Chapter 15: Tracing Evolutionary History Flashcards
define adaptive radiations
periods of evolutionary change in which many new species evolve from a common ancestor
when do adaptive radiations often occur?
following the colonization of new unexploited areas or evolutionary innovations
what can result in adaptive radiations?
colonization
evolution acts upon
available diversity
“Evo-devo” combines…
evolutionary and developmental biology
new forms can evolve by…
changes in the number, sequences, or regulation of developmental genes
homeotic genes are AKA
master control genes
homeotic genes determine…
basic features
-where pairs of wings/legs develop on a fruit fly
profound alterations in body form can result from..
- changes in homeotic genes
- how/where homeotic genes are expressed
what might have facilitated the origin of new body forms?
new developmental genes that arose as a result of gene duplications
timing of gene expression changes…
phenotype
define heterochrony…
genetically controlled difference in timing/duration of a developmental process in an organism
describe the evolution of novel traits…
complex structures that evolve in stages from simpler version with
- the same basic function
- gradual adaptation of existing structures to new functions
define exaptation
co-opting a trait that evolved in one circumstance for a novel function
feathers are…
specialized forms of scales
an evolutionary trend may be the result of…
species persistence of natural selection in changing environments
define taxonomy
branch in biology concerned with identifying, naming, and classifying species
define a binomial
two-part scientific name assigned to species
describe the parts to a binomial name…
- genus
- specific epithet
binomials show
shared common ancestry
specific epithets
can be shared
define a phylogeny
the evolutionary history of a species or group of species
define systematics
discipline of biology that focuses on classifying organisms and determining their evolutionary relationships
define phylogenetic tree
a hypothesis of evolutionary relationships
a phylogenetic tree is constructed from…
homologous characters
what provides the evidence of common ancestry that’s used to determine phylogeny?
homologous structures and molecular sequences
define convergent evolution
similarities due to the similar adaptations in organisms from different evolutionary lineages
define analogy
similarity due to convergent evolution
birds and human forearm bones are
not homologous as wing but analogous as wings
flippers are ______, why?
analogous
bc they do not share a common ancester
cladistics groups
organisms on a phylogeny by common ancestry
define a monophyletic group
group consisting of ancestral species and all of its evolutionary descendants
paraphyletic and polyphyletic groups are NOT
natural
an organism’s evolutionary history is documented in its
genome
similar DNA sequences indicate
two species that have recently branched from a common ancestor
molecular systematics uses
DNA or other molecules to infer relatedness
homologous genes are found across
distantly related species
homologous genes can suffer from
convergent evolution or oversaturation
a molecular clock is a method that
estimates the time required for a certain amount of evolutionary change
what helps classify the major divisions in life?
molecular clock
the tree of life is originally based on
rDNA
what are the 3 domains that life is currently classified into?
- eukarya
- bacteria
- archaea
the tree of life shows us…
multiple horizontal gene transfers
these horizontal gene transfers include
transfers that resulted in the origin of eukaryotic cells
examples of horizontal gene transfers…
the endosymbiosis of mitochondria and chloroplasts
