertiary consumers occupy the top position as they feed on secondary consumers, which in turn feed on primary consumers, which feed on producers. This arrangement reflects the hierarchical organization of trophic levels in an ecosystem, where energy and nutrients flow from the base (producers) upward through successive consumer levels, but when listed in descending order of trophic level, the sequence begins with the highest consumers and ends with the producers.
d. b and c
c. Anabolism
a. Nitrogen cycle
c. i and ii
The productivity of the profundal zone is very low because this zone lies below the limnetic zone at considerable depth where light penetration is minimal or completely absent. Since the profundal zone lacks sufficient light energy, photosynthesis cannot occur effectively, and therefore the primary productivity is severely limited. The producers of the pond ecosystem, primarily phytoplankton, depend on light energy for photosynthesis to synthesize organic compounds. Without adequate light in the profundal zone, phytoplankton cannot survive or reproduce in significant numbers, resulting in very low primary productivity. The organisms present in this zone are mainly decomposers and detritivores that depend on organic matter settling from the upper zones, making it a zone of low energy availability and consequently low overall productivity.
Gross Primary Productivity (GPP) represents the total rate at which solar energy is converted into chemical energy in the form of organic compounds by autotrophs through photosynthesis within an ecosystem. It is the absolute maximum potential for energy capture. Net Primary Productivity (NPP), on the other hand, is the amount of energy that remains available to consumers after the producers have respired. It is the GPP minus the energy lost through the plant's own metabolic processes, primarily respiration. Therefore, GPP is always more efficient in terms of total energy capture than NPP, as NPP accounts for the energy utilized by the producers themselves for their survival and growth. The formula is NPP = GPP – Respiration.
The pyramid of energy is always upright because it represents the successive flow and transfer of energy at each trophic level in an ecosystem. Energy enters the ecosystem through photosynthesis by producers and is progressively transferred to primary consumers, secondary consumers, and tertiary consumers. However, at each trophic level, a significant portion of energy is lost through respiration, heat dissipation, and incomplete consumption, resulting in a gradual and continuous decrease in the amount of energy available at successive trophic levels. Consequently, the energy available to primary consumers is less than that available to producers, energy available to secondary consumers is less than that available to primary consumers, and so on. This consistent decrease in energy at each successive trophic level ensures that the pyramid of energy always maintains an upright shape, with the base being the largest and each successive level becoming progressively smaller.
- The removal of all the producers would cause the collapse of the entire food web.
- Primary consumers (or) herbivores, which feed on producers directly would die off because they would have nothing to eat.
- All the other animals in the food web would die too, because their food supplies would have gone.
- The population of the consumers would fall as the population of the producer fell.
- Producers are maintaining C02 and oxygen level in the atmosphere.
- If the producers are removed C02 and 02 cycle will be in imbalance in the atmosphere.
- It will leads to the depletion of respiratory gas oxygen as it is a by product of photosynthesis
- Food chain with plants → grasshopper → frog → snake → hawk
- The movement of energy from producers upto top carnivores is known as food chain.
- In this food chain energy flows from producers (plants) to primary consumers (grasshopper) to secondary consumer (frog) to tertiary consumer (snake) to predator (hawk)
- It shows linear network link.
Detritus food chain is generally present in all type of ecosystem.
Detritus food chain:
This type of food chain begins with dead organic matter which is an important source of energy. A large amount of organic matter is derived from dead plants, animals, and their excreta. This type of food chain is present in all ecosystems.
The transfer of energy from the dead organic matter, is transferred through a series of organisms called detritus consumers (detritivores)- small carnivores – large (top) carnivores with repeated eating and being eaten respectively. This is called the detritus food chain.
Significance:
* The detritus (dead plants, animals and their excreta) are breakdown into simple organic matter by the decomposers.
* It is an essential process for recycling and balancing the nutrient pool in an ecosystem.
The shape of the pyramid in a particular ecosystem varies depending on the characteristics of the organisms and their population dynamics at different trophic levels. In a forest ecosystem, the pyramid of numbers exhibits a spindle or waisted shape. This occurs because the base of the pyramid, representing the first trophic level (producers), consists of large-sized trees such as oak and pine, which are relatively few in number. The second trophic level (primary consumers) includes herbivores such as fruit-eating birds, elephants, and deer, which are more numerous than the producer trees because each tree can support many herbivores. The third trophic level (secondary consumers) includes carnivores such as foxes and snakes, which are fewer in number than the herbivores. The fourth trophic level (tertiary consumers) includes large predators such as lions, which are even fewer in number. This creates the characteristic spindle shape where the middle sections are wider than both the base and the apex. In contrast, in grassland ecosystems, the pyramid of numbers is typically upright because grass plants are numerous and small, supporting many herbivores, which in turn support fewer carnivores. In aquatic ecosystems with phytoplankton as producers, the pyramid of biomass may be inverted because phytoplankton are small but highly productive and reproduce rapidly, supporting a larger biomass of zooplankton consumers despite their smaller individual size.
To protect the ecosystem, we have to practice the following in our daily life.
* Buy and use only eco-friendly products and recycle them.
* Grow more trees.
* Choose sustained farm products (vegetables, fruits, greens, etc.) > Reduce the use of natural resources.
* Recycle the waste and reduce the amount of waste you produce.
* Reduce consumption of water and electricity.
* Reduce or eliminate the use of household chemicals and pesticides.
* Maintain your cars and vehicles properly. (In order to reduce carbon emission)
* Create awareness and educate about ecosystem protection among your friends and family members and ask them to find out solution to minimize this problem.
1. Primary succession:
The development of plant community in a barren area where no community existed before is called primary succession. The plants which colonize first in a barren area is called pioneer species or primary community or primary colonies. Generally, Primary succession takes a very long time for the occurrence in any region.
Example: Microbes, Lichen, Mosses.
