First 229 words of the document:
Genetic information, variation and relationships between organisms
(AQA AS Biology) PART 4 of 6 TOPICS
Species and taxonomy:
Two organisms belong to the same species if they can produce fertile offspring.
Physical and chemical makeup help distinguish members of species. Behaviours also does this too
where most behaviours are genetically determined. Courtship and mating are essential when it comes
to survival. Recognition of members helps to produce fertile offspring with a mate who is capable of
breeding, strong and healthy as well. Whilst doing this aggression should not be triggered. Courtship
Visual: Using colours
Behaviour: Dances or building nests
Pheromones: Chemicals released by an organism enabling it to communicate with other
members of its own species.
Phylogeny is a classification system which attempts to arrange species according to their evolutionary
origins and relationships. It uses a hierarchy in which smaller groups are placed into larger groups.
These groups are known as taxa and they do not overlap.
The taxons are: Domain, Kingdom, Phylum, Class, Order, Family, Genus and Species.
Each species is universally identified by a binomial consisting of the name of its genus first then the
NB: The 3 types of domain and the 5 types of kingdom do not need to be recalled for the AQA exam.