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Star-nosed mole: Pre-questions for discussion. Introduction to Evolution. Pink snout has 22 finger-like projections that can touch 12 objects in less than 1 second. Q: Why is this helpful? Lives underground and has paddle shaped feet Q: Why is this helpful?
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Star-nosed mole: Pre-questions for discussion Introduction to Evolution Pink snout has 22 finger-like projections that can touch 12 objects in less than 1 second. Q: Why is this helpful? Lives underground and has paddle shaped feet Q: Why is this helpful? Has great hearing but very poor vision? Q: Why?
The Process of Evolution Extinction Evolution
Objectives Today I will know... • Who is Charles Darwin • The meaning of survival of the fit • That Charles Darwin believed that individuals are more likely to survive if they have variations best suited to the environment. • Darwin’s theory of evolution is based on the ideas of natural variation and natural selection. • That species produce more offspring than can possibly survive. • Darwin’s theory of Evolution by natural selection is a process of change in species over time.
Who is Charles Darwin? • A 19th century (1800s) biologist • Observed adaptations of plants and animals • Adaptation- a feature that allows an organism to better survive in its environment Old Darwin Young Darwin
Most famous research took place at the Galápagos Islands ~near the equator west of South America GREAT BRITAIN EUROPE NORTH AMERICA ATLANTIC OCEAN The Galápagos Islands AFRICA Pinta Genovesa Equator Marchena SOUTH AMERICA Santiago Daphne Islands AUSTRALIA Pinzón Fernandina PACIFIC OCEAN Cape of Good Hope Andes Isabela Santa Cruz Santa Fe San Cristobal Tasmania Florenza Española Cape Horn New Zealand Tierra del Fuego
Darwin’s Focus on Adaptation • Darwin discovered: • Adaptations to the environment AND the origin of new species are closely related processes • Examples- Galápagos finches & Tortoises Beak Shape Shell Shape & Neck Length
Fig. 22-6 (a) Cactus-eater (c) Seed-eater (b) Insect-eater
IN YOUR NOTES SKETCH BEAK SHAPE AND WRITE THE TYPE OF FOOD THEY EAT! Fig. 22-6a (a) Cactus-eater
IN YOUR NOTES SKETCH BEAK SHAPE AND WRITE THE TYPE OF FOOD THEY EAT! Fig. 22-6b (b) Insect-eater
IN YOUR NOTES SKETCH BEAK SHAPE AND WRITE THE TYPE OF FOOD THEY EAT! Fig. 22-6c (c) Seed-eater
Darwin’s two main ideas: • Descent with modification: All organisms are related through descent from an ancestor that lived in the past • Fossil evidence proves this! • Natural selection: individuals that are best suited to their environment survive and reproduce • Increases the adaptation of orgs to their envmnt • If envmnt changes, new adaptations will appear OVER TIME b/c of natural selection
Darwin’s 4 Observations • Observation #1: Members of a population often vary greatly in their traits
Observation #2: Traits are inherited from parents to offspring (genetics) • Observation #3: All species are capable of producing more offspring than the environment can support • Observation #4: Because there is not enough food or other resources (limiting factors), many of these offspring do not survive
Survival of the Fit • Individuals with traits that give a better chance of surviving and reproducing • Have more offspring survive • Unequal ability of individuals to survive and reproduce • Leads to the accumulation of favorable traits in the population over generations
Survival of the Fit • Survival of the Fit: individuals with favorable heritable traits survive and reproduce at a higher rate than other individuals
Fig. 22-12 (a)A flower mantid in Malaysia (b)A stick mantid in Africa
Fig. 22-12a (a)A flower mantid in Malaysia
Fig. 22-12b (b)A stick mantid in Africa
Important Notes about Evolution • Individuals do not evolve; populations evolve over time… • Natural selection can only increase or decrease heritable traits in a population • N.S. does not create new traits! • Local environment determines traits selected for or selected against