2. Secondary succession:
The development of a plant community in an area where an already developed community has been destroyed by some natural disturbance (Fire, flood, human activity) is known as secondary succession.
Primary succession
Secondary succession
1. Developing in an barren area
Developing in disturbed area
2. Initiated due to a biological or any other external factors
Starts due to external factors only
3. No soil, while primary succession starts
It starts where soil covers is already present
4. Pioneer species come from outside environment
Pioneer species develop
from existing environment
5. It takes more time to complete
It takes comparatively less time to complete
Generally, This succession takes less time than the time taken for primary succession. Example: The forest destroyed by fire may be re-occupied by herbs over period of times.
3. Autogenic succession:
Autogenic succession occurs as a result of biotic factors. The vegetation reacts with its environment and modifies its own environment causing its own replacement by new communities. This is known as autogenic succession.
Example: In forest ecosystem, the larger trees produce broader leaves providing shade to the forest floor area. It affects the shrubs and herbs which require more light (heliophytes) but supports the shade tolerant species (sciophytes) to grow well.
4. Allogenic succession:
Allogeneic succession occurs as a result of abiotic factors. The replacement of existing community is caused by other external factors (soil erosion, leaching, etc.,) and not by existing organisms.
Example: In a forest ecosystem soil erosion and leaching alter the nutrient value of the soil leading to the change of vegetation in that area.
5. Autotrophic succession:
If the autotrophic organisms like green plants are dominant during the early stages of succession it is called autotrophic succession, this occurs in the habitat which is rich in inorganic substances. Since, green plants dominate in the beginning of this succession, there is a gradual increase in organic matter and subsequently the energy flow in the ecosystem.
6. Heterotrophic succession:
If heterotrophic organisms like bacteria, fungi, actinomycetes, and animals are dominant during the early stages of succession it is called heterotrophic succession. Such a succession takes place in organic habitats. Since heterotrophs dominate in the beginning of such succession, there will be a gradual decrease in the energy content.
- A graphical representation of the amount of organic material (biomass) present at each successive trophic level in an ecosystem is called pyramid of biomass.
- In grassland and forest ecosystems there is a gradual decrease in biomass of organisms at successive trophic levels from producers to top carnivores (tertiary consumer)
- Therefore these two ecosystems show pyramids as upright
- No.of producers → 1000
- No.of primary consumers → 500
- No.of secondary consumer → 150
- No.of the tertiary consumer is lesser than Secondary consumers (50)
Reed-swamp stage, phytoplankton stage, shrub stage, submerged plant stage, forest stage, submerged free floating stage and marsh medow stage.
(1) Phytoplankton stage – It is the first stage of succession consisting of the pioneer community like blue green algae, green algae, diatoms, bacteria, etc., The colonization of these organisms enrich the amount of organic matter and nutrients of pond due to their life activities and death. This favors the development of the next serai stages.
(2) Submerged plant stage – As the result of death and decomposition of planktons, silt brought from land by rain water, lead to a loose mud formation at the bottom of the pond. Hence, the rooted submerged hydrophytes begin to appear on the new substratum.
Example: Vallisneria and Hydrilla etc. The death and decay of these plants will build up the substratum of pond to become shallow.
(3) Submerged free floating stage – During this stage, the depth of the pond will become almost 2-5 feet Hence, the rooted hydrophytic plants and with floating large leaves start colonising the pond.
Example: Rooted floating plants like Nelumbo, Nymphaea and some free floating species like Azolla, and Pistia are also present in this stage. By death and decomposition of these plants, further the pond becomes more shallow.
(4) Reed-swamp stage – It is also called an amphibious stage. During this stage, rooted floating plants are replaced by plants which can live successfully in aquatic as well as aerial environment.
Example: Typha, Phragmites, Sagittaria and Scirpus etc. At the end of this stage, water level is very much reduced, making it unsuitable for the continuous growth of amphibious plants.
(5) Marsh meadow stage – When the pond becomes swallowed due to decreasing water level, species of Cyperaceae and Poaceae colonise the area. They form a mat-like vegetation with the help of their much branched root system. This leads to an absorption and loss of large quantity of water. At the end of this stage, the soil becomes dry and the marshy vegetation disappears gradually and leads to shurb stage.
(6) Shrub stage – Here areas are invaded by terrestrial plants like shrubs (Salix and Comus) and trees (Populus and Alnus). These plants absorb large quantity of water and make the habitat dry. Further, the accumulation of humus with a rich flora of microorganisms produce minerals in the soil, ultimately favouring the arrival of new tree species in the area.
(7) Forest stage – It is the climax community of hydrosere. A variety of trees invade the area and develop any one of the diverse type of vegetation.
Example.Temperate mixed forest (Ulmus, Acer and Quercus), Tropical rain forest (Artocarpus and Cinnamomum ) and Tropical deciduous forest (Bamboo and Tectona).
12th Bio Botany Guide Ecosystem Additional Important Questions and Answers
I. Choose the correct answer
- Abiotic components play vital role in an ecosystem.
- The total inorganic substances present in any ecosystem at a given time is called standing quality (or) standing state.
- Autotrophs are organism which can manufacture the organic compounds from simple inorganic components through a process called photo synthesis.
- Eg. Green plants. They are called as producers.
- The amount of living materials present in a population at a given time is known as standing crop.
- Which is expressed in terms of number (or) biomass per unit area.
- Its functions are energy creation and sharing of energy.
- It is the way to cycling of materials between the living and nonliving component of the ecosystem.
- The rate of biomass production per unit area in a unit time is called productivity.
- It can be expressed in terms of gm / m2 / yr (or) kcal / m2 / yr
- The total quantity (or) weight of organism in a give area is called biomass.
- It can be measured as fresh weight (or) dry weight (or) carbon weight of organisms.
