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2010-10-13 02:03:23

Chapters 22-25: Mechanisms of evolution
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  1. Darwin's theory of Evolution stated
    Species are not immutable; they change over time

    The process that produces these changes is natural selection.
  2. True/False: Populations do not evolve individuals do.
    False: Individuals do not evolve, Populations do.
  3. What are the Three Goals of Population Genetics?
    Explain Origin and Maintenance of Genetic Variation

    Explain the patterns and organization of genetic Variation

    Understand the mechanisms that cause changes in allele frequencies in populations.
  4. ___ ___ is the sum of al copies of all alleles at all loci found in a population
    Gene Pool
  5. What is P and Q of the hardy weinburg Theorm? What is the difference between P^2, Q^2, and 2PQ?
    • P is the frequency of dominant alleles in a population
    • Q is the frequency of recessive alleles over population
    • P^2 is the frequency of Homozygous dominant individuals
    • Q^2 is the frequency of Homozygous REcessive individuals
    • 2PQ is the frequency of Heterozygous dominant individuals
  6. Hardy Weinburg Theorm helps study evolution of a given gene locus in a gene population by
    Determining the allele frequency, and using the frequency to predict allele and genotype frequencies.
  7. What are the five conditions to the hardy weinburg theorm to be at equilibrium?
    • no net mutations
    • no gene flow
    • very large population
    • random mating
    • no natural selection
  8. Notes on Mutation
    the only source of new alleles, which will undergo natural selection

    Spontaneous, can be environment related

    very rare, 1 mutation per 10,000 alleles per Generation

    Must be in Germ cells

    Must be expressed in Phenotype

    More often harmful then helpful
  9. Notes on Genetic Drift
    A change in allele frequency due to random events

    fixed allele, when an allele frequency equals 1.00

    bottleneck effect, where a catastrophe leads to alleles not dominantly represented in population to become a fixed allele.

    founder effect, a small population of a larger population migrates to another location. There their alleles become different from the initial popluation
  10. Notes on effects of Natural Selection on quantitative variation in traits
    Stabilizing selection, where traits will favor an intermediate trait

    Directional selection, where traits will favor one extreme trait (i.e homozygous dominant, or recessive)

    Disruptive selection, where traits of both extremes are favor, excluding any intermediate trait.

    Sexual Selection, where sexual dimorphism existed and the physical attractiveness or fitness improves the access of mating
  11. Notes on Maintaining genetic Variation
    Neutral Variating, Allele that has no effect on fitness, but if an incident occurs a mutation can lead to a successfull usage of this allele

    Sexual reproduction, independent assortment, crossing occurs with genetic recombination, random fertilization.

    Frequency dependent selection, where polymorphism is maintained when the fitness of a genotype depends on its frequency in a population. ex. left mouth scale eating fish vs. right mouth scale eating fish

    Environmental variation, variations can occur at different locations.
  12. ___ is how new species come to being
  13. The ___ ___ Concept, was where Carolus Linnaeus described species on the basis of their appearance, shape, and form.
    The Morphological Species Concept
  14. ___ ___ is when the female and male appearance of the same species do not resemble each other
    Sexual Dymorphism
  15. ____ is when there are many phenotypes for a single genotype within one species.
  16. ___ ____ Concept, is where species are groups of actually or potentially interbreeding natural populations which are reproductively isolated from other groups.
    Biological Species Concept. Does not apply to asexual organisms
  17. Speciation that results when a population is divided by a physical barrier is known as
    Allopatric speciation, or geographic speciation.

    A population forms a new species while it is geographically isolated from parent populations. It can cause changes in allele frequencies and there forms a REproductive barrier for interspecies reproduction.
  18. A Partition of a gene pool without physical isolation is called
    sympatric speciation

    A small population becomes a new species without geographic separation. Change between a few individuals results in an obstacle in interspecies reproduction.
  19. ____ is the production within an individual to have an extra chromosome, because the chromosome failed to separate in meiosis, but their gametes can still create reproducible offspring. These offspring cannot reproduce with parent generation, but can with other offspring generations

    Odd Number of Chromosomes results in a sterile offspring, because homologous chromosomes do not pair properly
  20. ____, is when the chromosomes fail to separate, resulting in sterile offspring.

