The Sixth Extinction? Topic Seven

-ltUIsnrQ -ltUIsnrQ Facing the Sixth Extinction

Changing Biodiversity Biodiversity is rapidly decreasing. The rate of extinction is approximately 70 species per day. The amounts of species that are forming isn’t even close to the amounts of species that are dying off.

Extinction Definition: The disappearance of every individual of a species from the entire planet Reduces biodiversity Example: The dodo bird. It had no predators until the Portuguese explorers brought cats, rats, dogs and pigs who ate the bird.

Extirpation Definition: The local extinction, or the disappearance of a species from a particular area. Reduces biodiversity Example: Grizzly bears have been extirpated from the prairies. They are now only found in wooded areas.

Causes of Extinction and Extirpation Natural causes: – Volcanic eruptions – Floods – Fires – Disease – Overspecialization (needs are too specific) – Lack of food due to overpopulation Mass extinction happens over a short period of time and is usually caused by catastrophic events.

Causes of Extinction and Extirpation Human causes: – Habitat destruction – Introduction of non-native species – Over-hunting – Short-term extinction happens over a long period of time and is usually caused by new inhabitants or changes in the environment.

Endangered and Threatened Animals Endangered Animals – Animals that are in immediate danger of extinction or extirpation. – Example: Swift fox who was once common in Alberta Threatened Animals – Species that are likely to become endangered if their current declines are not reversed. – Example: Wood bison and the woodland caribou of Alberta

Human Impacts on Biodiversity 1.Increasing population – Through better food and increase medical knowledge, the population is living longer and expanding. – This causes a demand for housing, logging, mining, farming

1.Not watching our footprint – We’re very quick to decide that what we do doesn’t matter in the scheme of things, so we don’t watch how we live our lives very carefully – By only thinking of ourselves, biodiversity is rapidly decreasing.

Impacts can be seen by looking at indicator species. By looking at the presence or the absence of certain species, like tree frogs and grizzly bears, we can judge the overall health of the area. pets-kids/amphibians-kids/frog-leopard-kids / pets-kids/amphibians-kids/frog-leopard-kids /

VA&feature=c4-overview- vl&list=PLJicmE8fK0Eh88ix1co6RG4pDcRjpaPj 4 Disappearing frogs - Kerry M. Kriger VA&feature=c4-overview- vl&list=PLJicmE8fK0Eh88ix1co6RG4pDcRjpaPj 4 ds/animals-pets-kids/amphibians-kids/frog- leopard-kids/ ds/animals-pets-kids/amphibians-kids/frog- leopard-kids/

Review Questions 1.Name 5 ways in which humans have had an impact on biodiversity in your location? 2.In general, there is more biodiversity in the bird life in the tropics than in the North. Why has Hawaii lost at least 50 species of birds in the last several years? 3.Does your daily life affect biodiversity on the planet? Explain your answer.