OCR - A-Level - Biology - Evidence used in Classification

Biological Molecules
1. More similar molecules, more closely related
  1. Determines closeness of relation as well as spp group
Cytochrome C
1. A protein used in respiration which differs between species
2. Compare amino acid sequences to determine drift of closeness of relation
  1. More similar sequence, more closely related.
3. Can take you to a certain point
  1. E.g. Humans are identical to chimpanzees
  2. Other methods are needed to classify further
DNA
1. Genetic code is a sequence of base pairs
  1. Differences in base pairs between species originated from mutation, to evolution
    1. Comparing DNA identifies similarities and differences
      1. More different, less related
RNA
1. Sequences of base pairs
Convergent evolution
1. Organisms that aren't closely related develop similar traits due to environmental factors
3 Domain Classification
1. Eukaryote
  1. Similar enzymes for synthesising RNA
    1. Similar mechanisms DNA replication and RNA synthesising
      1. Production of some proteins that bind to their DNA
2. Prokaryote
  1. Bacteria (Eubacteria)
    1. Different cell membrane structure
      1. Flagella with a different internal structure
        Different enzymes for synthesising RNA
        Different mechanisms for DNA replication and RNA synthesising
        No proteins bound to genetic material
  2. Archaebacteria (Archaea)

Resource summary

	Created by Josh Anderson over 7 years ago