Grass Primary Productivity:
* The total amount of food energy (or) biomass produced in an ecosystem
* It is done by autotrophs through the process called photosynthesis
Grass Secondary Productivity:
* The total amount of plant material ingested minus (-) materials lost as faeces.
* It is done by herbivores by the process called ingestion.
Net Primary Productivity:
* The proportion of energy which remains after respiration loss in the plant.
* Net primary productivity is calculated in producers.
Net Secondary Productivity:
* Stored energy (or) biomass per unit area per unit time after respiratory loss.
* Net secondary productivity is calculated in consumers.
Several factors significantly influence the primary productivity of plants, which is the rate at which producers convert light energy into organic matter. The inherent characteristics of the plant species present in an area, such as their photosynthetic efficiency and growth rates, play a crucial role. The photosynthetic capacity of the plants themselves is a primary determinant. Environmental conditions are also critical: the availability of essential nutrients in the soil, the intensity and duration of solar radiation, and the amount of precipitation directly impact photosynthesis and growth. Soil type influences nutrient and water availability, while topographic factors can affect light exposure and microclimates. Ultimately, a combination of these biotic and abiotic environmental factors determines the overall primary productivity of an ecosystem.
- NPP = GPP – Respiration
- Thus it is the difference between gross primary productivity and respiration is net primary productivity.
- Grey carbon is stored in fossil fuel like coal, oil and biogas deposits in the lithosphere
- Brown carbon is stored in industrialized forest wood used in making commercial articles.
- Blue carbon is stored in the atmosphere.
- Black carbon is emitted from diesel engine gas and coal fired power plants.
- The transfer of energy in an ecosystem between trophic levels can be termed as energy flow.
- It is the key function in an ecosystem.
- The crow has omnivorous type of Nutrition.
- They eat cereals, fruit and seeds, small insects and worms.
- They eat dead & decaying animals body and keep the environment clean, so known as scavengers of the sky.
- They occupy several trophic levels in the food chain.
- When they eat some fruits they swallow the seeds which are dispersed along with the excreta.
- However unlike certain pollination and insects they are not considered vital organisms because their loss from the ecu system mav cause drastic impacts, leading to the extinction of rhe. it partk ular plant species which can’t be pollinated in the absence of the particular insect/bird.
- However when crow is absent, then its niche in the food chain will be kept vacant ecological, this will be drastic change occur some other organism mav evolve to occupy the same neche in the long run.
The first law of thermodynamics is related to the conversion of light energy into chemical energy. This law, also known as the law of conservation of energy, states that energy cannot be created or destroyed but can only be transformed from one form to another. In photosynthesis, light energy from the sun is converted into chemical energy stored in the form of glucose and other organic compounds within plant cells. This conversion process demonstrates the principle of energy transformation governed by the first law of thermodynamics, where the total energy remains constant even as it changes from one form to another.
- The interlocking pattern of a number of food chain form a weblike arrangement called food web.
- It is known as basic unit of ecosystem to maintain its stability in nature.
- It is called homeostasis.
- The concept of ecological pyramids was introduced by Charles Elton in the year 1927.
- Thus ecological pyramids are called Eltonian pyramids.
An ecological pyramid is a graphical representation that illustrates the relationship between different trophic levels in an ecosystem. It depicts the structure and function of the ecosystem by showing the biomass, number of individuals, or energy content at each successive trophic level, starting from producers at the base and moving up through primary, secondary, and tertiary consumers.
- There is a gradual decrease in energy transfer at successive tropic levels from producers to the upper levels.
- Therefore, the pyramid of energy is always upright.
A pyramid of energy is a graphical representation that illustrates the flow of energy through successive trophic levels in an ecosystem. It shows the amount of energy available at each level, typically measured in units of energy per unit area per unit time (e.g., kilocalories per square meter per year). Due to energy loss at each transfer, these pyramids are always upright, with the base (producers) having the most energy and each subsequent level having significantly less.
Decomposition is the essential process for recycling and balancing nutrients in an ecosystem. It is a process in which detritus is broken down into simple organic matter by decomposers such as bacteria and fungi. Through decomposition, complex organic compounds are converted into simpler inorganic nutrients that can be reabsorbed by plants and other organisms, thereby completing nutrient cycles and maintaining the balance of essential elements like nitrogen, phosphorus, and carbon within the ecosystem.
Limnology
It is the studv of biological, chemical physical and geological components of inland fresh water aquatic ecosystem (ponds, lakes etc)
Oceanography:
It is the study of biological, chemical, physica I and geological components of ocean.
- Sea grasses and mangroves of estuarine and coastal ecosystems are the most efficient in carbon sequestration.
- Hence these ecosystems are called blue carbon ecosystem.
Carbon sequestration is the process of capturing and storing carbon dioxide from the atmosphere in carbon sinks such as oceans, forests, and soil. This process helps reduce the concentration of greenhouse gases in the atmosphere and plays a crucial role in mitigating climate change. Carbon is sequestered through photosynthesis by plants and trees, which incorporate atmospheric CO₂ into their biomass, and through the dissolution of CO₂ in ocean water where it may be stored for long periods or converted into carbonate compounds.
Provision of habitat, nutrient recycling, primary production, succession Odd one out: Succession.
Reason: Replacement of one type of plant community by other of the same place is known as succession. While others are supporting services of ecosystem services.
Odd one out: Lichen
Reason: Lichen is related to primary succession. While others are related to phytoplankton stage of hydrosere.
The slogan for the safety of the environment should emphasize responsible interaction with ecosystems, ensuring their preservation for future generations. A suitable slogan is: “Use Ecosystem. But don’t lose ecosystem. Make it sustainable.” This highlights the importance of utilizing natural resources judiciously while actively working towards maintaining the health and functionality of ecosystems for long-term viability.
