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Understanding Evolution: Fossils, Living Evidence, and Natural Selection

Explore the evidence of evolution through fossils in sedimentary rock layers and similarities in living organisms like DNA, homologous structures, and vestigial organs. Learn Darwin's theory on descent from a common ancestor, divergent evolution, and natural selection. Understand patterns of evolution like coevolution, convergent evolution, and speciation.

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Understanding Evolution: Fossils, Living Evidence, and Natural Selection

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  1. EVIDENCE OF EVOLUTION I.FOSSILS USUALLY FOUND IN SEDIMENTARY ROCK LAYERS. “OLD AT THE BOTTOM & NEW AT THE TOP!”

  2. II. EVIDENCE IN LIVING ORGANISMS • A. DNA, RNA, & ATP ARE SIMILAR BETWEEN ALL SPECIES.

  3. B. HOMOLOGOUS STRUCTURES: • BODY STRUCTURES THAT ARE SIMILAR IN FUNCTION AND EARLY DEVELOPMENT.

  4. EX. FORELIMBS OF THE BAT, PENGUIN, ALLIGATOR, & HUMAN. • STRUCTURES LOOK DIFFERENT, YET COME FROM THE SAME STRUCTURES OF THE EMBRYO.

  5. D. VESTIGIAL ORGANS: • STRUCTURES/ORGANS THAT SERVE NO USEFUL FUNCTION. • EX. TAILBONE, APPENDIX, EAR MUSCLES, BODY HAIR, NICTITATING MEMBRANE.

  6. Top 10 Useless Limbs and Other Vestigial Organs

  7. III. DARWIN’S SAYS… • LIVING ORGANISMS EVOLVED THROUGH GRADUAL CHANGES OF EARLIER FORMS. • THIS IS “DECENT FROM A COMMON ANCESTOR”.

  8. DARWIN’S POINTS ARE THE MAIN BASIS OF EVOLUTIONARY THOUGHT TODAY.

  9. IV. PATTERNS OF EVOL.TYPE 1. - COEVOLUTION • A CHANGE IN ONE, TRIGGERS A CHANGE IN ANOTHER. • EX. FLOWERING PLANTS AND THE INSECTS THAT POLLINATE THEM.

  10. TYPE 2. - CONVERGENT EVOL. • UNRELATED SPECIES APPEAR SIMILAR. • BASED ON LIVING IN SIMILAIR ENVIRONMENTS. • EX. DOLPHINS, SHARKS, & PENGUINS

  11. ANALOGOUS STRUCTURES- • STRUCTURES SIMILAR IN APPEARANCE & BEHAVIOR, YET ARE FROM DIFFERENT CELL ORIGINS • EX. BUTTERFLY WINGS & BAT WINGS

  12. TYPE 3 - DIVERGENT EVOL. • RELATED SPECIES BECOME LESS ALIKE. • DUE TO MIGRATING TO DIFFERENT ENVIRONMENTS • EX. RED FOX (FORESTS) AND KIT FOX (DESERTS) • BROWN BEARS & POLAR BEARS

  13. V. NATURAL SELECTION“NATURE’S WAY TO SELECT EVOLUTION”

  14. A. STABILIZING SELECTION • SELECTION OF THE AVERAGE FORM OF A TRAIT. • NOT THE EXTREME • EX. INFANT BIRTH WEIGHT

  15. B. DIRECTIONAL SELECTION • SELECTION OF ONE OF THE EXTREME VARIATIONS OF A TRAIT. • EX. BEAK SHAPE ON THE GALAPAGOS • EX. ANTIBIOTICS

  16. C. DISRUPTIVE SELECTION • SELECTION OF BOTH EXTREMES OF A VARIATION. • EX. BEAK SIZE AND AVAILABLE SEED SIZE • “BIG BEAK & BIG SEEDS” • “LITTLE BEAK & LITTLE SEEDS”

  17. D. SEXUAL SELECTION • CHOICE OF A MATE BASED ON THE PRESENCE/ ABSENCE OF CERTAIN TRAIT/S. • EX. CHARLES MANSON, MICHAEL JACKSON

  18. **ARTIFICIAL SELECTION • EX. SELECTIVE BREEDING • HUMANS SELECT CERTAIN TRAITS FOR A DESIRED OUTCOME. • EX. DOGS, FRUITS & VEGGIES

  19. VI. SPECIATION - FORMING OF A NEW SPECIES THROUGH THE PROCESS OF EVOLUTION.

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