Classification and phylogeny

1
Classification and phylogeny

• ByChangting Luo

2
What is Classification

• Classification in biology is arranging living
  organisms into groups.

3
Reasons for classification

• Species identificationIt is easier to find out
  to which species an organism belongs with
  organisms classified rather than forming a
  disorganized catalogue.
• Predictive valueIf several members of a group
  have a characteristic,another species in this
  group will probably also have this
  characteristic.
• Evolutionary linksSpecies that are in the same
  group probably share characteristic because they
  have evolved from a common ancestor,so the
  classification of groups can be used to predict
  how they evolved.

4
Natural classification VSArtificial
classification

• Natural classification is base on homologous
  structures-structures that have a common
  evolutionary origin,even if their function is
  different

• Artificial classification is base on analogous
  structure-structures with a common function,but a
  different evolutionary origin.

5
Natural classification VSArtificial
classification
6
Biochemistry and common ancestry

• Similarities between living organisms in their
  biochemistry
• All use Dna as their genetic material
• All use the same universal genetic code, with
  only a few insignificant variations.
• All use the same 20 amino acid in their proteins.
• All use left and not right handed amino acids
• ResultAll organisms havd evolved from a
  ancestor.

7
Phylogeny and biochemistry

• Tracing evolutionary links and origins is called
  phylogeny.
• Phylogenetics using the biochemistry like
  structure of a protein(dna)to figure out the
  relationship between the organisms.

8
Example

• Nymphalidae phylogeny