Fragmentation is the process of breaking down detritus into smaller particles by detritivores such as bacteria, fungi, and earthworms. This mechanical and biological breakdown increases the surface area of organic matter, making it more accessible for further decomposition and nutrient release. Fragmentation is an important initial step in the decomposition process that facilitates the action of decomposers and accelerates the cycling of nutrients back into the ecosystem.
Humification is a process by which simplified detritus is changed into a dark coloured amorphous substance called humus. This occurs during the later stages of decomposition when partially decomposed organic matter is further broken down and transformed by microorganisms and chemical processes. Humus is a stable, nutrient-rich organic compound that improves soil structure, water retention, and fertility, and serves as a reservoir of nutrients for plant growth.
Oceanography is the scientific study of the oceans, encompassing their physical, chemical, geological, and biological components. It investigates phenomena such as ocean currents, tides, wave action, the composition of seawater, the formation of ocean basins, marine life, and the interactions between the ocean and the atmosphere. Understanding these aspects is crucial for comprehending global climate patterns, marine ecosystems, and resource management.
The placement of humans in food chains is variable due to their diverse dietary habits, making them adaptable consumers. Many humans are omnivores, consuming both plant and animal matter. Consequently, they can occupy multiple trophic levels. If a human consumes plants, they are at the secondary trophic level. If they consume herbivores (like cows or goats, which are primary consumers), they are at the tertiary trophic level (3rd). If they consume animals that eat herbivores, or other carnivores, they can be placed at the quaternary trophic level (4th). For instance, if a human eats salmon, and the salmon consumes other fish, the human would be positioned at the fourth trophic level in that specific food chain.
- The amount of light available for photosynthesis of plants is called photosynthetically active radiation.
- Which is between the range of 400 – 700 nm of wave length.
- Generally plants absorb move blue and red light for efficient photosynthesis.
- Only 2 -10% of the solar energy is used by green plants for photosynthesis.
Green Carbon:
* It is the carbon stored in the biosphere.
* It is done by the process of photosynthesis by green plants.
Grey Carbon:
* It is the carbon stored in fossil fuel. (Coal, oil, biogas)
* It is done by the process of decomposition in the lithosphere.
Primary productivity and secondary productivity are two distinct concepts in ecosystem energy flow. Primary productivity is the chemical energy or organic matter generated by autotrophs through the processes of photosynthesis and chemosynthesis. It represents the total amount of organic matter produced by producers and serves as the ultimate source of energy for all organisms in the ecosystem, from bacteria to humans. Secondary productivity, on the other hand, is the amount of energy stored in the tissues of heterotrophs or consumers. It represents the energy that is consumed and assimilated by consumers at various trophic levels from the organic matter produced by primary producers. While primary productivity is the source of energy for the entire ecosystem, secondary productivity is the source of energy present in particular organisms or trophic levels and is always less than primary productivity due to energy loss during transfer between trophic levels.
- It states second law of thermodynamics.
- Usually energy transformation cannot be 100% efficient.
- As energy is transformed from one organism to another in the form of food, where as a large part of energy is dissipated as heat through respiration. (Eg.) Ten percent law.
- This law was proposed by Lindeman (1942)
- During transfer of food energy from one trophic level to other, only about 10% stored at every level and rest of them 90% is lost in respiration, decomposition in the form of heat.
- Hence the law is called ten percent law.
It begins with dead organic matter.
Which is an important source of energy
* Transfer of energy from Detritus → Detritivores → Small carnivores → Top carnivores
* This type of food chain is present in all ecosystems.
- A – Rabbit
- B – Mouse
- C – Lizard
- Food web is constructed to describe species interaction called direct interaction.
- It can be used to illustrate indirect interaction among different species.
- It can be used to reveal different patterns of energy transfer in terrestrial and aquatic ecosystems.
- There are three different shapes of pyramids present in pyramid of number.
- Pyramid of number in grassland and pond ecosystem are always upright in shape.
- In forest ecosystem it is spindle shaped.
- In parasite ecosystem it is inverted.
According to the pyramid of biomass, different ecosystems exhibit different shapes. In grassland and forest ecosystems, the pyramid of biomass is upright, showing a typical decrease in total biomass at each successive trophic level. In pond ecosystems, the pyramid of biomass is inverted, where the biomass of consumers may exceed that of producers due to the high reproductive rate and rapid turnover of aquatic producers like phytoplankton compared to their relatively large consumer populations.
- In grassland and forest there is a gradual decrease in biomass of organisms from producers to top carnivore.
- There fore it is always upright.
- In pond ecosystem the bottom of the pyramid is occupied by the producers which are small organisms posses least biomass.
- So the value gradually increases towards the tip of the pyramid.
- Therefore pyramid of biomass is always inverted in shape.
Humification and mineralization are two distinct but sequential processes involved in the decomposition of organic matter. Humification is the process where simplified detritus, such as dead plant and animal remains, is transformed into a dark-colored, amorphous, and complex organic substance known as humus. Humus is relatively resistant to further microbial decomposition and plays a vital role in soil structure and fertility. Mineralization, on the other hand, is the subsequent release of inorganic nutrients, such as nitrates, phosphates, and sulfates, from the humus. This process is carried out by specific microbes that break down the complex organic compounds in humus, making essential nutrients available for uptake by plants.
Catabolism is the process by which decomposers produce extracellular enzymes in their surroundings to break down complex organic and inorganic compounds into simpler ones. These enzymes are secreted by decomposers such as bacteria and fungi into the environment where they act on dead organic matter and other complex substances. Through catabolism, large molecules are broken down into smaller, soluble compounds that can be absorbed by the decomposers for their own metabolism and energy production, while simultaneously releasing nutrients that become available for uptake by other organisms in the ecosystem.
