Habitat destruction
Habitat destruction
- Biodiversity is the number of different species in an area.
- Humans destroy habitats (where organisms live) by:
- clearing land for housing, crops and livestock,
- extracting resources (e.g. mining),
- pollution of fresh water and the sea.
- This changes food webs and harms habitats.
Practice
Biodiversity means:
Biodiversity is the variety of different species living in an area.
Deforestation
- Deforestation (cutting down forests) causes:
- lower biodiversity and the extinction of species,
- loss of soil (no roots to hold it, so it washes away),
- more flooding,
- more carbon dioxide in the air (fewer trees to take it in).
Practice
Deforestation can cause which problems? (Choose all that apply.)
Removing trees loses soil, increases flooding and adds carbon dioxide; biodiversity falls, not rises.
Practice
Without tree roots to hold it, soil is washed away after deforestation.
Tree roots bind the soil; once the trees are gone, rain washes the soil away.
You've got it
Key idea
- biodiversity = number of species; habitats are destroyed by clearing land, mining and pollution
- deforestation → lower biodiversity, extinction, soil loss, flooding, more carbon dioxide
- damaging food webs harms whole ecosystems