Transcript The Sixth Extinction? - Calgary Christian School

The Sixth Extinction?
Topic Seven
http://www.youtube.com/watch?v=eY
-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:
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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.
• http://video.nationalgeographic.com/video/kids/animalspets-kids/amphibians-kids/frog-leopard-kids/
• http://www.youtube.com/watch?v=NvP6j4Dj0
VA&feature=c4-overviewvl&list=PLJicmE8fK0Eh88ix1co6RG4pDcRjpaPj
4
Disappearing frogs - Kerry M. Kriger
• http://video.nationalgeographic.com/video/ki
ds/animals-pets-kids/amphibians-kids/frogleopard-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.