    Odd Number of Chromosomes results in a sterile offspring, because homologous chromosomes do not pair properly
  21. ___, is where a meitotic error, results in a viable fertile hybrid with new chromosome Number from parents, where the parents can be of different species.

    Odd Number of Chromosomes results in a sterile offspring, because homologous chromosomes do not pair properly
  22. ___ Reproductive barriers, prevent individuals of different species or populations from interbreeding, before fertilization
    Prezygotic Reproductive Barriers

    Prezygotic Mechanisms,

    • Habitat isolation
    • Temporal Isolation (different seasons)
    • Mechanical Isolation (anatomical barriers)
    • Gametic isolation (chemical attration)
    • Behavioral Isolation ( behavioral recognition)
  23. ___ Reproductive barriers, prevent individuals of different species or populations from interbreeding, after fertilization
    Postzygotic Reproductive Barriers

    • Low hybrid zygot viability, die before reproductive age
    • low hybrid adult viability, weak adults
    • hybrid infertility, sterile offspring
  24. Notes, Hybrid zones may form if reproductive isolation is incomplete
  25. ____ ____ is if the speciation results in an array of species that live in a variety of environments and differ in the characteristics they use to exploit those environments
    Adaptive Radiation

    Each species has same parent but they become different through occupying different. Ecological niches.
  26. ____ is the full set of genes within an organism
  27. Genes evolve when base changes occur in
    Nucleotide sequence

    Nucleic acids evolve

    Proteins evolve
  28. Gene Sequence alignment compares homologous parts of macromolecules, and identify if they were inherited from common ancestors.
  29. A similarity Matrix is constructed to look at different sequences between species and compare. More different the more time species has been evolving away from each other and less different means they are closer together.
    These mathematical models calculate evolutionary divergence.
  30. Mechanics of Molecular Evolution
    • Silent (synonymous mutations) - substitutions or missense, does not change the amino acid
    • non-synonymous mutations - nonsense where a stop codon is made, does change the amino acid sequence
  31. Neutral Theory of evolution
    Assumes that most mutations are harmful or helpful but are infrequent, neutral and not subject to natural selection, differences in related species are due to genetic drift.

    Concludes that the rate at which 2 populations diverge is constant, because the mechanism of evolution that acts is genetic drift causing it to be fixed in population (alleled/gene fixation)
  32. Molecular clocks show
    the timeline of divergence btw species
  33. Phylogenies and how they are constructed:
    Systematics is the study of
    Diversity; naming and classifying species, with binomial nomenclature.(italicized/underlined)

    First Word Capitolized and a noun (genus)

    Second is lowercase (adjective)

    Phylogeny is the study of the evolution of species
  34. Phylogenies and how they are constructed:
    Hierarchial Classification
    Categories and taxon(tasa), species, Genus, Family, Order, Class, Phylum(phyla), kingdom, and doman

    Phylogeny is the study of the evolution of species
  35. Phylogenies and how they are constructed:
    NOTES; monophyletic groups are clades(paraphyletic or polyphyletic groups are not valid)
    Clades are any taon that consists of all the evolutionary descendants of a common ancestor.

    Phylogeny is the study of the evolution of species
  36. Phylogenies and how they are constructed:
    Select and In Group and Out groups

    Select Characters to compare morphological, developmental, behavioral, and molecular
    (ancestral vs derived character)
    Out groups are distantly related (ancestral) to in Group members
  37. _____ are shared derived characteristics between in Group
  38. Phylogenies and how they are constructed:
    Homologous vs Homoplastic Characters
    Homoplastic characters result from convergent evolution or from evolutionary reversal. ex. wigs of humming bird and bumble bees; bat vs bird wing; aravian boa egg vs live births (evolutionary reversal)

    Homologous characters resule from divergent evolution. ex. mammalian forelimb,
  39. Phylogenies and how they are constructed:
    Character Tables put organisms in order ant to construct phylogenetic tree
  40. Phylogenies and how they are constructed:
    Parcimony Principle is
    A simplier explanation withe ther smallest evolutionary changes (usually turns out to be right, but not always). It can be difficult to determine if homologous or homoplastic characteristic though.