BRAINCAKEChanging Biodiversity
Biodiversity is not fixed. It changes over time as a result of natural events and, today, mainly because of human activities. Current rates of extinction are thought to be many times higher than natural background rates.
Human activities that reduce biodiversity
1. Habitat loss and fragmentation: clearing forests, draining wetlands and building roads and towns. This is the biggest single cause of biodiversity loss. Small, separated fragments of habitat support small populations, which lose genetic diversity and are more likely to die out.
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Key terms in this lesson
- index of diversity
- A single number that measures the biodiversity of a habitat, taking into account both species richness and the abundance of each species.
- habitat fragmentation
- The breaking up of a large habitat into smaller, separated patches, often by human land use.
More in Biodiversity
- Endemic Species
- Species Abundance
- Index of Diversity
- Biodiversity of Different Habitats
- Allele Frequency
- Measuring Genetic Biodiversity
- Hawaii
- Ethical Argument for Biodiversity
All 22 lessons in Biodiversity · All Edexcel AS-level Biology topics