Anne Bjorkman - Global change Flashcards
Climate change and extinction
No extinction to date has definitely been linked to climate changed, although the effect of climate change, such as loss or change of habitat, could lead to lower effective population sizes, and eventually extinction.
Acid rain
Pollution. Greatly affected forests and lake ecosystems. Pollution from factories. Has declined now.
Pesticides
Bad for amphibians and pollinators. Amphibians have very permeable skin, pass chemicals 100x faster than mammals.
How can species respond to climate change?
Phenotypic plasitcity: change within an individual, not genetic.
Evolutionary adaptation: selection over time, genetic.
Migration/dispersal: range shift
Small populations extinction
More likely to expreience genetic drift and inbreeding depression, leading to reduced genetic diversity. There is a greater chance of demographic stochasticity. Extreme weather or similar events can increase the risk of extinction.
Extinction vortex
A diagram showing how small populations lead to extinction.
Sall range extinction
Species that have a small, narrow range are more likely to become extinct.
Long generations extinction
Long generations increase risk of extinction, takes a long time for the species to adapt. Takes a long time to reach maturity, might die before.
Large mammals extienction
Bigger mammals have a higher risk of extinction. Might be because of humans, or because they have a hard time adapting.
Species on islands extienction
They have a hard time dispersing. Small populations. “Naive” prey. True islands and when we create habitat islands.
Specialist vs generalist extinction
Species with highly specialized food or habitat requirements are more at risk of extienction than generalists. Spotted owl, or mutualists.
Cycads
300 million years old, the oldest seed bearing plants on earth. Habitat loss, long time to grow from seed, desired as an ornamental - poaching. The group at a highest risk for extinction globally.
