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Phylogeny Review

Phylogeny Review. District AP Biology Session. Evolution. is the change in a population over time Lamarck was the first to have a widely accepted theory of evolution Acquired characteristics – use and disuse

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Phylogeny Review

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  1. Phylogeny Review District AP Biology Session

  2. Evolution • is the change in a population over time • Lamarck was the first to have a widely accepted theory of evolution • Acquired characteristics – use and disuse • Example: Giraffes needed long necks to get food, so each generation stretched it’s neck and passed the longer neck to the next generation (until the necks became quite long).

  3. Darwin and natural selection • Book – On the origin of Species • Each offspring produces more offspring than can survive • Offspring compete for limited resources • Organisms in every population vary (different traits) • Traits tend to be heritable • The individuals with the most favorable traits are most likely to survive, reproduce, and pass these traits to offspring Question 6, 31

  4. Support for Evolutionary Theory • paleontology – fossils • distributions of plant and animal populations around the world • “ontogeny recapitulates phylogeny” – Gould • comparative anatomy • Molecular biology – DNA sequencing, amino acid analysis, use of mitochondrial DNA Question 19-22

  5. Comparative Anatomy Question 14, 25 • Analogous structures- same function, but evolved independently (fly and bird wing) • Homologous structures – similar structures with different functions

  6. Variation • Genetic variability – no two individuals are alike • How did we get it? • Gametogenesis and fertilization • Crossing over during meiosis • New alleles only through mutation!

  7. Population GeneticsHardy-Weinberg • Relative allele/genotype frequencies are stable over time: • Example: • The allele for red flowers (R) are dominant to white flowers (r) • Green pods can be RR or Rr • Yellow pods must be rr • Assign p to the frequency of one allele (R) and q to the frequency of the other (r) Question 7

  8. The sum of the frequencies must be one: p + q = 1 If you know the frequency of one allele, then you know the other The sum of the frequencies of the genotypes must also be one: p2 + 2pq + q2 = 1

  9. Hardy-Weinberg Equilibrium5 conditions: • Need a large population • No mutations can occur within the population • No immigration or emigration (gene flow) • Mating must be random • No natural selection The above conditions, when met, assure a stable population. If any of the above conditions are not met, changes in allele frequencies occur causing evolution!

  10. Genetic Drift • Random increase or decrease in alleles • Founder effect – type of genetic drift where a small number of individuals move to a new location (immigration) and populate the new location

  11. Bottleneck effect – another type of genetic drift when the population undergoes a dramatic decrease in numbers. The small group left behind is subject to genetic drift. Question 33

  12. Modes of evolution: • Divergent evolution – 2 or more species descending from a common ancestor • Convergent evolution – 2 unrelated species with similar traits living in the same type of environment Question 17

  13. Types of selection: • Directional – a phenotype at an extreme is favored, very few of the other extreme are present • Stabilizing – organisms at the extremes are “weeded out” favoring the common phenotype • Disruptive – Favors both extremes, opposite of stabilizing

  14. Speciation • Allopatric – interbreeding within two populations is prevented by a geographic barrier • Sympatric – formation of a new species without a geographic barrier • Geographic isolation • Behavioral isolation • Temporal isolation • Adaptive radiation – many species from one where multiple niches are open Questions 1, 18, 27

  15. Types of macroevolution

  16. Urey – Miller experimentOrigins of organic molecules Question 30

  17. Figure 25.7 Hierarchical classification

  18. Figure 25.12 Cladistics and taxonomy

  19. Figure 26.16 Our changing view of biological diversity Question 16

  20. Figure 27.2 The three domains of life

  21. History of the Kingdoms

  22. Phylogenyevolutionary relationships • Taxonomy – classifying organisms based on their traits • Taxa from most inclusive to least inclusive: • Domain Do • Kingdom Kings • Phylum Play • Class Chess • Order On • Family Fancy • Genus Gold • Species Stools? Question 28

  23. Taxonomy Question 4 • Binomial nomenclature – scientific name = Genus species • Problems - • Different systems of classification • Changes as we learn more about biology • Now we can use DNA, and amino acids similarities to group organisms

  24. Kingdom Monera • Are prokaryotes • Single, circular DNA molecule • No histones • Reproduce asexually by binary fission • Exchange DNA in conjugation, transformation, or transduction • May contain plasmids • Classified by: • Size • Shape • Habitat • Metabolism • Energy sources

