Evolution by Natural Selection

1. Evolution by Natural Selection Chapters 14-18

2. History • Charles Darwin, DOB 1809, On the Origin of Species by Means of Natural Selection, HMS Beagle – 1831-36 • Greeks – life arose in water and more complex followed simpler ones • Later Aristole said life was fixed (ps. he’s wrong) • Judeo-Christians agreed • Mid 1700s fossils of “strange animals” were found • Jean Baptiste de Lamark suggested acquired traits were inherited. Used = got better, Unused = go away. (ps…he’s half wrong)

3. History • Dad wanted him to get into medicine, then he went to become a priest – Met John Henslow – took a cruise. • While on the boat he read Principles of Geology by Charles Lyell. • “mountains rise cm by cm” • The way the rain falls today is the same way it fell 1billion years ago. • UNIFORMITARIANISM • Learned about Thomas Malthus • Human population should be huge but - War, Disease, Famine limits the population

4. History • So Darwin is on a cruise… • Finds sea animal fossils thousands of feet above sea level • Finds FINCHES similar to the mainland but 600miles out to sea GALAPAGOS ISLANDS • Realizes that kids look like parents After his trip, he thinks about this stuff for a little while…like 20years • Alfred Wallace sends him a paper that is the same idea that he has come to and Darwin quickly publishes. The conclusion…?

5. Descent with Modification • Organisms that exist today are modified versions of older organisms. • The environment chooses the organisms that are best fit to reproduce (natural selection). • The better fit the organism the more babies it will produce, the more of those genes are in the gene pool. • Traits that help an organism survive better and make more babies are ADAPTATIONS

6. Evidence – 6 pieces • 1. Fossils • 2. Biogeography • 3.Homologous/Analogous Structures • 4. Embryology • 5. Molecular Biology (macromolecules) • 6. Vestigial Structures

7. 1. Fossils • Traces of long dead organisms • Sediments • Law of superposition: • Which happened first, tree falling or it snowed? • Fossil Record: The theoretical ‘stack’ of all fossils, in order

8. Fossil Lab • Align and fix the locations in place. Answer the following questions: • Which locality is the oldest? How do you know? • Which locality is the youngest? Where might you find this in the Earth’s crust? • Approximately how many years are represented in your localities? Are there any huge gaps? • Why aren’t all the fossils in the same place? • Is there a pattern to the complexity of the fossils? • How do fossils form? What does this tell you about the organisms that we find as fossils (or what about the one’s we don’t find)? • Do you think fossils are strong evidence for evolution? Why or why not.

9. 2. Biogeography • Organisms that are relatively close (NJ and PA) are more alike than organisms that are far apart. • More pouched animals in Austrailia • Galapagos Finches

10. 3.Homologous/Analogous Structures • ‘Homo’ means … so these are parts in different species of animals that are the same. • Analogous – same function but different structure

11. Figure 13.11

12. 4. Embryology • In the early stages of development, many species are similar.

13. 5. Molecular Biology (macromolecules) • Large compounds in organisms are sometimes similar • Protein • Hemoglobin • Starch

14. 6. Vestigial Structures • Remnants of structures that served a purpose in ancestral organisms but have little or no function now. • Appendix • Wisdom teeth • Tails

15. Natural Selection • The organism that is best fit to the environment makes the most babies and passes on the most genes. • DEPENDS COMPLETELY ON GENETIC MAKEUP • Individual variation (longer legs, sharper teeth, darker color) • If its not the environment choosing but people we call it ARTIFICIAL SELECTION • Cows • Sheep • Bacteria • Chemicals - ddt

16. Gene pool – all of the genes in a population • Population – a group of mating individuals in the same place at the same time. • We can identify if evolution is taking place based on the Hardy-Weinburg Equation • p2 + 2pq + q2 = 1 • Certain events can cause evolution to occur more quickly • Bottle neck event • Founder event • Gene flow – immigration, emmigration • Mutation

17. Figure 13.22

18. Figure 13.23

19. Sometimes evolution occurs in a specific pattern • Directional Selection • Disruptive Selection • Stabilizing Selection

20. Taxonomy • Names and groups organisms according to their characteristics and evolutionary history • Carolus Linnaeus (1707-1778) • Binomial Nomenclature • Species identifier • Varieties- peach and nectarine • Subspecies – different area • A species is defined as organisms that can reproduce and form fertile offspring.

21. SystematicsvsCladistics • Systematics – classification in the context of evolution • Fossil record • Morphology • Phylogenic tree • Cladistics – derived characters • Cladograms • Weird relationships

22. Domains – • Eukarya • Bacteria • Archaea • Kingdom • Phylum • Class • Order • Family • Genus • Species

23. Kingdoms (Modern Bio p348-9) • Animalia • Plantea • Fungi • Protista • Eubacteria • Acheabacteria

24. Story of Life • What is living? • Order • Regulation/Homeostasis • Growth and Development • Energy Utilization • Respond to the environment • Reproduction • Evolution • Spontaneous Generation- living things from nonliving things (frogs came from mud) • Francesco REDI 1650: Disproved spontaneous generation with meat, flies, jars • Lazzaro SPALLANZANI 1750: Disproved spontaneous generation with boiled broth, new story-vital force • Louis PASTEUR 1850: Disproved both spontaneous generation and vital force with s-shaped flask

26. Story of Life • Miller and Urey Experiment on how life began • Water + ammonia + • CO2 + Nitrogen = • Organic compounds! • PROKARYOTES • Endosymbiosis- • Lynn Margulis 1950 • One or a few microorgs • Living together became • our organelles = • EUKARYOTES

27. Prokaryotes • Found everywhere • Kingdoms Bacteria, Archaea • Mostly unicellular and very small • No nucleus or organelles • Shapes: Bacilli, cocci, spirochete • Photoauto/heterotroph- Chemoauto/hetero- how they eat • Pathogen

28. Eukaryotes • Lynn Margulis- endosymbiont theory • Smaller prokary climbed inside larger prokay and was happy together • Kingdoms Protista, Plant, Fungi, Animals • Larger cells, have nucleus and organelles • VERY diverse