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Adaptation: Darwin

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Adaptation: Darwin s Voyage Chapter Seven Holt Text – PowerPoint PPT presentation

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Title: Adaptation: Darwin


1
AdaptationDarwins Voyage
  • Chapter Seven Holt Text

2
Charles Darwin
  • 1. Who was Charles Darwin?

3
  • British Naturalist
  • In 1831, set out on a 5-year trip around the
    world.
  • Job to learn as much as possible about the
    living things he saw.

4
HMS BeagleLife Science Evolution (click here)
5
Darwins Excellent Adventure
  • 2. What did Darwin observe?
  • 2. Great diversity of living things.
  • Collected 1,000s of plant and animal samples
  • Took MANY notes

6
  • 2. What did Darwin observe?
  • 2. First stops were in Brazil, Argentina and
    later Galapagos Islands.

7
  • 2. What did Darwin observe?
  • 2. Noticed that some species were present in
    several locations however they had some
    different traits.

Click pic
8
  • 3. What is a species?
  • 3. A group of similar organisms that can mate and
    produce fertile offspring.
  • 1.7 million species identified so far

9
Darwins Finches
  • 4. How were the animals different?
  • 4. Finches
  • Darwin noticed that the finches on the Galapagos
    Islands were similar to the ones found in Equador
    but slightly different.

10
(No Transcript)
11
  • He noticed that the beaks of the finches had
    adapted to the way each finch usually gets food.

12
Galapagos Finches
13
  • 4. How were the animals different?
  • 4. Iguanas-
  • On S. America green with small claws (live in
    rain forest)
  • On G. Islands gray with larger claws (live on
    beach)

14
  • 4. How were the animals different?
  • 4. On G. Islands
  • Tortoises had different shell shapes and patterns
    on different islands.

15
Darwins Thinking
  • 5. What was Darwins hypothesis?
  • 5. Island animals were separated from mainland
    relatives. Each population adapted to its
    environment.

16
  • 6. What is an adaptation?
  • 6. A trait that helps an organism survive and
    reproduce.

17
  • 7. Example of adaptation?
  • 7. For finches that ate insects, those with
    sharpest beaks were able to catch more bugs.
  • These survived longer and were more likely to
    reproduce.
  • Their offspring likely to have sharp beaks

18
  • 7. Example of adaptation?
  • 7. Iguanas
  • (Compare those who lived in the jungle to those
    on the island beach.)

19
  • 8. What is evolution?
  • 8. Gradual change in a species over time.
  • Happens over many years.

20
Darwins Theory of Natural Selection
  • 9. What was Darwins book called
  • 9. The Origin of Species
  • It summarized his ideas about how organisms adapt

21
Darwins Theory of Natural Selection
  • 9. What is natural selection?
  • 9. Process by which individuals that are better
    adapted to their environment are more likely to
    survive and reproduce.

22
  • 9. What is natural selection?
  • 9. Nature selects for certain traits in an
    organism because of conditions in the environment.

23
  • 10. Natural selection is like _________.
  • 10. Selective breeding
  • It works to produce organisms with the best
    traits.

24
  • 11. Four factors that affect natural selection
  • 11.
  • OCVS

25
  • 11. Three factors that affect natural selection
  • 11. Overproduction
  • Most species produce many more offspring than can
    survive.
  • Increases chances that at least one will survive.

26
  • 11. Three factors that affect natural selection
  • 11. Competition
  • Food and other resources limited. Offspring must
    compete to get food, escape predators.
  • The strongest ones will survive.

27
  • 11. Three factors that affect natural selection
  • 11. Variation
  • Different alleles of genes give different traits.
  • Some traits help organism survive. Ex faster
    swimmers

28
  • 11. Three factors that affect natural selection
  • 11. Successful Reproduction
  • The best adapted organisms are likely to have
    many offspring that survive.

29
  • 12. Role of genes in adaptation
  • 12. Genes carry instructions for traits and are
    passed from parent to offspring.

30
  • 13. How do new species form?
  • 13. A group of individuals gets separated from
    the rest long enough for traits to evolve.
  • (By a river, ocean, earthquake, mountains)

31
  • 14. Examples of adaptation
  • 14. Monarch butterfly and viceroy moth.

32
Viceroy Moth Monarch Butterfly
33
  • 14. Examples of adaptation
  • 14. Peppered Moth

34
Peppered Moth
Dark Variety
Light Variety
35
  • The usual form of the peppered moth Biston
    betularia in northern Europe has a light
    'peppered' pattern of coloration. The moth rests
    on tree branches and its color pattern
    camouflages it against predatory attack. The
    camouflage only works against the right
    background birds are more likely to eat poorly
    camouflaged moths, which therefore have a lower
    fitness.
  • The light coloration of tree branches is mainly
    caused by lichens that grow there. Smoke
    pollution in the industrial revolution in the UK
    killed these lichens near to industrial areas,
    leaving tree branches black. At about this time,
    around 1830, a 'melanic' form of the peppered
    moth becomes increasingly common in contemporary
    moth collections. The melanic form is camouflaged
    on dark tree branches. Through the 19th century,
    the melanic form increased in frequency until,
    near industrial regions, it was the normal type
    of the moth. The increase was almost certainly
    driven by natural selection.
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