BIODIVERSITY

SPECIES AND TAXONOMY

SPECIES: groups of organisms that are capable of breeding to produce living, fertile offspring

THE BINOMIAL SYSTEM

• generic name - the genus to which the organism belongs
• specific name - the speices to whiich the organism belongs
• printed in italics and underlined when handwritten
• first letter of generic name in italics, all of specific name in lowercase
• specific name written as sp. if not known

COURTSHIP BEHAVIOUR

• members of a species have similar/the same genes
• will resemble one another physically and biochemically - helps them distinguish between members of their own species and members or others
• the same for behaviour
• courtship behaviour enables individuals to...

- recognise members of their own species (ensures fertile offspring will be produced upon mating

- identify a mate capable of breeding (both partners need to be sexually mature, fertile and receptive

- form a pair bond (leads to successful mating and bringing up of offspring)

- synchronise mating (maximum probability of sperm and egg meeting)

- become able to breed (physiological state that allows mating to occur

CLASSIFICATION - the grouping of organisms

ARTIFICIAL CLASSIFICATION

• divides organisms according to differences that are useful at the time
• e.g. colour, size, number of legs - ANALGOUS CHARACTERISTICS: the same function but not the same evolutionary origins
• e.g. the wings of birds and butterflies have the same function but didn't come about for the same reasons

PHYLOGENETIC CLASSIFICATION

• based upon evolutionary relationships between organisms and their ancestors
• classifies species into groups using shared features derived from these ancestors
• arranges groups into a herarchy - groups contained in larger composite groups with no overlap
• partly based on HOMOLOGOUS CHARACTERISTICS: the same evoltuionary origins regardless of their functions (e.g. human arms, bird wings, horse legs)

TAXONOMY - the theory and practice of biological classification

DOMAIN - Bacteria, Archaea, Eukarya

Bacteria

• no membrane-bound organelles
• unicellular
• 70S ribosomes
• murein cell walls
• single loop of DNA but no histones

Archaea

• similar genes and protein synthesis to eukaryotes
• membranes contain fatty acid chains attached to glycerol by ether linkages
• no murein in cell walls
• more complex form of RNA polymerase

Eukarya

• membrane-bound organelles
• membranes contain fatty acid chains attached to gylcerol by ester linkages
• when they posess a cell wall it does not contain murein
• 80S ribosomes

KINGDOM

PHYLUM

CLASS

ORDER

FAMILY

GENUS

SPECIES

PHYLOGENY

• the evolutionary relationship between organisms, usually represented by a tree diagram whereby the more recent two species' common ancestor, the more closely related they are

DIVERSITY WITHIN COMMUNITIES

SPECIES DIVERSITY: the number of different species and the number of individuals of each species…