Chapter 15 - Evolution Flashcards
evolution
change in genetic makeup of a population with time
evolution is explained by constant propagation of
new variations in genes of species
some new variations in genes of species impart an
adaptive advantage
evidence of evolution (6)
fossil record comparative anatomy comparative embryology comparative biochemistry (physiology) vestigial structures geographic barriers
fossils are ______ of evolutionary change
most distinct evidence
fossils represent the remains of
an extinct ancestor
fossils are generally found in
sedimentary rocks
types of fossils (5)
actual remains petrification imprints molds casts
actual remains (fossils) like
teeth
bones
actual remains (teeth, bones) are found in
rock
tar pits
ice
amber
amber
fossil resin of trees
petrification is the process in which
minerals replace cells of an organisms
imprints (fossils)
impressions left by an organism
example of imprints
footprints
molds form in
hollow spaces of rocks
molds form in hollow spaces of rocks as the
organism within decays
casts are formed by
minerals deposited in molds
comparative anatomy includes
homologous structures
analogous structures
homologous structures
similar structure
same origin
homologous structure demonstrate similar evolutionary patterns with late _____ due to differences in _____
divergence;
exposure to evolutionary forces
examples of homologous structures
wings of a bat
flipper of a whale
forelegs of the horses
arms of man
analogous structures
similar structure
different origin
analogous structures have similar functions with different evolutionary origins and entirely different
patterns of development
example of analogous organs
wings of a fly (membranous)
wings of a bird (bony and covered with feathers)
example of different pattern of development in analogous structures - wings of a fly vs wings of a bird
wings of a fly are membranous
wings of a bird are bony and covered with feathers
embryology
stages of development
stages of development of the embryo resemble stages in an organisms
(comp. embryology)
evolutionary history
in humans, the two layer gastrula is similar to the structure of the
(comp. embryology)
hydra (cnidarian)
in humans, the three-layer gastrula is similar in structure to the
(comp. embryology)
flatworm
gill slits are present in the human embryo - this indicates a common ancestry with
fish
the similarity of stages in human embryonic development suggests
common ancestry and development history
the earlier the stage at which development beings to diverge, the more
dissimilar the adult organisms will be
it is very difficult to differentiate between the embryo of a human and that of a gorilla until
relatively late in the development of each embryo
embryological development suggests other evidence of evolution in other
organisms
avian embryo has teeth, suggesting
comp. embryology
reptile stage
larvae of some mollusks resemble
comp. embryology
annelids
human embryo posses a
comp. embryology
tail
most organisms demonstrate the same basic needs and _____ processes
(comp biochem)
metabolic
most organisms require the same (food)
comp biochem
nutrients
most organisms have the similar cellular _____
organelles
most organisms have similar energy storage forms
ATP
respiratory processes
comp biochem
are similar in most organisms
similarity of enzymes involved in respiratory processes suggests that all orgnaisms must contain some
DNA sequences in common
the closer the organisms in the evolutionary scheme, the greater the similarity of their ____ and _____
(comp biochem)
chemical constituents
genetic information
chemical constituents
enzymes
hormones
antibodies
blood
since the closer the organisms in the evolutionary scheme, the greater the similarity of their chemical constituents and genetic code, we can conclude that all organisms
were descended from a common, primitive ancestral form
chemical similarity of the blood of different organisms very closely parallels the
evolutionary pattern
chimps blood shows close similarity to that of a _____ but is very different from that of a ____ or ____
human;
rabbit, fish
more time that has elapsed since the divergence of two species, the more ____ their biochemical characteristics
different
vestigial structures are structures that appear to be _____ but apparently had some ______
useless;
ancestral function
vestigial organ in humans: appendix
small and useless
in herbivores - assists with digestion of cellulose
vestigial organ is humans: tail
reduced to few useless bones (coccyx) at the base of the spine
coccyx
human tail at base of spine: useless
vestigial organs in horses: splints
on legs of horses
remains of 2 side toes of Eohippus
vestigial organ in python: legs
reduced to useless bones embedded in sides of adult
vestigial leg bones in python similar to that of
whale - hand-limb bones
species multiplication generally accompanied by
migration
species multiplication is generally accompanied by migration in order to lessen
intraspecific competition
separation of a widely distributed population by emerging geographic barriers increases the likelihood of
genetic adaptations on either side of the barrier
each population may evolve specific adaptations to the
environment which it occupies
in addition to adaptive changes, populations may accumulate _____ changes
neutral - random, non-adaptive
adaptations of populations separated by geographic barrier will remain _____ to the population in which they evolve, as long as
unique;
interbreeding is prevented by the barrier
in time, genetic differences of a once unified population separated by a barrier will reach the point where successful interbreeding
