TOPIC 7

• PHENOTYPE?

  expression of the genetic constitution of an organism and its interactions with the environment

  -> observable/ biochemical characteristics
• TEST CROSSES?

  F1 CROSS: homozygous dominant x homozygous recessive

  F1 OFFSPRING: heterozygous

  F2: heterozygous x heterozygous
• HOW TO GET THE RATIO OF GENETIC CROSSES TO BE CLOSER TO THEORETICAL RATIO?

  increase sample size
• EXAMPLE OF MULTIPLE ALLELES?

  blood type
• DEGREES OF FREEDOM?

  T TEST: (n1 - 1) + (n2 -1)

  CHI-SQUARED: n - 1

  SPEARMAN'S RANK CORRELATION: number of pairs of data
• EQUATION FOR CHI-SQUARED?

  $\chi^2=$$\sum_{ }^{ }\frac{\left(O-E\right)^2}{E}$
• GENE POOL?

  all alleles of the genes of all the individuals in a population at a given time within a given area
• ALLELIC FREQUENCY?

  number of times an allele occurs within the gene pool at a given time within a given area
• CONDITIONS OF HARDY WEINBERG PRINCIPLE?

  • no mutations
  • no migration
  • random mating
  • population size is large
  • no natural selection pressures
• GENETIC BOTTLENECK?

  • event causing large reduction in population size
  • reduces number of different alleles in gene pool
  • reduce genetic diversity
  • usually leads to inbreeding
• FOUNDER EFFECT?

  • type of genetic bottleneck
  • few organisms from population start new colony
  • small number of different alleles (which ones due to chance)
  • frequency of each allele in new colony different to original
• GENETIC DRIFT?

  • small population
  • chance can affect which alleles passed onto next generation
  • gradual change in allele frequencies due to chance and not natural selection
• ECOSYSTEM?

  dynamic system consisting of biotic factors interacting with abiotic factors
• POPULATION?

  group of interbreeding individuals of the same species that live in the same habitat at the same time
• CARRYING CAPACITY?

  total population size supported by the ecosystem
• COMMUNITY?

  all the various populations in a habitat at a given time
• ECOLOGICAL NICHE?

  role of an organism in its ecosystem, including the biotic and abiotic conditions to which an organism is adapted to survive/ reproduce/ maintain viable population
• MICROHABITAT?

  smaller habitat with its own microclimate within a larger habitat
• COMPETITIVE EXCLUSION?

  principle stating two species cannot occupy the same niche in the same environment simultaneously
• FEATURES OF SUCCESSION?

  • abiotic environment becomes less hostile
  • greater number of habitats and niches
  • increased biodiversity
  • more complex food webs
  • increased biomass
• PREVENTING SUCCESSION?

  • mowing grass
  • herbicides
  • deforestation
  • grazing animals (eat grass seeds)
• CHARACTERISTICS OF PIONEER SPECIES?

  nitrogen-fixers/ tolerance to salinity or low pH
• ASSUMPTIONS OF MARK RELEASE RECAPTURE?

  • no migration
  • birth and death rate are equal
• AUTOSOMAL LINKAGE?

  gene loci are found on the same chromosome so they are inherited together unless crossing over occurs
• EVOLUTION?

  change in allele frequency of organisms in a population over time