11U Evolution Unit 4

• What is evolution?

  Any change in the heritable traits within populations through successive generations
• Can an INDIVIDUAL evolve?


  No!
• Heritable traits can be structural, physiological, or behavioral
• Characteristics/Mutations can be neutral, beneficial, or harmful
• Evolution results in the diversity of genes which allows species to survive environmental changes
• What does the theory of catastrophism suggest?


  The Earth has gone through many global catastrophes which have wiped out entire species
• What does the theory of uniformitarianism suggest?


  Geological changes are slow and gradual. These processes occur today and have not changed throughout Earth's history.
• What are homologous structures?

  They are similar in anatomy and development pattern, HOWEVER their functions are different
• What are analogous structures?

  Similar in functions HOWEVER are different in anatomy and development pattern
• Are homologous or analogous structures passed down from ancestors?

  Homologous structures.
• Convergent evolution occurs when organism that are exposed to similar environmental pressures develop similarities in their appearance
• Divergent evolution occurs when a common ancestor developed different adaptations due to different environmental pressures which caused their appearance to become distinct
• Convergent evolution CAN'T be traced back to a common ancestor
• What phrase is commonly used to describe Darwin's theory of evolution?

  Survival of the fittest
• What phrase is commonly used to describe Lamarck's theory of evolution?

  Habitat modifies form
• What is the "scientific" meaning of "Survival of the fittest"?

  Organisms that are BEST suited for their environment are the fittest and survive long enough to reproduce
• Main ideas of Natural selection:

  1: There MUST be competition among organisms for survival

  2: There is VARIATION within a population

  3: Organisms adapt accordingly to their environment

  4: Must be able to mate
• What is speciation?

  New species arise from existing ones through the accumulation of genetic changes over time.
• What is a species?

  Group of organisms that can interbreed and produce fertile offspring.
• What is artificial selection?

  Selective breeding of plants and animals by humans to promote desirable traits. (Same as natural selection however instead of nature favoring traits it's humans)
• What animals did Darwin's closely study on his travels to the Galapagos Islands?

  Finches
• Vestigial Structures are body parts with no apparent function but may have a function in the past
• The 5 main key categories that support the theory of evolution by natural selection are:

  1: Biogeography

  2: Fossil records/paleontology

  3: Comparative Biochemistry

  4: Comparative Anatomy

  5: Comparative embryology
• What is microevolution?

  A change in a populations gene pool over a SHORT period of time
• What are the 5 mechanisms of microevolution?

  Bottleneck and Founder effect, Gene flow, Non-random mating, mutations, natural selection
• Three types of natural selection: Directional, Disruptive, and Stabilizing
• Stabilizing selection favors the intermediates of a population and is against extreme traits
• Directional selection favors one extreme of a population while being against the other extreme
• Disruptive selection favors both extremes of a population while being against the intermediate
• Pre-zygotic isolating mechanisms prevents the mating or fertilization
• What are the 5 types of pre-zygotic isolating mechanisms?

  ecological, temporal, behavioral, mechanical, and gametic.
• Temporal isolation occur when two species are separated by timing barriers

  Example: Different blooming seasons or mating seasons
• Ecological isolation occurs when a species is geographically isolated from other species within the same habitat

  Example: Water snakes, terrestrial garter snakes
• Behavioral isolation occurs when a certain behavior used for breeding prevents the interbreeding of two species
• Mechanical isolation occurs when differences in the structure of sex organs prevents fertilization

  Example: Lock and key system for insect genitals
• Gametic isolation occurs when mating occurs but the formation/fertilization of a zygote fails

  • Chemical incompatibilities (PH)
  • Biochemical barriers (Receptor recognition)