Lecture 6/7 Flashcards
What is Gene Flow (Migration)?
The flow of individuals of the same species from one population into another
What can Gene Flow do?
Alter allelic frequencies
Introduce New Genetic Variation
What happens to two populations that maintain a lot of gene flow?
They will become more genetically similar over time.
What does speciation require?
Maintaining no gene flow between populations
What are Phylogenetic Trees?
Depict evolutionary relationships between different taxa and are based on common ancestry
How are species more closely related?
If they have a more recent common ancestor
What do Phylogenetic trees help us to understand?
- How closely related taxa are (evolutionary history)
- Understand trait evolution - why two taxa may be similar/share traits
- Useful tool for tracking emergent diseases
How are Phylogenetic Trees Drawn
- Blocks vs Diagonal Lines
- Horizontal vs Vertical
- Relative time vs absolute time
- Extant species only vs including extinct species
What could you use to construct an evolutionary tree?
- Any heritable features of your taxa
- Historically morphological and behavioural traits
- Molecular traits (genetics, proteins, sequences)
What is a Sister Taxa?
Closest relatives of one another on the displayed tree
What is an Outgroup?
Most distantly related taxa to other terminal nodes on the tree
What is a Monophyletic Clade?
A common ancestor and all of its descendants (keeping everything/able to cut it off from its branch)
What is not a Clade?
Common ancestor and a subset of its descendants
What should you do when asked to compare the relatedness between two different pairs of taxa:
- Find the most recent common ancestor
What can traits help us understand?
Trait Evolution (where a new trait may have evolved from)
