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AP Biology Then along comes Darwin… 1831-1836 22 years old!

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Presentation on theme: "AP Biology Then along comes Darwin… 1831-1836 22 years old!"— Presentation transcript:

1 AP Biology Then along comes Darwin… 1831-1836 22 years old!

2 First to describe how evolution can occur. Descent with modification from natural selection explained 1. unity of life 2. diversity of life 3. relationship between organisms & their environment

3 natural selection = differential reproductive success random changes

4 AP Biology Warbler finch Woodpecker finch Small insectivorous tree finch Large insectivorous tree finch Vegetarian tree finch Cactus finch Sharp-beaked finch Small ground finch Medium ground finch Large ground finch Insect eaters Bud eater Seed eaters Cactus eater Warbler finch Tree finches Ground finches Then along comes Darwin… Ancestral species Descendant species & those dang finches!

5 AP Biology Correlation of species to food source Adaptive radiation Seed eaters Flower eaters Insect eaters Rapid speciation: new species filling niches, because they inherited successful adaptations.

6 6 AP Biology adaptive radiation  genetic divergence from one to many species. Why? Ability to fill a niche. Use a resource, adapt to a new habitat, etc.  Competitive exclusion - only one species can fill the exact same niche for any length of time. Competition for the same resources will cause one to adapt to new conditions or be excluded 4

7 AP Biology (a) Cactus eater. The long, sharp beak of the cactus ground finch (Geospiza scandens) helps it tear and eat cactus flowers and pulp. (c) Seed eater. The large ground finch (Geospiza magnirostris) has a large beak adapted for cracking seeds that fall from plants to the ground. (b) Insect eater. The green warbler finch (Certhidea olivacea) uses its narrow, pointed beak to grasp insects. Beak variation in Galapagos finches

8 8 AP Biology EVIDENCE  Homology  Embryology  Fossil record  SIMILAR STRUCTURES FROM SPECIES THAT ARE EXTINCT (FOSSIL RECORDS) COMPARED TO MODERN SPECIES 6

9 AP Biology Glyptodont fossils Modern armadillos Modern sloth Sloth fossils Why should extinct species & living species be found on the same continent?

10 AP Biology  The process of evolution drives the diversity and unity of life cells DNA

11 AP Biology 1. What are the lines of evidence that support Darwin’s ideas? Fossil record Millions of years ago 50 100 150 200 250 300 350 400 450 500 550 605550454035302520151050 Equus Hyracotherium Mesohippus Merychippus Nannippus Body size (kg)

12 AP Biology 2. What are the lines of evidence that support Darwin’s ideas? Terminal bud Lateral buds Brussels sprouts Cabbage Flower cluster Leaves Cauliflower Flower and stems BroccoliWild mustard Kohlrabi Stem Kale Artificial selection

13 13 AP Biology ARTIFICIAL SELECTION  ONLY SPECIES WITH A FAVORED TRAIT ARE ALLOWED TO BREED 12

14 AP Biology Selective breeding the raw genetic material (variation) is hidden there Text


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