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Evidences of Evolution 1. Fossils 2. Comparative Morphology –Bessey’s Dicta.

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Presentation on theme: "Evidences of Evolution 1. Fossils 2. Comparative Morphology –Bessey’s Dicta."— Presentation transcript:

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2 Evidences of Evolution 1. Fossils 2. Comparative Morphology –Bessey’s Dicta

3 Homologous Structures Derived From Leaves

4 Evidences of Evolution 1. Fossils 2. Comparative Morphology –Bessey’s Dicta

5 Evidences of Evolution 1. Fossils 2. Comparative Morphology –Bessey’s Dicta

6 Evidences of Evolution 1. Fossils 2. Comparative Morphology –Bessey’s Dicta 3. Comparative Physiology –C3, C4, CAM

7 Evidences of Evolution 1. Fossils 2. Comparative Morphology –Bessey’s Dicta 3. Comparative Physiology –C3, C4, CAM 4. Biochemistry –proteins and DNA

8 Evidences of Evolution 1. Fossils 2. Comparative Morphology –Bessey’s Dicta 3. Comparative Physiology –C3, C4, CAM 4. Biochemistry –proteins and DNA (macromolecules) (micromolecules) flavinoides – anthocyanin/ betalains - (10 fams) = Caryophyllales

9 Evidences of Evolution 1. Fossils 2. Comparative Morphology –Bessey’s Dicta 3. Comparative Physiology –C3, C4, CAM 4. Biochemistry –proteins and DNA 5. Vestigial Organs –staminoids

10 Evidences of Evolution 1. Fossils 2. Comparative Morphology –Bessey’s Dicta 3. Comparative Physiology –C3, C4, CAM 4. Biochemistry –proteins and DNA 5. Vestigial Organs –staminoids 6. Geographical Distribution –Continental Drift

11 Continents during Creataceous 100 mya

12 Geographically Separated, Morphologically Similar Plantanus occidentalis Plantanus hispanica

13 Evidences of Evolution 1. Fossils 2. Comparative Morphology –Bessey’s Dicta 3. Comparative Physiology –C3, C4, CAM 4. Biochemistry –proteins and DNA 5. Vestigial Organs –staminoids 6. Geographical Distribution –Continental Drift 7. Development -

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15 Evidences of Evolution 1. Fossils 2. Comparative Morphology –Bessey’s Dicta 3. Comparative Physiology –C3, C4, CAM 4. Biochemistry –proteins and DNA 5. Vestigial Organs –staminoids 6. Geographical Distribution –Continental Drift 7. Development - 8. Selective Breeding –Brassica

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18 Carboniferous Period 300 mya

19 Kingdom: Plantae 1. Waxy Cuticle 2. Gametangia –archegonia, antheridia 3. Embryos 4. Pigments 5. Thick spore walls – homosporous  heterosporous

20 Evolution from Green Algae to Plants

21 Nontracheophytes vs. Tracheophytes Tracheophytes have vascular tissue. –Xylem tracheids vessel elements –Phloem seive tubes comapion cells

22 First Tracheophytes (vascular plants): Division: Rhyniophyta Rhynia Cooksinia– M. Silurian 420 mya Rhynia – L. Devonian 360 mya

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26 Phylum: Sphenophyta Horsetails

27 Phylum:Cycadophyta cycads

28 Phylum:Ginkgophyta ginkgo

29 Phylum:Gnetophyta Welwitchia

30 Phylum:Coniferophyta conifers

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32 Phylum: Anthophyta flowering plants

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35 Charles Darwin 19thC

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37 Acquired Characteristics vs. Natural Selection Acquired characteristics –J. B. Lamarck Natural Selection –C. Darwin –A. Wallace

38 Darwin’s Tenets 1. Many more individuals are born than will survive. 2. There is variation among individuals. 3. Individuals with certain characteristics have a better chance of survival and reproducing than individuals with other characteristics. 4. At least some of the characteristics resulting in differential reproduction are heritable. 5. Enormous spans of time are available for slow, gradual change.

39 Species?? Groups of actually or potentially interbreeding natural populations which are reproductively isolated from other such groups. –Ernst Mayr Harvard 1940

40 Evolutionary Divergence

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42 Evolutionary Divergence Allopatric Speciation Allopatric Speciation

43 Phylogenetic Hierarchy Kingdom –Division (Phylum) Class –Order »Family » Genus » species

44 Isolating Mechanisms for Species (Character Displacement) 1. Mechanical (Reproductive) Isolation – flower structure –Aquilegia canadensis –A. formosa –A. ecalcarota –Asclepias 2. Habitat Isolation –Plantanus occidentalis –P. orientalis –P. acerifolia 3. Seasonal Isolation –Pinus radiata Feb. –P. muricata April

45 Enhancement of Cross-pollination (within species) 4. Mechanical 5. Chemical

46 Form an occasional variation within a species Scarlet Gilia –Red, Yellow Variety Chestnut Oak –var. accumata, var. prinoides

47 Population Genetics Alleles - color in scarlet gilia –RED (R) dominant –Yellow (r) recessive

48 Hardy - Weinberg Equilibrium Gene frequencies in a population will not change if: 1. No plant has an adaptive advantage. 2. No immigration or emigration. 3. No mutations.

