DAT Evolution and Ecology Flashcards
Microevolution
the changes in allele
frequencies that occur over time within a
population due to mutation, selection, gene
flow, gene drift, and nonrandom mating.
Macroevolution
the patterns of changes in
groups of related species over broad periods of
geologic time. Patterns determine phylogeny
(evolutionary relationships among species and
groups of species). These patterns can be used
to establish a phylogenetic tree.
Use and disuse
body parts can develop with
increased usage and unused parts are
weakened.
Inheritance of acquired characteristics
(idea is incorrect) body
features acquired during one’s lifetime can be
passed down to offspring.
Natural transformation of species
organisms
produce offspring with changes, transforming
each consecutive generation to be slightly
more complex.
Natural selection
survival of the fittest
without any luck. Allele frequencies increase or
decrease in order to adapt to the environment.
Descent with modification
Over time and
generations, traits providing reproductive
advantage become more common within the
population.
Fossil types:
actual remains, petrification,
imprints, molds, and casts.
Biogeography
The geography that describes
the distribution of species.
Ontogeny:
The development of an organism.
Phylogeny:
The evolutionary development and
diversification of a species.
Embryology
similar stages of development
among related species establishes evolutionary
relationships.
Homologous structures (anatomy)
body parts
that resemble one another between
different species that descended from a
common ancestor.
Analogous structures
- body parts that
resemble one another between different
species that evolved independently.
They have similar structures as
adaptations to similar environments.
Comparative biochemistry
organisms with a
common ancestor mean they have common
biochemical pathways.
Stabilizing selection
the bell curve favors an
intermediate, like how the average height in
humans is in the middle.
Directional selection
the favoring of traits
that is at one extreme of the range. Traits at
opposite extremes are selected against.
Industrial selection
the selection of dark-
colored, melanic, varieties in various species of
moths, like the peppered moth, as a result of
industrial pollution. This is a specific type of
directional selection.
Disruptive selection
this selection occurs
when the environment favors extreme or
unusual traits while selecting against common
traits.
Intersexual selection
females choose
superior males, which increases thefitness of the offspring.
Intrasexual selection
when males
compete and fight with other males for
better mating opportunities. Males
increase fitness of offspring by
maximizing quantity.
Sexual dimorphism
the differences in
appearance of males and females, which
is a form of disruptive selection. This
occurs because female choice leads to
traits and behaviors in males that are
favorable to females.
Artificial selection
- this is a form of directional
selection carried out by humans when they
breed favorable traits, and is not natural
selection.
Mutation
new alleles could be introduced to
the population with genetic mutations.
Diploidy
Diploid organisms have two copies
of each chromosome.
Outbreeding
mating with unrelated partners
results in mixing of different alleles and creating
new allele combinations.
Balanced polymorphism
the maintenance of
different phenotypes in a population. One
phenotype is usually the best and thus has
increased allele frequency.
Hybrid vigor (heterosis)
superior
quality of offspring resulting from
crosses between two different inbred
strains, species, or varieties of
organisms.
Frequency-dependent selection
(minority advantage)
occurs when
least common phenotypes have a
selective advantage.
Neutral variation
these are variations that are
passed down without any selective value, such
as fingerprints in humans.
Geographic variation
variation of a species is
dependent on climate or geographic
conditions. A
Gene flow
- the introduction and removal of
alleles from the population when individuals
leave (emigration) or enter the population.
Genetic drift
the random increase and
decrease of an allele by chance. Genetic drift
has a larger effect on small populations.
Founder effect
when a small group of
individuals migrate to a new location,
the gene pool of the small group will be
less than the original population. After
successive generations, the genetic
makeup will be unique from the original
population.
Bottleneck effect
occurs when the
population undergoes a dramatic
decrease in size due to natural
catastrophes or other events. The
population is now vulnerable to genetic
drift, and the gene pool is much smaller.
Hardy-Weinberg Equation:
p2 + 2pq + q2 = 1 (all individuals sum to 100%)
p + q = 1 (all alleles sum to 100%)
p (Hardy-Weinberg Equation:)
frequency of the dominant allele
q (HW)
frequency of the recessive allele
p2 (HW)
frequency of homozygous dominant
individuals
q2
frequency of homozygous recessive
individuals
2pq
frequency of heterozygous individuals
Allopatric speciation
- this speciation occurs
when the population is divided by a
geographic barrier.
Dispersal
the group is isolated by
being physically removed from the
original location of the larger group
Vicariance
- the group is isolated by a
geographic barrier but is in the same
overall location of the larger group
Sympatric speciation
this is the formation of new
species without the presence of geographic barriers.
Polymorphism
A population of
insects has different colors. One color can
camouflage to different substrates, but the
insects in other colors cannot and will be
eaten. Only insects with the advantageous
color will mate as they are the ones that
survive. The insects with this specific
advantageous color are now isolated from
other subpopulations
Polyploidy
possessing more than the normal
two sets of chromosomes, such as 3n or 4n, is
considered polyploidy. This can lead to
reproductive isolation, such as in plants.
