bio chapter 24/25
BMP4
-causes cells to undergo apoptosis and die -in developing chickens it destroys the webbing between feet
In mice, coat color depends on two alleles of a gene conferring the presence of pigment (the dominant allele, C) or the absence of pigment (the recessive allele, c). If the frequency of the recessive allele c is 0.60 in a population of mice, what proportion of the gametes in that population will carry the c allele?
.60
An allele with frequency of _____ has become eliminated in a population.
0
Suppose plants with the genotype FRFR produce red flowers, plants with the genotype FRFW produce pink flowers, and plants with the genotype FWFW produce white flowers. If the frequency of the FR allele is 0.2 and the frequency of the FW allele is 0.8, what is the frequency of pink flowers?
0.32 2(.8)(.2) = .16X2 = .32
In pea plants, a gene with two alleles determines whether the flowers are purple or white. If the frequency of the allele for purple flowers is 0.55 and the frequency of the allele for white flowers is 0.45, the frequency of gametes carrying the purple flower allele will be
0.55
In a diploid species, how many copies of a given allele are present in an individual who is heterozygous for the gene? 2 4 1 0
1
When an allele is fixed in a population, its frequency is 50% 100% 0% 80%
100
frequency of the genotype Rr
2pq
Hox genes are divided into ______ groups along a chromosome, based on their relative similarities.
4
Based on their relative similarities Hox genes are divided into: 5 groups along a chromosome 6 groups along a chromosome 4 groups along a chromosome 2 groups along a chromosome
4 groups in clusters along the chromosome
The MN blood group in humans is determined by two alleles of a single gene. In a population containing 90 individuals with genotype MM and blood group M, 80 individuals with genotype MN and blood group MN, and 30 individuals with genotype NN and blood group N, what is the frequency of the genotype MN?
= .40 or 40%, take the 80 people with phenotype MN and divide by 200 total in the population
Consider a population of flowers in which the genotype CRCR produces red flowers, CRCW produces pink flowers, and CWCW produces white flowers. If the frequency of the CR allele is 0.2 and the frequency of the CW allele is 0.8, what is the frequency of the red flower genotype?
= 0.04 - multiply .2X.2 because .2 to the 2nd power
A particular gene segregates two alleles, and the dominant allele has a frequency of 0.9. What is the frequency of the recessive allele?
= 0.1 because The sum of the two allele frequencies is 1.0. Therefore, 1.0 is 0.9 = 0.1.
In radishes, genotype RR is red, genotype Rr is purple, and genotype rr is white. In a population of radishes consisting of 100 red radishes, 100 purple radishes, and 300 white radishes, what is the frequency of the genotype rr?
= 0.6 (300/500)
evolutionary lineage concept
A group of individuals that form a line of descent, with new species arising through speciation from an immediate ancestral species
If genotype AA produces an average of 5 offspring, genotype Aa produces an average of 3 offspring, and genotype aa produces an average of 2 offspring, which genotype is the most fit? Aa aa AA
AA
Who proposed the biological species concept?
Ernst Mayr
If the Hardy-Weinberg equilibrium is met, what is indicated? Very slow and continuous evolution is occurring with no increased adaptation. Evolution leading to a population better adapted to the environment is occurring. The population does not satisfy the assumptions of the Hardy-Weinberg equation. Evolution is not occurring because the alleles in the population remain the same.
Evolution is not occurring because the alleles in the population remain the same.
True or false: Populations must be completely geographically isolated in order for allopatric speciation to occur.
False - although some interbreeding may occur among populations that are not completely geographically separated, gene flow may be limited enough so that the populations become two different species over time.
How is a species defined according to the ecological species concept?
Members of a species have the same set of habitat requirements and influence the environment and other species in a similar way.
Select the conditions that must be met for a population to be in Hardy-Weinberg equilibrium. Evolution is occurring. Natural selection is not occurring. Mating is random. The population is very large. Migration occurs frequently.
Natural selection is not occurring. Mating is random. The population is very large. -Hardy-Weinberg equilibrium requires that migration does not occur so that alleles are not introduced into or removed from the population.
Which factors can cause microevolution to happen? Two populations evolve the same trait and exhibit molecular homology. Hardy-Weinberg equilibrium is achieved. New genetic variation is introduced into a population. Evolutionary forces change allele frequencies from one generation to the next.
New genetic variation is introduced into a population. Evolutionary forces change allele frequencies from one generation to the next.
A dominant allele is found in a population with a frequency of 0.8. As the environment begins to change, the dominant allele is not favored. Scientists find that the frequency of the dominant allele decreases by half each generation. Is Hardy Weinberg equilibrium maintained?
No, Hardy-Weinberg equilibrium is not maintained. As the environment changes, microevolution occurs.
Which of the following is an example of assortative mating in humans? Selection of a mate from a different ethnic background Selection of a mate from the same ethnic background Selection of a mate who shares a recent common ancestor
Selection of a mate from the same ethnic background
A group of related organisms that maintains a distinctive set of attributes in nature is known as a(n):
Species
examples of gametic isolation
Sperm and eggs of different species of sea urchin are unable to unite because the structure of a sperm protein is not recognized by the egg. Pollen landing on a flower stigma of a different species fails to generate a pollen tube, preventing fertilization.
