unit 7 AP bio

  1. Hardy-Weinberg equilibrium
    Model that determines genetic makeup of a population that is not evolving so that it can be compared to the genetic makeup of a population. If it is the same then the population is not evolving; if it is not the same then the population may be evolving.
    1.1. p: Frequency of dominant alleles in a population
    1.2. q: Frequency of recessive alleles in a population
    1.3. p²: Percentage of homozygous dominant individuals
    1.4. 2pq: Percentage of heterozygous individuals
    1.5. q²: Percentage of homozygous recessive individuals

  2. RNA World Hypothesis
    Suggests that RNA (not DNA or proteins) is what stores genetic information.

  3. Comparative morphology
    (evidence of common ancestry in eukaryotes) analysis of the structures of living and extinct organisms.

  4. Molecular homology
    many species share similar DNA and amino acid sequences.

  5. Homology
    characteristics in related species that have similarities even if the functions differ.

  6. Analogous structures
    structures that are similar but have separate evolutionary origins.

  7. Homologous structures
    characteristics that are similar in two species because they share a common ancestor.

  8. Fossil record
    gives a visual of evolutionary change over time; evidence of evolution.

  9. Embryonic homology
    many species have similar embryonic development.

  10. Vestigial structure
    structures that are conserved even though they no longer have a use.

  11. Convergent evolution
    similar adaptations that have evolved in distantly related organisms due to similar environments.

  12. Node
    A hypothetical last common ancestor on phylogenetic trees.

  13. Cladogram
    Hypothetical relationships between species in terms of morphology.

  14. Monophyletic group
    Section of a phylogenetic tree that shows a common ancestor and its descendants.

  15. Synapomorphy
    Characteristic derived from a common ancestor that two or more species share.

  16. Outgroup
    The most distantly related organism in a cladogram.

  17. Basal taxon
    Species on a phylogenetic tree that branches off early.

  18. Derived characteristic
    Characteristic that appears over generations and wasn’t present in an ancestor.

  19. Paraphyletic group
    Section of a phylogenetic tree that shows organisms where some share a common ancestor but not all.

  20. Phylogenetic tree
    A family tree that follows relationships of different species and common ancestors.

  21. Sister taxa
    Organisms that are each other’s closest relative on a phylogenetic tree, sharing a node.

  22. Ancestral characteristic
    Characteristics that are present in descendants because they were in ancestors.

  23. Polyphyletic group
    Section of a phylogenetic tree that shows organisms that don’t share a common ancestor.

  24. Species
    a group able to interbreed and produce viable, fertile offspring.

  25. Speciation
    formation of new species (impacted by geography).

  26. Temporal isolation
    (prezygotic barrier) species breed at different times of the day, year, or season.

  27. Sympatric speciation
    a new species evolves in the same geographic area as the ancestral species.

  28. Reduced hybrid viability
    (post-zygotic barrier) The genes of different parent species may interact in ways that impair the hybrid’s development or survival.

  29. Macroevolution
    large evolutionary patterns (ex. adaptive radiation, mass extinction).

  30. Divergent evolution
    groups with the same common ancestor evolve and accumulate differences resulting in the formation of a new species.

  31. Gametic isolation
    (prezygotic barrier) proteins on the surface of gametes do not allow for the egg and sperm to fuse.

  32. Habitat isolation
    (prezygotic barrier) Species live in different areas or they occupy different habitats within the same area.

  33. Prezygotic barrier
    Things that stop fertilization from happening.

  34. Behavioral isolation
    (prezygotic barrier) unique behavioral patterns and rituals separate species.

  35. Reduced hybrid fertility
    (post-zygotic barrier) a hybrid can develop into a healthy adult, but it is sterile.

  36. Hybrid breakdown
    (post-zygotic barrier) the hybrid of the first generation may be fertile, but when they mate with a parent species or one another, their offspring will be sterile.

  37. Microevolution
    change in allele frequencies within a single species or population (natural and sexual selection, genetic drift, gene flow).

  38. Postzygotic barrier
    Things that prevent speciation (breeding between species) after reproduction.

  39. Mechanical isolation
    (prezygotic barrier) the reproductive anatomy of one species does not fit with the anatomy of another species.

  40. Punctuated equilibrium
    when evolution occurs rapidly after a long period of no change.

  41. Gradualism
    when evolution occurs slowly over hundreds, thousands, or millions of years.

  42. Allopatric speciation
    a physical barrier separates species, geographically isolated.

  43. Adaptive radiation
    if a new habitat or niche becomes available, species can diversify rapidly.

  44. Natural selection
    A trait gives an organism an advantage over others so that it allows the organism to survive enough to reproduce.

  45. Fitness
    How fit an organism is to reproduce.

  46. Differential survival / reproduction
    Some traits will allow organisms to outcompete others for resources and more likely to survive and reproduce.

  47. Evolution
    Change in frequency of inherited genes in a population over multiple generations.

  48. Biotic factors
    Living factors of an ecosystem (ex. plants, animals).

  49. Abiotic factors
    Nonliving factors of an ecosystem (ex. sunlight, water).

  50. Variation
    Different versions of the same trait. More variation is better for a population’s longevity.

  51. Common ancestor
    Can be determined using a phylogenetic tree, most recent node.

  52. Biogeography
    (evidence of evolution) the distribution of animals and plants geographically.

  53. Selective pressure
    A factor that increases or decreases the reproductive success of a population. Positive pressure increases that trait’s percentage, negative decreases.

  54. Adaptation
    Frequency of the advantageous traits will increase in a population over generations.

  55. Microevolution
    small scale genetic changes in a population.

  56. Gene flow
    The transfer of alleles into or out of a population due to fertile individuals or gametes.

  57. Mutation
    change in the DNA sequence of an organism.

  58. Genetic drift
    chance events that cause a change in allele frequency from one generation to the next, leading to loss of variation, can cause harmful alleles to be fixed.

  59. Bottleneck effect
    When a large population is reduced by a non-selective disaster.

  60. Founder effect
    When individuals become isolated from a large population and establish a new small population in the gene that differs from the large population, losing genetic diversity.

  61. Nonrandom mating
    When organisms are more or less likely to mate with each other.

  62. Artificial selection
    humans purposefully breeding animals to select for desirable traits.

  63. Population
    a group of individuals of the same species that live in the same area and interbreed to produce fertile offspring, consists of all types of alleles.

  64. Gene pool
    a population’s genetic makeup.

  65. Allele frequency
    How common an allele is in a population.

  66. Directional selection
    Gene flow, certain members of a population have certain phenotypes that eventually move toward one direction (ex. People getting taller overall) can lead to new species.

  67. Disruptive selection
    Selective pressures cause a certain trait to be less expressed in a population (ex. People becoming either taller or shorter but not medium height) can lead to new species.

  68. Stabilizing selection
    Maintaining of certain traits over time, cannot create new species.

  69. Sexual selection
    a type of natural selection that explains why many species have unique/showy traits.

  70. Fixed / fixed allele
    When there’s only one allele type present in a gene pool.

  71. Biological species concept
    Species that interbreed and produces viable, fertile offspring.

  72. Reproductive barrier
    Factors that prevent speciation between two different species.

  73. Reproductive isolation
    organisms from the two populations cannot pass on their genetic code through reproduction for several generations.