The Importance of Biodiversity (CIE IGCSE Biology)
Revision Note
Author
PhilExpertise
Biology Project Lead
Human Pressures on Other Species
Biodiversity
- Is defined as the number of different species that live in a particular area
- Human activities have tended to force biodiversity downwards, whereas, high biodiversity is needed for stable ecosystems
- Habitat destruction by humans is a major downward pressure on biodiversity
Reasons for Habitat Destruction
- The increasing human population of the planet is causing destruction of many habitats from rainforest to woodland to marine
- Many habitats are destroyed by humans to make space for other economic activities, or by pollution from these activities, and this reduces the biodiversity of these areas
- This interrupts food chains and webs, meaning that more species may die because their prey is gone
- The main reasons for habitat destruction include:
Deforestation
- Deforestation is the clearing of trees (usually on a large scale)
- If trees are replaced by replanting it can be a sustainable practise
- Generally the trees are being cleared for the land to be used in a different way (for building, grazing for cattle, planting of monocultures such as palm oil plantations etc) and therefore it is not sustainable
- As the amount of the Earth’s surface covered by trees decreases, it causes increasingly negative effects on the environment and is a particularly severe example of habitat destruction
- Undesirable effects of deforestation include:
- Extinction of species
- Loss of soil
- Flooding
- Increase of carbon dioxide in the atmosphere
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