Leaching, also called eluviation, is the process of movement of decomposed water-soluble organic and inorganic compounds from the surface layers to the lower layers of soil by water. This process is particularly important in enriching the lower layers of soil with nutrients and minerals that have been released during decomposition. Water percolating through the soil carries dissolved nutrients downward, contributing to soil development and making nutrients available at greater depths where plant roots can access them.
A biogeochemical cycle is the circulation of nutrients and elements within the ecosystem or biosphere. It refers to the cycling of materials such as carbon, nitrogen, phosphorus, and water between the living organisms (biotic components) and the non-living environment (abiotic components) including the atmosphere, hydrosphere, and lithosphere. These cycles ensure that essential nutrients are continuously recycled and made available for use by organisms, maintaining the balance and sustainability of ecosystems.
- Phosphorus, sulphur, calcium are called as sedimentary cycles.
- Which are present as sediments on earth.
- Sedimentary cycles are very slow its take a long time to complete its circulation, because nutrient elements may get locked in the reservoir pool.
- The circulation of carbon between organisms and environment is known as carbon cycle.
- Cycling of carbon between organisms and atmosphere is consequence (event) of two reciprocal process of photosynthesis and respiration.
Ecosystem resilience, also called ecosystem robustness, is the ability of an ecosystem to resist damage and recover quickly from disturbances. Ecosystems are frequently subjected to various disturbances such as fire, flood, predation, infection, and drought, which can remove significant amounts of biomass and disrupt ecological processes. Despite these disturbances, ecosystems possess inherent mechanisms and characteristics that allow them to withstand the damage and restore themselves to their original state or a similar functional condition. This resilience is an important property that enables ecosystems to maintain their structure and function over time and is influenced by factors such as biodiversity, genetic variation, and the presence of key species that can facilitate recovery.
- Close the tap when not in use.
- Switch off the electrical gadgets when not in use.
- Never use plastics and replace them with biodegradable products.
- Always use ecofriendly technology and products.
The three Rs for the safety and benefits of the environment are reduce, reuse, and recycle. Reduce refers to minimizing the consumption of resources and the generation of waste by using less material and energy in daily activities. Reuse involves using products and materials multiple times in their original form or for different purposes before discarding them, thereby extending their useful life. Recycle refers to processing used materials into new products, which conserves natural resources and reduces the amount of waste sent to landfills. Together, these three Rs represent a comprehensive approach to changing one's lifestyle and consumption patterns to minimize environmental impact, conserve resources, and promote sustainability for the benefit and safety of the environment.
- Food web is constructed to describe species interaction called direct interaction
- It can be used to illustrate indirect interaction among different species.
- It can be used to study bottom up or top down control of community structure.
- It can be used to reveal different patterns of energy transfer in terrestrial and aquatic ecosystems.
Carbon exists in various forms and reservoirs within the Earth's systems. Green carbon is the carbon stored in the biosphere, primarily in living organisms and organic matter, captured through photosynthesis by green plants. Grey carbon is the carbon sequestered in fossil fuels like coal, oil, and natural gas deposits within the lithosphere, formed from ancient organic matter. Blue carbon refers to the carbon stored in marine and coastal ecosystems, such as mangroves, seagrasses, and salt marshes, as well as in the atmosphere and oceans. Brown carbon is carbon stored in industrialized forests, specifically in wood used for commercial products and often associated with biomass energy. Black carbon, also known as soot, is a product of incomplete combustion from sources like gas and diesel engines and coal-fired power plants, and it significantly impacts climate and air quality.
d. Fragmentation – Release of inorganic nutrients from the humus. This is the incorrect pair because fragmentation is the physical breakdown of dead organic matter (detritus) into smaller pieces by the action of detritivores and environmental factors, which increases surface area for microbial decomposition. It does not directly release inorganic nutrients; rather, it facilitates the process. The release of inorganic nutrients from humus is actually accomplished through mineralization or nutrient cycling, not fragmentation. Humification (option a) correctly describes the conversion of detritus into dark humus. Eluviation (option b) correctly refers to the downward movement of organic and inorganic compounds through soil layers. Detritus (option c) correctly identifies dead plants and animal waste as the starting material for decomposition.
The term ecosystem was proposed by A.G. Tansley (1935), who defined it as.
* The system resulting from the integration of all the living and non living factors of the environment.
Whereas Odum (1962) defined ecosystem as
* Eco system is structural and functional unit of ecology.
* Ecosystem comprises of two major components
i) Abiotic ii) Biotic components
i) Abiotic (non-living) components:
Edaphic Factors – Soil, air, soil water and pH of soil.
Topography factors – Latitude altitude Organic components – Carbohydrates, protein’s lipids and humic substances
Inorganic substances:
C, H, O, N and P. Abiotic components play vital role in any ecosystem hence it is important for standing quality.
ii) Biotic (living) components:
It includes all living organisms like plants, animal, fungi and bacteria.
* They form the trophic structures of any ecosystem.
* It has two components
i) Autotrophic components ii) Heterotrophic components
i) Autotrophic components:
Autotrophs are plants (or) producers which can manufacture the organic compounds from simple inorganic components through a process called photosynthesis.
ii) Heterotrophic components:
Heterotrophs are organisms which consume the producers are called consumers. They are two types
i) Macro consumers ii) Micro consumers
* Macro consumers are herbivores, carnivores and omnivores.
* Micro consumers are called decomposers. (Eg.) Bacteria, actinomycetes and fungi
* Biotic components are essential to construct the food chain, food web and ecological pyramids.
- The amount of light available for photosynthesis of plants is called photosynthetically active radiation.
- Which is between the range of 400 -700 nm wavelength. Which is essential for photosynthesis and plant growth.
- Generally plants absorb more blue and red light for efficient photosynthesis.
- Of the total sunlight, 34 percent that reaching the atmosphere is reflected back into the atmosphere, moreover 10% is held by ozone.
