Classification and Evolution

Classification basics

classification- arranging organisms into groups based on their similarities and differences

taxonomy- study of classification

taxonomic hierarchy:

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

5 Kingdoms

Prokaryotae: EG bacteria, Features prokaryotic unicellular no nucleus less than 5 um

Protoctista: EG algae, Features eukaryotic usually aquatic single celled or simple multicelled

Fungi: EG moulds, Features eukaryotic chitin cell wall saprotrophic single celled or multicellular

Plantae: EG mosses, Features eukaryotic multicellular cellulose cell wall photosynthesis autotrophic

Animalia: EG insects, Features eukaryotic multicellular no cell wall heterotrophic

Phylogeny- study of the evolutionary history of groups of organisms

Cladistics: taking phylogeny into account when arranging organisms into groups

the evolution of classification systems

classification used only use observable features; or anatomical, today classification is based on anatomical, embryological, fossil and molecular evidence

molecular evidence: analysising similarities in proteins and DNA

new technologies can result in new discoveries being made

The 5 kingdoms got replaced by the 3 domains in 1990, Domain: bacteria, archaea and eukarya

prokaryotae were separated into bacteria and archaea, the other kingdoms went into eukarya

Variation

intraspecific- variation within species

interspecific- variation between species

continuous variation- individuals in a population vary within a range

discontinuous variation- 2 or more distinct categories that each individual falls into

causes of variation

Genetic variation: different species have different genes. individuals of the same species have same genes but different forms called alleles. the alleles make up the genotype, differences in genotype cause variation in phenotype.

Environmental variation: differences caused by the environment and upbringing.

both genetic and environmental: environmental factors can infulence how some characteristics develop.

investigating variation

Mean- average of the values collected in sample

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