Autopolyploidy
when an organism
has more than two sets of
chromosomes, both of which are
from the same parental species
Allopolyploidy
when a organism
has more than two sets of
chromosomes, but they come from
different species
Hybridization
- two different closely related
species mate and produce a hybrid along a
geographic boundary called a hybrid zone
Adaptive radiation
the rapid evolution of
many species from a single ancestor.
Prezygotic isolation
this type of isolation
prevents fertilization before mating is
attempted, and so a zygote is not formed.
Habitat isolation
species do not
encounter each other because they live
in different habitats, even if they live in
the same geographical area
Temporal isolation
- species reproduce
at different seasons/times
Behavioral isolation
some species will
not reproduce with each other if they do
not perform the correct courtship rituals
Mechanical isolation
occurs when
male and female genitalia are not
compatible
Gametic isolation
male and female
gametes do not recognize each other.
The male gametes also may not survive
in the environment of the female
gametes
Postzygotic isolation
if a zygote does form,
there are postzygotic methods to maintain
reproductive isolation.
Hybrid inviability
the zygote fails to
develop properly and dies before
reaching reproductive maturity
Hybrid sterility
hybrids become
functional adults but cannot reproduce
Hybrid breakdown
hybrids produce
offspring that have reduced viability/
fertility. The hybrid’s children cannot
reproduce
Divergent evolution
this type of evolution
occurs when two or more species that
originated from a common ancestor become
increasingly different over time as a result of
speciation.
Convergent evolution
type of evolution
occurs when two unrelated species evolve to
share more similar traits due to adapting to a
similar environment (analogous traits).
Parallel evolution
this type of evolution
occurs when two related species make similar
evolutionary changes after their divergence
from a common ancestor.
Coevolution
occurs between
two species. Each causes the other one to
evolve, which results in the evolution of both
species.
Phyletic gradualism
this theory says that
evolution occurs by the gradual accumulation
of small changes.
Punctuated equilibrium
says that
evolutionary history consists of geologically
long periods of stasis (stability) with little or no
evolution followed by geologically short
periods of rapid evolution.
Timeline
- Earth and the atmosphere formed
through volcanoes - Primordial seas formed
- Complex molecules were synthesized
- Polymers formed and self-replicated
- Organic molecules became
protobionts - Primitive heterotrophic prokaryotes
formed - Primitive autotrophic prokaryotes
formed - Ozone layer formed which ended
abiotic chemical evolution - Eukaryotes formed
Vestigial structures
structures that appear to
be useless but had ancestral function. For
example, humans have vestigial appendixes
and tails, horses have vestigial splints, and
pythons have vestigial reduced leg bones
Mullerian mimicry
- two or more harmful
species that are not closely related but share
one or more common predators, have come to
mimic each other’s warning signals
Batesian mimicry
- this is slightly different from
Mullerian mimicry in that a harmless species has
evolved to imitate the warning signals of a
harmful species directed at a common predator
Parapatric speciation
occurs
without a geographic barrier, so the population
is continuous, but it still does not mate
randomly.
Peripatric speciation
this is very similar to
allopatric speciation in that a population is
isolated and prevented from exchanging genes
from the “main” one, but one of the
populations is much smaller than the other, so it
is subject to accelerated genetic drift along
with differing selection pressures
Anagenesis/phyletic evolution
the gradual
evolution of a species without any branching; it
is a straight path of evolution
Cladistics
method of classification according
to the proportion of measurable characteristics
held in common between two organisms. The
more characteristics they share, the more
recently they diverged from common ancestor
Clade
a group of species that includes a
common ancestor and all of its descendants. A
clade is also known as a monophylum
Sere
a particular stage of an ecosystem
Mold
an organic matter that leaves an
impression in rocks or in inorganic matter. Later,
the organic matter decays and leaves a
negative impression
Cast
a type of fossil formed when a mold is
filled in
Deme
- a small local population of the same
species that regularly interbreed.
Autotrophic anaerobes
chemosynthetic
bacteria
Autotrophic aerobes
green plants and
photoplankton
Heterotrophic anaerobes
- yeast
Heterotrophic aerobes
amoebas,
earthworms, and humans
Symbiosis
- a relationship between two
species.
Mutualistic
the relationship is
beneficial to both species
Commensalism
the relationship is
beneficial to one species and neutral to
the other species
Parasitism
the relationship is beneficial
to one species but detrimental to the
other species
Synapomorphies
shared traits derived from
an evolutionary ancestor common to all
members of a group
Analogous traits
similar characteristics
resulting from convergent evolution, therefore
they are not derived from a common ancestor
Law of parsimony
this is also known as
Occam’s Razor, which states that the simplest
explanation is most likely correct.
Monophyletic
the ancestral species
and all its descendants
Paraphyletic
- the ancestral species and
some but not all descendants
