Evidence for Evolution by Natural Selection

Evidence for Evolution by Natural Selection Critical Question: What are the 7 evidences of evolution Hunting for evolution clues… Elementary, my dear, Darwin!

Evidence supporting evolution • Fossil record • Anatomical record (4) • Molecular record • Artificial selection

1. Fossil record • Layers of rock contain fossils • new layers cover older ones creates a record (story) over time

? ? ? Complete seriesof transitionalfossils ? We found the fossil — no joke! Land Mammal Where are theintermediate fossils? Someone’s idea of a joke! Ocean Mammal But the joke’s on them!!

2. Embryology – study of embryos • Shows similarities organisms have at a very early stage of development • The more similar the DNA, the more similar the embryos develop all vertebrate embryos have a “gill pouch” at one stage of development

How could thesevery different animalshave the same bones? 3. Homologous Stuctures • Limbs built from the same bones (structure) that perform different functions • Think – same structure

4. Analogous Structures • Structure that have the same function, but different structure on the inside How is a birdlike a bug? Solving a similar problem with a similar solution

5. Vestigial organs • organs & structures that remain in an organism, that serve no function or purpose in the organism • Hind leg bones on whale fossils Why would whales have pelvis & leg bones if they were always sea creatures? Because they used to walk on land!

Dog Human Macaque Bird Frog Lamprey 8 32 45 125 67 0 10 20 30 40 50 60 70 80 90 100 110 120 6. Molecular (down the the molecules) record • Comparing DNA & Proteins • All organisms use the same genetic code! (DNA) • The more similar the DNA the more related the organisms • compare common genes • compare common proteins number of amino acids different from human hemoglobin

7. Artificial selection • Humans “naturally select” traits they want in an organism “descendants” of wild mustard

Selective Breeding Humans create the change over time “descendants” of the wolf

Evidence for Evolution by Natural Selection Critical Question: What are the 7 evidences of evolution? QUIZ TOMORROWWWWW!!!! Hunting for evolution clues… Elementary, my dear, Darwin!

Artificial Selection gone bad! • Unexpected consequences of artificial selection Pesticide resistance Antibiotic resistance

Insecticide resistance • Spray the field, but… • insecticide didn’t kill all individuals • variation • resistant survivors reproduce • resistance is inherited • insecticide becomes less & less effective

Any Questions??

Natural Selection of Strawfish How does natural selection affect genes? How do genes affect evolution?

1. No Predator Preferences No selection force in one specific direction. No clear pattern of change.

2. Predator Prefers BLUE Selection against blue. Fewer blue fish and fewer blue alleles.

3. Predator Prefers GREEN Selection against green. Fewer green fish but same variation in alleles.

4. GREEN is Camouflaged Selection against blue & yellow. More green fish but same variation in alleles.

Niche Placental Mammals Australian Marsupials Burrower Marsupial mole Mole Anteater Numbat placental mammal Anteater Nocturnal insectivore Marsupial mouse Mouse marsupial mammal Climber Spotted cuscus Lemur Sugar glider Glider Flying squirrel Stalking predator Tasmanian cat Ocelot Chasing predator Wolf Tasmanian “wolf” Parallel Evolution not closely related filling similar roles in nature, so have similar adaptations

Vestigial organs • Structures on modern animals that have no function • remains of structures that were functional in ancestors • evidence of change over time • some snakes & whales have pelvis bones & leg bones of walking ancestors • eyes on blind cave fish • human tail bone

Evidence for Evolution by Natural Selection