Classification
Classification
- Nomenclature: naming of organisms
- Binomial: biological name of an organism → Genus species (eg Homo sapiens)
- Taxon: set of organisms within a category / taxonomy / study of biological classification
- Different levels of taxons:
Kingdom King's
Phylum Pupils
Class Can
Order Only
Family Find
Genus Great
species Success - Five Kingdoms:
- Prokaryotae
- Protoctista
- Fungi
- Plantae
- Animalia
Human classification
-
- Kingdom: Animalia (no cell wall, eat other organisms)
- Phylum: Chordata
- Class: Mammalia (produce milk from mammary glands)
- Order: Primates
- Family: Hominidae
- Genus: Homo
- Species: sapiens
- Most basic unit of biological classification
- Members of a species are similar (phenotype) to each other but different from other species
- Similarity can be
- physical (branching pattern of trees)
- biochemical (haemoglobin structure)
- immunological (antibody against an antigen equally effective)
- development (similar growth of embryos)
- ecological (occupy identical ecological niche)
- Similarity can be
- Members of a species are able to reproduce giving fertile offspring
- Each species is reproductively isolated from every other species
- Prevents exchange of genes
- Species keep special characteristics that distinguishes them
- Each species is reproductively isolated from every other species
- Biochemical
Cytochrome c- Protein used in cellular respiration and found in mitochondria
- Count number of amino acids that organisms differ by
- Higher number, more distant ancestor
DNA hybridisation
- Denature/ 'unzip' DNA from 2 different species
- Mix them to allow complementary base pairing
- Heat the hybrid DNA - the higher the temperature to separate the strands the greater the similarity, (more base pairing = more energy required to separate hybrid DNA strands)
Anatomical
- Similar anatomical structure, more closely related
Embryological
- Similar stages of development due to common ancestor
Immunological
- Human blood serum is injected into a test animal
- Test animal recognizes foreign proteins (antigens) and produces antibodies
- Serum blood of immunized test animal is added to all test tubes
- Add human serum to one test tube (control)
- Add serum of other organisms to other test tubes (compare with control)
- Antigen-antibody complexes form and precipitate from solution
- Higher amount of precipitation, closer related to humans
Behavioural
- Similar behaviour due to common ancestor
- Primates live in social groups, communicate by facial expression, long parental care
Classification
Classification of Living Things