49 Difficulties in interpreting Evolutionary Change Convergence - polyphyletic –Cactaceae, Euphorbiaceae ------------------------------------------ Divergent - monophyletic –Lamiaceae, Verbenaceae

50 Interpreting Evolutionary Change 1. Vegetative characteristics are more liable to evolutionary change. (Also have a high degree of “genetic plasticity”.) 2. Reproductive characteristics are most conservative and are best for determining the evolution of taxa. “Good Characteristic” - heritable and not affected much by the environment.

51 Interpreting Evolutionary Change

52 Bessey’s Dicta 1. Woody plants came before herbs. 2. Perennials before biennials or annuals. 3. Alternate leaves are primitive; opposite or whorled are advanced. 4. Bisexual flowers are primitive. 5. Many parted spirally arranged flowers are primitive to all other arrangements.

53 Bessey’s Dicta 5. Many parted spirally arranged flowers are primitive to all other arrangements. 6. Hypogyny is primitive to epigyny and perigyny. 7. Numerous separate carpels are primitive to fewer fused carpels.

54 Bessey’s Dicta 8. Pollen grains with 1 pore preceded those with 1 or more pores. 9. Axile placentation preceded free central placentation. 10. Single fruits preceded aggregate fruits formed from several ovaries. 11. The capsule preceded the drupe or berry.

55 Mechanisms for Evolutionary Change 1. Gene Mutations - –changes in sections of the DNA on chromosomes (rare) 2. Chromosomal Mutations - –the normal (2n) chromosome number is not maintained –POLYPLOIDY 40% - 70% of plant species Autopolyplody

56 POLYPLOIDY mint species - Europe –Galeopsis pubsescens 2n = 16 (8 prs.) –Galeopsis speciosa 2n = 16 (8 prs.)

57 POLYPLOIDY mint species - Europe –Galeopsis pubsescens 2n = 16 (8 prs.) –Galeopsis speciosa 2n = 16 (8 prs.) –ALLOPOLYPLOID doubling of chromosome no. in 2 different species –Galeopsis pubescens X speciosa 4n = 32 artificial hybrid –Galeopsis tetrahit 4n = 32 natural species (one step evolution)

58 POLYPLOIDY –Modern Speciation –Spartina pectinata 2n = 62 USA –Spartina townsedii 2n = 60 Europe –Spartina pectinata X townsendii (4n) = 122 England 1870 sterile Spartina anglica (4n) 2n = 122 England 1890 fertile Allopolyploidy Sympatric Speciation - no geographical barrier

59 POLYPLOIDY Tragopogon Salsiflies, Goatsbeards –T. porrifolius –T. dubius –T. pratensis Allopolyploids: Sympatric Speciation –T. miscellus 4n T. pratensis X dubius (chloroplasts) –T. mirus T. pratensis X porrifolius Allopolyploids more common than diploids today.

60 Polyploids Diploids vs. Polyploids

61 POLYPLOIDY –Raphanus (radish) X Brassica (cabbage) --> 4n tetraploid – 2n 2n

62 3. Reshuffling or Recombination of Existing Genes Normal Diploid Condition (2n) Homologous Pairs Crossing over - Arboreous (A), Fruticose (a) L. leaves (L), S. leaves (l) A a L l

63 3. Reshuffling or Recombination of Existing Genes Normal Diploid Condition (2n) Homologous Pairs Crossing over - Arboreous (A), Fruticose (a) L. leaves (L), S. leaves (l) a A L l

64 3. Reshuffling or Recombination of Existing Genes Random Assortment –how the different chromosomes combine in gametes Fertilization –the many different combinations in eggs and sperm combine

65 Modern Theory of Organic Evolution 1. There is a tremendous amount of variability in the gene pool of each organism (each species). 2. Organisms have changed through time. 3. Evolutionary change is directed by natural selection.

66 Evolutionary Change A change in the gene frequency of a gene in a gene pool. If an organism is incapable of changing as the environment changes? EXTINCTION

67 Classification Theories ( Attempts to Determine “Natural Groupings”) Traditional Taxonomy, Traditionalists –Are not opposed to making value judgments (weighted characteristics) in construction phylogenetic trees. Use para and polyphylogeny Phylogenetic Taxonomy, Cladists –Use only objective data when constructing monophyletic evolutionary trees. Also use computers and numerical comparison of unweighted characteristics for cladograms.


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