4.5 Classification

• The concept of species:

  • Individuals of one species are similar to one another, but different from other species.
  • Individuals of one species are capable of breeding to produce fertile offspring.
• What are the difficulties in defining organisms as distinct species?

  Species are not fixed and evolve over time.

  Large variation can exist within one species.

  Can't always see reproductive behaviour:

  • Extinct.
  • Reproduce asexually.
  • Geographically isolated.
  • Unethical to carry out breeding experiments.
• Courtship Behaviour:

  Behaviour that is genetically determined and has evolved over time. For a species to survive, courtship rituals and successful mating is essential.
• How does courtship behaviour increase the probability of successful mating?

  • To recognise members of the same species, allowing a generation of fertile offspring.
  • To recognise a mate of the opposite sex.
  • To form a pair bond which will lead to successful raising of offspring.
  • To synchronise mating for when individuals are sexually mature, fertile and receptive to mating.
  • To stimulate gamete release.
• What is the binomial system of naming species?

  This is how each species is universally identified using a binomial consisting of the name of its genus and species.
• If you’re typing out a name of a species on a laptop you have to write in in italic and use a capital letter for the genus.

  If you’re writing it you underline it as it’s hard to write in italic
• What does a phylogenetic classification system attempt to do?

  It attempts to arrange species into groups based on evolutionary origins and relationships. It uses a hierarchy in which smaller groups are placed within larger groups, with no overlap. Which is based on characteristics.
• What are the three domains?

  Eukarya, Bacteria and Archaea.
• What are the five kingdoms?

  Animalia, Plantae, Fungi, Protoctista and Prokaryotae.
• List the taxon classification list in order and include a mnemonic.

  Domain, Kingdom, Phylum, Class, Order, Family, Genus and Species.

  Karl, Puts, Condoms, On, For, Good, Sex