Topic 1: Origins of Life

1. Topic 1: Origins of Life

2. Origin of the Solar System Earth is estimated to be ~4.6byo Radiometric dating of rocks & meteors Nebula: cloud of gas & dust in space Nebula Hypothesis: Gravity pulled much material together (Sun formed) Planets: remaining materials

3. Hypothesis: Energy from lightning created organic materials from inorganic ingredients Experimental Set-Up: Ammonia, H2O vapor, Methane, CO2 gases added Electricity added (simulate lightning) Result: Amino Acids & later nucleotides Miller and Urey's Big Experiment

4. Geologic Change Early belief: Earth ~6,000 years old Life remained unchanged “New” Observations Rock layers contained differing fossils Deeper/older fossils less complex Environmental changes thought to affect life characteristics

5. Charles Darwin Observed: Organisms have variations based upon environment Some variations proved helpful in particular environment Natural Selection: Process where organisms with favorable traits survive and reproduce Major concept in biology published in The Origin of Species (1859)

6. Topic 2: The Theory ofNatural Selection

7. Four factors: 1) Overpopulation: more offspring are born than can survive 2) Variation: individuals of a population have differences 3) Adaptation: Some variations allow better survival 4) Descent w/ modification: Offspring w/ advantages will make up more of a population Natural Selection

8. Which rabbit is best adapted?

9. Which rabbit is best adapted?

10. Struggle for Survival Populations do not grow unchecked Limiting Factors: food, water, shelter, disease, predators Fitness: measure of the ability to survive & produce more offspring predators disease

11. Changing Environments Earth’s environments gradually change Mountains created Ocean valleys dry up Rivers create canyons Variations allow some to survive changing environments With adaptation: more likely to survive & reproduce Without adaptation: more likely to perish

12. Are new environments being created and destroyed?

13. Topic 3: The Evidence to Support Evolution Theory

14. Defined: Collection of known fossils Most found in sedimentary rock Age determined by depth Law of Superposition: new rock forms on top of older rock Evidence Conclusions: 1) Newer fossils are more complex 2) Common ancestors: similarities between ancient & modern life The Fossil Record

15. Radiometric Dating Isotopes: atoms of the same element with differing neutrons Ex: 12Carbon and 14Carbon 12C = 6 protons + 6 neutrons 14C = 6 protons + 8 neutrons 14C decays at known rate Fossil age determined by comparing ratio of 12C to 14C Wider ratio = older samples

17. 24 Hour Life Timeline Land plants & fungi Multicellular plants Dinosaurs appear Land prokaryotes Scale: 1 minute = 3 million years Amniotic egg Apes (LUCA) prokaryotes Fish (first vertebrates) Land animals Unicellular eukaryotes Dinosaurs extinct Outside links Link 1 Link 2

18. Show transitions between groups of organisms Archaeopteryx: shares both bird & reptile features Basilosaurus: early whale with tiny hind legs Tiktaalik: early fish with legs Evidence Conclusion : Indicates common ancestry Missing Link Fossils

19. flipper arm leg wing Homologous Structures walking flight grasping swimming • Defined: similar body structures with very different functions • Different environments lead to adaptations • Ex: The forelimbs of animals • Evidence Conclusion : Indicates common ancestry

20. Defined: Organs which have lost most or all their original function Vestigial Human Parts: Gill slits = once used to breath oxygen in water Yolk sac = once used to nourish developing embryo Appendix = once used to digest plants Evidence Conclusion : Indicates common ancestry Vestigial Structures

21. Human Embryo w/ Vestigial Structures

22. Snake femurs (leg bones) are vestigial

23. Pelvic bones of whales are vestigial

24. Nictitating membrane is vestigial in humans

25. DNA, proteins, & amino acids compared More related species have more similar chemistry Evidence Conclusion : Indicates common ancestry Biochemical Evidence

26. Different species show similar development Different body plans become noticeable later in development Evidence Conclusion : Indicates common ancestry Embryo Development

27. Antibiotics: chemicals designed to kill bacteria Antibiotic Resistance: Bacteria are adapting to the use of antibiotics Example of natural selection Importance: Bacteria infections are becoming harder to treat Antibiotic Resistance Bacteria No bacteria Fungus

28. Most bacteria killed Strong Survive Antibiotic Resistance Strong Reproduce

29. Antibiotic Resistance Bad Good

30. Pesticides: Chemicals designed to kill pests (rodents, insects) Pesticide Resistance: pests are adapting to the use of pesticides Example of natural selection Importance: Crops are being destroyed by pests Pesticide Resistance "crop dusting"

31. Topic 4: Speciation donkey horse mule

32. Speciation Defined: evolution of a new species Species: group of organisms that can interbreed and produce fertile offspring Factors that lead to evolution Natural Selection Gene flow Mutations Sexual selection Genetic drift

33. Gene Flow Defined: Movement of genes from 1 population to another Increases variations in a population (new genes introduced) If gene flow prevented No variations exchanged Populations isolated Organisms adapt to their own environment

34. Genetic Drift Defined: Changes in gene pool due to chance (not natural selection) More likely in smaller populations Ex: Natural disaster Pre-forest fire (left picture): Blue is more advantageous Post-forest fire (right picture): Due to more red survivors, red has the advantage to reproduce Survival unrelated to adaptations; Random

35. Geographic Isolation Mountains, rivers, canyons, oceans may separate apopulation Gene flow stopped Each population adapts to its isolated environment Over time, genetic differences accumulate between the groups

36. Kaibab Squirrel (Grand Canyon)

37. Behavioral Isolation Gene flow prevented due to different mating rituals Populations unable to reproduce Differences accumulate between both groups

38. Temporal Isolation Gene flow prevented due to time interference 1) Mate at different seasons 2) Some active at night (nocturnal) Differences accumulate between both groups

39. Topic 5: Patterns in Evolution

40. Divergent Evolution Defined: closely related species become increasingly different Cause: Different environments Ex: Red fox (forest) vs. Kit fox (desert)

41. Convergent Evolution Defined: different species evolve similar traits due to similar habitats Survival advantage to a particular environment Ex: Tuna (fish) and dolphins (mammals) Unrelated species with a similar environment (ocean) Faced similar evolutionary pressures

42. Coevolution Defined: 2 or more species evolve in response to changes in each other Ex: Plants and Insects Plants: provide insects with nectar Insect: transfers pollen from one plant to another

43. How Fast Does Evolution Occur? No exact time frame Gradualism: slow & steady change of 1 species into another Small changes continually build Punctuated Equilibrium: Rapid periods of evolution Due to sudden environment change Ex: Mammal diversity exploded after dinosaur extinction Examples of both models exist