Biology 101 Final

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  1. Allele Frequency
    Abundance of a particular allele among members of a population
  2. directional selection
    mode of natural selection in which phenotypes at one end of a range of variation are found
  3. genetic equilibrium
    theoretical state in which a population is not evolving
  4. lethal mutation
    mutation that drastically alters phenotype; causes death
  5. microevolution
    change in allele frequencies in a population or species
  6. neutral mutation
    a mutation that has no effect on survival or reproduction
  7. stabilizing selection
    mode of natural selection in which intermediate phenotypes are favored over extremes
  8. disruptive selection
    mode of natural selection that favors two forms in a range of variation; intermediate forms are selected against
  9. sexual selection
    mode of natural selection in which some individuals out-reproduce others of a population because they are better at securing mates
  10. balanced polymorphism
    maintance of two or more alleles for a trait in some populations, as a result of natural selection against homozygotes
  11. bottleneck
    reduction in population size so severe that it reduces genetic diversity
  12. fixed
    refers to an allele for which all members of a population are homozygous
  13. founder effect
    change in allele frequencies that occurs after a small number of individuals establish a population
  14. genetic drift
    change in allele frequencies in a population due to chance alone
  15. gene flow
    the movement of alleles into and out of a population, as by individuals that immigrate or emigrate
  16. inbreeding
    nonrandom mating among close relatives
  17. reproductive isolation
    absence of gene flow between populations; part of speciation
  18. speciation
    process by which new species arise from existing species
  19. allopatric speciation
    speciation pattern in which a physical barrier that seperates members of a population ends gene flow between them
  20. sympatric speciation
    pattern in which speciation occurs in the absenceof a physical barrier
  21. coevolution
    the joint evolution of two closely interacting species; each species is a selective agent for traits of the other
  22. exaptation
    adaptation of an existing structure for a completely different pupose; a major evolutionary novelty
  23. extinct
    refers to a species that has been permanetly lost
  24. macroevolution
    patterns of evolution that occur above the species level
  25. mass extinction
    simultaneous extinction of many lineages
  26. stasis
    macroevolutionary pattern in which a lineage persists with little or no change over evolutionary time
  27. adaptive radiation
    a burst of genetic divergences from a lineage gives rise to many new species
  28. key innovation
    an evolutionary adaptation that gives its bearer the opportunity to exploit a particular environment more efficiently or in a new way
  29. taxon (taxa)
    a group of organisms
  30. taxonomy
    science of naming and classifying species
  31. character
    quanifiable, heritable characteristic or trait
  32. clade
    a group of species that share a set of characters
  33. cladistics
    method of determining evolutionary relationships by grouping species into clades
  34. cladogram
    evolutionary tree diagram that shows a network of evolutionary relationships among clades
  35. evolutionary tree
    type of diagram that summarizes evolutionary relationships among a group of species
  36. monophyletic group
    an ancestor and all of its descendants
  37. phylogeny
    evolutionary history of a species or groups of species
  38. sistrer groups
    the two lineages that emerge from a node on a cladogram
  39. hydrothermal vent
    submerged opening where hot, mineral-rich water streams out
  40. protocells
    membranous sacs that contain interacting organic molecules
  41. RNA world
    hypothetical early interval when RNA served as the material of inheritance
  42. endosymbiosis
    one species lives inside another
  43. eukaryote
    organism that encloses in DNA in a nucleus; a protist, plant, fungus, or animal
  44. ozone layer
    atmospheric layer with a high concentration of ozone that prevents much UV radiation from reaching Earth's surface
  45. prokaryote
    single-celled organism in which the DNA resides in the cytoplasm; a bacterium or archaean
  46. stromatolites
    dome-shaped structures composed of layers of prokaryotic cells and sediments; form in shallow seas
  47. plasmid
    of a prokaryote, a small ring of nonchromosomal DNA with a few genes
  48. prokaryotic conjugation
    one prokaryotic cell transfers a plasmid to another
  49. prokaryotic fission
    method of asexual reproductionin which one proyotic cells divides and forms two identical descendant cells
  50. strain
    a subgroup within a species that has a characteristic trait or traits
  51. archaea
    prokaryotic domain most closely related to eukaryotes; most members live in extreme environments
  52. bacteria
    most diverse prokaryotic domain
  53. decomposer
    organism that breaks organic material down into its inorganic subunits
  54. extreme halophile
    organism that lives where the salt concentration is high
  55. extreme thermophile
    organism that lives where the temperture is very high
  56. methanogen
    organism that produces methane gas as a metabolic by-product
  57. nitrogen fixation
    process of combining nitrogen gas with hydrogen to form ammonia
  58. normal flora
    collection of micro-organisms that normally live in or on a healthy animal or person
  59. pathogen
    organism that infects another organism and causes disease
