Exploring Evolution: Origins, Processes & Impacts on Life

1. Principles of evolution , our heritageand The Origins of Life What was life like a long time ago How did we come into being?

2. Evolutionary History • Darwin did not come up with his theories all by himself. • Malthus and others set up a foundation that would allow Darwin to think as he did. • Others came up with the same theory Independently

4. The “species problem” • Why do populations of organisms change over time? • If an organism is present in a particular area, it must be perfect for that area, so why then do exotic species pose a threat?

5. Evolution vocabulary words • Evolution: Change in lines of descent over time. • Microevolution: series of changes that give rise to a new species (population). • Macroevolution: major large scale patterns of change in groups of living organisms. • Population: a group of individuals of the same species

6. Populations evolve not individuals. • Populations exhibit great variability. When this variability changes over time is when we get new species. (micro evolution) • Sources of variation within a population • mutations create new alleles • crossing over during meiosis leads to new combinations of alleles • independent assortment mixes alleles

7. Microevolution Processes • Mutation • Natural selection • Genetic Drift • Gene flow • Reproductive isolation

8. Mutation • Any heritable change in DNA sequence. • Three types • lethal mutation • neutral mutation • beneficial • The vast majority of mutations are probably invisible or harmful.

9. Natural selection • Is the major process to produce populations that have different characteristics. • First described by Darwin • if a trait is more adaptive it improves the chances of producing offspring (adaptation) • it gives more of its alleles to the following generation (greater fitness)

10. Genetic drift • Random fluctuation of allele frequencies over time • Works better in small populations • Influenced by who starts a population • Bottleneck effect • Founder effect

11. Gene Flow • Genes flow with the individuals of a population • Physical flow tends to minimize genetic variation, like shuffling the deck.

12. Reproductive Isolation and speciation • Species: are populations of individuals that can interbreed. • When separated by 10,000 or more generations many species can no longer interbreed. • Types of isolation • geographic, behavioral, biochemical

13. Rates of evolutionary change • Gradualism: Evolution is a slow and methodical process • Punctuated equilibrium: Evolution occurs in rapid bursts followed by long periods without change

14. Evidence for Microevolution • Biogeography • Fossil record • Comparative morphology • Comparative biochemistry

16. Life Evolved on the Earth about 3.8 Billion Years Ago • Small organic molecules joined to form larger molecules • Genetic material originated • Organic molecules aggregated into droplets • Figure 22.4 (p. 514)

19. A phylogenetic tree

20. The process of fossilizaiton

21. Homologous structures

28. Human evolution We are a class of organisms called Mammals

29. Nerve cord Vertebrae (backbone) Brain Mammals are vertebrates

30. Hair Long infancy (comparatively) Flexibility in responses due to large brain Produce milk (mammary glands) Mammals

32. Primates • Monkeys & Apes Physically and Biochemical similar

35. Hominoids: • Chimps and Man • Common ancestor about 5 million years ago

37. Evolutionary Trends from primate to human • Upright walking • Precision and Power grip • Daytime color vision w/ depth perception • More generalized teeth for omnivore diet • Increase in brain size allows for new and abstract behavior

40. Origins of primates • 60 mya- nighttime omnivores • 40mya Daytime larger brains • 35mya ancestor to monkeys and apes and humans

43. Humans • Roughly 200,000 years old (from H. erectus) • 15,000 years in the Americas • 35,000 years in Asia decline of Neanderthal • 2 modes • Multiregional hypothesis (humans from independent evolution in europe, asia, africa and Australia • Out of Africa, one ancestor

44. We are evolving now • Our evolution is cultural not morphological

47. Topic Ecosystems Biosphere: the portion of the earth that supports life: land, air water

48. Ecology: • The study of the interactions of organisms with each other and theenvironment.

49. More words: • Habitat: The place an organism lives • Community: collections of populations in a habitat. • Niche: physical and biological conditions under which a species can live (an organisms role) • specialist: has very narrow growth conditions • generalist: will grow under a wide range of conditions

50. Biology Major Undeclared liberal arts Relationships in ecology habitat community specialist niche generalist