UPSC MainsZOOLOGY-PAPER-I201910 Marks150 Words
Q16.

Biome.

How to Approach

This question requires a comprehensive understanding of biomes – their definition, characteristics, types, and global distribution. The answer should begin with a clear definition of a biome, followed by a discussion of the major biome types, highlighting their key features (climate, vegetation, fauna). A structured approach, categorizing biomes based on dominant vegetation or climate, is recommended. Mentioning the factors influencing biome distribution (temperature, precipitation, altitude) will add value. Focus on providing a holistic overview rather than exhaustive detail for each biome.

Model Answer

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Introduction

A biome is a large geographic area characterized by specific climate conditions, animal populations, and plant life. These communities of plants and animals have adapted to the particular environment, creating a distinct ecosystem. Biomes are crucial for understanding global biodiversity patterns and the interconnectedness of life on Earth. The distribution of biomes is not uniform; they are influenced by factors like latitude, altitude, rainfall, and soil type. Understanding biomes is increasingly important in the context of climate change and its impact on ecosystems worldwide.

Defining Biomes and Influencing Factors

Biomes represent a synthesis of climate, terrain, and organisms. They are broader than ecosystems, encompassing multiple ecosystems within a single region. The primary factors determining biome distribution are:

  • Temperature: A major determinant, influencing metabolic rates and species distribution.
  • Precipitation: The amount and seasonality of rainfall dictate vegetation types.
  • Altitude: Changes in altitude mimic changes in latitude, creating altitudinal biomes.
  • Soil Type: Soil composition affects nutrient availability and plant growth.
  • Sunlight: Intensity and duration of sunlight influence photosynthetic rates.

Major Biome Types

1. Terrestrial Biomes

These are land-based biomes, categorized by dominant vegetation:

  • Forest Biomes:
    • Tropical Rainforests: High rainfall, high biodiversity (e.g., Amazon, Congo).
    • Temperate Deciduous Forests: Moderate rainfall, seasonal temperature changes, trees that lose leaves annually (e.g., Eastern North America, Western Europe).
    • Boreal Forests (Taiga): Long, cold winters, coniferous trees (e.g., Canada, Russia).
  • Grassland Biomes:
    • Savannas: Tropical grasslands with scattered trees (e.g., African Savanna).
    • Temperate Grasslands (Prairies, Steppes): Moderate rainfall, fertile soils (e.g., Great Plains of North America, Eurasian Steppe).
  • Desert Biomes: Low rainfall, extreme temperatures, specialized plant and animal adaptations (e.g., Sahara, Mojave).
  • Tundra Biomes: Permafrost, low-growing vegetation, cold temperatures (e.g., Arctic Tundra).

2. Aquatic Biomes

These are water-based biomes:

  • Freshwater Biomes: Rivers, lakes, ponds, wetlands. Characterized by low salt concentration.
  • Marine Biomes: Oceans, coral reefs, estuaries. Characterized by high salt concentration.

Biome Distribution – A Global Perspective

Biome Climate Vegetation Geographical Location
Tropical Rainforest Hot & Humid Dense forests, broadleaf trees Amazon Basin, Congo Basin, Southeast Asia
Desert Hot & Dry Cacti, shrubs, sparse vegetation Sahara, Arabian Desert, Australian Outback
Tundra Cold & Dry Mosses, lichens, dwarf shrubs Arctic regions, high mountains
Temperate Deciduous Forest Moderate, seasonal Deciduous trees (oak, maple) Eastern North America, Western Europe

Conclusion

Biomes are fundamental units in ecological studies, providing a framework for understanding the distribution of life on Earth. Their characteristics are shaped by complex interactions between climate, geography, and biological factors. The increasing threat of climate change and habitat destruction poses a significant risk to biome integrity, potentially leading to biodiversity loss and ecosystem disruption. Conservation efforts focused on preserving biome diversity are crucial for maintaining the health of our planet and ensuring the sustainability of ecological processes.

Answer Length

This is a comprehensive model answer for learning purposes and may exceed the word limit. In the exam, always adhere to the prescribed word count.

Additional Resources

Key Definitions

Ecotone
A transitional zone between two biomes, exhibiting characteristics of both.
Climax Community
The stable, final stage of ecological succession in a biome, representing the most complex and resilient community.

Key Statistics

Approximately 60% of the world’s terrestrial surface is covered by just five major biomes: forests, grasslands, deserts, tundra, and savannas.

Source: WWF (as of 2023 knowledge cutoff)

The world has lost approximately 420 million hectares of forest since 1990, equivalent to an area larger than the European Union.

Source: Food and Agriculture Organization of the United Nations (FAO), 2020

Examples

Coral Reefs

Coral reefs, found in tropical marine biomes, are among the most biodiverse ecosystems on Earth, supporting approximately 25% of all marine life.

Frequently Asked Questions

How does altitude affect biome distribution?

As altitude increases, temperature decreases and precipitation often increases. This creates conditions similar to those found at higher latitudes, leading to altitudinal zonation of biomes (e.g., forests at lower elevations, alpine tundra at higher elevations).

Topics Covered

Environmental ScienceEcologyBiome, Ecosystems, Terrestrial Biomes, Aquatic Biomes