Evolution Notes

1. Evolution Notes

2. Part 1

3. Charles Darwin • Born in England • Traveled around on HMS Beagle - Set Sail in 1831 • Collected many specimens • Father of the idea of Evolution

4. Voyage of The Beagle

5. Darwin & The Galapagos • Galapagos Islands are a small group of islands 1000km west of South America • Studied Tortoises and Finches on the islands. • Used geography of islands and differentiation of species to figure out evolution

6. Galapagos Islands

7. Galapagos Islands • Although they were closetogether, the islands had very different climates. • The smallest,lowest islands were hot, dry, and nearly barren. • Hood Island - sparse vegetation. • The higher islands had greaterrainfall and a different assortment of plants and animals. • Isabela Island - rich vegetation • Allowed for different species of the same animal --> formed through evolution!

8. Galapagos Finches

9. Galapagos Finches

10. Galapagos Tortoises

11. Galapagos Blue-Footed Booby • Male dances and shows its feet to the female to attract her • Female chooses male with brightest feet and best dance • Sexual selection! • Sexual selection is a trait or behavior that acts on an organism's ability to obtain a mate

12. Darwin’s Thoughts • On his travel home, he began to think of his observations. • He found…characteristics of many animals and plants varied noticeably among thedifferent islands of the Galapagos • According to this hypothesis, these separatespecies would have evolved from an original SouthAmerican ancestor species after becoming isolated fromone another

13. Inherited Variation and Natural Selection • Darwin noted that plant andanimal breeders used heritable variation, whatwe now call genetic variation, to improve cropsand livestock. • Artificialselection: nature provided the variation, andhumans selected those variations that theyfound useful. • A.K.A Selective Breeding

14. Better Picture of Artificial Selection

15. Natural Selection • Each organism has different advantages and disadvantages • Individual best suited for environment survive and REPRODUCE • Pass these traits onto offspring, and they are more able to survive and reproduce • Occurs only when a few survive • Remember: differences (genes) in offspring occur at random!

16. Darwin’s Concept of Evolution • Biggest contribution is his idea of the mechanism behind Evolution • The Struggle for Existence • Survival of the Fittest • Descent with Modification

17. Struggle For Existence • Struggle for existence:means that members of each speciescompete regularly to obtain food, living space, and other necessities of life. • Predators that are faster win • Prey that are better camouflaged or protected win

18. Survival of the Fittest • Fitness: ability of an individualto survive and reproduce in its specific environment. • Result of adaptations • Adaptation: any inherited characteristic that increases anorganisms chance of survival

19. Survival of the Fittest • Survival of the Fittest: the idea that individuals that arebetter suited to their environment survive and reproduce more successfully • A.K.A. Natural selection

20. Descent with Modification • Natural selection produces organisms that havedifferent structures • Descent with modification: each living species has descended, with changes,from other species over time