Biodiversity, Gene

• Genetic Diversity


  Number of different alleles of genes in a population
• Evolution


  Change in allele frequency over many generations in a population
• Natural selection results in species becoming better adapted to their environment
• Directional selection - selection that favors individuals with a particular phenotype, occurs with a change in environment
• Stabilising selection : selection that favours individuals with intermediate phenotypes, occurs with no change in environment
• First name is genus, second is species
• Why do different species look similar?

  Live in similar environments

  Have similar selection pressures

  Similar alleles will have the selective advantage

  Produces similar/same proteins therefore have similar characteristics
• What is a hierarchy?


  Smaller groups arranged within larger groups

  No overlap between groups
• Domain - Archaea, Prokaryotes, Eukaryotes

  Kingdom

  Phylum

  Class

  Order

  Family

  Genus

  Species
• Classification methods?

  • DNA base sequences
  • mRNA base sequence
  • Amino acid base sequence
  • Immunological - comparing self antibody shape
  • Physical features
• All organisms share a common ancestor
• Species diversity : The number of different species and individuals in a community.
• Species richness : The number of different species in a particular area at the particular time.
• Ecosystem diversity : The variety of different ecosystems in a particular area.
• Low biodiversity not a concern - eg. Antarctica, Deserts HOWEVER decrease in biodiversity is a cause for concern often caused by human activity
• Farming reduces biodiversity:

  • destruction of hedgerows
  • selective breeding
  • monocultures (only growing 1 plant species)
  • overgrazing
  • filling in ponds/wetlands
• Courtship : Essential for successful mating and species regulation
• Species : A group of similar organisms that can breed to produce fertile offspring
• Importance of courtship:

  • Enables them to recognise own species and opposite sex
  • Synchronised mating behaviour- indicates sexually mature and in season
• To ensure survival of offspring:

  • Forms a pair bond
  • Choose a strong and healthy mate