EVOLUTION

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Chapter 15

• EVOLUTION

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chapter 15.1

• Evolution change over time
• -- facts, observations, hypotheses about
  the history of life

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chapter 15.1

• Charles Darwin sailed on the Beagle around the
  world -- 1831-1836
• -- naturalist who studied plant and animal
  life
• -- noticed lifes great diversity
• -- wondered how it happened
• -- collected fossils, saw great fossil
  diversity
• -- noticed plants animals were well adapted
  for survival

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chapter 15.1
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chapter 15.1

• Beagle traveled around the world

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chapter 15.1

• Darwins trip observed land tortoises marine
  iguanas
• -- saw great variety in birds
• -- noticed that geographical isolation led
  to changes in members of the same species
• -- his ideas were radical for the time

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chapter 15.1

• Many people of the time thought that the Earth
  was only a few 1000 years old did not think
  that any creatures had ever changed

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chapter 15.2

• Naturalist had once enrolled in medical
  school (against his wishes) and when
  offered a place on the HMS Beagle he took it
• Well-read studied the works of Lyell,
  Malthus, and Wallace
• Hutton Lyell - described processes that shaped
  the Earths surface and must have happened long
  ago

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Chapter 15.2

• Lamarck proposed that by selective use or
  disuse of organs, organisms acquired or lost
  certain traits
• Tendency toward perfection all organisms are
  changing to help them live more successfully
• Use and disuse organisms can alter the size or
  shape of particular organs by using their bodies
  in new ways
• Inheritance of acquired traits altered bodies
  could be passed on to offspring

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Chapter 15.2

• Whats wrong with Lamarcks theory?
• Didnt understand genetics
• Didnt know that organisms behavior has no
  effect on its heritable characteristics
• Malthus economist
• Noted that babies were being born faster than
  people were dying
• He reasoned that the human population could grown
  exponentially and result in insufficient food and
  living space

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Chapter 15.3

• Artificial selection
• Darwin noticed the great variation among species
• Nature provides the variation and humans selected
  those variations that were useful

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chapter 15.3

• Darwins solutions THE THEORY OF EVOLUTION AND
  NATURAL SELECTION
• Found that the Galapagos Islands had very similar
  species on different islands that had different
  characteristics
• Saw different tortoises, iguanas finchs on
  different islands and different from mainland
• Darwin explained his view in a book The Origin
  of Species by Natural Selection (published in
  1859)

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chapter 15.3

• EVOLUTION genetic change or decent with
  modification occurs over time

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Chapter 15.3

• STRUGGLE FOR EXISTENCE
• Darwin was convinced that there was a force in
  nature like artificial selection used by humans
• Observed competition for food, living space and
  other necessities
• Some prey are faster than others, better
  camouflaged they catch more prey than others

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chapter 15.3

• SURVIVAL OF THE FITTEST Darwin said that all
  organisms differ slightly those that happen
  to be most suited to the environment will
• survive and reproduce!

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Chapter 15.3

• FITNESS
• Ability of an individual to survive and reproduce
• ADAPTATION
• Fitness is the result of adaptations
• Adaptations are any individual characteristic
  that increases an organisms chance of survival

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What is the purpose of the adaptation in this
animal?
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What would happen?

• Suppose a small group of humans are rocketed at
  warp speed to Planet X. Planet X has no ozone
  layer to protect its surface from cancer-causing
  radiation. Native plants and animals have
  evolved to live safely there. Below the surface,
  the planet has a network of underground tunnels,
  just a meter in diameter, that are inhabited by
  carnivorous predators.

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What would the humans look and act like after
evolving for 100,000 years on Planet X?
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chapter 15.3

• COMMON DESCENT the idea that all living things
  share common ancestors
• Darwin proposed that over time, natural selection
  produces organisms that have different
  structures, occupy different niches and habitats
• As a result, modern species would look different
  from their ancestors

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chapter 15.3

• NATURAL SELECTION mechanism of evolution
• When individuals vary in one or more traits
  (variation), there may be slight differences in
  the ability to
• survive and reproduce

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chapter 15.3

• Natural selection depended on mutations to happen
  and be beneficial depending on the circumstances
  and the environment!

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chapter 15.3

• EVIDENCE OF EVOLUTION
• FOSSIL RECORD
• Fossils form when an organism becomes buried in
  mud, volcanic ash, or sediments
• Over time the organic remains become replaced
  with inorganic minerals

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chapter 15.3

• Darwin found fossil evidence that did not fit
  idea of no change

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Chapter 15.3

• GEOGRAPHIC DISTRIBUTION OF LIVING SPECIES
• Species of finches found in Galapagos by Darwin
  demonstrate adaptations that caused evolution of
  one species into several adaptive radiation

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chapter 15.3

• EVIDENCE FOR CHANGE OVER TIME
• HOMOLOGOUS STRUCTURES similar structures that
  develop from similar tissue in embryological
  development

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chapter 15.3

• Similar in various species provides strong
  evidence that all four-limbed vertebrates have
  descended, with modification, from common
  ancestors

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chapter 15.3

• VESTIGIAL ORGANS organs that seem to have no
  function or purpose
• Unable to explain why they are there
• Examples human appendix, pelvic bones of a
  whale, dewclaw in dogs

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Chapter 15.3

• EMBRYOLOGY
• Many embryos share similar characterisitics
  during certain stages

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chapter 15.3
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chapter 15.3

• THE THEORY OF EVOLUTION
• GENETIC VARIATION AMONG THE SPECIES
• OVERPRODUCTION
• STRUGGLE FOR EXISTENCE
• DIFFERENTIAL SURVIVAL AND REPRODUCTION

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CHAPTER 15.3

• NATURAL SELECTION
• STRUGGLE FOR EXISTENCE
• SURVIVAL OF THE FITTEST
• DESCENT WITH MODIFICATION

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chapter 15.3

• Why study evolution?
• Evolution is the unifying link of all living
  things
• It is still being tested and revised
• Evolution is change and change is a SLOW but
  constant part of biology

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chapter 15.3

• EXAMPLES OF QUICK EVOLUTION
• Peppered Moth Industrial melanism

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chapter 15.3

• RESISTANCE OF BACTERIA TO ANTIBIOTICS
• Antibiotics easily wipe out most bacteria
• However, if one cell is resistant to antibiotics
  due to natural variation and
• SURVIVES AND REPRODUCES
• A billion resistant bacteria will be produced by
  that one survivor in 10 hours!!!!!!!!!!!!