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
