2.1c Identification and taxonomy Flashcards
Identification of an organism
the identification of an organism in a sample can be made using classification guides, biological keys, or analysis of DNA or protein.
Classified
Organisms can be classified by both taxonomy and phylogenetics
Taxonomy
It involves the identification and naming of organisms and their classification into groups based on shared characteristics.
Classic taxonomy classification is based on morphology (structure of organisms).
Phylogenetics
Phylogenetics is the study of the evolutionary history and relationships among individuals or groups of organisms.
It uses heritable traits such as morphology, DNA sequences, and protein structure to make inferences about an organisms evolutionary history and create a phylogeny (phylogenetic tree) - a diagrammatic hypothesis of its relationships to other organisms.
Genetic evidence can reveal relatedness obscured by divergent or convergent evolution.
Why is it good to know taxonomic groups?
Familiarity with taxonomic groupings allows predictions and interfences to be made about the biology of an organism from better known (model) organisms. Nematodes, arthropods and chordates are examples of taxonomic groups.
Model Organisms
Model organisms are those that are either easily studied or have been well studied. Information obtained from them can be applied to other species that are more difficult to study directly.
Examples of model organisms
Bacterium E.coli, the flowering plant Arabidopsis thaliana, the nematode C.elegans, the arthropod Drosophila melanogaster (a fruit fly), mice, rats and zebrafish which are all chordates, have been very important in the advancement of modern biology.
Divergent evolution
Is the accumulation of differences as species from a common ancestor undergo changes over time e.g. changes to the pentadactyl limb in mammals.
Convergent evolution
Is where similar structures have evolved from different ancestries e.g. wings in bats and birds.
