classification + evolution

• classification

  the process of naming and organising organisms into groups based off of their characteristics
• domain → kingdom → phylum → class → order → family → genus → species
• what is the advantage of the binomial naming system

  it is universal; a name is the same everywhere in the world
• five kingdoms

  prokaryote, protoctista, fungi, plantae, animalia
• three domains

  bacteria, archaea, eukaryota
• how was the domain system developed

  by observing molecular differences in organisms to determine their phylogeny
• classification v phylogeny

  classification - sorting organisms into groups

  phylogeny - investigating evolutionary relationships between organisms
• explain how natural selection results in evolution

  • random mutations result in new alleles
  • some alleles provide advantages against selection pressure, so some organisms are more likely to adapt and survive
  • their offspring receive the advantageous alleles, and have evolved to have a new characteristic
• how did darwin and wallace contribute to the theory of evolution

  • observed that birds have different beak shapes
  • concluded that birds with the beak shape most suitable for the food they have are more likely to survive
• give other evidence for evolution

  • fossils - allow us to compare today's organisms with extinct organisms
  • genomic dna - sequencing of dna can show how closely two species are related
  • molecular evidence - all organisms' proteins are made from the same 20 amino acids
• what causes mutations

  genetics - random mutations, random fertilisations

  environmental - climate, diet, culture etc.
• intraspecific variation

  differences within a species
• interspecific variation

  differences between different species
• continuous data - e.g leaf size

  • no distinct groups
  • quantitative
  • controlled by a few genes
  • strongly influenced by environment
• explain how spearman's rank results are interpreted

  • closer to 1 - more positive correlation
  • around 0 - no correlation
  • closer to -1 - more negative correlation
• types of adaptation

  • anatomical (body structure) eg. thick fur
  • physiological (body processes) eg. venom production
  • behavioural (actions) e.g hibernation
• implications of evolution

  • bacterial antibiotic resistance means infections are harder to treat
  • pesticide resistance means entire crops could be destroyed
• discontinuous - e.g flower colour

  • distinct categories
  • qualitative
  • controlled by a lot of genes
  • unaffected by environment
• natural selection

  1. random mutation causes genetic variation
  2. selection pressure e.g predators causes competition to survive
  3. advantageous mutations lead to survival by outcompeting
  4. advantageous allele is heritable so offspring have advantageous allele
  5. change in allele frequency over many generations which is known as evolution