is impossible
if successful interbreeding becomes impossible within a population, _____ would be maintained if the geographic barrier were removed
reproductive isolation
example of geographic barriers and evolution: marsupials
line of pouched mammals paralleling development of placental mammals developed on Australian side of large water barrier - geographic barrier protected more primitive pouched mammals from competition with modern placental mammals
water barrier of australia resulted in uniquely
Australian plants and animals
examples of uniquely australian plants and animals
kangaroo
duckbill platypus
pouched wolves
eucalyptus tree
systematics
study of evolutionary relationships
phylogeny
evolutionary history of a group of organisms
phylogenetic relationships - species should be _____ to their ancestors
somewhat similar
because of divergence, similarities between species and ancestors will
fade with time since separation increases
cladistics
used to classify organisms based on phylogenetic relationships
cladograms constructed to predict
how an ancestor has evolved into its proposed descendants
cladogram is composed of
subtrees
subtrees of cladogram called
clade
members of a clade possess some kind of
derived characteristic that distinguishes from other clade
in constructing clades, scientists utilize the principal of
parsimony
parsimony
least complex explanation
ex of parsimony: if one cladogram assumes 5 evo events and the other assumes 2 then:
the latter will be more accepted
“use and disuse” and “inheritance of acquired characteristics” are
Lamarck buzz phrases
Lamarckian Evolution was
WRONG
principle of lamarckian evolution
new organs or changes in existing ones arose because of the needs of the organism
amount of change of organs depends on
lamarck
use or disuse of organ
theory of use and disuse based on
fallacious understanding of genetics
any useful characteristic acquired in one generation was thought to be
(lamarck)
passed on to the next
example of lamarck theory: giraffes
early giraffes stretched their necks to reach for leaves on higher branches of trees
offspring believed to inherit long necks as a result of excessive use
the theories of acquiring characteristics has been disproved by
modern genetics
only these can be inherited
changes in the DNA of the sex cells
only changes in the DNA of the ____ cells can be inherited
sex
changes acquired during an individuals life are changes in characteristics and organization of
somatic cells
_____ disproved lamarck use and disuse with mice
weissman
to disprove lamarck, weissman (using mice)
cute off tails of mice for 20 generations
the 21st was born with tails
in drawin’s theory of evolution, pressures in the environment select for
organism most fit to survive and reproduce
Darwin’s basic agents leading to evolutionary change (6)
overpopulation variations competition (struggle for survival) natural selection inheritance of the variations evolution of new species
overpopulation (darwin 1)
more offspring are produced than can survive - insufficient food, air, light, space to support entire population
variations (darwin 2)
darwin observed differences (variation) between offspring and parents
darwin did not know source of variation between offspring and parents - explained by
de vries
de vries and variation
mutations cause variations
mutations - can be ____ or ____; most are ____
beneficial; harmful; harmful
competition - struggle for survival (darwin 3)
developing pop must compete
due to competition, many young ____ and adults ____
must die;
remain constant from gen to gen
natural selection (darwin 4)
some organisms may have variable adaptations that are advantageous for survival
natural selection encapsulated in phrase
survival of the fittest
inheritance of variation (darwin 5)
individuals that survive (favorable variations) live to adulthood, reproduce, transmit favorable genes
favored genes eventually
dominate gene pool
evolution of new species (darwin 6)
over many generations of natural selection, favorable changes are perpetuated in species
accumulations of favorable changes eventually result in (darwin 6 cont’d)
significant changes to gene pool - new species evolves
physical changes in gene pool perpetuated or selected for by
environment
example of evolution of new species - DDT-resistant insects - illustrates natural selection
rapid evolution of DDT-resistant insects - change in env: intro of DDT –> favorable change for DDT-resistant flies
mutants existed before environmental change –> conditions select for survival of these DDT-resistant flies
chance variations occur due to ___ and ____
mutations; recombination
individual is more “fit” and likely to survive if
variation is “selected for” by environment
survival of the fittest leads to an increase of
favorable genes in gene pool
population includes
all members of particular species inhabiting given location
gene pool
sum total of all alleles for any given trait in population
gene frequency
decimal fraction representing presence of allele for all members of population that have particular gene locus
p (gene frequency)
frequency of dominant allele
of particular gene locus
q (gene frequency)
frequency of recessive allele
of particular gene locus
for a given gene locus (equation)
p + q = 1
evolution can be viewed as
hardy-weinberg principle
result of changing gene frequencies within a population
gene frequency is the relative frequency of
hardy-weinberg principle
particular allele
the gene pool is stable when
hardy-weinberg principle
gene frequencies of a population are not changing
