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V O L U T I O

V O L U T I O. MODERN THEORIES OF EVOLUTION. Jean Baptiste de Lamarck Believed that species evolved from preexisting species because they needed to adapt to changes in the environment . LAWS OF USE AND DISUSE

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V O L U T I O

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  1. V O L U T I O

  2. MODERN THEORIES OF EVOLUTION Jean Baptiste de Lamarck Believed that species evolved from preexisting species because they needed to adapt to changes in the environment. LAWS OF USE AND DISUSE • Characteristics that are used become stronger and better developed than those not needed. • Developed traits are the traits passed onto offspring

  3. Lemark’s Giraffe

  4. So what’s the problem…? • DNA determines physical traits; unless DNA changes, the trait will not change • Only mutations in gametes can be passed on to offspring Regular baby + = or baby bodybuilder

  5. WHO DISPROVED LAMARCK? • Weisman - He cut off the tails of mice for 22 generations, allowed them to mate, and each generation of offspring (including the 23rd) had normal length tails.

  6. Weisman proved that you CAN’T inherit an AQUIRED trait!!!

  7. CHARLES DARWIN • Born 2/12/1809 • Died 4/19/1882 • Accepted a position as a ship’s naturalist (scientist) on the British vessel HMS Beagle heading for South America

  8. CHARLES DARWIN • While aboard the HMS Beagle he was able to collect fossils and biological samples from around the world.

  9. CHARLES DARWIN • Studied hundreds of species and found a common set of characteristics between organisms found on different islands and continents.

  10. CHARLES DARWIN

  11. CHARLES DARWIN • 1838, Darwin wrote a book called: The Origin of Species • Darwin’s Theories are the most widely accepted (and expanded upon) by today’s scientific community.

  12. Natural Selection • Organisms with more favorable variations of traits make these organisms better able to survive and reproduce that those with unfavorable trait variations. • Which means that nature selects the survivors • “Survival of the Fittest” – a common phrase for natural selection Crab claws have evolved over time depending on their feeding habits

  13. Natural Selection • According to Darwin, populations (all members of the samespecies living in the same area), adapt to their environment over time. In explaining how & why this occurs, Darwin described the SIX MAJOR PRINCIPLES OF NATURAL SELECTION:

  14. SIX MAJOR PRINCIPLES OF NATURAL SELECTION • Overproduction – species produce more offspring than needed because only a few will live to reproduce. • Competition– space and food are limited and species compete to survive. • Variation – variations occur & important ones increase the chance for survival.

  15. Adaptations – some organisms inherit favorable traits that increase survival and chance for reproduction. • Natural Selection– organisms with favorable variations will reproduce in large numbers and the offspring will inherit these variations. • Speciation– over many generations, favorable variations increase, and unfavorable variations disappear… leads to creation of a new species.

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