- a. Tundra
- b. Taiga
- c. Desert
- d. Oceans
Tundra is the coldest biome with very low temperatures, short growing seasons and permafrost.
a
- a. Ecosystems
- b. Biome
- c. Environment
- d. None of the above
An ecosystem (singular of ecosystems) is the smallest functional unit of the biosphere where organisms interact with each other and their environment.
a
- a. Producers
- b. Decomposers
- c. Consumers
- d. None of the above
Decomposers (bacteria and fungi) break down dead matter and recycle nutrients back into the environment.
b
- a. Saline and sandy
- b. Limited moisture availability
- c. Cold temperature
- d. Humid
Xerophytes are adapted to environments with limited water (dry conditions), having features like thick cuticle, reduced leaves, or succulent stems.
b
- a. because it is too wet.
- b. because the temperature is too warm.
- c. because the soil is too thin.
- d. because the soil is poor.
Rainforest soils are typically poor in nutrients because heavy rainfall leaches minerals from the soil; clearing forests for large-scale agriculture exhausts the thin nutrient layer quickly, making it unsustainable.
d
An estuary (brackish water habitat) occurs where rivers meet the sea and fresh and salt water mix, supporting unique, highly productive communities.
Estuary
Producers (plants, algae, some bacteria) synthesize organic compounds from inorganic sources using sunlight (photosynthesis) or chemical energy, hence called autotrophs.
True
Heterotrophs cannot synthesize organic food and obtain energy by consuming autotrophs or other heterotrophs; therefore R explains why A is true.
Both A and R are true; R correctly explains A.
The biosphere includes multiple ecosystems that change over time due to natural and human-induced factors; it does not imply a single unchanging or uniformly stable ecosystem.
False — Corrected: The biosphere comprises many ecosystems which are dynamic rather than a single stable ecosystem.
Biodiversity hotspots are areas with high endemism and threat; researchers used this concept to prioritise conservation efforts and allocate resources where most needed.
Both A and R are true; R correctly explains A.
An ecosystem is a community of living organisms interacting with each other and with their physical environment.
ecosystem
Consumers (animals and some microbes) obtain organic food by eating producers or other consumers and are therefore called heterotrophs.
Consumers
A food web is a system of interlocking and interdependent food chains showing feeding relationships in an ecosystem.
Food web
A biome is a large ecological community of plants and animals adapted to a particular climate and environment, e.g., desert, tundra, rainforest.
Biome
Desert biomes are dominated by xerophytic vegetation—plants adapted to dry conditions such as cacti, succulents and drought-resistant shrubs with water-conserving features.
Xerophytes (xerophytic vegetation)
It comprises all ecosystems and living organisms along with their interactions with air, water and soil — essentially the global ecological system that supports life.
The biosphere is the zone of Earth where life exists, including parts of the atmosphere, hydrosphere and lithosphere.
It includes biotic components (producers, consumers, decomposers) and abiotic components (light, water, soil, temperature) with interactions that cycle nutrients and transfer energy.
An ecosystem is a functional unit consisting of a community of living organisms and their non-living environment interacting as a system.
Biodiversity (biological diversity) refers to the variety and variability of living organisms, including genetic variation within species, the number of different species, and the variety of ecosystems in which they occur. It underpins ecosystem services and resilience.
Biodiversity is the variety of life at genetic, species and ecosystem levels.
Loss of biodiversity means a reduction in the variety of living organisms and the genetic variation within them; it occurs through species extinction, habitat fragmentation and degradation, invasive species, pollution and overuse of resources, leading to weakened ecosystem functions.
Loss of biodiversity is the decline in number and variety of species, genetic diversity and ecosystems, often due to extinction, habitat destruction, pollution and overexploitation.
Terrestrial biomes are classified by climate and vegetation and include tropical rainforests, tropical deciduous forests, savannas, deserts, temperate grasslands, temperate forests, Mediterranean shrublands, boreal forests (taiga), tundra, and mountain (alpine) regions.
Major terrestrial biomes: tropical rainforest, tropical deciduous/monsoon forest, savanna, desert, temperate grassland, temperate deciduous forest, Mediterranean, taiga (boreal forest), tundra, and alpine/mountain biomes.
Producers (e.g., green plants, algae) perform photosynthesis and form the base of food chains. Decomposers (e.g., bacteria, fungi) decompose dead matter into inorganic nutrients, maintaining nutrient cycles.
Producers make organic food from inorganic materials (autotrophs); decomposers break down dead organisms and recycle nutrients (heterotrophs).
Terrestrial biomes: determined mainly by temperature and rainfall, include forests, tundra, deserts. Aquatic biomes: include lakes, rivers, estuaries, oceans; factors include salinity, sunlight penetration and water movement.
Terrestrial biomes occur on land (forests, deserts, grasslands) and are classified by vegetation and climate; aquatic biomes occur in water (freshwater, marine) and are classified by salinity, depth and flow.
Tropical vegetation occurs in hot, wet climates (e.g., rainforests) with tall trees, a closed canopy, rich biodiversity and thin nutrient-poor soils due to heavy leaching. Desert vegetation consists of drought-resistant (xerophytic) plants with adaptations like reduced leaves, deep roots or water storage to survive very low precipitation and extreme temperatures; soils are often sandy or rocky and low in organic matter.
Tropical vegetation: dense, multilayered forests, high biodiversity, evergreen and deciduous trees, high rainfall and warm temperature. Desert vegetation: sparse, xerophytic plants (cacti, shrubs), low biodiversity, adaptations to conserve water, very low rainfall and extreme temperatures.
