Chapter 20 Phylogenies and the history of life

phylogeny

the evolutionary history of a species and its relationship to other species

what are the 2 types of phylogenetic trees?

rooted and unrooted

what are rooted trees?

they have a single lineage(at base) that represents common ancestor

what is an unrooted tree?

it shows relationships but not a common ancestor

What are the 3 domains of life ?

bacteria, archaea, and eukarya

who proposed all life on Earth can be classified into 3 domains?

microbiologists Woese, Kandler, and Wheelis

Is archaea more closely related to bacteria or eukarya?

eukarya bc they share a common ancestor where as bacteria does not

Which of the 3 domains of life are prokaryotes ?

bacteria and archaea

What are characteristics of bacteria ?

the cells do not contain a nucleus

What are characteristics of archaea?

the cells do not contain a nucleus and they have a different cell wall from bacteria

What are characteristics of eukarya?

the cells do contain a nucleus including plants, animals, fungi, and protists

animals under animal kingdom do not have what?

a cell wall

what does a root indicate on a phylogenetic tree?

an ancestral lineage gave rise to all organisms on the tree

what does a branch point indicate on a phylogenetic tree?

where 2 lineages diverged

basal tax on

a lineage that evolved early and remains unbranched

sister taxa

2 lineages stem from the same branch point (node)

polytomy

a branch with > 2 lineages that is an unresolved pattern of divergence

what does rotation of a branch point do?

it does NOT change the information in a phylogenetic tree

what else is a branch point called?

a node

taxa

group(s) of organisms

what are examples of taxa ?

species, family, domain, etc.

Taxa that share a more recent common ancestor w/ one another are…

more closely related than are taxa who’s most recent common ancestor is older

what is a clade?

a grouping that includes a common ancestor and all the descendants (living and extinct) of that ancestor

monophyletic group

consists of an ancestral species and all of its descendants

paralytic group

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

polyphyletic group

includes distantly related species but not their most recent common ancestor

what’s another way to display a phylogenetic tree?

with different characters placed in different groups based on the characteristics they share

The length of the branch does not indicate amount of time passed since the split(node) unless what?

unless specified

taxonomy

grouping or classifying species tg based on similarities and differences

Is taxonomy based on evolutionary relationships?

no

what does binomial nomenclature mean?

scientific name

who created binomial nomenclature and when?

Carl Linnaeus in the 1800s

what should be done to the binomial nomenclature?

the Genus should be capitalized and both the genus and species should be italicized

what is hierarchical classification?

physical characteristics displayed by a hierarchical model

what can the taxonomic classification system also be called?

Linnaean system

going from domain to subspecies is that more specific or more general?

more specific

what is singular taxa?

tax on

what’s the order from kingdom to species of animals ?

animals

chordates

mammals

primates

hominids

homo

homo sapiens

what are advantages of phylogenetic classification?

it tells evolutionary history and doesn’t rank organisms nor suggest 2 identically ranked groups are comparable

what does Linnaean classification do?

ranks groups of organisms artificially into kingdoms, phyla, orders, etc. that most closely reflects evolutionary history

cladistics

a method of determining phylogeny or hypothesizing relationships among organisms is

analysis of organisms depends on…

characters : anatomical or physiological or behavioral or genetic sequences

shared ancestral character

a characteristic is found in the ancestor of a group bc all organisms in the radon or clade have that trait

shared derived character

a characteristic is found in only some organisms of the group bc this characteristic derived at some point but doesn’t include all ancestors of the tree

based on DNA the most parsimonious tree requires ?

the fewest base changes

principle of maximum parsimony

starting w all of the homologous traits in a group of organisms, scientists look for the most obvious and simple order of evolutionary events that led to the occurrence of those traits

why does phylogeny matter?

bc it enriches our our understanding of how genes, genomes, species evolve