A man was walking along a deserted beach at sunset. As he walked he could see a young boy in the distance, as he drew nearer he noticed that the boy kept bending down, picking something up and throwing it into the water. Time and again he kept hurling

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• A man was walking along a deserted beach at
  sunset. As he walked he could see a young boy in
  the distance, as he drew nearer he noticed that
  the boy kept bending down, picking something up
  and throwing it into the water.Time and again he
  kept hurling things into the ocean.
• As the man approached even closer, he was able to
  see that the boy was picking up starfish that had
  been washed up on the beach and, one at a time he
  was throwing them back into the water.
• The man asked the boy what he was doing, the boy
  replied, "I am throwing these washed up starfish
  back into the ocean, or else they will die
  through lack of oxygen.
• "But", said the man, "You can't possibly save
  them all, there are thousands on this beach, and
  this must be happening on hundreds of beaches
  along the coast. You can't possibly make a
  difference."The boy looked down, frowning for a
  moment then bent down to pick up another
  starfish, smiling as he threw it back into the
  sea. He replied, "It makes a huge difference to
  this one!"
• ?

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Species at Risk

• You dont have to copy down notes that are in
  italics

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• What is a habitat?
• The space that a species needs to live and grow
• Food
• Water
• Living space
• Shelter

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• Species at Risk
• An organism that is at the risk of extinction due
  to threats caused by humans
• There are 4 types of species at risk
• Special concern
• Threatened
• Endangered
• Extirpated
• And Extinct, though this is not at risk anymore.

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Special Concern

• A species that may become threatened or
  endangered because of a combination of biological
  characteristics and identified threats
• Eg. Polar bear global warming causes Arctic ice
  to melt (calving)

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Threatened

• A species that may become endangered unless
  actions are taken to reverse the factors reducing
  its population
• Eg. Humpback whale commercial hunting/fishing,
  collisions with ships, lack of food

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Endangered

• A species at imminent threat of extinction
• Swift fox loss of habitat in the prairies,
  poisoned, trapped

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Extirpated

• Extinct in certain regions but exist in other
  parts of the world
• Eg. paddlefish destruction/blockage of spawning
  grounds, pollution, overexploitation

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Extinct

• Well, you know not found anywhere on Earth
  anymore
• Eg. passenger pigeon-- overexploitation, loss of
  habitat with disappearing deciduous forests
• Its actually stuffed ?

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The Importance of All Species

• The disappearance or decrease of a species will
  effect many other species (up to 30) within their
  ecosystem
• Think of a scale if one side has more mass, its
  unbalanced. Nature will always try to reach an
  equilibrium, but a disturbance can cause it to
  fluctuate again. Now think of a 1000-sided scale.
• With more biodiversity though, the populations
  will return to its original balance faster as
  there are more species to counteract the
  disturbance

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• For example, in a simple food chain like this,
  one change can affect every other species. Say
  humans started sport hunting hawks
• Hawk population decreases
• Snake population increases
• Mouse population decreases
• Grasshopper population increases

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Home(CLASS)work

• Pg. 85-86 6, 7, 8