Biomes as large-scale ecological units defined by vegetation, climate, and geography. Factors influencing biomes: Climate (temperature and precipitation), latitude, altitude, and soil type. Biotic and abiotic components: Interaction between living organisms and their physical environment.

1. BIOMES
(COMMUNITIES ON
A GLOBAL SCALE)
Dr. Vividha Raunekar

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A biome is a large area of the Earth or ocean with a similar
climate, landscape, and plant and animal life
biosphere, relatively thin life-supporting stratum of
Earth's surface, extending from a few kilometres into
the atmosphere to the deep-sea vents of the ocean.
An ecosystem is a community of organisms and their
physical environment interacting together. Environment
involves both living organisms and the non-living physical
conditions.
In ecology, a community is a group or association of
populations of two or more different species occupying the
same geographical area at the same time
A population is a group of the same species living in the
same area.

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Introduction to Biomes
•Definition: Biomes as large-scale ecological units defined by
vegetation, climate, and geography.
•Factors influencing biomes: Climate (temperature and precipitation),
latitude, altitude, and soil type.
•Biotic and abiotic components: Interaction between living organisms
and their physical environment.

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Tropical Rainforests
•Location: Near the equator, including the Amazon
Basin (South America), Congo Basin (Africa), and
Southeast Asia.
•Climate:
• High temperature (20–30°C) year-round.
• High rainfall (over 2000 mm annually).
•Characteristics:
• Dense, multilayered vegetation with a closed
canopy.
• High biodiversity (e.g., jaguars, tucans, orchids,
bromeliads).
•Threats: Deforestation for agriculture, logging, and
urbanization.

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Savannas
•Location: Africa (e.g., Serengeti), South America,
and Australia.
•Climate:
• Warm temperatures (20–30°C).
• Seasonal rainfall (500–1500 mm annually), with
distinct wet and dry seasons.
•Characteristics:
• Grasses dominate, with scattered trees like
acacias and baobabs.
• Large herbivores (e.g., elephants, giraffes) and
predators (e.g., lions, cheetahs).
•Threats: Overgrazing, agriculture, and climate
change.

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Deserts
•Location: Sahara (Africa), Gobi (Asia), Mojave
(North America), Atacama (South America).
•Climate:
• Extreme temperature variations (hot deserts:
30–50°C during the day, cold deserts: below
freezing).
• Low precipitation (less than 250 mm annually).
•Characteristics:
• Sparse vegetation (cacti, succulents).
• Animals adapted to conserve water (e.g.,
camels, fennec foxes).
•Threats: Desertification due to overuse of land and
water resources.

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Temperate Grasslands
•Location: Prairies (North America) Prairies are enormous
stretches of flat grassland with moderate temperatures,
moderate rainfall, and few trees. , steppes (Eurasia), pampas
(South America).
•Climate:
• Moderate temperatures (0–25°C).
• Rainfall ranges from 250–750 mm annually.
•Characteristics:
• Dominated by grasses with few trees.
• Support grazing animals like bison and antelope.
•Threats: Conversion to agricultural land and overgrazing.

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Temperate Deciduous Forests
•Location: Eastern North America, Europe, East Asia.
•Climate:
• Four distinct seasons.
• Moderate rainfall (750–1500 mm annually).
•Characteristics:
• Trees lose leaves in autumn (e.g., oaks,
maples).
• Diverse fauna, including deer, foxes, and
migratory birds.
•Threats: Logging, habitat fragmentation, and urban
sprawl.

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Boreal Forests (Taiga)
•Location: Canada, Russia, Scandinavia.
•Climate:
• Long, cold winters and short, mild summers.
• Moderate precipitation (300–850 mm annually,
mostly as snow).
•Characteristics:
• Evergreen conifers like spruce, fir, and pine.
• Animals adapted to cold (e.g., lynx, moose,
wolves).
•Threats: Logging, mining, and climate change.
Wild elk in boreal forest, Banff National
Park

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Tundra
•Location: Arctic regions (Alaska, Canada, Siberia)
and alpine zones.
•Climate:
• Cold temperatures (-30°C to 10°C).
• Low precipitation (150–250 mm annually).
•Characteristics:
• Permafrost underlies soil, limiting plant growth.
• Mosses, lichens, and low shrubs dominate.
• Fauna includes caribou, arctic foxes, and
polar bears.
•Threats: Melting permafrost, oil exploration, and
habitat loss.

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Mediterranean (Chaparral)
•Location: Mediterranean Basin, California, Chile,
South Africa, Australia.
•Climate:
• Mild, wet winters and hot, dry summers.
• Rainfall ranges from 300–600 mm annually.
•Characteristics:
• Vegetation adapted to drought and fire (e.g.,
shrubs, olive trees).
• Fauna includes small mammals, reptiles, and
birds.
•Threats: Urbanization and wildfires.

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Freshwater Biomes
•Location: Rivers, lakes, wetlands worldwide.
•Characteristics:
• Support diverse aquatic plants, fish and
amphibians.
• Crucial for drinking water, agriculture, and
biodiversity.
•Threats: Pollution, eutrophication, and overfishing.

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Marine Biomes
•Location: Oceans, coral reefs, and estuaries.
•Characteristics:
• Cover 70% of Earth’s surface.
• Coral reefs host immense biodiversity.
• Marine life includes phytoplankton, fish, whales, and sharks.
•Threats: Overfishing, coral bleaching, and ocean acidification.

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Climate and Biome Distribution
Key Points:
•How climate determines biome distribution:
• Role of temperature and precipitation.
• Seasonal variations and their impacts on biodiversity.
•Correlation between latitude, altitude, and biome diversity
(e.g., from equator to poles; from base to summit of
mountains).
Example:
•Comparison of temperate grasslands and tropical
rainforests.

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Human Impacts on Biomes
Key Points:
•Habitat destruction, urbanization, and land-use changes.
•Climate change and its differential impact on biomes
(e.g., coral bleaching in marine systems, tundra thawing).
•Conservation strategies:
• Protected areas (e.g., national parks, marine
reserves).
• Restoration ecology.
Examples:
•Deforestation rates.
•Effects of melting Arctic ice on global sea levels.

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Case Study Analysis:
•Group discussion- Wildfire in Los Angeles

20. THANK YOU