Pg. 116 Guided Reading Ch 15. Pg. 117 Ek Paragraph-Ch 15 EK 1A1 Write EK Restate EK 3 examples-at least 2 sentence each.

Transcription

1 Mon 2/3 Collect: Experimental Organizer. Today: Movie Notes: Darwin s Dangerous Idea. Next class: Transformation Lab Homework: Guided Reading for Ch 15

2 Pg. 116 Guided Reading Ch 15 Pg. 117 Ek Paragraph-Ch 15 EK 1A1 Write EK Restate EK 3 examples-at least 2 sentence each.

3 In: pg 118 T or F Evolution is a theory and has not been proven to the satisfaction of the scientific community. T or F Charles Darwin was the first person to propose that living things evolve T of F Natural selection results in more perfect structures over time.

4 Pg. 119 Movie: Darwin s Dangerous Idea Notes Take notes from movie and do Cornell Notes from them.

5 Out Write a brief paragraph describing Darwin s Tree of Life and its importance to his theories.

6 Wed. 2/5 Collect: Guided Reading-Ch 15 Today: Transformation Lab 1 Next class: Tranformation Lab 2 and INB check. Homework: Do your own notes on Ch. 15 from PPT.

7 Ch. 15 Darwin and Evolution Student assignment Take your own Cornell Notes. Add at least 3 pictures from the power point. Don t forget your summary! Due next class

8 Pg. 121 Ch. 15 Darwin and Evolution

9 Evolution: the change in gene frequency within a population over time Natural selection: populations of organisms change over generations if individuals having certain heritable traits leave more offspring than others (differential reproductive success = survival of the fittest) Evolutionary adaptations: a prevalence of inherited characteristics that enhance organisms survival and reproduction

10 Darwin s finches Differences in beaks allowed some finches to successfully compete successfully feed successfully reproduce pass successful traits onto their offspring

11 In historical context Other people s ideas paved the path for Darwin s thinking competition: struggle for survival population growth exceeds food supply land masses change over immeasurable time

12 Voyage: November 24, 1859, Darwin published On the Origin of Species by Means of Natural Selection

13 Essence of Darwin s ideas Natural selection heritable variation exists in populations over-production of offspring more offspring than the environment can support competition for food, mates, nesting sites, escape predators differential survival successful traits = adaptations differential reproduction adaptations become more common in population

14 Where does Variation come Mutation from? random changes to DNA errors in mitosis & meiosis environmental damage Sexual reproduction mixing of alleles genetic recombination new arrangements of alleles in every offspring new combinations = new phenotypes

15 LaMarckian vs. Darwinian view LaMarck in reaching higher vegetation giraffes stretch their necks & transmits the acquired longer neck to offspring Darwin giraffes born with longer necks survive better & leave more offspring who inherit their long necks

16 Evidence supporting evolution Fossil record transition species Anatomical record homologous & vestigial structures embryology & development Molecular record protein & DNA sequence Artificial selection human-caused evolution

17 Fossil Record

18 Fossil record Layers of sedimentary rock contain fossils new layers cover older ones, creating a record over time fossils within layers show that a succession of organisms have populated Earth throughout a long period of time

19 Fossil record A record showing us that today s organisms descended from ancestral species

20 What does it mean to be related to vs. descended from? Related to = 3 guys, one bro, one cousin, one good friend. Place bet on which is bro, what would you base it on? (appearance) then pick out cousin, again based on appearance. Why does cousin look more like me than friend? Bc more recent common ancestor, parents gave you genes/dna. Related means share some DNA, bc share ancestor. More closely related, is more common dna, more recent ancestor. All humans look alike, most my genes and all other humans genes are exactly the same, 99.9%, only differ one letter out of I m related to everyone in room Vs. Descended from: Am I descended from my bro, cous, friend? Doesn t make sense. Same cell type as chimps, over 98% DNA is exactly identical. Only way we can get DNA is from our ancestors must be an ancestor in common a ways back. Same thing with gorillas (96%) & sharks (?%. Teeth, eyes, vertebrae, liver, kidney, etc.) Am I descended from chimps, gorillas,sharks no silly question, related but not descended, common ancestor was not a chimp or shark, etc.