- Remaining 56% reaches the earths surface out of this 56%, only 2 – 10% of solar energy is used by green plants for photosynthesis while the remaining portion is dissipated as heat
- PAR is generally reported as millimoles / square meter / second by using silicon photo voltic detector.
- Which detect only 400 – 700 nm wavelength of light.
- PAR values range from 0 to 3000 millimoles / square meter / second.
- At night PAR is zero and during midday in summer, PAR often reaches 2000 – 3000 millimoles /square meter / second.
1.Primary productivity:
The chemical energy or organic matter generated by autotrophs during the process of photosynthesis and chemosynthesis is called primary productivity. It is the source of energy for all organisms, from bacteria to human.
a. Gross Primary Productivity (GPP):
The total amount of food energy or organic matter or biomass produced in an ecosystem by autotrophs through the process of photosynthesis is called gross primary pro-ductivity
b. Net Primary Productivity (NPP):
The proportion of energy which remains after respiration loss in the plant is called net primary productivity. It is also called as apparent photosynthesis. Thus the difference between GPP and respiration is known as NPP.
NPP = GPP – Respiration
NPP of whole biosphere is estimated to be
about 170 billion tons (dry weight) per year. Out of which NPP of oceanic producers is only 55 billion tons per year in unit time.
Factors affecting primary productivity:
* Factors affecting primary productivity depends upon the plant species of an area
* Their photosynthetic capacity, availability of nutrients solar radiation, precipitation, soil type and other environmental factors.
* It varies in different types of ecosystems.
Secondary productivity is the amount of energy stored in the tissues of heterotrophs or consumers per unit area per unit time. It represents the rate at which consumers accumulate biomass and energy from the food they consume. Secondary productivity has two main types. Gross secondary productivity is equivalent to the total amount of plant material ingested by the herbivores minus the materials lost as faeces, representing the energy assimilated by consumers. Net secondary productivity is the storage of energy or biomass by consumers per unit area per unit time after accounting for respiratory losses, which represents the actual growth and reproduction of consumer populations. Community productivity is calculated as the rate of net synthesis of organic matter or biomass by a group of plants per unit area per unit time. It is measured by determining the increase in total plant biomass over a specified period in a defined area, accounting for losses due to respiration, decomposition, and herbivory. This measurement is essential for understanding the overall energy flow and productivity dynamics within an ecosystem.
A trophic level refers to the position of an organism in the food chain.
* The number of trophic levels is equal to the number of steps in the food chain.
* The green plants (producers) occupying the first trophic level (TA are called producers.
* The energy produced by the producers is utilized by the plant eaters (herbivores) they are called primary consumers and occupies the second trophic level (T 2 ).
* Herbivores are eaten by carnivores, which occupy the third trophic level (T 3 ).
They are also called secondary consumers or primary carnivores.
* Carnivores are eaten by the other carnivores, which occupy the fourth trophic level (T 4 ). They are called the tertiary consumers or secondary carnivores.
* Some organisms which eat both plants and animals are called as omnivores (Crow). Such organisms may occupy more than one trophic level in the food chain.
Laws of thermodynamics:
The storage and loss of energy in an ecosystem is based on two basic laws of thermodynamics.
i) First law of thermodynamics
* It states that energy can be transmitted from one system to another in various forms. Energy cannot be destroyed or created.
* As a result, the quantity of energy present in the universe is constant.
* Example: In photosynthesis, the product of starch (chemical energy) is formed by the combination of reactants (chlorophyll, H 2 O, CO 2 ). ‘ “
Starch is acquired from the external sources (light energy) and so there is no gain or loss in total energy. Here light energy is converted into chemical energy.
* Light energyv → Chemical energy
ii) Second law of thermodynamics Usually energy transformation cannot be 100% efficient. As energy is transferred from one organism to another in the form of food, a portion of it is stored as energy in living tissue, whereas a large part of energy is dissipated as heat through respiration. Example: Ten percent law Ten percent law: During transfer of food energy from one trophic level to other, only about 10% stored at every level and rest of them (90%) is lost in respiration, decomposition and in the form of heat. Hence, the law is called ten percent law.
The movement of energy from producers upto top carnivores is known as food chain,
* Generally, there are two types of food chain, (1) Grazing food chain and (2) Detritus food chain.
1. Grazing food chain: Main source of energy for the grazing food chain is the Sun. It begins with the first link, producers (plants) The second link in the food chain is primary consumers (mouse) which get their food from producers. The third link in the food chain is secondary consumers (snake) which get their food from primary consumers. Fourth link in the food chain is tertiary consumers (eagle) which get their food from secondary consumers.
2. Detritus food chain: This type of food chain begins with dead organic matter which is an important source of energv. A large amount of organic matter is derived from the dead plants, animals and their excreta. This type of food chain is present in all ecosystems.
The transfer of energy from the dead organic matter, is transferred through a series of organisms called detritus consumers (detritivores)- small carnivores – large (top) carnivores with repeated eating and being eaten respectively. This is called the detritus food chain.
Graphic representation of trophic structure and function in successive trophic levels of an ecosystem is called ecological pyramid (or) Eltonian pyramid.
Figure 7.8: Pyramids of numbers (individuals per unit area) in different types of ecosystems, Upright – A) Grassland ecosystem B) Pond ecosystem, Spindle shaped – C) Forest ecosystem,
Inverted – D) Parasite ecosystem
Pyramid of number:
* A graphical representation of the number of organism present at each successive trophic level in an ecosystem is called pyramid of number.
* There are different shapes, pyramid of number in grassland and pond ecosystem are always upright. Because
* There is a gradual decrease in number of organisms in each trophic level from Producer → Primary consumer then → Secondary consumer and finally → Tertiary consumer.
* Pyramid of number in forest ecosystem looks spindle shaped. Because
* In forest ecosystem, large sized tree (producer) which are lesser in number, herbivores are more in number than produces.
