Life On Earth Flashcards
(13 cards)
What is biodiversity?
The term used to describe the variety of species present in an ecosystem.
What is a habitat?
The place where an organism lives
e.g. A pond, soil, leaf litter, rock pool
What is population?
The total number of organisms of one species that live in a particular habitat
e.g. The number of red deer on a moorland
What is a community?
All the different populations of organisms living in a habitat
What is an ecosystem?
All the organisms living in a particular habitat and the non-living components with which the organisms interact
What affects a biodiversity?
- Abiotic Factors
- Biotic Factors
- Human Activities
What are abiotic factors?
Non-living, physical factors that affect organisms
e.g pH, temperature, light intensity, moisture, oxygen availability, wind speed, humidity
What are biotic factors
These are related directly to living organisms
e.g. Grazing, predation, disease, competition for food and space
How does human activity affect biodiversity?
They influence both abiotic such as pH and temperature and biotic factors including grazing and predation, which affects organisms within an ecosystem
Give examples of habitat destruction and how they affect biodiversity
Clearing of tropical rainforests (deforestation)
- Complete removal of biodiversity from an area, leading to climate change
Overgrazing of grassland by cattle
- Loss of biodiversity, leading to soil erosion and desertification
Give examples of pollution and how they affect biodiversity
Polluting the atmosphere by burning of fossil fuels
- Loss of lichens and other plants which then affect food chains
Discharging untreated sewage into waterways
- De-oxygenation of water and collapse of food chains
Give examples of hunting and fishing and how they affect biodiversity
Over hunting of game animals
- Extinction of key species and wider effects on many food chains
Overfishing
- Loss of fish stocks and collapse of marine food chains
Give examples of conservation and how they affect biodiversity
Setting up wildlife reserves
- Protects habitats and wild populations, restoring biodiversity
Captive breeding of endangered species
- Increases wild populations through release schemes
