Unit 9 - Natural Ecosystems & Human Activity

Key Words + Topics

Abiotic Components to an Ecosystem

oxygen, pH levels, humidity, light, water, temperature, salinity

Biotic Interactions to an Ecosystem

competition, pollination, predation

Biotic Component to an Ecosystem

decomposers, producers, primary consumers, secondary consumers, tertiary consumers

Methods to Estimating Biodiversity in Ecosystems

pitfall traps, pooters, quadrats & transects (ACFOR)

Causes of Habitat Loss

1. Drainage of Wetlands

2. Deforestation

3. Intensive Agricultural Practices

Causes of Deforestation

1. Roads & Settlements

2. Subsidence & Commercial Farming

3. Rock & Mineral Extraction

4. Timber Extraction/Logging

Impacts of Habitat Loss

loss of biodiversity, genetic depletion

Impacts of Deforestation

climate change, habitat loss (=> loss of biodiversity & genetic depletion), soil erosion & desertification

Why do we need sustainable management for forests?

1. Because trees are carbon stores (not carbon sinks)

2. Water cycles (transpiration)

3. Prevention of soil erosion (Interception)

4. Biodiversity as a genetic resource

5. Fulfils basic human needs: food, industrial raw materials & medicine

6. Ecotourism (tourism in which the participants travel to see the natural world)

Population

all the organisms of the same species living in a defined area

Community

a group of populations of different species that live together in an area and interact with each other

Trophic Level

a feeding level within a food chain or web

Climax Community

the stable community characteristic of an area that persists as long as the climate does not change

Ecosystem

All the living things (biotic factors) together with all the non-living things (abiotic factors) in an area

Brackish Water

water that is salty but not as salty as seawater

Niche

the role of a species within an ecosystem

Habitat

the place within the ecosystem where an organism lives

Biodiversity

all the species within an ecosystem as well as all the variations within a species (genetic diversity) and the many different ecosystems in an area

Strategies for Conserving Biodiversity & Genetic Diversity in Ecosystems

1. Zoos & Captive Breeding

2. World Biosphere Reserves (core area, buffer zone, transition zone)

3. Extractive Reserves

4. Sustainable Forestry (selective logging, agroforestry, alley cropping)

5. Sustainable Harvesting of Wild Plants and Animal Species

6. National Parks: an area of land protected by the government to preserve entire ecosystems

7. Wildlife Corridors: a link of wildlife habitat, generally native vegetation, which joins 2 of more larger areas of similar wildlife habitats

8. Sustainable Tourism & Ecotourism

9. Wildlife & Ecological Reserves: areas where the focus of management of an area is on the wildlife and ecology

10. Seed Banks

Carbon Cycle

how Carbon is stored, used and released in the environment