Adaptation: Darwin

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AdaptationDarwins Voyage

• Chapter Seven Holt Text

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Charles Darwin

• 1. Who was Charles Darwin?

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• 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.

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HMS BeagleLife Science Evolution (click here)
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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

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• 2. What did Darwin observe?

• 2. First stops were in Brazil, Argentina and
  later Galapagos Islands.

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• 2. What did Darwin observe?

• 2. Noticed that some species were present in
  several locations however they had some
  different traits.

Click pic
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• 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

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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.

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• He noticed that the beaks of the finches had
  adapted to the way each finch usually gets food.

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Galapagos Finches
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• 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)

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• 4. How were the animals different?

• 4. On G. Islands
• Tortoises had different shell shapes and patterns
  on different islands.

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Darwins Thinking

• 5. What was Darwins hypothesis?

• 5. Island animals were separated from mainland
  relatives. Each population adapted to its
  environment.

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• 6. What is an adaptation?

• 6. A trait that helps an organism survive and
  reproduce.

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• 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

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• 7. Example of adaptation?

• 7. Iguanas
• (Compare those who lived in the jungle to those
  on the island beach.)

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• 8. What is evolution?

• 8. Gradual change in a species over time.
• Happens over many years.

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Darwins Theory of Natural Selection

• 9. What was Darwins book called

• 9. The Origin of Species
• It summarized his ideas about how organisms adapt

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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.

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• 9. What is natural selection?

• 9. Nature selects for certain traits in an
  organism because of conditions in the environment.

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• 10. Natural selection is like _________.

• 10. Selective breeding
• It works to produce organisms with the best
  traits.

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• 11. Four factors that affect natural selection

• 11.
• OCVS

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• 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.

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• 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.

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• 11. Three factors that affect natural selection

• 11. Variation
• Different alleles of genes give different traits.
• Some traits help organism survive. Ex faster
  swimmers

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• 11. Three factors that affect natural selection

• 11. Successful Reproduction
• The best adapted organisms are likely to have
  many offspring that survive.

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• 12. Role of genes in adaptation

• 12. Genes carry instructions for traits and are
  passed from parent to offspring.

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• 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)

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• 14. Examples of adaptation

• 14. Monarch butterfly and viceroy moth.

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Viceroy Moth Monarch Butterfly
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• 14. Examples of adaptation

• 14. Peppered Moth

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Peppered Moth
Dark Variety
Light Variety
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• 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.