start of life x hwe x natural selection

• What is considered Life?

  • uses energy
  • multiple cells
  • maintains and processes information
  • reproductive
  • growth
• Miller-Urey Experiment

  • primordial soup
  • abiotic synthesis
  • clay = Fe + Zn
• 4 Hypothesized Steps of Life

  • abiotic synthesis
  • macromolecules
  • formation of Protobionts
  • origin of hereditary information
• Central Dogma

  Dna to RNA to Protein
• Accumulation of O2

  • 2.3 billion years ago
• Plato

  • typological thinking
  • variation is unimportant
• Lamarck

  • species change through time
  • life changes spontaneously
  • things are not related
  • no common ancestry
• Charles Darwin and Wallace

  • species can go extinct
  • species share a common ancestor
• Misconceptions of Natural Selection

  • selection does not change individuals
  • not goal oriented
  • adaption is not perfect
• Modes of Selection

  • Directional
  • Stabilizing
  • Disruptive
  • Sexual
• Directional

  • favors one extreme phenotype
  • purifying selection --> lowers/eliminates
  • deletion alleles
• Stabilizing

  • decreases genetic variability
  • narrows
  • no change in average value over time
• Disruptive Selection

  • eliminates average value
  • increases genetic variation
  • plays a role in speciation
• Fitness is the ability to produce surviving fertile offspring in a population
• adaption

  • heritable trait
  • increases fitness
  • fitness depends on environment
• Sexual Selection

  • differences in ability to attract mates
  • competition to reproduce
  • intersexual
  • intrasexual
• intersexual selection

  • behavioral, attractiveness
• intrasexual

  • male competition
• Charles Darwin Theory of Evolution

  • Steady change
  • Gradualism
  • Common ancestry
  • Speciation
  • Natural Selection
• Fruit Flies

  • both inter and intra sexual
  • female choice: store sperm inside their bodies and choose one
  • male competition: sperm fight against other sperms
  • longer sperm has advantage
• alleles version of genes (A or a)
• genotypes are combination of alleles (Aa, AA, aa)
• phenotypes are observable traits (black, blue)
• homozygous is one allele (AA, aa)
• heterozygous is two different alleles (Aa)
• dominant is one over the other trait (A)
• recessive gets dominated (a)
• Hardy-weinberg Equilibrium

  • allele frequencies: p + q = 1
  • genotype frequencies: p2 + 2pq + q2 = 1
• HWE assumptions

  • random mating
  • no natural selection
  • no genetic drift
  • no gene flow
  • no mutation
• achondroplasia

  • short-limbed dwarfism
  • cause: poor bone formation from cartilage
  • allele is lethal when homozygous (aa)
• Non-random mating

  • selfing, inbreeding
  • losing heterozygotes after time of constant mating
  • not HWE, no 2pq
  • genotype frequency changes
  • allele frequency no change
  • bad alleles
• Genetic Drift

  • Coin-flip
  • change in allele frequencies by chance
  • drift randomly w/ respect to fitness
  • caused by sampling error
  • big effect on small population
  • outcome: fixation or loss of allele
• Gene Flow

  • movement of individuals between population
  • fluctuation
  • cause: one individual that leaves population, joins another, and breed
  • homogenizes population; make the populations similar