4.03 Threats to Biodiversity

Match

Review: Match each term with the correct definition.

• a species adapted to thrive in a specific habitat

• 
  

  species that have a large impact on their environment relative to their abundance

• species monitored for early warnings that a community or ecosystem is being damaged

• 
  

  a species adapted to thrive in a variety of habitats

specialist species

keystone species

indicator species

generalist species

• 
  specialist species

• keystone species

• 
  indicator species

• 
  generalist species

Extinction Rates

The background extinction rate is the rate at which organisms would naturally be expected to go extinct.
The background extinction rate is 50 to 100 times greater than what is expected by scientists.

The current extinction rate, or number of species that go extinct over a given period of time, is estimated to be 40,000 species per year.

Multiple Choice

What is the difference between the current extinction rate and the background extinction rate?

• The current extinction rate is higher than the background extinction rate due to human activities.

• The current extinction rate is lower than the background extinction rate due to conservation efforts.

• The background extinction rate refers to the natural rate of species loss over time, while the current extinction rate is influenced by sudden events like climate change.

• The background extinction rate is the same as the current extinction rate because both measure species loss.

Multiple Choice

Which of the following describes a species that is likely to become endangered?

• A species that will qualify as vulnerable in the near future.

• A species that only exists in captivity.

• A species that is not a focus of species conservation.

• A species that has declined 30 percent to 50 percent in population over ten years.

Multiple Choice

Which of the following levels of conservation could be used to describe a species that has an abundant population size?

• 
  vulnerable

• endangered

• least concern

• near threatened

Human Impacts on Biodiversity

The major causes of extinction today are:

• habitat destruction

• invasive species

• climate change

• overharvesting

• pollution

Multiple Choice

Which of the following is an example of human activity contributing to extinction?

• Habitat destruction

• Natural selection

• 
  Seasonal changes

• 
  Predation

Multiple Choice

Which of the following statements best describes the primary objective of captive breeding programs in conservation?

• preservation of diversity and species survival

• domestication of wild species

• exhibition in zoos for public entertainment

• 
  exploitation of wildlife for commercial purposes

Multiple Choice

Which of the following human impacts on biodiversity would best be addressed by using habitat restoration practices?

• overfishing in marine ecosystems

• 
  removal of trees from a forest

• 
  ground pollution

• 
  overhunting in terrestrial ecosystems