What is the founder effect? The change in allele frequencies due to genetic drift acting on a small population that has colonized a new location The change in allele frequencies due to genetic drift acting on a population that has undergone a bottleneck The decrease in body size that occurs due to natural selection acting on island populations The transfer of genes from a large population into a nearby smaller population that recently became connected to the larger population
The change in allele frequencies due to genetic drift acting on a small population that has colonized a new location
What is macroevolution? The evolutionary changes that result in the formation of new species The process in which mutation results in the addition of new alleles to the genetic makeup of a species Evolutionary processes that occur only in eukaryotic species Changes in allele frequency within a population of members of the same species
The evolutionary changes that result in the formation of new species
What axis in the body does the hox gene help form?
The head to tail axis
Paedomorphosis example
The retention in an adult organism of the juvenile features of its evolutionary ancestors. the infant skull of a human and a chimpanzee both contain a rounded skull and small jaw
What type of traits does sexual selection tend to favor? Traits that are intermediate in form Traits exhibiting two or more extremes from an array of phenotypes Traits that increase an individual's ability to find a mate and mate successfully Traits that are more rarely seen in the population
Traits that increase an individual's ability to find a mate and mate successfully
Which of the following is an example of temporal isolation as a prezygotic isolating mechanism? After the successful mating of members of two different mouse species, the sperm fails to unite with the egg. Two populations of deer are separated by a mountain range, preventing them from coming into contact with one another. Two species of plants live within the same area but one flowers (reproduces) in the fall and the other in the spring. Females of one species of bird are not attracted to the breeding plumage of males of another species.
Two species of plants live within the same area but one flowers (reproduces) in the fall and the other in the spring
What is the bottleneck effect? a reduction in alleles due to negative-frequency dependent selection in a population that survived a natural disaster a change in allele frequencies due to genetic drift in a population that was dramatically reduced a decrease in allele frequencies in a population due to stabilizing selection a change in allele frequencies due to genetic drift in a population that colonized a new habitat
a change in allele frequencies due to genetic drift in a population that was dramatically reduced
Biological species concept
a group of individuals that can successfully interbreed to produce viable, fertile offspring
ecological species concept
a group of individuals that require the same habitat resources and influence the environment and other species in similar ways
Natural selection results in changes called ______ in a population. new mutations genetic drift adaptations nonrandom mating
adaptations
What phenomenon causes a single ancestral species to evolve into a wide array of descendant species with diverse habitats, forms, or behaviors that occurs often as a result of colonization of a new area?
adaptive radiation
In a population, the frequency of a gamete carrying a particular allele is equal to the frequency of the _____ in the population
allele
______ speciation results when a population becomes geographically isolated from other populations.
allopatric
A physical separation of members of populations that causes speciation is known as:
allopatric speciation
Speciation that occurs as a result of physical separation of members of a species is known as
allopatric speciation
evo-devo (evolutionary developmental biology)
attempts to understand how genetic changes can drive morphologic change and can drive speciation
A vast number of species have yet to be classified. This is especially true among _______ and _______ which are difficult to categorize into distinct species.
bacteria and archaea
Hox genes determine an animal's
basic body plan
The inability of the female of one species of meadowlark to recognize a male of a different species as a potential mate because of the differences in their songs is an example of
behavioral prezygotic isolation
The evolutionary biologist Ernst Mayr proposed one of the first species concepts, called the
biological species concept - different species cannot interbreed
In mammals, multiple Hox genes have been duplicated to form four _________ in which the genes are close to each other along a chromosome.
clusters
During ______ selection, individuals at one extreme of a phenotypic range have greater reproductive success in a particular environment.
directional
Which type of selection favors individuals at one extreme of a phenotypic range who have greater reproductive success in a particular environment? balancing selection diversifying selection stabilizing selection directional selection
directional selection
What is the relationship between Hox gene evolution and animal evolution? Duplication of Hox genes and clusters of those genes correlate with major diversification events in animal history. Animals undergo dramatic changes in shape as a result of elimination of Hox genes from the genome due to meiotic abnormalities. The evolution of Hox genes and evolution of animals are unrelated. The appearance of Hox genes in the genome of animals is related to a decrease in speciation rate.
duplication of hox genes and clusters of those genes correlate with major diversification events in animal history
more complicated body plans contain _____ of ancestral hox genes that specialize and function to turn on _______ in different locations of the body
duplications, genes
e fact that Hox genes are found in all animals indicates that they originated very _______ in animal evolution
early
Comparing the development of different organisms in an attempt to understand their ancestral relationships is associated with which of the following fields of biology?
evo-devo
The idea that a species should be defined solely based on separate lineages is known as the _______ ________ species concept
evolutionary lineage
Adaptive radiation occurs when organisms: undergo autoploidy and alloploidy exploit a variety of new environments occupy the same habitat as their ancestral species remain in the same, stable environment
exploit a variety of new environments
True or false: Due to genetic drift, alleles with high fitness tend to become fixed in populations, and alleles with lower fitness tend to become lost.
false
True or false: The Hardy-Weinberg equilibrium is usually met in populations in changing environments
false
True or false: Populations must be completely geographically isolated in order for allopatric speciation to occur.
false Although some interbreeding may occur among populations that are not completely geographically isolated, gene flow may be limited enough so that the populations become two different species over time.
