species and taxonomy
Cards (17)
- A species is the basic unit of classification, a group of organisms that can interbreed and produce fertile offspring.
- Hybrids are when different species interbreed to produce infertile offspring, this is due to the odd number of chromosomes.
- Classification is the arrangement of organisms into groups of various sizes on the basis of shared features.
- Taxonomy is a form of classification that focuses on physical similarities between different species.
- The Linnaean taxonomy is the basis of the classification systems used today. It uses a hierarchy in which smaller groups are placed in larger groups with no overlap between groups.
- Taxonomic groups:
- Domain
- Kingdom
- Phylum
- Class
- Order
- Family
- Genus species
- The three domains are bacteria, archaea and Eukarya.
- Vertebrates are split into:
- Mammals
- Fish
- Reptiles
- Amphibians
- Birds
- Invertebrates are split into:
- Cnidarians
- Flatworms
- True worms
- Molluscs
- Echinoderms
- Arthropods
- Binomial names include the organisms genus and species.
- Phylogenetic classification looks for common features that must be due to common ancestors, not to evolutionary pressure.
- A good indicator of relatedness is the similarity of sections of non-coding DNA.
- Comparing amino acid sequences can be used to determine relations, however its not as useful as DNA base sequence comparisons because it does not show non-coding sections.
- Proteins of different species can also be compared using immunological techniques. Antibodies of one species will react to antigens in the blood of another. The more antibody-antigen complexes form the more closely related species A and B are.
- Simple courtship behaviours are things like releasing pheromones and calling.
- Complex courtship behaviours include: singing, dancing and building nests.
- A stimulus which causes an instinctive behavioural sequence that is relatively invariant within species and almost inevitably runs to completion. Different species will have different stimuli.