9.2 Evidence Use In Classification Flashcards
Anatomical:
Classification related to the anatomy and structure and function of organisms and their parts
Biochemical:
Characterised by, produced by or involving chemical reactions in living organisms - usually DNA and proteins are compared
Embryological:
Classification related to embryo development
Immunological:
Classification related to the body’s natural defences or immunity against disease (immune response)
Behavioural:
Classification related to behavioural interactions
How does biochemical evidence help in classification:
- Enables scientists to confirm phylogenies and disprove others
- Can date each split in the lineage
- DNA-DNA hybridisation compares the total genomes of different species (measuring the degree of genetic similarity - determines genetic distance, more similarity in genomes=less time for mutation)
- Protein sequencing establishes homologies
- Amount of molecular change a protein shows can be used as a molecular clock to date evolutionary events
Example of biochemical =
Sequence homologous of cytochrome c used to construct a phylogenetic tree for species across a wide range of taxa
How does anatomical help in classification?
- Determine relationships between organisms based on overall degree of similarity or by tracing the appearance of key characteristics
- Homologies suggest that they all descended from a common ancestor with that feature
Examples of anatomical:
-Bones of the forelimb of air-breathing vertebrates are composed of similar bones arranged in a comparable pattern - common ancestry
How does embryological help in the classification?
-Early embryos look very similar; it is only in the later stages of development that the embryos look different - evolved from a common ancestor
Example of embryological:
All vertebrate embryos have a tail-like structure early in their development, but only some of them have a tail in the later stages
