Extinction

Extinction

What is extinction?

Extinction:

• A species is extinct if no members of that 

  species are still alive.

• Most organisms that have ever lived on Earth are now extinct.

Natural and Man Made Factors that lead to extinction

Natural Factors

• Natural extinction have occurred throughout geologic history.

• Organisms that could not survive changes due to volcanic eruptions and global warming, global cooling during ice ages, changes in oxygen levels in seawater, or a massive impact from an asteroid or comet became extinct.

• Not all have been necessarily negative in that extinction often clear the way for new kinds of life.

Man-Made Factors

• Man-made factors have caused extinctions in more recent times, such as the cutting of the rainforest regions, removing natural habitats, over-harvesting, and pollution.

Scientists have evidence to support claims that...

• humans have contributed to the extinction of many species throughout human history, including the woolly mammoth. 

• many plants and animals are likely to become extinct in the near future as a result of the negative impact of human activities (clear-cutting, water and air pollution, etc.) on the environment.

• human effects on the environment could threaten some biological resources that organisms, including humans, may need for survival.

Multiple Choice

Which of these reasons for extinction are man-made?

• global warming

• global cooling during ice ages

• air pollution

• changes in oxygen levels in seawater

Multiple Select

Which of these reasons for extinction are not man-made?

• global warming

• global cooling during ice ages

• air pollution

• changes in oxygen levels in seawater