Phylogenetics Flashcards
What is the theory of phylogenetics?
- Every organism on Earth evolved from a common ancestor (LUCA)
- Tries to look at the way speciation gives rise to species
Why is phylogenetics important for agriculture?
- 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
Why is phylogenetics important for conservation?
- 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
What is phylogenetics?
The study of evolutionary relationships between species or molecular sequences (DNA, RNA, AA)
How do we determine phylogenetic relationships?
- Look for shared and derived characters
- Indicates all species in a clade share a common ancestor
- More similar characteristics = more closely related
What is cladistic analysis?
Comparison of features across animals
What are the different types of characters?
- Pleisomorphic: primitive, ancestral, general
- Apomorphic: derived, more recent
- Synapomorphic: shared and derived
- Autopomorphic: unique, derived but not shared, not useful for determining relationships
What are vestigial characters?
Rudimentary organs or structures with no apparent function e.g. appendix: diet has changed so no longer needed
What are homologous characters?
- Characters inherited from a common ancestor
- Same basic plan but different function
What are analogous characters?
- Not inherited from common ancestor
- Similar function but different structures
What is convergent evolution?
Independent development of similar structures in unrelated organisms as they evolve in similar environments
How does DNA phylogenetics work?
- Nucleotides at each position are homologous characters
- Useful when homologous morphology is absent e.g. plants vs. animals
What is an outgroup?
An ancestral taxa which helps determine ancestral vs. derived character states
What is a taxon?
A name for any rank
What is taxonomy?
Methods and rules to used to make name origins