  60. vector
    animal that transmits a pathogen between its hosts
  61. contractile vacuole
    in freshwater protists, an organelle that collects and expels excess water
  62. flagellated protozoan
    member of a heterotrophic lineage of protists that have one or more flagella
  63. foraminiferan
    heterotrophic protist that secretes a calcium carbonate shell
  64. pellicle
    layer of proteins that gives shape to mady unwalled, single-celled protists
  65. plankton
    community of tinydrifting or swimming organisms
  66. protist
    a eukaryote that is not a fungus, plant, or animal
  67. algal bloom
    population explosion of single-celled aquatic organisms such as dinoflagellates
  68. apicomplexan
    parasitic protist that enters and lives inside the cells of its host
  69. bioluminescent
    able to use ATP to produce light
  70. ciliate
    single-celled, heterotrophic protist with many cilia
  71. dinoflagellates
    single-celled, aquatic protists typically with cellulose plates and two flagella; may be heterotrophic or photosynthetic
  72. water mold
    heterotrophic protist that forms a mesh of nutrient-absorbing filaments
  73. brown alga
    multicelled, photosynthetic protists with brown accessory pigments
  74. diatom
    single-celled photosynthetic protist with brown accessory pigments and two-part silica shell
  75. green alga
    single-celled, colonial, or multicelled photosynthetic protists belonging to the group most closely related to land plants
  76. red alga
    single-celled or multicelled photosynthetic protist with red accessory pigment
  77. amoeba
    single-celled heterotrophic protist that moves and feeds by extending pseudopods
  78. bacteriophage
    virus that infects prokaryotes
  79. celluar slime mold
    heterotrophic protist that usually lives as a single-celled predator. when conditions are unfavorable, cells aggregate into a cohesive group that can form a fruiting body
  80. plasmodial slime mold
    heterotrophic protist that moves and feeds as a multinucleated mass; forms a fruiting body when conditions are unfavorable
  81. virus
    infectious particle that consists of protein and nucleic acid and replicates only inside a living cell
  82. lysogenic pathway
    bacteriophage replication pathway in which the virus becomes integrated into the host's chromosome and is passed to its descendants
  83. lysis
    breaking of a cell's plasma membrane; results in death of the cell
  84. lytic pathway
    bacteriophage replication pathway in which the virus replicates in its host and quickly kills it
  85. disease
    condiction that arises when a pathogen interferes with an organism's normal body functions
  86. endemic disease
    a disease that remains present at low levels in a population
  87. epidemic
    a disease spreads rapidly through a population
  88. oandemic
    a disease spreads worldwide
  89. sporadic disease
    a disease that breaks out occasionally and affects only a small portion of a population
  90. bryophyte
    member of an early evolving plant lineage that does not have vascular tissue; such as a moss
  91. cuticle
    secreted covering at a body surface
  92. gametophyte
    haploid gamete-forming stafe in a plant life cycle
  93. lignin
    material that stiffens cell walls of vascular plants
  94. phloem
    vascular tissue that distributes sugars
  95. plant
    multiceled, photosynthetic organism; develops from an embryo that forms on the parent and is nourished by it
  96. sporophyte
    diplois spore-forming stage in a plant life cycle
  97. stomata
    adjustable pores in a plant cuticle
  98. vascular plant
    a plant that has xylem and phloem
  99. xylem
    vascular tissue that distributes water and dissolved mineral ions
  100. epiphyte
    plant that grows on the trunk or branches of another plant but does not harm it
  101. rhizome
    stem that grows horizontally along the ground
  102. megaspore
    in seed plants, a haploid cell that gives rise to a female gametophyte
  103. microspore
    in seed plants, a haploid cell that gives rise to a male gametophyte (pollen grain)
  104. ovule
    of seed plants, chamber inside which the female gametophyte forms
  105. pollination
    delivery of pollen to female part of a plant
  106. secondary growth
    increase in diameter of a plant part
  107. wood
    lignin-stiffened secondary growth of some seed plants
  108. conifers
    cone-bearing gymnosperms
  109. carpel
    female part of a flower
  110. double fertilization
    in flowering plants, one sperm fertilizes the egg, forming the zygotee, and another fertilizes a diploid cell, forming what will become endosperm
  111. endosperm
    nutritive tissue in an angiosperm seed
  112. eudicots
    largest lineage of angiosperms; includes herbaceous plants, woody trees, and cacti
  113. flower
    specialized reproductive shoot of a flowering plant
  114. fruit
    mature ovary tissue that encloses a seed or seeds
  115. monocots
    lineage of angiosperms that includes grasses, orchids and palms
  116. ovary
    of angiosperms only, a floral chamber that holds one or more ovules
  117. pollinator
    animal that moves pollen from one plant to another, thus facilitating pollination
  118. stamen
    male part of a flower
  119. fungus
    spore-producing heterotroph with cell walls of chitin that feeds by extracellular digestion and absorption
  120. hypha
    a single filament in a fungal mycelium
  121. mycelium
    mass of threadlike filaments (hyphae) that make up the body of amulticelled fungus
  122. saprobe
    organism that feeds on wastes and remains
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Biology 101 Final
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