Threats to Biodiversity

Question 1

what is the main threat to biodiversity?

Answer 1

• combination of growth of the human population and the exploitation of resources

Question 2

habitat loss

Answer 2

• species die when ecosystems are replaced
  Example:
• Sumatra contains 2/3 of the orangutang species, 3rd on Borneo, all critically endangered, Sumatran Tiger and Asian Elephant which are endangered
• Sumatran forests are cleared for timber and palm oil plantations

Question 3

overharvesting

Answer 3

• specifically threatens marine and freshwater species
• Atlantic Cod vulnerable due to trawling
• tragedy of the commons - oceans are neutral ground, fair game for harvesting
• whales reproduce slowly, at risk of endangerment and extinction
• sharks, groupers, coral reefs damaged
• pet trade and hunting is cause for concern

Question 4

Invasive and Exotic Species

Answer 4

• result of increased trade
• often have a rapid increase, resetting ecological conditions
• Asian carp in American rivers now make up 95% of biomass
• zebra mussels, kudzu vines
• nile perch in lake victoria eating cichlid species

Question 5

Climate Change

Answer 5

• warming due to the greenhouse effect
• melting of artic and sea ice, leads to loss of islands (inundation)
• colder climates shift further to poles
• temp and rain variations effect spacing and phenology (timing of life cycle occurrences)
• warming causes coral to expel zooxanthellae, leads to bleaching and death