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Charles Darwin

Charles Darwin. Timeline of Darwin’s life. Born 1809 Study (Edinburgh and Cambridge) 1825-1831 Voyage of the Beagle 1831-1836 Retired to Down 1842 The Origin of Species 1859 Died 1882. Not just an Evolutionist. Not even a biologist to start with Collected beetles for fun

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Charles Darwin

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  1. Charles Darwin

  2. Timeline of Darwin’s life • Born 1809 • Study (Edinburgh and Cambridge) 1825-1831 • Voyage of the Beagle 1831-1836 • Retired to Down 1842 • The Origin of Species 1859 • Died 1882

  3. Not just an Evolutionist • Not even a biologist to start with • Collected beetles for fun • Studied geology more seriously • Considered himself a geologist throughout the Beagle voyage and for some time after • Famous for working out how coral atolls are formed

  4. An atoll is a ring-shaped coral reef, island, or series of islets. An atoll surrounds a body of water called a lagoon. Sometimes, atolls and lagoons protect a central island. Channels between islets connect a lagoon to the open ocean or sea.

  5. His books (not just on evolution) • Emotions • Climbing plants • Domestication • Cross and self fertilization • Orchids • Worms • Autobiography • Beagle voyage • Coral reefs • Volcanic islands • Geology of South America • Barnacles • Species • Man

  6. Contributor’s to Darwin’s thinking included: Charles Lyell- Uniformitarianism is the assumption that the natural processes operating in the past are the same as those that can be (1797-1875) observed operating in the present. Georges Cuvier – species extinction (1769-1832)

  7. More people that contrubutored to Darwin’s ideas. • Thomas Malthus- struggle for existence 1766-1834 • Jean Baptisite de Lamarck- evolution by acquired characteristics 1744-1829

  8. Alfred Russell Wallace • Thought of natural selection at the same time as Darwin (1959) • Wrote to Darwin, collaborated with Darwin on solidifying the theory of evolution through natural selection. • Darwin had been working on book • Published a “letter” jointly • Wallace didn’t put in the years of data that Darwin did. • Darwin published The Origin of Species without Wallace

  9. Darwin was Miscredited • Died famous for evolution (which was not his idea) • Natural selection was his big idea--not widely accepted, even among his supporters • Darwin remained convinced • Only 40-50 years later did scientists appreciate his foresight.

  10. Charles Darwin’s Ideas • Naturalist on the HMS Beagle, Five year journey • Visits the Galapagos Islands • He studied many organisms that were unique to the islands, but similar to elsewhere. • After 22 years he proposed the process of natural selection.

  11. The Voyage of the Beagle

  12. Darwin’s Finches

  13. Darwin’s Trip to the Galapagos

  14. Galapagos Islands • 500-600 miles west off the coast of Ecuador • Located directly on the equator • Cold ocean coming from the south and warm ocean current coming from the north meet at the islands

  15. Galapagos Islands • Islands are of volcanic origin (much like the Hawaiian islands) • The oldest islands are thought to be 5-10 million years old. (much younger than South America) • Started as a “blank slate.”

  16. Joining the Beagle Voyage • Not paid for 5 years on Beagle. • Actually, he had to pay! • Was the “Naturalist” • Was lucky to get on • Replaced someone who was shot in a duel • his father opposed him going • Mainly asked because of his class, to keep Captain Fitzroy company • It was the making of him

  17. Galapagos, 1835 • Portrayed as a “Eureka” experience. • Did not recognize significance until back in England, 1837. • Worked out theory much later. • First inkling of natural selection in 1838. • Tortoises & finches were key evidence

  18. How did living things get to the islands? • Remember they have to survive a 500 mile journey. • Rafting on debris or chunks of land. • Birds may fly or be blown out in a storm.

  19. How would you survive in this environment?

  20. Galapagos Islands

  21. Marine Iguana • Have been thought to evolve from an ancestor similar to what we know as a green iguana.

  22. Live by swimming in the ocean and scrapping algae off rocks. Marine Iguana Only known iguana that swims.

  23. Marine Iguana Characteristics • Flat Nose – Why? • To scrape algae off rocks.

  24. Marine Iguana Characteristics • Long, flat tail • Allows it to swim in the ocean • Big claws • Allows it to hold onto rocks while feeding

  25. Marine Iguana Characteristics • White stuff on back – What is it? • Salt – Salt glands in nose– eats salty foods and the glands allow it to sneeze the salt out • Black Color – Why? • Allows it to warm up after being in the cold ocean

  26. Land Iguana • Have been thought to evolve from an ancestor similar to what we know as a green iguana.

  27. Lives on the land Is an Herbivore, eating mostly the fruit and pads of cactus Land Iguana

  28. Land Iguana Characteristics • Bigger jaw/mouth than the marine iguana – WHY? • Allows it to eat cactus • Lighter coloring –WHY? • Doesn’t heat up as fast.

  29. Land Iguana Characteristics • Neck flap (gular sack) WHY? • Acts as a cooling system, allows heat to escape body • Short, stubby legs – Why? • Allows it to support it’s big weight • Bigger Body – WHY? • Resists heating up in the desert sun

  30. SOMETHING TO THINK ABOUT • Why did the land iguana and marine iguana evolve so differently from one another?

  31. Galapagos Tortoise

  32. Galapagos Tortoise • Have been thought to evolve from an ancestor similar to our desert tortoise.

  33. Galapagos Tortoise Characteristics • Live around 150 years • There were around 250,000 around Darwin’s time. • Numbers have declined to 15,000 or less. • Key source of meat for pirates and explorers.

  34. Continued • High shell at neck – Why? • Allows it to stretch to reach food. • Bigger body size – Why? • Takes longer for an organism to warm up in the hot desert sun.

  35. Plants Evolve Too!

  36. Flies and feeds at night Swallow-tail Gull

  37. Swallow-tail Gull Characteristics • Dark, Black coloring – WHY? • Allows it to fly at night without being spotted by Frigate Bird • Red Ring around the eye – WHY? • Red eye ring is thought to attract more light to allow bird to see at night. • White spot on beak – WHY? • When feeding at night chicks can peck on the white spot to tell the mother where they are.

  38. Mockingbird • Mockingbirds will peck at the iguanas, tortoises, and other birds and drink their blood during hard times when water is scarce. • This is an example of a behavioral adaptation.

  39. How have humans impacted the islands? • Introduced Exotic Species • Pigs, dogs, cats • Invasive species of plants • Tourism • Many people travel to the islands • While the islands are mostly national parks and quite regulated, they have to deal with the conservation problems that humans yachts and trash bring to the islands. • Increase in Population • People are moving to the islands looking for work • The increase in tourism brings the need for more workers • This puts more pressure on the natural resources of the islands

  40. Natural Selection • A mechanism for change in populations.

  41. Natural Selection 1. In nature, organisms produce more offspring than can survive.

  42. 2. In any population, individuals have variations.

  43. 3. Individuals with certain useful variations survive in their environment, passing those variations to the next generation. “Survival of the Fittest”

  44. 4. Over time, offspring with certain variations make up most of the population and may look entirely different from their ancestors.

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