Environmental Science Unit I

Environment and Ecosystems

• The environment encompasses physical, chemical, and biological systems, motivating a multidisciplinary approach to study ecosystems.
• Ecosystems contain both living (biotic) and non-living (abiotic) components that interact to sustain life.
• Structure of ecosystems includes producers (like plants), consumers (herbivores, carnivores), and decomposers (fungi, bacteria).
• Energy flows through ecosystems in a unidirectional manner; only about 10% is passed along trophic levels.
• Ecological succession refers to the sequential changes in community structure until a stable ecosystem forms.

Types of Ecosystems

• Forest Ecosystems: Diverse habitats with trees providing shade and habitat for various species.
• Grassland Ecosystems: Dominated by grasses, they exist in regions with insufficient rainfall for tree growth.
• Desert Ecosystems: Characterized by low rainfall and extreme temperatures, home to specially adapted plants and animals.
• Aquatic Ecosystems: Include various freshwater (ponds, lakes) and marine (oceans, estuaries) environments with rich biodiversity.

Biodiversity and Conservation

• Biodiversity is crucial for ecosystem functioning and resilience; it entails the variety of living beings and their habitats.
• Conservation methods include both in-situ (protecting species in their natural habitats) and ex-situ (preserving species in captivity).
• The International Union for Conservation of Nature (IUCN) maintains categories of species based on their extinction risk, from "Least Concern" to "Extinct."

Ecological Principles

• Homeostasis refers to biological systems' tendency to maintain equilibrium despite changes in the environment.
• Limiting factors (like water, nutrients) play a crucial role in the productivity of ecosystems.
• First law of thermodynamics highlights energy conservation, whereas the second law indicates energy transformation leads to increased entropy.

Food Webs and Chains

• Food chains represent linear energy transfer, while food webs illustrate complex interconnections among different organisms.
• Each ecosystem plays vital roles, such as nutrient retention, climate regulation, and supporting biodiversity.

Threats to Biodiversity

• Major threats include habitat destruction, pollution, climate change, and introduction of invasive species.
• Human activities accelerate species extinction rates, impacting ecosystem stability and resilience.

Extinction Categories

• Extinction categories defined by IUCN include:
  • Extinct: No remaining individuals.
  • Endangered: High risk of extinction, significant population decline.
  • Vulnerable: High risk of endangerment in the wild.

Public Awareness and Policy

• Public engagement is critical for effective climate change adaptation and sustainability practices.
• Communities must be educated on environmental risks and how they can contribute to resilience-building actions.

Ecosystem Services

• Ecosystems provide essential services such as water purification, flood control, and climate regulation.
• Anthropogenic effects include pollution and habitat degradation, necessitating awareness and intervention strategies.

Conservation Strategies

• In-situ methods focus on protecting ecosystems and promoting sustainable resource usage, including protected areas and wildlife corridors.
• Ex-situ methods involve preserving biodiversity through gene banks, botanical gardens, and zoological institutions.