Ch. 26 Phylogeny

phylogeny

evolutionary history of a species/group of related species

systematics

discipline that classifies organisms based on evolutionary history

morphology

Linnaeus’ system of taxonomy that is based on resemblances

binomial nomenclature

naming system created by Linnaeus that writes a species name as Genus species

domain, kingdom, phylum, class, order, family, genus, species

list the hierarchal classifications in order of increasing specificity

taxon

group at any level of hierarchy

no

Does the Linnaean system always reflect evolutionary relationships?

branch point

represents divergence of two evolutionary lineages from a common ancestor on a phylogenetic tree

evolutionary lineage

sequence of ancestral organisms leading to a particular descendant taxon

sister taxa

groups that share a common ancestor that isn’t shared by any other group

basal taxon

lineage that diverges from all other members of the group earliest in history

patterns of descent

Do phylogenetic trees show patterns of descent or phylogenetic similarity?

no

Can a taxon evolve from its sister taxon?

homologies

phenotypic and genetic similarities due to shared ancestry (ex. human limb structure vs. whale limb structure)

analogies

similarities due to convergent evolution (ex. insect wings vs. bird wings)

more

the more similarity between complex structures, the ____ (more/less) likely they evolved from a common ancestor

less

the closer related species are, the ____ (more/less) sites they’ll have along their DNA sequence that differ

point mutation

type of genetic alteration in which a single nucleotide base is added, deleted, or changed

cladistics

system of organization that groups organisms primarily by common ancestry

clade

group of species that includes an ancestral species and all its descenedants

monophyletic groups

group that consists of ancestor and all its descendants (only type of group that is considered a clade)

paraphyletic group

group that consists of ancestral species and some (not all) of the descendants

polyphyletic group

group that consists of distantly related species but not their most recent common ancestor

shared ancestral character

character that originated in an ancestor of the taxon (ex. having a backbone compared to those in a vertebrate clade)

shared derived character

evolutionary novelty unique to a particular clade (ex. hair on mammals when compared to other vertebrates)

outgroup

species/group of species closely related to but not part of the group of species being studied (the ingroup)

ancestral

Are the characters shared by an outgroup and an ingroup assumed to be ancestral or evolutionary?

once

each derived character is assumed to have arisen ____ (once or twice) in the ingroup

branch length

part of a phylogenetic tree that can reflect time that has passed or the number of genetic changes

maximum parsimony

most likely tree is the one that requires the fewest evolutionary events

maximum likelihood

most likely tree to have produced a given set of DNA data based on probability rates and how DNA changes over time

phylogenetic bracketing

predicts that features shared by two closely related groups will present in their ancestor and all its descendants

increases

genetic mutations ____ (increase/decrease) opportunities for evolutionary change

orthologous genes

type of homologous gene in which homology is the result of a speciation event and occurs between genes found in different species

paralogous genes

type of homologous gene in which homology is the result of gene duplication and occurs between gene copies within a species

molecular clock

approach used to estimate absolute time of evolutionary change; estimate is based o observation that some genes appear to evolve at a constant rate

true

limitation of molecular clock approach: (true/false) some genes evolve in irregular bursts, rather than clocklike precision

true

limitation of molecular clock approach: (true/false) the rate of evolution deviates from the average periodically, even in reliable clocklike genes

false

limitation of molecular clock approach: (true/false) the same gene cannot evolve at different rates in different taxa

true

limitation of molecular clock approach: (true/false) some clocklike genes evolve at dramatically different rates from each other

more

the less critical a gene is, the ____ (more/less) mutations will be neutral and the faster change will be

horizontal gene transfer

movement of genes from one genome to another; can occur by exchange of transposable elements and plasmids, viral infection, and possibly fusion of organisms

and

horizontal gene transfer played a role in the evolution of prokaryotes ____ (and/not) eukaryotes

harder

horizontal gene transfer makes it ____ (easier/harder) to construct a phylogenetic tree

true

true/false: eukaryotes can acquire nuclear genes from bacteria and archaea