AP Bio - Unit 7: Evolution

• All species have a common ancestor
• Gene pool: all genes/ alleles in a population
• If there are any changes in the gene pool of a population it is said to be evolving
• Hardy Weinberg Equilibrium: evolution will NOT occur if 5 conditions are meet
• Hardy Weinberg Equilibrium?

  1. Large Population: The bigger the population, the less likey of evolution?
  2. No natural selection: all individuals are equally fit
  3. No mutations
  4. No gene flow: no organisms leaving/ entering the population
  5. Random mating: no selection of mates

  • The opposite will lead to evolution
• Founder Effect: Individuals become isolated from bigger pop., the smaller group may have gene pool the does not reflect bigger pop.

  • Founder pop. evolves differently than bigger pop.
• Bottleneck effect: pop. numbers or diversity drops dramatically

  • reduces the size of pop drastically
  • causes: environmental disaster, hunting, habitat destruction
  • numbers may recover, diversity does not
  • the gene pool of survives marked differently
• Genetic drift: change in allele frequencies due to random events

  • important for evolution in small pop.
  • can result in a loss of alleles and a decrease in diversity
  • greater effect on smaller pop. (the small pop. are there because of founder effect or bottleneck)
• Bottlenecks and founder effect are examples of genetic drift BUT bottleneck is when a large portion of a gene gets wiped out and founder is when few members of a large pop. migrate
• Species: can mate in nature and produce viable and fertile offspring
• Speciation: The process by which a population of organisms becomes reproductively isolated from other populations
• Reproductive Isolation: Barries that prevent two species from mating
• Allopatric: geographical separation of populations, usually due to a barrier (e.g. a river)
• Sympatric: Occurring in the same geographic area but not necessarily in the same population.
• Prezygote: impede mating/fertilization

  1. Geographical isolation
  2. Temporal (time) isolation
  3. Behavioral isolation
  4. Mechanical isolation
• Postzygote: Prevents offspring from developing into a survivable, fertile adult
• Evidence of evolution:

  1. Shared characteristics
  2. Microevolution
  3. Fossil record
  4. Embryology
  5. Anatomy/Morphology
  6. Biogeography
  7. Comparing DNA and protein sequence
• Share characteristics: have the same genetic code, central dogma (protein synthesis), and glycolysis (aerobic respiration)
• MIcroevolution: evolution taht can happen within our lifetime (short time period)
• Fossil record: the further back in time you go, the less complex organisms become
• Embryology: embryos of different species develop similarly (almost identical)
• Anatomy/morphology: similarities between animals that are not closely related

  • Homologous structures: body parts that resemble one another in different species
  • Vestigial structures: remnants of functional structures that ancestors may have used but do not have a purpose now
  • Analogous structure: similar function but not in structure and does not derive from a common ancestor
  • Convergent evolution: similar environments and natural selection to produce similar adaptations
• Biogeography: distribution of living things on earth
• Comparing DNA and protein synthesis: similar species have similar DNA and protein sequences
• Adaptive radiation: rapid increase in species numbers with a common ancestor
• History of Life

  1. Prokaryotes
  2. Oxygen
  3. Eukaryotes
  4. Multicellular
  5. Animals
  6. Age of fish
  7. Age of reptiles (dino)
  8. Age of mammals