Chapter 26: Diversity and the Tree of Life Flashcards
Explain what it means to be more closely related in the context of common ancestry.
If two organisms A and B are more closely related to one another, it means they have a more recent common ancestor than organisms A and C.
Define phylogeny
The evolutionary history of a taxonomic group
Define systematics
Establishing degrees of relatedness among both living and extinct species
Define taxon
The named taxonomic unit at any level of the hierarchy
Define clade
A group of taxis that includes an ancestor and all of its descendants
Define monophyletic group
A group that includes an ancestor and all of its descendants (clade)
Define paraphyletic group
A group that contains an ancestor and SOME but NOT ALL of its descendants
Descendants = future generations
Define polyphyletic group
A group of taxa with different common ancestors
Excludes their one common ancestor
Define sister taxa
Group of organisms that share an immediate common ancestor
List all the parts of a phylogenetic tree
- Ancestral Lineage
- most basal (far back) node in the tree
- Branch Root
- common ancestor of all species on the tree
- Branch Point (Node)
- where lineages diverge
- Polytomy
- a branch where more than two groups diverged (unresolved)
What are other applications of phylogenetics?
- Epidemiology
- evolution of HIV in a patient spread through population
- Murder Investigation
- Finding the source of a particular organism (anthrax bacteria)
- Identifying the species of which whale meat originated
What are homologies?
Genetic, phenotypic similarities that are the result of a shared ancestry
What are analogies?
Genetic, phenotypic similarities that developed independently of a shared ancestry (they do not have common ancestors)
What is a shared ancestral character?
A character that originated in an ancestor of the taxon
What is a shared derived character?
An evolutionary novelty unique to a particular clade
E.g. How mammals have hair