* In final tertiary consumers are lesser in number than the secondary consumer.
* In a parasite ecosystem the pyramid of number is always inverted because
* Its starts with single tree, there is gradual increase in the number of organisms in successive
trophic levels from producers to tertiary consumers.
* Question 9.
Write about the mechanism of decomposition ? What are the factors affecting decomposition, (or) Describe about an essential process for recycling and balancing the nutrient pool in an ecosystem.
* Decomposition is a step wise process of degradation mediated by enzymatic reactions. Detritus acts as a raw material for decomposition.
* a. Fragmentation – The breaking down of detritus into smaller particles by detritivores like bacteria, fungi and earth worm is known as fragmentation.
* b. Catabolism – The decomposers produce some extracellular enzymes in their surroundings to break down complex organic and inorganic compounds in to simpler ones. This is called catabolism
* c. Leaching or Eluviation – The movement of decomposed, water soluble organic and inorganic compounds from the surface to the lower layer of soil or the carrying away of the same by water is called leaching or eluviation.
* d. Humification – Detritus is changed into dark coloured amorphous substance called humus. It is highly resistant to microbial action, therefore decomposition is very slow.
* e. Mineralisation – The release of inorganic nutrients from the humus is called mineralisation.
* Decomposition is affected by climatic factors like temperature, soil moisture, soil pH oxygen and also the chemical quality of detritus.
A graphical representation of the amount of organic material (biomass) present at each successive trophic level in an ecosystem is called pyramid of biomass.
* In grassland and forest ecosystems, there is a gradual decrease in biomass of organisms at successive trophic levels from producers to top carnivores (Tertiary consumer). Therefore, these two ecosystems show pyramids as upright pyramids of biomass.
* However, in pond ecosystem, the bottom of the pyramid is occupied by the producers, which comprise very small organisms possessing the least biomass and so, the value gradually increases towards the tip of the pyramid. Therefore, the pyramid of biomass is always inverted in shape.
Figure 7.9: Pyramids of biomass (dry weight per unit area) in different types of ecosystems.
Upright – A) Grassland ecosystem Inverted – C) Pond ecosystem
- Pond ecosystem is a self sustaining and self regulatory fresh water ecosystem, which shows a complex interaction between the abiotic and biotic components in it.
- A pond ecosystem consists of dissolved inorganic (CO 2, O 2, Ca, N, Phosphate) and organic substances (amino acids and humic acid) formed from the dead organic matter.
- The function of pond ecosystem is regulated by few factors like the amount of light, temperature, pH value of water and other climatic conditions.
- Biotic components: They constitute the producers, variety of consumers and decomposers (microorganisms).
- A variety of phytoplankton like Oscillatoria, Anabaena, Eudorina, Volvox and Diatoms. Filamentous algae, floating plants, rooted floating plants are the major producers of a pond ecosystem.
- zooplanktons, benthos, secondary consumers like water beetles and frogs tertiary consumers (carnivores) like duck, crane and some top carnivores which include large fish, hawk,man, etc.
- They are also called as microconsumers. They help to recycle the nutrients in the ecosystem.
- The cycling of nutrients between abiotic and biotic components is evident in the pond ecosystem, making itself self sufficient and self regulating.
Sedimentary cycles are very slow. They take a long time to complete their circulation. Because during recycling, nutrient elements may get locked in the reservoir pool there by taking a very long to come out and continue circulation.
* It is a type of sedimentary cycle. Already we know that phosphorus is found in the biomolecules like DNA, RNA, ATP, NADP and phospholipid molecules of living organisms.
* Bulk quantity of phosphorus is present in rock deposits, marine sediments and guano.
It is released from these deposits by weathering process.
* The producers absorb phosphorus in the form of phosphate ions, and then it is transferred to each trophic level of food chain through food.
* Again death of the organisms and degradation by the action of decomposers, the phosphorus is released back into the lithosphere and hydrosphere to maintain phosphorus cycle.
The varieties of benefits obtained from ecosystems are generally categorized into four main types of ecosystem services. Provisioning services include the direct products obtained from ecosystems such as food, fresh water, fuel, fiber, and medicinal plants. Regulating services are the benefits obtained from the regulation of ecosystem processes, including air quality maintenance, climate regulation, water purification, pollination, and pest control. Supporting services are the natural processes that maintain all other ecosystem services, such as nutrient cycling, soil formation, and primary production. Cultural services are the non-material benefits that people obtain from ecosystems, including recreational opportunities, aesthetic appreciation, spiritual and religious values, educational benefits, and cultural heritage. These four categories together represent the comprehensive range of ways in which ecosystems contribute to human well-being and environmental sustainability.
Mangrove ecosystems provide a multitude of essential services to both nature and human beings. They serve as critical habitats and nurseries for a diverse array of aquatic plants and animals, supporting biodiversity and fisheries. Mangroves also yield valuable resources such as medicine, fuel wood, and timber. Functioning as a natural buffer, they connect sea and rivers, effectively balancing sedimentation processes and preventing soil erosion along coastlines. Furthermore, their dense root systems and vegetation help dissipate the force of waves and storm surges, offering protection against cyclones, tsunamis, and high tides. Additionally, mangroves contribute to windbreak formation, produce oxygen, sequester significant amounts of atmospheric carbon dioxide, and mitigate the impact of salt spray from oceanic waves.
To protect ecosystem, we have to practice the following in our daily life.
* Buy and use only ecofriendly products and recycle them.
* Grow more trees.
* Choose sustained farm products (vegetables, fruits, greens, etc.)
* Reduce the use of natural resources.
* Recycle the waste and reduce the amount of waste you produce.
* educe consumption of water and electricity.
* Reduce or eliminate the use of house-hold chemicals and pesticides.
* Maintain your cars and vehicles properly. (In order to reduce carbon emission)
Create awareness and educate about ecosystem protection among your friends and family members and ask them to find out solution to minimise this problem.
