Notes on Ecosystems, Biomes, and Trophic Levels

Introduction to Ecosystems

  • Ecology:

    • Originates from Greek words: oikos (house/place to live) and logos (study of).

    • Focuses on interactions between organisms and their environments (biotic and abiotic).

Components of an Ecosystem

  • Abiotic Factors: Nonliving components (water, air, nutrients, rocks, heat, solar energy).

  • Biotic Factors: Living components (plants, animals, microbes, waste products).

Levels of Organization in Ecology

  1. Biosphere: Global ecosystem with all life interactions.

  2. Ecosystem: Community of species interacting biotically and with abiotic factors.

  3. Community: Different species populations in a particular area.

  4. Population: Individuals of the same species in the same area.

  5. Organism: Individual living being.

Types of Ecosystems

  • Natural Ecosystems: E.g., oceans, forests, lakes.

  • Artificial Ecosystems: E.g., crop fields, urban parks.

Biomes Classification

  • Terrestrial Biomes: Include tundra, taiga, temperate forests, grasslands, chaparral, deserts, and tropical rainforests.

  • Aquatic Biomes: Include marine environments (oceans, coral reefs, estuaries) and freshwater environments (lakes, rivers, wetlands).

Terrestrial Biomes Breakdown

  • Tundra:

    • Location: Arctic regions.

    • Climate: Cold, low precipitation.

    • Vegetation: Mosses, lichens, dwarf shrubs.

    • Biodiversity: Limited (e.g., caribou, arctic foxes).

  • Taiga:

    • Location: Northern North America.

    • Climate: Cold, moderate precipitation (mostly snow).

    • Vegetation: Coniferous trees (pines, spruces).

    • Biodiversity: Species adapted to cold (moose, bears).

  • Temperate Forests:

    • Location: Eastern North America.

    • Climate: Moderate temperatures, high precipitation.

    • Vegetation: Deciduous and coniferous trees.

    • Biodiversity: Rich (deer, bears, various bird species).

  • Grasslands:

    • Location: Central North America, Eurasia.

    • Climate: Moderate rainfall and distinct seasons.

    • Vegetation: Dominated by grasses, few trees.

    • Biodiversity: Herbivores (bison), predators (wolves).

  • Chaparral:

    • Location: Coastal regions (Mediterranean climates).

    • Climate: Mild, wet winters and hot, dry summers.

    • Vegetation: Shrubs, small trees.

    • Biodiversity: Various birds and mammals.

  • Deserts:

    • Location: Found globally.

    • Climate: Extreme temperature variations, low moisture.

    • Vegetation: Sparse, adapted to conserve water.

    • Biodiversity: Reptiles, rodents, various insects.

  • Tropical Rainforest:

    • Location: Equatorial regions.

    • Climate: Warm, high rainfall.

    • Vegetation: Dense, multi-layered forests.

    • Biodiversity: Extremely high (numerous species).

Aquatic Biomes Features

  • Marine Biomes: Cover 71% of Earth, include coral reefs – rich in biodiversity; estuaries where fresh and saltwater mix.

  • Freshwater Biomes: Include lakes, ponds, rivers, streams, wetlands – have varying chemical compositions.

Ecosystem Dynamics

  • Trophic Levels: Each organism's role within the food chain.

    • Producers: Autotrophs (e.g., photosynthesis).

    • Primary Consumers: Herbivores.

    • Secondary Consumers: Carnivores.

    • Decomposers: Break down dead organic material.

Food Chains and Webs

  • Food Chain: Linear sequence showing energy flow (e.g., Grass → Deer → Lion).

  • Food Web: Complex interactions between multiple food chains illustrating energy transfer.

Example Food Chains

  • 3-Step: Grass → Insect → Frog

  • 5-Step: Grass → Insect → Frog → Snake → Eagle

Energy Transfer in Trophic Levels

  • Energy decreases (10%) at each trophic transfer; minimal energy left after multiple organisms in the chain.

  • Humans, being omnivores, can occupy various trophic levels, affecting the chain's balance.

Human Impact on Ecosystems

  • Human activities can shorten food chains, disrupt food webs, and impact biodiversity. Example: Removal of top predators alters community dynamics.