3.8 - threats to biodiversity

• Define bottleneck effect

  Small populations lose the genetic variation necessary to enable evolutionary responses to environmental change
• why can loss of genetic diversity be critical ?

  inbreeding can result in poor reproductive rates
• how can degradation of edges of habitat fragments result in decreased biodiversity?

  increased competition between species
• how can isolated fragments of habitat be linked?

  habitat corridors
• benefit of a habitat corridor?

  allows movement of animals between fragments increasing their access to food and a mate
• what is an introduced species?

  humans have moved intentionally or accidentally to new geographical locations
• define naturalised species?

  species that become established within wild communties
• define invasive species?

  naturalised species that spread rapidly and eliminate native species therefore reducing species diversity
• In biodiversity, what term describes human activity that can reduce populations to low levels?

  overexploitation