Chapters 14-16 Evolution

1. Chapters 14-16 Evolution College Prep Biology Mr. Martino

2. Concept 16.1- Prokaryotic Life • Early Earth contained carbon monoxide, carbon dioxide, and water vapor; little oxygen • The introduction of lightening created small organic molecules. • Amino acids, sugars, lipids, nitrogen bases found in DNA, RNA, and ATP • RNA molecules have been observed to self-replicate w/o enzymes in solutions containing nucleotides • Led to the formation of DNA • The Oxygen Revolution • Cyanobacateria are photosynthetic prokaryotic bacteria that live in water that give of oxygen as a waste product

3. I. Introduction • - 50,000 years ago - began to domesticate dogs • - 14,000 years ago - started to develop different varieties (subspecies or breeds) • Used artificial selection – choosing desired traits • Evolution: genetic change in a line of descent through successive generations

5. Early Beliefs & Discoveries • “It seems to me the disease called sacred…has a natural cause, as other diseases have. Men think it divine merely because they do not understand it. But if they called everything divine that they did not understand, there would be no ending to divine things!…If you watch these fellows treating the disease, you see them use all kinds of incantations and magic – but they are also careful in regulating diet. Now if food makes the disease better or worse, how can they say it is the gods who do this?…It does not really matter whether you call such things divine or not. In Nature, all things are alike in this, in that they can be traced to preceding causes.” – On The Sacred Disease (400 B.C.)

6. 2000 years ago it was believed disease came from “angry gods” • Aristotle attempted to find explanations for natural occurrences • 15th century naturalists attempted to describe & catalog all organisms 14.2 Early Evidence for Evolution 1) Biogeography:study of world distribution of organisms

7. Australian Emu African ostrich South American Rhea

8. 2)Comparative morphology:study of body plans between major groups of organisms • Ex. Bones of human arm, whale flipper, bat wing • Ex. Why are there hind limb bones in pythons, tail bones in humans, etc?

13. Late 1600’s – geologists began mapping layers of rocks and found • 3) Fossils: preserved remains or markings • Identified patterns and specific sequences of life in layers • Noticed similarities yet differences with living organisms

14. 4) Molecular Biology • The study of the genetic code and protein sequences of species • If sequences are similar, than species are closely related

15. 5) Comparative Embryology – embryos of closely related species follow similar developmental stages • All vertebrates have an embryonic stage where pouches form on the this side of the throat

17. 6) Taxonomy – the classification of organisms

18. A. Catastrophism: Georges Cuvier (anatomist) who felt life was created at one time - many destroyed by catastrophe • B. Acquired Traits: Jean Baptist Lamarck – organisms develop characteristics if needed & lose what is not needed • C. Natural Selection:Charles Darwin - • 1831 – Charles Darwin began 5 yr voyage on HMS Beagle • Theology degree from Cambridge University • Ship’s naturalist – collected samples • Observed: • Fossils resembled living species • Earthquakes and volcano eruptions • Marine animal fossils high up in mountains • Galapagos Island species were similar yet different • Read (and influenced by) Charles Lyell’s Principles of Geology - Earth is old and changing 14.1 A Flurry of New Theories

19. D. Galapagos Islands - volcanic islands in Pacific • Many very unique species • Darwin spent many years studying there

21. Aristotle believed species were unchanging and did not evolve • Western Judeo-Christian culture adopted Aristotle’s views • Earth and all species are perfect and unchanging • Earth +/- 6000 years old • All life designed as is by creator • Mid 1700’s Georges Buffon suggested Earth was old • E. Theory of Uniformity:Earth is gradually, uniformly, and repetitively changing • Directly challenged catastrophism & current beliefs of the time A Young Charles Darwin

22. Darwin’s Theory • 1836 – Darwin returned, did many years research - had many questions • Ex.Fossils of 10’ long armadillo-like glyptodonts only in regions where armadillos are now found • Descent with modification? • Read Thomas Malthus – clergyman/economist who observed struggles for existence in humans as result of populations growing faster than resources • If environment restricts # of reproducing individuals - which are chosen torepro.?

23. A. Darwin’s main ideas: • 1. Overproduction of offspring • 2. Variety among individuals of a population • 3. Varying traits passed to offspring • 4. Natural Selection: individuals of a population who were genetically fit for their environment are most likely to survive and reproduce • Based on artificial selection of farmers & breeders • reproductive fitness - best suited individuals tend to leave more offspring 5. Populations must remain stable in size. Fossils of giant sloth and glyptodont

24. 1840’s Darwin developed an essay with all the main points of his theory • Delayed publishing due to fear of results • Mid – 1850’s Alfred Wallace developed a similar theory • 1858 – colleagues presented Wallace’s paper and some of Darwin’s essay to scientists • B. 1859 – On the Origin of Species by Means of Natural Selection was published • Descent with modification • Fueled further research • Unity within diversity Video: Who was Charles Darwin?

