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PowerPoint presentation that highlights chapters 13 and 14 in Campbell's Essential Biology (3rd. edition). It can also be used for Miller & Levine's Biology (2006 Ed.) for chapters 15-18.

PowerPoint presentation that highlights chapters 13 and 14 in Campbell's Essential Biology (3rd. edition). It can also be used for Miller & Levine's Biology (2006 Ed.) for chapters 15-18.



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    Evolution_PMSD_Biology Evolution_PMSD_Biology Presentation Transcript

    • Evolution
    • Evolution = “Descent with Modification”
      Organisms evolved due to being spread over different habitats and therefore adapting and modifying themselves to fit the habitat.
      Natural Selection
      • A population of organisms can change over generations if certain inheritable traits leave more offspring than others and those others get the chance to reproduce and continue the lineage.
      • Evolutionary Adaptation
    • Descent with modification
    • Evolutionary Adaptation
    • Evidence of Evolution:Fossil Record
      Fossils chronologically ordered in rock layers
    • Evidence of Evolution:Biogeography
      Geographic distribution of species: Australian marsupials
      Evidence of Evolution:Comparative Anatomy and Embryology
    • Evidence of Evolution:Molecular Biology
      Notice that a Chimp is more genetically related to a human than to an Old World Monkey!
    • Adaptive Evolution
      Natural Selection = Editing
      The finches of The Galapagos Islands: The original finch developed into 14 different species. What was the cause for the offshoots?
    • Darwinism Meets Genetics
      A population is the smallest unit of evolution.
      Natural selection acts on individuals.
      However the evolutionary impact of natural selection is only apparent in tracking how a population changes over time.
      Population Genetics emphasizes the extensive genetic variation within populations and tracks the genetic make-up of populations over time.
      Not all variation in a population is inheritable.
      Only the genetic component of variation is relevant to natural selection.
      Many variable traits in a population result from the combined effect of several genes.
    • Analyzing Gene Pools
      A Gene pool consists of all alleles (different forms a gene may have for a trait) in all the individuals making up a population.
      A reservoir for the next generation’s genes.
      Recall: Homozygous (RR) and Heterozygous (Rr) Dominant and Recessive (rr)
      Hardy Weinberg Formula (1908)
      Helps to calculate the frequencies of genotypes in a gene pool from the frequencies of alleles and vice versa.
      p2 + 2pq + q2 = 1
      p = RR
      pq = Rr
      q = rr
    • Practice Using The Hardy-Weinberg Formula
      p2 + 2pq + q2 = 1
      p = 0.6 q = 0.4
      What are the genotypic frequencies of their offspring?
      0.36 + 2(0.24) + 0.16 = 1
      36% RR
      48% Rr
      16% rr
    • Microevolution
      1. Genetic Drift
      Def: A change in the gene pool of a small population due to chance.
      The best measure of Darwinian fitness is the number of fertile
      offspring an individual leaves.
    • Genetic equilibrium- allele frequencies
      remain constant.
      To maintain equilibrium…
      Random mating
      Population must be very large
      No immigration or emmigration
      No mutations
      No natural selection
    • Types of Genetic Drift
      a. The Bottleneck Effect
      An event that usually reduces the overall genetic variability in a population.
      b. The Founder Effect
      Genetic Drift in a new colony
      i.e. The Galapagos Islands
    • Microevolution Cont.
      2. Gene Flow
      Def: The genetic exchange with another population.
      3. Mutations
      A change in an organism’s DNA sequence.
      Ultimate source of genetic variability.
      4. Natural Selection
      Directional Selection (selecting in favor of an extreme phenotype)
      Disruptive (Diversifying) Selection (leads to a balance between two or more contrasting phenotypic forms)
      Stabilizing Selection (maintains variation in a narrow range)
      • Resistant Genes
      • Immediate Benefits
      • Long term Disaster
      • Evolution direct connection to daily lives
    • Macroevolution
      Def: Major biological changes evident in fossil record.
      Nonbranching evolution (transform a population enough for it to be designated a new species.)
      Branching evolution (splits a lineage into two or more species)
    • The Origins of Species
      Ernst Mayr
      Studied the diversity of birds in New Guinea (1927)
      Biological species concept
      Species = “groups of interbreeding natural populations that are reproductively isolated from other such groups.”
