chapter 26 ap bio

phylogeny

the evolutionary history of a species or group of related species

systematics

classifies organisms and determines their evolutionary relationships

taxonomy

the ordered division and naming of organisms

phylogenetic tree

diagram showing evolutionary relationships of organisms with a common ancestor; resembles a tree

outgroup

a group that one does not belong to or identify with; acts a comparison group

homologies

phenotypic and genetic similarities due to shared ancestry

analogy

similarties dye to convergent evolution

convergent evolution

occurs when similar environmental pressures and natural selection and produce similar adaptations in organisms from different evolutonary lineages

homoplasies

analogous structures that evolved independently

molecular systematics

uses DNA and other molecular data to determine evolutionary relationships

cladistics

groups organisms by common descent

clade

a group of species that includes an ancestral species and all its descendants

mononphyletic

includes a common ancestor and all of its descendants

paraphyletic

consists of an ancestral species and some, but not all, of its descendants

polyphyletic

consists of various species with different ancestors

shared ancestral character

a character that originated in an ancestor of the taxon

plesiomorphy

an ancestral character

shared derived character

an evolutionary novelty unique to a particular clade

synapomorphy

shared derived character

maximum parsimony

applying the simplest, most obvious way with the least number of steps

maximum likelihood

given certain rules about how DNA changes over time, a tree can be found that reflects the most likely sequence of evolutionary events

phylogenetic bracketing

allows us to predict features of an ancestor from features of its descendants

rRNA

DNA that codes for rRNA changes slowly and is useful for investigating branching points

mtDNA

evolves rapidly and can be used to explore recent evolutionary events

gene duplication

increases the number of genes in the genome, providing more opportunities

orthologous genes

found in a single copy in the genome and are homologous between species (diverge after speciation occurs)

paralogous genes

result from gene duplication, so are found in more than one copy in the genome

molecular clock

model that uses comparisons of DNA sequences to estimate phylogeny and rate of evolutionary change

early species classification

plants or animals

five kingdoms

monera, protistam plantae, fungi, animalia

3-domain system

bacteria, archaea, eukarya

tree of life

based largely on rRNA; suggests that eukaryotes and archaea are more closely related than to bacteria

horizontal gene transfer

movement of genes from one genome to another