vocab

taxonomy - the science of categorisation or classification

taxa - a group of one or more population of an organism, or organisms, seen by taxonomists to form a unit

clade - a group of organisms with a single common ancestor & common characteristics

• evidence for placing organisms in same clade, can be taken from base sequence of gene or corresponding amino acid sequence of a protein

• morphological traits could also be used to assign organisms to clade

• can divided into smaller groupings

calibration point - a period of time in which the exact moment at which 2 species diverged, is known

• is needed in order to calculate how long ago 2 species had shared a common ancestor

cladogram - a diagram in cladistics that shows variation amongst organisms or can be used to investigate evolutionary links

• contains: root, node, and terminal branch

root - the initial ancestor common to all the organisms in the cladogram

node - a hypothetical common ancestor

• more nodes there are between species, the more distantly related they are

terminal branches - extant species at end of branches (species that still exist)