Chapter 24 & 25- Macroevolution

Phylogeny: demonstrates the evolutionary history of a species or groups of species; show patterns of descent, no phenotypic similarity; they do not generally indicate when a species evolved or how much change occurred (these things have to be noted in a tree to be considered); cannot be assumed that one taxon evolved from the taxon next to it, just that they had a common ancestor.

Understand taxonomy and binomial nomenclature

taxonomy: system created to order the division and name of organisms

binomial nomenclature:

• the first part of the name is the genus 

  • ex. drosophila

• the second part called the specific epithet is unique for each species 

  • ex. drosophila melanogaster

first letter is capitalized and entire species name is italicized

• ex. D. melanogaster

Know how to read phylogenetic trees and consider relationships between organisms (more-or-less related compared to other members of the tree)

Key vocab words to know and understand: taxa/taxon, branch point, clade, basal taxon, sister taxa, outgroup

taxa/taxon: named group of organisms

branch point: represents the divergence of two taxa from a common ancestor  

clade: group of species that includes an ancestral species and all its descendants

basal taxon: diverged early in the history of a group and origin near the common ancestor of the group

sister taxa: groups that share immediate ancestor 

outgroup: species that is closely related to the ingroup, the various species benign studied. 

Be able to describe homology vs. analogy

homology: similar due to shared ancestry/divergent evolution

analogy: similar due to convergent evolution; similar environments caused unrelated species to develop similar adaptive traits

Molecular homologies are based on similarity at the DNA (or protein) level; phylogenetic trees based on DNA sequences changes: length of a branch can reflect number of genetic changes. 

Homoplasies are examples of phenotypes/characteristics that are similar between organisms that are unrelated (e.g. both bats and bugs can fly)

Shared ancestral characters: originated in an ancestor of a taxon 

Shared derived characters: evolutionary novelty that is unique to a clade or taxon - Some characters can be both ancestral and derived depending on context

Define and be able to apply maximum parsimony to creation of phylogenies 

maximum parsimony: make a family tree for species by choosing the simplest explanation—meaning the tree that needs the fewest changes in traits or DNA.

Be able to read and interpret phylogenetic trees