Ch. 8: Survival of Species

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Ch. 8 Survival of Species

• Vocabulary
• species, extinct, fossil, reproduce, endangered
  species, habitat, pollutant

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What Is a Species?

• A species is a group of organisms that can
  reproduce with each other and create offspring
  (babies.)
• Animals that are not part of the same species
  cannot have offspring.
• If I were to attempt to mate a cat and a dog,
  they would not produce kittens or puppies.

• ______________

3
Reproduction

• Reproduction occurs when plants or animals make
  more of their own kind.
• Every plant and animal on Earth dies, but a
  species is considered successful if its members
  are able to reproduce.
• If a species is having trouble reproducing, or
  reproduces slowly that species is considered
  endangered.

4
Extinction

• In the last chapter we discussed adaptations.
• Sometimes an ecosystem will change, because of
  climate or the introduction or loss of a new
  plant or animal species.
• If the plants and animals in an ecosystem cannot
  adapt to the new temperatures, plants, or animals
  they will die out.
• If all of a certain type of plant or animal dies,
  that species becomes extinct.
• We know that species have become extinct before,
  because paleontologists have discovered fossils
  of plants and animals that dont exist anymore.

5
Extinction Events

• Sometimes the balance of an ecosystem changes.
• There are many natural causes for this to happen.
• Some of the natural causes are
• Climate Change
• Ecosystem Change
• Flooding
• Predators
• Meteor, Asteroid, or Comet Strike
• Sometimes humans can change their environment and
  cause extinctions.
• Some human-made causes are
• 1. Overhunting
• 2. Habitat Destruction
• 3. Pollution

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Natural Extinction Events

• Climate Change Where the temperature changes
  from warm to cold, or from cold to warm
• It doesnt need to change a lot, a few degrees is
  enough to change the climate of the Earth
  entirely.

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Natural Extinction Events

• Ecosystem Change Jungles change into deserts, or
  forests turn into grasslands.
• Natural forest fires, if the plants are not
  adapted to fire, can cause large tracks of forest
  to burn down and change the ecosystem from a
  forest to a grassland for many years.

8
Natural Extinction Events

• Flooding After land gets flooded, if it does not
  have any place to drain, the plants and animals
  that used to live there cant anymore.
• In the case of a flash flood, a large amount of
  water can inundate an area in a matter of minutes.

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Natural Extinction Events

• Predators When a new species enters an area, it
  can throw an entire ecosystem out of whack.
• Maybe the new animal eats all the prey that the
  lives in the area the old predators will die
  out.
• Maybe someone plants a flower that takes over a
  meadow, choking out all the grasses that used to
  live there.

10
Natural Extinction Events

• Meteor, Asteroid, or Comet Strike It has been
  shown that asteroids and meteors strike the Earth
  very frequently with no ill effects.
• When a large enough asteroid, meteor, or comet
  strikes the Earth, though it can throw up dust
  and dirt into the atmosphere causing climate
  change.
• Paleontologists think this is what happened to
  the dinosaurs.

• Most scientists agree that the Yucatan
  Peninsula in Mexico was caused by the asteroid
  strike that killed the dinosaurs.

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Human-Made Extinction Events

• Overhunting In the past, humans have hunted
  animals to extinction.
• The Tasmanian tiger, the passenger pigeon, and
  the dodo bird are three examples of species
  humans have hunted to extinction.
• We try not to do this anymore.

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Human-Made Extinction Events

• Habitat Destruction Humans have not always been
  careful about the amount of trees that they cut
  down, or where they build their homes.
• When this happens, entire species of plants and
  animals can be destroyed.

• Clearcut forest

13
Human-Made Extinction Events

• Pollution We also havent always been careful
  about where we are putting our trash and poisons.
• If they are dumped in the wrong stream or area
  they can cause the extinction of plants and
  animals.

• Used oil being
• dumped into a lake

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Questions About Chapter 8

1. What happens when a living thing reproduces?
2. What is a habitat?
3. Give three examples of extinct animals.
4. How does extinction work?
5. Write down 2 natural causes of extinction
6. What are 2 human-made causes of extinction?