when the gene pool is stable, the population is
hardy-weinberg principle
not evolving
5 idealized conditions of hardy weinberg
- population very large
- no mutations
- mating is random
- no net migrations into or out of population
- genes in pop are equally successful at reproducing
hardy weinberg principle
under 5 idealized conditions, a certain equilibrium will exist between all genes in gene pool
hardy weinberg principle is explained by
hardy weinberg equation
hardy weinberg equation
p^2 + 2pq + q^2 = 1
for a gene and locus with only two alleles, T and t, p =
frequency of allele T
for a gene and locus with only two alleles, T and t, q =
frequency of allele t
for a given gene locus, p + q = 1, because combined frequencies of all alleles must
total 100%
(p + q)^2 = 1^2 —->
p^2 + 2pq + q^2 = 1
in the hardy weinberg equation, p^2 =
frequency of TT (homo dom)
in the hardy weinberg equation, 2pq =
frequency of Tt (het)
in the hardy weinberg equation, q^2 =
frequency of tt (homo rec)
the hardy weinberg equation may be used to determine ______ in the absence of microevoluationary change
gene frequencies of a large pop
individuals from a nonevolving pop can be randomly crossed to determine that
(hardy weinberg equation)
gene frequencies remain constant from gen to gen
no population can be represented indefinitely by the hardy-weinberg eq. because
such idealized conditions do not exist in nature
real populations have _____ gene pool and ____ population
unstable;
migrating
agents of microevolutionary change
natural selection mutation assortive mating genetic drift gene flow
agents of microevolutionary change are all deviations from the
5 conditions of hardy-weinberg
natural selection
genotypes with fav. variations are selected through natural selection and frequency increases in gene pool
mutations
mutations change allele frequencies in a population - shifting gene equilibria
assortive mating
if mates not chosen randomly, relative genotype ratios will be affected and will depart from h-w equil
on average, allele frequencies in a gene pool
remain unchanged
example of non random mating
mate selected for phenotype
mate selected for proximity
genetic drift
changes in comp of gene pool due to chance
examples of genetic drift
bottleneck
founder
genetic drift is most pronounced in ____ populations
small
deme
small local population
maybe many demes belonging to a specific
species
example of a deme: beavers
along a specific portion of a river
members of a deme resemble one another more closely than they resemble
members of other demes
members of a deme are closely related genetically because
mating between members of same deme occurs more frequently
members of same deme are influenced by similar ______ factors and are thus subject to _____
environment;
same selection process
development of new species occurs when
gene pools within a species become sufficiently different so that two individuals cannot mate and produce fertile offspring
gene flow is impossible between two
different species
factors leading to speciation
genetic variation changes in environment migration to new environments adaptation to new environments natural selection isolation
adaptive radiation
emergence of a number of lineages from a single ancestral species
single species may diverge into
adaptive radiation
number of distinct species
differences between species which have diverged are those
adaptive to distinct lifestyle - niche
darwin’s galapagos finches are classic example of adaptive radiation
single species of finch underwent adaptive radiation resulting in 13 separate species, some on the same island (short period of time)
adaptive radiation minimizes
competition
speciation to minimize competition enables each emerging species to become
firmly established in its own niche
types of speciation
demes development of new species adaptive radiation evolutionary history isolation
dissimilar species evolved from
evolutionary history
a common ancestor
phylogeny
evolutionary history
evolutionary history visualized as
branching tree
in a branching tree (evo. history), common ancestor is found at ____ and modern species found at _____
trunk;
tips of branches
groups within branches on evolutionary tree develop in similar ways when
exposed to similar environments
convergent evolution
groups within branches develop in similar ways when exposed to similar environments
example of convergent evolution
fish and dolphins - belong to different classes of chordates
dolphins and fish evolved similarly because they
convergent evo
adapted to aquatic life
descendants of ancestral pouched mammal
pouched wolf
anteater
mouse
mole
pouched mammals have developed ____ to placental mammals
parallel
counterparts to descendants of ancestral pouched mammale
placental wolf
anteater
mouse
mole
pouched mammals and placental mammals faced similar, though ______ separate environments
geographically
because placental and pouched mammals faced geographically separate environments, they
developed similar adaptations
these concepts form the basis of the methods employed in developing system for classification of living things
adaptive radiation
phylogeny
convergent evolution symbol
A
divergent evolution symbol
V
parallel evolution symbol
U
genetic isolation results from
geographic isolation of a population in two groups
when groups are isolated from one another, there is no ___ between them
gene flow
any differences arising from mutations or new combinations of genes will be _____ in the isolated population
maintained
over time, changes from isolation may become significant enough to make
mating impossible —> species formed
