taxonomy and phylogeny

Question 1

what is taxonomy? how are similar taxa brought together?

Answer 1

• The science of naming and classifying organisms - according to similarity
  
  • Taxa that are most similar are brought together in a genus, genera that are most similar are placed in the same family, etc

Question 2

what are systematics? who is will hennig?

Answer 2

• The field of biology that studies and tries to establish phylogenies (evolutionary histories)
• Often confused with taxonomy
• Includes taxonomy and concept of methods and systems
• Willi hennig (1913 = 1913 - 1976)
○ German entomologist
○ Father of phylogenetic systematics or cladistics (1950)

Question 3

what are claudistics based on?

Answer 3

• Based on character that most clearly reveal evolutionary relationships
  
  • Many characters can be measured, but not all are useful
  • The most convenient way of presenting evolutionary relationships among a group of organisms is a phylogenetic tree or cladogram

Question 4

what are synapomorphies?

Answer 4

• Synapomorphies: shared derived characters
homology
• Phylogenies should be directly related to classification

Question 5

what is plesiomorphic?

Answer 5

• Plesiomorphic: primitive character state
○ Earliest
○ Original character state that gve rise to derived state

Question 6

apomorphic?

Answer 6

• Apomorphic: derived character state
○ Advanced or descended
○ Character state derived from primitive state

Question 7

what are homologous characters? what do they indicate?

Answer 7

• Similarities due to shared ancestry
• Sharing of homologies among species indicates that they have evolved from a common ancestor that possessed the same feature
• Do not necessarily have the same function
•

Question 8

what are the basic rules of cladistics?

Answer 8

• All species in a natural group (clade) share the most recent common ancestor
• All species that share this ancestor must be included in the group
Goal is to produce a monophyletic tree

Question 9

what does monophyletic mean? para? poly?

Answer 9

• Monophyletic
○ A taxon in which all species share a common ancestor and all species derived from that common ancestor
• Paraphyletic
○ A taxon in which all species share a common ancestor, but not all species derived from that common ancestor are included
• Polyphyletic
○ Derivation of a taxon from two or more ancestral sources

Question 10

define clade, root, node, branch, and sister groups

Answer 10

• Clade: a group of two or more taxa that includes both their common ancestor and all descents
  
  • Root: the common ancestor of all taxa
  • Node: a branch point in a tree
  • Branch: defines the relationship between the taxa in terms of descent and ancestry
  • Sister groups: two clades resulting from the splitting of a single lineage

Question 11

how can you use synapomorphies?

Answer 11

•
• Use synapomorphies to produce a phylogenetic tree:
○ Compare the ingroup to the outgroup