Phylogenetics

Question 1

What is the theory of phylogenetics?

Answer 1

• Every organism on Earth evolved from a common ancestor (LUCA)
• Tries to look at the way speciation gives rise to species

Question 2

Why is phylogenetics important for agriculture?

Answer 2

• Knowing the relationships between plants is important for genetic engineering
• e.g. corn closely related to teosinte so can use pathogen-resistant genes from teosinte in corn

Question 3

Why is phylogenetics important for conservation?

Answer 3

• Increasing pressure on habitats
• Have to decide which areas to conserve
• Choose areas with most genetically diverse species
• Greater likelihood of surviving in the future as able to adapt
• A closely related group might all die

Question 4

What is phylogenetics?

Answer 4

The study of evolutionary relationships between species or molecular sequences (DNA, RNA, AA)

Question 5

How do we determine phylogenetic relationships?

Answer 5

• Look for shared and derived characters
• Indicates all species in a clade share a common ancestor
• More similar characteristics = more closely related

Question 6

What is cladistic analysis?

Answer 6

Comparison of features across animals

Question 7

What are the different types of characters?

Answer 7

• Pleisomorphic: primitive, ancestral, general
• Apomorphic: derived, more recent
• Synapomorphic: shared and derived
• Autopomorphic: unique, derived but not shared, not useful for determining relationships

Question 8

What are vestigial characters?

Answer 8

Rudimentary organs or structures with no apparent function e.g. appendix: diet has changed so no longer needed

Question 9

What are homologous characters?

Answer 9

• Characters inherited from a common ancestor

- Same basic plan but different function

Question 10

What are analogous characters?

Answer 10

• Not inherited from common ancestor

- Similar function but different structures

Question 11

What is convergent evolution?

Answer 11

Independent development of similar structures in unrelated organisms as they evolve in similar environments

Question 12

How does DNA phylogenetics work?

Answer 12

• Nucleotides at each position are homologous characters

- Useful when homologous morphology is absent e.g. plants vs. animals

Question 13

What is an outgroup?

Answer 13

An ancestral taxa which helps determine ancestral vs. derived character states

Question 14

What is a taxon?

Answer 14

A name for any rank

Question 15

What is taxonomy?

Answer 15

Methods and rules to used to make name origins

Question 16

What is binomial nomenclature?

Answer 16

Genus species

Question 17

What is the purpose of classification?

Answer 17

Information:

• Storage
• Retrieval
• Prediction

Question 18

What are the different taxonomical classification?

Answer 18

• Monophyletic: all descendants of a common ancestor
• Paraphyletic: excludes some descendants
• Polyphyletic: unrelated taxa grouped together (possibly due to convergent evolution)

Question 19

What is a clade?

Answer 19

A group of organisms related by descent defend by homologous synapomorphic characters