Taxonomy

Classification is the grouping of animals

Taxonomy is the theroy of classification

Relationships in a natural classification are based upon homologous pairs.

• These homologous characteristics have similar evolutionary origins, regardess of their functions in the adult species.
• For example the arm of an adult and the wing of a bird have both the same structure and evolved from a common ancestor, therefore they are homologous

An easy way to find out how closely related a species is is by counting how many DNA nucleotides bases match from one to the next!

For example

Guinea pig AAATATCACTAGGAGGATACGATACGGTTA

mouse AATTATCACTACCAGGGTACGATAAAGTTA

there are 26 hydrogen bonds that connect the matching nucleotide bases together

There are two main forms of biological classifcation, each with their own purpose

Artifical classification

• divides organisms according to their present differences
• these may include colour, number of legs, size etc
• these are ANALOGOUS characterisics
• - they have the same function but do not have the same evolutionary origins

Natural classification

• are organised into evolutionary relationships between organisms and their ancestors.
• the species are then put into groups of shared features, ie how many legs/fur/feathers, derived from their ancestors
• they are then grouped into a hierarchy, where groups are contained within larger composite groups with no overlap

Definitions of sepcies

SPECIES CAN REPRODUCE AND HAVE LIVING, FERTILE OFFSPING!!!!

They are similar to one another but different from members of other species

• they have similar genes and therefore look very alike, psysically and biochemical.
• they occupy the same ecological niche - similar patterns of deveopment

They are capable of breeding to produce living offspring

• therefore able to mass produce
• they belong to the same gene pool

Taxonomy is the study of each group within a natural biological classification, and their positions in hierarchical order. These are known as taxonomy ranks!

Kingdom- is the largest group, where each organism is placed

Phylum- this is the largest group within the kingdom, organisms in these section have a body plan radically different from any other phylum

Class- diversity within each phylum divides into classes

Order- divided from class, organisms that have additional features in common

Family- Divided from the order, organisms with differences less obvious

Genus- divided from family, which is then divided into species

Species!!

It can be hard to remember the ORDER of the above so here are a few rhymes to help you,

KING, PHILIP, COUNTS, ON, FUN, GREAT, SEX!!!!

KING, PRAWN, CURRY, OR, FAT, GREASY, SAUSAGES!!!

The evolutionary relationship between organisms is known as PHYLOGENY

• The phylogeny of an organism reflects the evolutionary branch that it is led up to it
• The phylogentic relationships of different species are usually represented by a tree-like diagram called a PHYLOGENTIC TREE
• In these diagrams, the oldest species is at the base of the tree. The most recent species are represented at the ends of the branches.

common ancester