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Learning Objectives at the End

Learning Objectives at the End. Know Darwin’s history and how he discovered a “new” view on biology. Species : groups of organisms that can mate AND produce FERTILE OFFSPRING (this is a working definition, it is not perfect). Hinny or Mule (sterile).

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Learning Objectives at the End

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  1. Learning Objectives at the End • Know Darwin’s history and how he discovered a “new” view on biology

  2. Species: groups of organisms that can mate AND produce FERTILE OFFSPRING (this is a working definition, it is not perfect)

  3. Hinny or Mule (sterile) Horse Donkey Not  Same Species 

  4. Tigon or Liger (Both essentially sterile) Tiger Lion Not  Same Species 

  5. Insect C (sterile) Insect F (fertile) 1. Insect A Insect B 2. Insect D Insect E A & B : different species of insect D & E : same species of insect Species: groups that can mate AND produce FERTILE OFFSPRING

  6. For the sake of Honesty: It IS possible for female Ligers and • Tigons to have offspring with male lions. But keep in mind • All were conceived in captivity (under human supervision) • 2) There is no case of Ligers or Tigons living in the wild • They exist only as entertainment to tourists

  7. Sea turtles: lay 50-200 eggs at once Fur Trees: has at least 10,000 seeds in its’ life

  8. Four Postulates to be considered: Are they TRUE OR FALSE ? 1) Individuals in a species show variety in their traits (ex: speed, intelligence, eyesight, etc) TRUE or FALSE 2) Some of these variations are passed on from parents to offspring (so offspring tend to resemble their parents) TRUE or FALSE

  9. Four Postulates to be considered: TRUE OR FALSE ? 3) In every generation, more offspring are born than will survive (limited resources leads to competition for access to those resources ex food, shelter, mates) TRUE or FALSE 4)*** The ability to survive and reproduce is NOT random: Individuals who Survive and Reproduce are those whose traits (genes)will be passed on; unlike those who are unable to survive and reproduce*** TRUE or FALSE

  10. Pg 6 In his own words (Mr. Y’s are in parentheses) : “ As many more individuals of each species are born than can possibly survive;and as there is a frequently recurring struggle for existence (competition)3, it follows that any being (life), if it vary however slightly in any manner profitable to itself, under the complex and sometimes varying conditions of life1, will have a better chance of surviving, and thus benaturallyselected.From the strong principle of inheritance, any selected variety will tend to propagate (pass down and spread) its new and modified form. 2 and 4” -Charles Darwin “The Origin of Species”

  11. Charles Darwin (1809-1882) - Started out as geologist; so he was very aware of the major patterns in the fossil records - 1831: At 22 years old he journeyed aboard the H.M.S. Beagle as the the ship’s naturalist. They sailed around the world over a period of 5 years. - Most of the 5 years Darwin spent on land studying why certain species live in certain places and not others (South America, Australia, etc). Made thousands of observations and collected hundreds of known and unknown species

  12. Flightless Cormorant (Galapagos Islands) South American Cormorant

  13. Charles Darwin (1809-1882) - Darwin spent 25 years reviewing the observations he collected on the trip. Early on (1838) he developed an idea of “descent with modification”, but spent his time (25 yrs) finding the evidence to support his ideas from his ship’s notes -He didn’t Publish his idea until 1859, and only after hearing that another scientist (Wallace) was very close to the same conclusions

  14. Things to remember about Darwin and The Theory of Evolution by Natural Selection - there are more misconceptions about Evolution by Natural Selection than any other topic in biology - Darwin made his argument knowing nothing about genetics at all. He only knew that offspring somehow inherited traits similar to their parents - Darwin did NOT invent the theory of evolution. He simply suggested the method by which evolution was occurring in nature that also explained the major trends in the fossil records as well -Natural Selection places a prime importance in life’s ability to survive and reproduce End

  15. Faternal Twins Alyer Family: Jamacian & Caucasian (use video Mr. Y)

  16. Evidence For Evolution by Natural Selection Evidence Darwin did NOT Know: Evidence Darwin Knew: Fossil Record: shows extinctions and that species changed over long time, he also knew about the Law of Superposition Fossil Record: he knew nothing about half-life (λ) or how to tell how old the earth really is or exact age of fossils Embryology: he knew that certain features in embryos were not in the adults (ex legs in snakes) Comparative Biochemistry: knew nothing about DNA or genes or proteins or ATP (only knew parents looked similar to kids somehow) Comparative Anatomy: knew of vestigial organs in creatures and of homologous and analogous structures How speciation worked: did not know of need for reproductive isolation to make new species, only that the environment pushed the ‘better’ adaptations to help survival and reproduction Artificial Selection: he knew how people selected for different dogs, horses, pigs, and farm plants

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