Exam 2 Flashcards
Species
A group of organisms that exchange genes within the group, but cannot do so with other groups
Biological species concept
Species are classified through reproductive isolation
Morphological species concept
Species are classified through morphological traits
Phylogenetic species concept
Species are classified through evolutionary history
Synapomorphy
A trait found in certain groups and their common ancestor but is missing in more distant ancestors
Speciation
The formation of a new species
Allopatric speciation
Geographic isolation that creates new species
Dispersal
Movement of individuals from one place to another
Vicariance
Physical splitting of a habitat
Sympatric speciation
Speciation occurs between populations in the same geographic area
Sympatry
Populations live in the same geographic area
Extrinsic factors
Disruptive selection due to environmental difference or mate preference (outside the organism)
Intrinsic factors
Chromosomal mutations (inside the organism)
Polyploidy
Condition of possessing more than two complete sets of chromosomes
Autopolyploidy
Mutation results in the doubling of chromosome number and all chromosomes come from the same species
Allopolyploidy
Parents of different species mate and an error in mitosis occurs
Phylogeny
Branching evolutionary history of related species
Phylogenetic tree
A graph that allows us to visualize phylogeny
Systematics
Discipline of biology that characterizes and classified the relationships among all organisms on earth
Branch
A line represent a species or other taxon through time
Root
Most ancestral branch of a tree
Tip
Endpoint of a branch, representing living or extinct species
Outgroup
A taxon that diverged before the rest of the taxa that are the focus of the study
Node/fork
A point within the tree where a branch splits into two or more branches, represents the most recent common ancestor