Chapter 1-7 Flashcards
Coreceptor inhibitors.
These bar HIV from entering host cells in the first place by preventing them from latching onto the host cell’s CCR5 molecules.
Fusion inhibitors.
These bar HIV from entering host cells by interfering
with HIV’s gp120 or gp41 proteins.
Reverse transcriptase inhibitors.
Some, like AZT, inhibit reverse tran-
scriptase by mimicking the normal building blocks of DNA. Others inhibit
reverse transcriptase by interfering with the enzyme’s active site.
Integrase inhibitors.
These block HIV’s integrase from inserting HIV’s
DNA into the host genome, preventing the transcription of new viral RNAs.
Protease inhibitors.
These prevent HIV’s protease enzyme from cleaving
viral precursor proteins to produce mature components for new virions.
microevolution.
First, species are not immutable, but change through
time. In a population of birds, for example, the average beak size may change from
one generation to the next.
speciation.
lineages
split and diverge, thereby increasing the number of species.
macroevolution.
over long periods of time, novel forms of life can derive from
earlier forms. Tetrapods, for example, arose from a lineage of fish.
vestigial structures.
A vestigial structure is a useless or rudimentary version of a body part that has an
important function in other, closely allied, species.
fossil
any trace of an organism that lived in the past.
fossil record.
The worldwide collection
of fossils
law of succession.
The general pattern of
correspondence between fossil and living forms from the same locale
transitional forms,
A species that exhibits
traits common to ancestral and derived groups,
especially when the groups are sharply differentiated.
processed pseudogenes.
A pseudogene that
originated when a messenger RNA from which
the introns had already been removed was reverse-transcribed and inserted into the genome.
exons
A nucleotide sequence that occurs between introns and that remains in the messenger
RNA after the introns have been spliced out.
intron
A noncoding stretch of DNA nucleotides that occurs
between the coding regions of a gene and that
must be spliced out after transcription to produce a functional messenger RNA.
retrotransposon
Transposable elements
that move via an RNA intermediate and contain the coding sequence for reverse transcriptase; closely related to retroviruses.
uniformitarianism
The assumption (some-
times called a “law”) that processes identical to those at work today are responsible for events that occurred in the past; first articulated by James Hutton, the founder of modern geology.
natural selection
A difference, on average,
between the survival or fecundity of individuals with certain phenoypes compared with individuals with other phenotypes.
Darwinian fitness
The extent to which an
individual contributes genes to future generations, or an individual’s score on a measure of performance expected to correlate with genetic contribution to future generations (such as life-time reproductive success).
adaptation
A trait that increases the ability of
an individual to survive or reproduce compared
with individuals without the trait.
adaptive
Describes a trait that increases the
fitness of an individual relative to that of individuals lacking the trait.
heritability
In the broad sense, that fraction
of the total phenotypic variation in a population that is caused by genetic differences among individuals; in the narrow sense, that fraction of the total variation that is due to the additive effects of genes.
evolutionary tree
A diagram (typically an
estimate) of the relationships of ancestry and descent among a group of species or populations; in paleontological studies the ancestors may be known from fossils, whereas in studies of extant species the ancestors may be hypothetical constructs. Also called a phylogenetic tree or phylogeny.
root
The location on a phylogeny of the
common ancestor of a clade.
transitions
In DNA, a mutation that substitutes a purine for a purine or a pyrimidine for a pyrimidine.
evolutionary relationships
Patterns of genealogical kinship among species resulting from
descent with modification from common ancestors. Species A and B are more closely related to each other than either is to C if A and B share a more recent common ancestor than either shares with C.
sister species
The species that diverged from
the same ancestral node on a phylogenetic tree.
derived characters
A character present in
one or more species in a clade that was not present in the clade’s common ancestor; an evolutionary novelty; also known as an apomorphy; used in contrast with ancestral character.
apomorphy
A character present in one or
more species in a clade that was not present in the clade’s common ancestor; an evolutionary novelty. Also known as a derived character.
plesiomorphy
An ancestral character; that is,
a character present in the common ancestor of a clade.
synapomorphy
A shared, derived character;
in a phylogenetic analysis, synapomorphies are used to define clades and distinguish them from
outgroups.
monophyletic group
The set of species (or populations) descended from a common ancestor.
paraphyletic group
A set of species that includes a common ancestor and some, but not all, of its descendants.
polyphyletic group
A set of species that are
grouped by similarity, but not descended from a common ancestor.
polytomy
A node, or branch point, on a phylogeny with more than two descendant lineages emerging.
