Environmental Science: Ecosystem Ecology
Introduction to Ecosystems
- Definition: Ecosystems are large areas containing both living (biotic) and non-living (abiotic) materials.
- Example: Giant kelp forests.
- Producers: Kelp converting sunlight into food.
- Herbivores: Sea urchins feeding on kelp.
- Carnivores: Sea otters feeding on sea urchins.
Importance of Keystone Species
- Definition: Species that have a disproportionately large effect on their ecosystem.
- Example: Sea otters in kelp forests.
- Impact: Removal of sea otters can lead to an increase in sea urchin populations, creating urchin barrens and disrupting the ecosystem.
Levels of Organization in Ecology
- Individual: Single organism, e.g., a sea urchin.
- Population: All individuals of a species in an area.
- Community: All populations in a specific area.
- Ecosystem: Community plus abiotic factors.
- Biomes: Larger areas defined by climate and habitat.
- Biosphere: The global sum of all ecosystems.
Terrestrial and Aquatic Biomes
Terrestrial Biomes
- Determinants: Average temperature and precipitation.
- Examples:
- Tropical rainforest (hot and moist).
- Savannah (hot with less precipitation).
- Deserts, forests, grasslands, tundra, etc.
Aquatic Biomes
- Determinants: Salinity, depth, and flow of water.
- Examples:
- Freshwater: Wetlands.
- Saltwater: Coral reefs, open oceans.
Ecosystem Interactions
Food Chains and Webs
- Producers: Organisms like plants and algae that create food through photosynthesis.
- Consumers:
- Herbivores: Eat plants only.
- Carnivores: Eat other animals.
- Omnivores: Eat both plants and animals.
- Food Chain: Shows direct feeding relationships.
- Arrow Direction: From food source to consumer.
- Food Web: Interconnected food chains in an ecosystem.
Decomposers
- Role: Recycle nutrients by breaking down dead material.
- Examples: Detrivores eat large amounts of decaying material.
Niche and Species Interaction
Niche
- Definition: The role or job of an individual in an ecosystem.
- Examples:
- Squirrels have temperature ranges for survival and reproduction.
- Dung beetles use dung as a food source.
Species Diversity and Adaptation
- Importance: High diversity contributes to ecosystem resilience.
Generalists vs. Specialists:
- Generalists: Raccoons that have broad diets and habitat needs.
- Specialists: Koalas that have specific dietary requirements.
Edge Effects
- Definition: Transitional areas between different ecosystems.
- Impact:
- Natural Edges: Can support diverse species.
- Human-Created Edges: Roads and trails can be detrimental.
- Protection Strategy: Larger protected areas with natural edges are more beneficial.
Summary
- Ecosystem organization from individuals to biomes.
- Interactions among producers, consumers, and decomposers.
- Role and impact of keystone species and niches.
- Importance of diversity and edge effects on ecosystem health.
This summary captures the key elements of ecosystem ecology, emphasizing the interconnectedness of organisms and their environments.