Savannas are warm grassland ecosystems with seasonal rainfall, grasses and occasional trees, rich in grazing animals. Tundra is a cold biome near the poles or on mountains, with permafrost, low-growing vegetation, short growing seasons and adapted cold-tolerant species.
Savannas: tropical/subtropical grasslands with scattered trees, distinct wet and dry seasons, moderate rainfall, warm temperatures, found in Africa, Australia, South America. Tundra: cold, treeless biome in high latitudes or altitudes, low temperatures, permafrost, low vegetation (mosses, lichens, dwarf shrubs), low biodiversity.
Biotic components: producers (plants), consumers (herbivores, carnivores, omnivores) and decomposers (fungi, bacteria). Abiotic components: physical and chemical factors like sunlight, climate, water, minerals and soil. Interactions among these components determine productivity, food chains/webs and nutrient recycling.
An ecosystem consists of biotic components (producers, consumers, decomposers) and abiotic components (sunlight, water, air, soil, temperature). These interact through energy flow and nutrient cycles.
Through photosynthesis producers convert solar energy to chemical energy; consumers transfer energy through trophic levels; decomposers recycle nutrients back to the soil. Ecosystems also purify water and air, regulate temperature and hydrological cycles, and provide resources and services vital for humans and other organisms.
Ecosystems provide essential functions such as production of organic matter (primary productivity), nutrient cycling, decomposition, habitat provision, regulation of climate and water, and support for food chains and biodiversity.
Aquatic biomes are categorized by water type (freshwater vs. marine), salinity, depth and flow. Freshwater biomes—rivers, lakes, streams, ponds—support species adapted to low salinity. Marine biomes—oceans, seas—have high salinity and include pelagic zones, benthic zones, and coral reefs. Estuaries are brackish areas where rivers meet the sea and are highly productive. Wetlands (marshes, swamps) are shallow water bodies rich in biodiversity and important for water filtration. Intertidal zones are regularly submerged and exposed, hosting specially adapted organisms. Each biome provides unique ecosystem services and habitats.
Aquatic biomes include freshwater (lakes, rivers, ponds), marine (oceans, seas), estuaries (where fresh and salt water mix), wetlands, coral reefs and intertidal zones; they differ mainly by salinity, depth, flow and nutrient levels and host distinct communities adapted to these conditions.
World Wildlife Day is observed on 3 March each year.
March 3
The International Day of Forests (International Day of Forest) is celebrated on 21 March each year.
March 21
World Water Day is observed on 22 March each year to highlight the importance of freshwater and advocate for sustainable management of water resources.
22 March
Earth Day is observed on 22 April each year to raise awareness about environmental protection.
22 April
World Environment Day is observed on 5 June each year to encourage worldwide awareness and action for environmental protection.
5 June
World Oceans Day is observed on 8 June each year to raise awareness of the role of the oceans in our ecosystem and the importance of their conservation.
8 June
Prairies (temperate grasslands) are mainly in the Great Plains of North America (from central Canada through the central USA). On a world outline map, mark central North America (between the Rocky Mountains and the Mississippi River).
Mark the central North American plain (Great Plains) — central USA and southern Canada.
The Downs (e.g., South Downs, North Downs) are chalk hills in southern England. On a world outline map, indicate southern England (coastal area south of London and east to West Sussex/Eastbourne for the South Downs).
Mark southern England (the South Downs along the English Channel coast).
On a world map mark a broad band north of the Arctic Circle across northern North America (northern Canada, Alaska, Greenland), northern Europe (Scandinavia), and northern Asia (Siberia). Also indicate alpine tundra on mountain ranges (e.g., Himalayas, Andes) above the tree line.
Tundra biomes are located in high northern latitudes across the Arctic: northern Canada and Alaska, Greenland, northern Scandinavia, and northern Russia/Siberia; alpine tundra occurs on high mountain tops worldwide.
On a world map mark the equatorial rainforest belt: across northern South America (Amazon), central Africa (Congo Basin), and the islands and coastal regions of equatorial Southeast Asia (Borneo, Sumatra, New Guinea, Malaysia, Indonesia).
Equatorial biomes occur in a narrow band along the equator: the Amazon Basin (northern South America), the Congo Basin (central Africa), and equatorial Southeast Asia (Indonesia, Malaysia, Papua New Guinea).
Start with the Sun as the ultimate energy source. Plants and plant-like organisms in the tundra (lichens, grasses, arctic wildflowers) capture solar energy and form the base of the food web (producers). Small herbivores such as lemmings and arctic hares eat lichens and grasses; larger herbivores like caribou and musk ox graze on tundra vegetation. Carnivores (wolves, hawks, and where applicable polar bears) prey on these herbivores — for example, wolves may hunt caribou or hares, hawks may prey on lemmings or young hares, and polar bears may take larger mammals when available. These feeding links form a web (many animals have multiple food sources and predators). When organisms die, decomposers break down the organic matter, returning nutrients to the soil and completing the cycle that sustains the producers. (Reconstructed from the diagram labels: Sun, Lichen, Grasses, Arctic Wildflower, Lemming, Arctic Hare, Caribou, Musk Ox, Wolf, Hawk, Polar Bear.)
Producers (lichen, grasses, arctic wildflower) use sunlight to make food. Primary consumers — lemming, arctic hare, caribou, musk ox — feed on those producers. Predators such as wolf, hawk and polar bear feed on these herbivores (different predators take different herbivores). Energy flows from the Sun → producers → herbivores → carnivores. Decomposers (not shown) recycle nutrients from dead plants and animals back to the soil, supporting the producers.