25. Video: Darwin – The Reluctant Rebel

27. Video: Scopes Monkey Trial What About God? • Is it possible to be religious and still consider the theory of evolution to be viable? • Must scientists be atheists just by choice of profession? • Darwin believed in both a Devine power AND natural selection… • Your opinion is for YOU to decide…. Video: Why is Evolution Controversial Anyway? Video: Courtroom Controversy Video: Personal Stories Video: Biblical Literalist

28. 14.3 Individuals Don’t Evolve – Populations Do • A.Darwin presented evidence to convince many scientists evolution occurs w/out supernatural intervention • - Later discoveries and DNA tech further support • - Fossils still a rich source of evolutionary evidence • - Individuals don’t evolve populations do Video: Isn’t Evolution Just A Theory?

29. Wild Mustard and Descendants

30. 14.4 – Darwin’s Natural Selection at Work • B. Population:group of same species living together in same place at same time that reproduce • - All have same basic – • Morphological traits (body plan) • Physiological traits (metabolic, growth, & repro. traits) • Behavioral traits (respond to stimuli in the same ways) • 1) Gene pool: sum total of all genes present within a population; genes are passed on within population • Darwin did not know about genetics- now genetics explains his ideas as population genetics: science of genetic change of a population • All of above traits vary in either qualitative or quantitative ways - two or more different morphs (polymorphisms) • Ex. White or purple flowers • 2) Species: group of populations whose individuals can interbreed and produce fertile offspring

31. Do we know this lady? Do we know this guy?! Same Species, different forms of a trait!!!

33. C. Sexually reproduced offspring are unique: • 1. Mutations (produce new alleles in gene pool) • 2. Crossing over during meiosis – new gene combinations • 3. Independent assortment during meiosis – new random mixtures of maternal and paternal chromosomes • 4. Fertilization – combines alleles of 2 parents • 5. Changes in chromosome number or structure Human gametes have one of 10600 possible allele combinations…not even 1010 are alive today! • You are one of a kind!

34. D. Allele Frequencies:how often certain alleles occur in population • E. Hardy-Weinberg Equilibrium: frequency of alleles in gene pool remains same unless acted upon • F. Microevolution: small changes in gene pool over many generations • G. Five conditions for Hardy-Weinberg equilibrium • 1. Population is large • 2. Population is isolated • 3. Mutations do not occur • 4. Mating must be random • 5. No natural selection • Rarely met in nature • Each gene has a specific mutation rate • Some mutations are lethal or neutral (doesn’t help or harm – Ex. Human fingerprint) • Advantageous mutations are passed on to offspring

35. 16.7 3 Forms of Natural Selection • A. Directional Selection: favors one extreme • Environmental change (peppered moth) • B. Stabilizing Selection: favors intermediate individuals, reducing extremes (human birth weight) • C. Disruptive Selection: favors both extremes, reducing intermediates (incomplete dominant phenotype fails)

37. Directional Selection Video: Evolution of Antibiotic Resistance • Results in resistant pests, parasites, and bacteria • Kills off weak, strong and immune survive • Results in more strong and immune pests & parasites • When exposed to problems, organisms either adapt, move, or die • According to fossil record, most die - those that survive often change enough to become new species Dies Lives Dies Dies Dies All survive!

39. Video: Why Does Evolution Matter Now? Video: Hygiene Hypothesis Video: Evolution of Drug Resistant Aids

40. D. Peppered Moths – 19th century England • - Industrial revolution caused moth population to change from light to dark • - Soot from factories settled on the trees

41. 16.8 Stabilizing &Disruptive Selection • A. Stabilizing seems to counteract effects of mutations, etc. and preserve phenotype • Reduces variation • Ex. Human birth weight

42. Living fossils, like the coelacanth, ginkgo, and horseshoe crab, are examples of organisms that are relatively unchanged (stabilized) from their distant ancestors Ginkgo Leaf Stabilizing Selection

43. Disruptive selection

45. Video: Importance of sex 16.9 Special Selections Video: Polyandry • A.Sexual Selection: occurs in organisms that have distinct male and female traits • B. Sexual Dimorphism: secondary sexual characteristics • Visible differences between males and females • Darwin’s sexual selection • Competitions for harem or females • Individuals of one sex are choosy about mate Video: Songbird Infidelity

46. Video: Tale of the Peacock Video: Asexual Repro Would mates select….

47. Video: Sweaty T-Shirts

48. 16.10 Gene Flow • A. Gene Flow:physical flow of alleles • 1) Immigration: moving into population • 2) Emigration: moving out of population • Reduces genetic variation • Enables separated populations to be genetically similar

49. 16.11 Genetic Drift • A) Genetic Drift:change in small gene pool due to chance • Greatest effect in small populations • 1) Bottleneck Effect: disaster greatly reduces gene pool • Unselective • Ex. Elephant seals – reduced to 20 & now have no variation in 24 genes • 2) Founder Effect: colonization of new location • Galapagos Islands

50. B. Inbreeding: nonrandom mating between closely related individuals • - Leads to homozygyotes • Endangered species have low genetic variability • Cheetahs, elephants, gorillas, rhinocerouses, Florida panther • Lower populations # = lower gene pool diversity • Ex. Cheetahs have 3 small populations • E. Africa – 1.4% heteros. • S. Africa - .04% heteros. • Reduced capability to adapt • Usually due to reduced habitat