21 Building family trees Closely related species (branches) share same line of descent until their divergence from a common ancestor

22 Body size (kg) Evolutionary change in horses Mesohippus Hyracotherium Merychippus Equus Millions of years ago Nannippus

23 Archaeopteryx Evolution of birds lived about 150 mya links reptiles & birds Smithsonian Museum, Washington, DC

24 Land Mammal????

25 Transitional Fossils Fossils are found that are the Missing Link between two groups

26 2006 Fossil Discovery of Early Tetrapod Tiktaalik missing link from sea to land animals

27 Anatomical record Homologous structures similarities in characteristics resulting from common ancestry

28 Homologous structures Similar structure Similar development Different functions Evidence of close evolutionary relationship recent common ancestor

29 colored leaves Homologous structures spines leaves succulent leaves needles tendrils

30 Analogous structures Separate evolution of structures similar functions similar external form different internal structure & development different origin no evolutionary relationship Don t be fooled by their looks! Solving a similar problem with a similar solution

31 Convergent evolution Flight evolved in 3 separate animal groups evolved similar solution to similar problems analogous structures Does this mean they have a recent common ancestor?

32 Convergent evolution Fish: aquatic vertebrates Dolphins: aquatic mammals similar adaptations to life in the sea not closely related Those fins & tails & sleek bodies are analogous structures!

33 Parallel Evolution Convergent evolution in common niches filling similar ecological roles in similar environments, so similar adaptations were selected but are not closely related marsupial mammals placental mammals

34 Parallel types across continents Niche Placental Mammals Australian Marsupials Burrower Anteater Nocturnal insectivore Mole Anteater Mouse Marsupial mole Numbat Marsupial mouse Climber Glider Stalking predator Lemur Flying squirrel Ocelot Spotted cuscus Sugar glider Tasmanian cat Chasing predator Wolf Tasmanian wolf

35 Vestigial organs Modern animals may have structures that serve little or no function remnants of structures that were functional in ancestral species deleterious mutations accumulate in genes for noncritical structures without reducing fitness snakes & whales remains of pelvis & leg bones of walking ancestors eyes on blind cave fish human tail bone This is not LaMarck s loss from disuse!

36 Vestigial organs Hind leg bones on whale fossils Why would whales have pelvis & leg bones if they were always sea creatures?

37 Vestigial Structures Vestigial structures are structures which do not serve any function in an organism Many species may have similar structures that do serve a purpose Wings on flightless birds Appendix (helps digestion) Tailbone (with tail) Wisdom teeth (before modern dentistry they were useful!)

38 Vestigial Genes Some of our genes are nonfunctional broken They have accumulated mutations over time making them do nothing, when in close relatives (like chimps), they actually have a purpose These are called pseudogenes Examples: Odor receptors, Vitamin C gene

39 Comparative embryology Similar embryological development in closely related species all vertebrate embryos have similar structures at different stages of development gill pouch in fish, frog, snake, birds, human, etc.

40 Nucleotide substitutions Molecular record Comparing DNA & protein structure universal genetic code! DNA & RNA compare common genes cytochrome C (respiration) hemoglobin (gas exchange) Closely related species have sequences that are more similar than distantly related species DNA & proteins are a molecular record of evolutionary relationships Horse/ donkey Sheep/ goat Why compare these genes? Rabbit/ rodent Llama/ cow Pig/ cow Dog/ cow Human/ cow Horse/cow Goat/cow Millions of years ago Human/kangaroo Human/rodent

41 Molecular Evidence (Homology) More closely related species have more similar proteins and genes Common genetic code among all organisms

42 Comparative hemoglobin structure Human Macaque Dog Bird Frog Lamprey Why does comparing amino acid sequence measure evolutionary relationships? Number of amino acid differences between hemoglobin (146 aa) of vertebrate species and that of humans

43 Artificial selection Artificial breeding can use variations in populations to create vastly different breeds & varieties descendants of wild mustard descendants of the wolf

44 Someone in Argentina decided they wanted tiny horses, selected the tiniest horses to breed, picked smallest and breed, took 150 years, had a full breeding strain of horses that were miniature, still same species. Darwin=insipient species, on their way to new species Selection = the mechanism for change

45 Natural selection in action Insecticide & drug resistance insecticide didn t kill all individuals resistant survivors reproduce resistance is inherited insecticide becomes less & less effective

46 Observational Evidence Evolution can be observed directly in many organisms. Examples: Bacteria antibiotic resistance Rhagoletis pomonella apple maggot fly Speciation is occurring between flies that eat hawthorns and flies that eat apples (an introduced plant in North America)

47 The two species are nearly identical, but are becoming more different over time. One species only lays eggs on apples, the other hawthorns.

48 Observations of Evolution Galapagos Finches Peter and Rosemary Grant began studying finches in 1973 and have observed changes in finch populations as a result of changes in seed size (over 35 years) They tracked weather (rainfall, temperature) and the food available (seed size) and saw how that influenced beak size

49

50 Friday 2/7 Today: Finish Transformation Lab, Finish Darwin s Dangerous Idea. Next Class: Review Ch.15 Notes, Start Ch. 16. Homework: Transformation Lab, Ch 16 Guided Reading.