CSET: Evol

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CSET: Evol
2015-09-18 22:06:31

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  1. Describe evidence, past and present, that supports the theory of
    evolution, including diagramming relationships that demonstrate shared
    characteristics of fossil and living organisms
    the fossil record - the ordered sequence of fossils as they appear in the rock layers, marking the passage of geologic time

    •  biogeography- geographic distribution of species, we find species where they are
    • because they evolved from ancestors that inhabited those regions

    • comparative anatomy- the comparison of body structures in different species, certain
    • anatomical similarities among species are signs of evolutionary history 

    comparative embryology- comparing early stages of development in different animal species  reveals additional homologies not visible in adult organisms 

    • molecular biology - if two species have genes with DNA sequences that match closely, biologists conclude that these sequences are homologous and must have
    • been inherited from a relatively recent common ancestor
  2. Explain the theory of natural selection, including adaptation, speciation and extinction
    • individuals whose inherited traits are best suited to the local environment are more likely than less fit individuals to survive and
    • reproduce 

    the individuals that function best should leave the most surviving offspring 

    • when challenged with a new environmental problem a population either adapts
    • through natural selection, dies off in extinction or populations that do
    • survive may change enough to become a new species in speciation
  3. List major events that affected the evolution of life on Earth (eg climate changes, asteroid impacts)
    the evolution of photosynthesis led to the formation of oxygen which transformed the atmosphere and allowed for growth in biodiversity

    increase in oxygen or other environmental changes lead to greater diversity 

    Earth's climate becomes warmer, massive glaciers formed on south pole causing many oceanic species to become extinct 

    large asteroid impact or an increase in volcanic activity leads to mass extinction of dinosaurs
  4. Explain why natural selection acts on the phenotype rather than the genotype of an organism
    the phenotype is what is actually expressed by the genotype 

    the phenotype is what interacts with the environment and affects fitness
  5. Predict the survival potential of various groups of organisms based on the amount of diversity in their gene pools
    greater genetic diversity in their gene pools leads to greater survival potential

    greater genetic diversity means greater chance of adaption to environmental changes
  6. Analyze fossil evidence with regard to biological diversity, episodic speciation and mass extinction
    periods of intense change in the fossil record separated by long periods of very little change 

    episodic speciation (mass change of species) follows a mass extinction due to availability of new niches 

    many fossil species appear suddenly in a layer of rock and persist essentially unchanged through several layers until disappearing suddenly
  7. Analyze the effects of evolutionary patterns on the diversity of
    organisms (eg genetic drift, convergent evolution, punctuated
    equilibrium, patterns of selection)
    genetic drift - a change in the gene pool of a population due to chance, decreases diversity 

    convergent evolution - species from different evolutionary branches may have certain structures that are superficially similar if natural selection has shaped analogous adaptations, decreases the diversity of organisms 

    punctuated equilibrium - long periods of little change or equilibirum, punctuated by abrupt episodes of speciation, leads to greater diversity

    patterns of selection - directional and stabilizing decrease diversity while disruptive increases diversity
  8. Explain the conditions for Hardy-Weinberg equilibrium and why they are
    unlikely to appear in nature, and solve equations to predict the
    frequency of genotypes in a population
    large population - no genetic drift can cause allele frequencies to change 

    isolation from other populations - gene flow can occur 

    no mutations - no new alleles enter the population

     random mating - individuals must pair by chance 

    no natural selection - certain alleles are not selected for or against

    unlikely to appear in nature because requires no evolution to be happening and evolution is always occurring, at least one of the conditions will be happening at all times

    • p2 + 2pq + q2 = 1
    • p2 = frequency of homozygous dominant 
    • q2 = frequency of homozygous recessive
    • 2pq = frequency of heterozygous 

    •  p + q = 1
    • p = frequency of dominant allele 
    • q = frequency of recessive allele
  9. Distinguish between the accomodation of an individual organism to its
    environment and the gradual adaption of a lineage of organisms through
    genetic change
    adaptation of a lineage of organisms leads to evolutionary change while the accommodation of an individual organism does not
  10. Describe a scenario that demonstrates the effects of reproductive or geographic isolation on speciation
    • a population is isolated from its population of the parent species by a geologic process such as a mountain range emerges or a
    • large lake forms several smaller lakes

    with its gene pool isolated, new species can form
  11. Explain the theoretical origins of life on Earth
    earliest organisms were all prokaryotes lacking a true nuclei 

    eukaryotes evolved from prokaryotes 

    multicellular eukaryotes evolved as colonies of single-celled organisms 

    plants and fungi colonize land
  12. Construct a branching diagram (cladogram) from a variety of data sources
    illustrating the phylogeny between organisms of currently identified
    taxonomic groups
    a distinct branch is a clade which consists of an ancestral species and all its descendants 

    identify clades by identifying homologies unique to a species or to a higher taxonomic cluster 

    the sequence of branching represents the order in which they evolved and when groups last shared a common ancestor