Ecosystem management strategies are designed to maintain the biodiversity and functional integrity of ecosystems. A key aspect involves identifying and utilizing flagship species, which are particularly sensitive to environmental changes and can serve as indicators of ecosystem health, signaling when an ecosystem is damaged. These strategies also acknowledge the inevitability of ecosystem change and aim to plan accordingly, adapting to natural or anthropogenic alterations. Ecosystem management is a crucial tool for achieving the sustainability of ecosystems, often integrated within broader sustainable development programs and projects. It also plays a vital role in identifying ecosystems that are degraded or in need of rehabilitation, guiding conservation and restoration efforts.
Ecological succession is a systematic and directional process of change in the structure of a plant and animal community over time, leading to a more stable climax community. It is driven by alterations in both abiotic factors, such as soil and climate, and biotic factors, including species interactions. During succession, there is a gradual progression in species diversity, total biomass, niche specialization among organisms, and an increase in the humus content of the soil. The food chains become more complex, evolving into intricate food webs. This process transforms unstable, early-stage communities into more stable, self-perpetuating ones, often progressing from simpler life forms to more complex ones and fostering greater interdependence between plants and animals.
Primary succession and secondary succession differ in several fundamental ways. Primary succession develops in a barren area with no previous soil or vegetation, while secondary succession develops in a disturbed area where soil is already present. Primary succession is initiated due to biological factors or other external factors acting on completely bare substrate, whereas secondary succession starts due to external disturbances in areas that already have established soil. In primary succession, no soil exists initially and must develop over time, while in secondary succession, soil cover is already present from the previous ecosystem. Pioneer species in primary succession come from outside the environment through dispersal mechanisms, whereas pioneer species in secondary succession develop from existing seeds, roots, or organisms already present in the soil. Primary succession takes considerably more time to complete because it must begin from bare rock or substrate and build soil while establishing vegetation, often requiring hundreds of years. Secondary succession takes comparatively less time to complete because the soil is already established and seeds or vegetative propagules are present, allowing faster recolonization and community reassembly, typically requiring decades rather than centuries.
The type of succession is hydrosere. It includes the following stages.
* Phytoplankton stage
* Submerged plant stage
* Submerged free floating stage
* Reed-swamp stage
* Marsh rnedow stage
* Shr ub stage
* Forest stage
1. Phytoplankton stage:
It is the first stage of succession consisting of the pioneer community like blue green algae, green algae, diatoms, bacteria, etc., The colonization of these organisms enrich the amount of organic matter and nutrients of pond due to their life activities and death. This favours the development of the next serai stages.
2. Submerged plant stage:
As the result of death and decomposition of planktons, silt brought from land by rain water, lead to a loose mud formation at the bottom of the pond. Hence, the rooted submerged hydrophytes begin to appear on the new substratum. Example: Chara, Utricularia. The death and decay of these plants will build up the substratum of pond to become shallow. Therefore, this habitat now replaces another group of plants which are of floating type.
3. Submerged free floating stage:
During this stage, the depth of the pond will become almost 2-5 feet. Hence, the rooted hydrophytic plants and with floating large leaves start colonising the pond. Example: Rooted floating plants like Nelumbo, Nymphaea and Trapa. By death and decomposition of these plants, further the pond becomes more shallow. Due to this reason, floating plant species is gradually replaced by another species which makes new serai stage.
4. Reed-swamp stage:
It is also called an amphibious stage. During this stage, rooted floating plants are replaced by plants which can live successfully in aquatic as well as aerial environment. Example: Typha
5. Marsh meadow stage:
When the pond becomes swallowed due to decreasing water level, species of Cyperaceae and Poaceae. They form a mat-like vegetation with the help of their much branched root system. This leads to an absorption and loss of large quantity of water. At the end of this stage, the soil becomes dry and the marshy vegetation disappears gradually and leads to shurb stage.
6. Shrub stage:
As the disappearance of marshy vegetation continues, soil becomes dry. Hence, these areas are now invaded by terrestrial plants like shrubs (Salix and Cornus) and trees (Populus and Alnus). These plants absorb large quantity of water and make the habitat dry. Further, the accumulation of humus with a rich flora of microorganisms produce minerals in the soil, ultimately favouring the arrival of new tree species in the area.
7. Forest stage:
It is the climax community of hydrosere. A variety of trees invade the area and develop any one of the diverse type of vegetation. Example: Temperate mixed forest 207
Significance of Plant Succession:
* Succession is a dynamic process. Hence an ecologist can access and study the serai stages of a plant community found in a particular area.
* The knowledge of ecological succession helps to understand the controlled growth of one or more species in a forest.
* Utilizing the knowledge of succession, even dams can be protected by preventing siltation
* It gives information about the techniques to be used during reforestation and afforestation.
* It helps in the maintenance of pastures.
* Plant succession helps to maintain species diversity in an ecosystem.
* Patterns of diversity during succession are influenced by resource availability and disturbance by various factors.
* Primary succession involves the colonization of habitat of an area devoid of life.
* Secondary succession involves the reestablishment of a plant community in disturbed area or habitat.
* Forests and vegetation that we come across all over the world are the result of plant succession.
The carbon cycle describes the continuous circulation and exchange of carbon atoms between the Earth's atmosphere, oceans, land, and living organisms. It involves processes such as photosynthesis, respiration, decomposition, combustion, and geological processes that move carbon between different reservoirs. Photosynthesis by plants removes carbon dioxide from the atmosphere, incorporating it into organic matter. Respiration by plants and animals releases carbon dioxide back into the atmosphere. Decomposition of dead organic matter also returns carbon to the soil and atmosphere. The burning of fossil fuels and biomass releases large amounts of carbon into the atmosphere, significantly impacting the cycle.