      Reproductive isolation blocks exchange of genes between species and keeps their gene pools separate.
      • Reproductive barriers between species
      • Zygote: fertilized egg
      • Pre-zygotic (factors that impede mating between species or hinder fertilization of eggs if mating is attempted)
      • Post-zygotic (mechanisms that operate should interspecies mating actually occur and form hybrid zygotes)
    • Isolating Mechanisms
    • Mechanisms of Speciation
      Allopatric Speciation
      A population forms a new species while geographically isolated from its parent population.
      Sympatric Speciation
      A small population becomes a new species in the midst of a parent population
      • Speciation occurs only with the evolution of reproductive barriers between the isolated population and its parent population.
      • If speciation occurs during geographic separation, the new species will not breed with its ancestral population, even if the two populations should come back into contact.
    • Sympatric Speciation
      Does not widely occur among animals but may account for over 25% of all plant species.
    • Notice how the hybrid bread wheat has a set of chromosomes from each of its ancestors: T. monococcum (AA), Triticum (BB), T. turgidum (AA BB), T. tauschii (DD)
      What can you notice about T. aestivum that might make it a good hybrid and the most important wheat species today?
    • Relative Dating:Fossil Record
      Fossils chronologically ordered in rock layers
    • Radioactive Dating
    • Continental Drift
    • Meteor of this size would have lowered the temperature of Earth due to the blocking of the sun by atmospheric dust.
      Theory: 65 million years ago a catastrophic event occurred killing off the dinosaurs and about ½ of the species inhabiting the Earth in a 10 million year time span.
    • The Origin of Life
      Stage 1: Abiotic Synthesis of Organic Monomers
      Amino Acids
      Chains of nucleotides
      Chains of DNA bases
      Chains of RNA bases
      Building blocks of protein
    • The Origin of Life
      Stage 2: Abiotic Synthesis of Polymers
      Monomers, such as amino acids, spontaneously fused together to form proteins.
    • The Origin of Life
      Stage 3: Origin of Self-Replicating Molecules
      Ribozyme: catalytic RNA used to fuel RNA replication
    • The Origin of Life
      Stage 4: Formation of Pre-cells
      Molecular packages with some properties of life.
      The gap between pre-cells and true cells is enormous!
      Natural Selection
    • The origin of
      eukaryotic cells
      Endosymbiotic Theory
      Membrane bound nuclear material
      More complex than prokaryotic cells
      Ancestors to fungi, plants and animals
    • Concept Map
      Section 17-2
      Evolution of Life
      Early Earth was hot; atmosphere contained poisonous gases.
      Earth cooled and oceans condensed.
      Simple organic molecules may have formed in the oceans..
      Small sequences of RNA may have formed and replicated.
      First prokaryotes may have formed when RNA or DNA was enclosed in microspheres.
      Later prokaryotes were photosynthetic and produced oxygen.
      An oxygenated atmosphere capped by the ozone layer protected Earth.
      First eukaryotes may have been communities of prokaryotes.
      Multicellular eukaryotes evolved.
      Sexual reproduction increased genetic variability, hastening evolution.
    • Convergent Evolution
      Process by which unrelated animals come to look like each other.
    • Tempo of Evolution
      Spurts of relatively rapid change
      Slow adaptations
    • Unrelated
      Intense environmental pressure
      Similar environments
      Small populations
      Different environments
      Convergent evolution
      Punctuated equilibrium
      Adaptive radiation
      Section 17-4
      that are
      can undergo
      can undergo
      can undergo
      can undergo
      can undergo
    • Classifying the Diversity of Life
      Reconstructing evolutionary history
      Radioactive dating = tool
      The study of biological diversity: past and present
      Identification, naming and classification of species
      Pioneer: Carolus Linnaeus (1707-1778)
      Binomial Nomenclature
      Homo sapien
    • Hierarchical Classification
      Which step is more specific?
      Class or Genus?
      How is Domain Eukarya different from Bacteria and Archaea?
    • Phylogeny
      • Evolutionary history of a species.
      • Tree is based on homologous structures, NOT analogous.
      • Two species will have more common nucleotide sequences based on how recently they branched from their common ancestor.
    • The Cladistic Revolution
      The Computer Age
    • 6 Kingdoms vs. 3 Domains