  25. Figure 27.5 Gram-positive and gram-negative bacteria

  26. ArcheabacteriaDomain - Archeae • Cell walls lack peptidoglycan (gram negative, smooth) • Ribosomes more like those of eukaryotes • Extremophiles – live in harsh environments • Methanogens – produce CH4 • Thermophiles – heat loving • Halophiles – salt loving Question 2

  27. Kingdom EubacteriaDomain Bacteria • Largest class of prokaryotes • Cell walls with peptidoglycan • Gram positive • Many different kinds: • Nitrifying • Cyanobacteria • Decomposers • Pathogens • Some do nitrogen fixation (important part of nitrogen cycle)

  28. Other classifications • Shape • Cocci • Bacilli • Spirilli

  29. Table 27.1 Major Nutritional Modes

  30. Table 27.2 A Comparison of the Three Domains of Life

  31. Protista • Eukaryotes • Most are unicellular (some are multicellular or in colonies) • Very diverse • Classified base on nutrition • Plant-like (autotrophes) • Animal-like (heterotrophes) • Fungus-like (decomposers)

  32. Plant-like • Euglenophyta – Euglena are both photosynthetic and predatory • Dinoflagellata – have 2 flagella • Chrysophyta – golden algae • Chlorophyta – green algae • Phaeophyta –brown algae, seaweeds • Rhodophyta – red algae • Bacillariophyta – diatoms, cell walls of silica Question 26

  33. Animal – likeProtozoans • Zoomastigina – move by flagella, Trychonympha in termite guts and Trypanosoma parasites • Rhizopoda – amoebas, eat by phagocytosis • Ciliophora – move by cilia, paramecium • Sporozoa – nonmotile and spore-forming, plasmodium (malaria) • Foraminifera – produce CaCO3 porous shells

  34. Figure 28.1a Too diverse for one kingdom: Amoeba proteus, a unicellular "protozoan"

  35. Figure 28.3 Euglena: an example of a single–celled protist

  36. Figure 28.17 Diatoms: Diatom diversity (left), Pinnularia (left)

  37. Fungus-likeMyxomycota • Large multinucleated masses • Slime molds • Some spore • Some produce gametes that can fuse to form diploid zygotes

  38. Kingdom - Fungi • Multicellular • Heterotrophes • Cell walls composed of chitin • Parasites, pathogens, and decomposers • Classified based on reproductive structures: • Zygomycota • Ascomycota • Basidiomycota • Deuteromycota Question 3, 15

  39. Absorption of nutrients • Mycelium composed of hyphae • Hyphae are long branches of cells that secrete enzymes • Food is digested externally then absorbed by hyphae

  40. Figure 31.4 Phylogeny of fungi

  41. Figure 31.7 The life cycle of the zygomycete Rhizopus (black bread mold)

  42. What is an animal? • Multicellular • Heterotrophs • No cell walls, cells held together by structural proteins (collagen) • Unique tissues: nervous and muscular • Most reproduce sexually • Probably evolved from a colonial, flagellated protist Question 29

  43. Early embryonic development Question 32

  44. Traditional phylogeny based on body-plans

  45. All animals with tissues develop from germ layers • Ectoderm: surface of the embryo • Outer covering of animal • Central nervous system if present • Endoderm: innermost layer • Lines digestive tube • Forms liver, lungs, digestive organs • Mesoderm: middle layer • Muscles and most other organs • Not present in Cnidarians or Ctenophors

  46. What’s a coelom? • Coelom = mesoderm-lined body cavity; fluid-filled space separating the digestive tract and outer body wall • Acoelomates: • Solid bodies, no cavity • Phylum Platyhelminthes • Pseudocoelomates: • Cavity not lined by mesoderm tissue • Phylum Nematoda and Rotifera • Coelomates • Have a true coelom • Functions of a body cavity: • Fluid cushions the suspended organs • Hydrostatic skeleton • Organs grow and move independently of outer body wall

  47. Coelomates are either protostomes or deuterostomes • Coelomates are divided based on their embryonic development into: • Protostomes • Mollusks • Annelids • arthropods • Deuterostomes • Echinoderms • chordates

  48. Protostome vs Deuterostome Question 23-24

  49. Porifera Cnidaria Ctenophora Platyhelminthes Rotifera Nemertea Mollusca Annelida Nematoda Arthropoda Echinodermata Chordata (primarily vertebrates) Invertebrate Phyla Overview Question 8-12

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