Chapter 26 Flashcards
phylogeny
the evolutionary history of a species or group of related species
systematics
classifies organisms and determines their evolutionary relationships
-use fossil, molecular, and genetic data to infer evolutionary relationships
taxonomy
the ordered division and naming of organisms
binomial
the two part scientific name of a species
genus
first part of the name of species
specific epithet
second part of name of species
the taxonomic groups from broad to narrow are … (8)
- domain
- kingdom
- phylum
- class
- order
- family
- genus
- species
taxon
a taxonomic unit at any level of hierarchy
phylogenetic trees
systematists depict evolutionary relationships
phylocode
which recognizes only groups that include a common ancestor and all its descendents
a phylogenetic tree represents …
a hypothesis about evolutionary relationships
branch point
represents the divergence of two species
sister taxa
groups that share an immediate common ancestor
rooted tree
includes a branch to represent the last common ancestor of all taxa in the tree
basal taxon
diverges early in the history of a group and originates near the common ancestor of the group
polytomy
a branch from which more than two groups emerge
phylogenetic trees show patterns of ____
descent, not phenotypic similarity
do phylogenetic trees indicate when species evolve or how much change occurred in a lineage?
no
to infer phylogenies systematists gather _____, ______, and ____
- information about morphologies
- genes
- biochemistry of living organisms
phenotypic and genetic similarities due to shared ancestry are ____
homologies
similarity due to convergent evolution
analogy
similarity due to shared ancestry
homology
convergent evolution
occurs when similar environmental pressures and natural selection produce similar (analogous) adaptations in organisms from different evolutionary lineage
homoplasies
Analogous structures or molecular sequences that evolved independently are also called
homoplasies
homology can be distinguished form analogy by….
comparing fossil evidence and the degree of complexity
the more complex two similar structures are, the more likely it is that they are ______
homologous
molecular systematics
uses DNA and other molecular data to determine evolutionary relationships
cladistics
groups organisms by common descent
clade
a group of species that include an ancestral species and all its descendants
do all groupings of organisms qualify as clades?
no
monophyletic
signifying that it consists of the ancestor species and all its descendants
paraphyletic grouping
consists of an ancestral species and some, but not all, of the descendants
polyphyletic grouping
consists of various species with different ancestors
in comparison with its ancestor, an organism has both ____ and ______
shared and different characteristics
shared ancestral character
a character that originated in an ancestor of the taxo
shared derived character
an evolutionary novelty unique to a particular clade
outgroup
a species or group of species that is closely related to the ingroup, the various species being studied
-outgroup is a group that has diverged before the ingroup
ingroup
the various species being studied
characteristics shared by the outgroup and ingroup are ….
ancestral characters that predate the divergence of both groups from a common ancestor
maximum parsimony
assumes that the tree that requires the fewest evolutionary events (appearances of shared derived characters) is the most likely
maximum likelihood
states that, given certain rules about how DNA changes over time, a tree can be found that reflects the most likely sequence of evolutionary events
gene duplications increases the number of genes in the genome, providing….
more opportunities for evolutionary changes
repeated gene duplications result in
gene families
like homologous genes, duplicated genes can be traced to ….
common ancestor
orthologous genes
found in a single copy in the genome and are homologous between species
-they can diverge only after speciation occurs
paralogous genes
result from gene duplication, so are found in more than one copy in the genome
-they can diverge within the clade that carries them and often evolve new functions
_____ genes are widespread and extend across many widely varied species
orthologous
molecular clock
uses constant rates of evolution in some genes to estimate the absolute time of evolutionary change
natural theary
states that much evolutionary change in genes and proteins has no effect on fitness and is not influenced by natural selection
• It states that the rate of molecular change in these genes and proteins should be regular like a clock
horizontal gene transfer
the movement of genes from one genome to another
- occurs by exchange of transposable elements and plasmids, viral infection, and fusion of organisms
- complicates efforts to build a tree of life
