Unit 3, AOS1, Topic 10: Threats to Biodiversity

Outline Modification as a threat to biodiversity

Changes in local environmental conditions, from natural or human-induced events, result in physical changes to an ecosystem

Outline Degradation as a threat to biodiversity

A reduction in the quality of a habitat

Outline Habitat Loss and Fragmentation as a threat to biodiversity

The fragmentation of habitats resulting in seperation of populations and the increased vulnerability of the fragmented species

Outline Over-exploitation as a threat to biodiversity

The use of resources faster than they can be replenished, impacting food webs and the broader ecosystem

Outline Inbreeding as a threat to biodiversity

Fragmented, isolated or reduced populations have an increased chance of homozygous young expressing undesirable inherited traits

Outline Loss of Critical Species as a threat to biodiversity

Loss of keystone species can result in the loss of dependent species and the restructuring of their ecosystems

Outline Biological Pollutants as a threat to biodiversity

Bioaccumulation - pollutants accumulate within an organism

Biomagnification - pollutant concentrations in organisms increase up the food chain

Outline Climate Change as a threat to biodiversity

Climate change exacerbates extreme and unpredictable weather events, changes ecosystem conditions and pushes species away from the equator as temperatures rise

Outline Disease as a threat to biodiversity

Deadlier diseases cause bottlenecks in genetics (sudden significant reductions in population size) or remove populations. They can effect multiple species.

Outline Introduced Species as a threat to biodiversity

Once successful, they are extremely hard to remove and can:

- spread foreign disease

- increase pressure on niches

- restructuring of trophic levels

- have damaging defensive strategies (eg. cane toad)

- even collapse ecosystems

CHALLENGE: Recall 10 threats to biodiversity

- Modification

- Degradation

- Habitat Loss and Fragmentation

- Over-exploitation

- Inbreeding

- Loss of Critical Species

- Biological Pollutants

- Climate Change

- Disease

- Introduced Species