True or false: Genetic drift causes alleles that increase fitness to become more common in a population.
false Genetic drift leads to random changes in allele frequencies. It does not depend on fitness.
True or false: Hox gene evolution and animal evolution are unrelated.
false Reason: Hox gene evolution and animal evolution bear striking parallels. For example, duplication of Hox genes and clusters of those genes correlate with major diversification events in the history of animals.
A change in allele frequencies due to genetic drift in a population that colonized a new location is called the founder effect. migration. the bottleneck effect. disruptive selection.
founder effect
The failure of pollen to produce a properly functioning pollen tube when it lands on the stigma of a flower of a different species is an example of ______ isolation. behavioral gametic habitat temporal
gametic
The transfer of alleles into or out of a population is called genetic drift. selective advantage. neutral variation. gene flow.
gene flow
Gremlin gene
gene in ducks that represses BMP4, stops apoptosis, and results in webbed feet
The concept of _______ suggests that each new species evolves continuously over long spans of time.
gradualism
Which of the following concepts suggests that each new species evolves continuously over long spans of time?
gradualism
In phenomenon known as heterochrony, genetic variation can influence the morphology of a species by controlling: pigmentation energy usage growth rates feeding behavior
growth rates
Lions (Panthera leo) are native to Africa and tigers (Panthera tigris) are native to Asia, so they never have an opportunity to interbreed. This is an example of _____ reproductive isolation.
habitat
Two species of the garter snake in the genus Thamnophis are found in the same geographic region. These species are not likely to meet and attempt to reproduce because one lives mainly in the water, whereas the other species spends most of its time on land. This is known as:
habitat isolation
Some of the morphological differences in closely related species may be attributed to genetic changes that affect growth rates of different body parts during development. What is this phenomenon called?
heterochrony
3 mechanisms that can alter the genetic composition of a population and result in speciation.
horizontal gene transfer, changes in chromosome number, natural selection acting upon random mutations
The evolution of increasingly complex animal body forms has been attributed to the prevalence of what types of genes in the genome?
hox genes
Which of the following is not a mechanism of prezygotic isolation? Behavioral isolation Hybrid breakdown Gamete isolation Habitat isolation
hybrid breakdown
Postzygotic isolating mechanisms prevent successful interbreeding among members of different species. _____ results when a zygote cannot successfully develop past the early stages of embryonic development.
hybrid inviability
The condition that occurs when an interspecies hybrid successfully develops but is unable to produce functional gametes is known as:
hybrid sterility
_____ results when an interspecies hybrid zygote reaches maturity but cannot produce viable gametes
hybrid sterilization
In what organisms are Hox genes found? in prokaryotes in prokaryotes and unicellular eukaryotes only in animals that are vertebrates only in animals that are invertebrates in all animals
in all animals
How are multiple Hox genes usually arranged in a chromosome? in a single pair in clusters in pairs at opposing ends singly
in clusters
Members of two different species of dragonfly can not mate because the grasping appendages of the male do not fit the body shape of the female. This is an example of:
mechanical isolation
For ________ to occur, two related phenomena are required. First, new genetic information has to be introduced into a population; Second, mechanisms have to alter the frequencies of existing genetic variation in a population.
microevolution
Gene flow is the result of variation in reproductive success. migration. nonrandom mating. natural selection.
migration
The movement of individuals between two established populations is called and causes gene flow between the two populations.
migration
According to the punctuated equilibrium model:
most new species accumulate unique features rapidly as they come into existence, then change little for long periods
Over time, _____ _____ results in adaptations in a population.
natural selection
What process explains how beneficial alleles that are heritable become more common in successive generations? heritability natural selection genetic drift migration evolution
natural selection
Genetic drift can promote _____ variation, which are changes in genes and proteins that do not affect reproductive success.
neutral
Developmental biologists have hypothesized that variation in Hox genes may have caused the formation of which of the following? cilia and flagella chloroplasts and mitochondria new body plans webbed feet eukaryotic cells
new body plans
Genetic drift selects for alleles with the highest fitness. no particular allele. alleles with intermediate fitness. alleles with the lowest fitness.
no particular allele
The type of nonrandom mating in which individuals with similar phenotypes are more likely to mate is called ______ mating.
non random
frequency of the genotype RR
p2
During embryonic development, coordination of cell division, cell migration, cell differentiation, and cell death leads to the morphological features encoded by the genome of that species --- a process called:
pattern formation
The genome of each species encodes a unique set of morphological features that arise in embryonic development through coordinated cell division, migration, differentiation and cell death. This process is called
pattern formation
Which of the following genes encode a protein that is a transcription factor controlling expression of genes involved in the development of the eye in rodents, humans, and other animals? Pax6 BMP4 Hox
pax6
one of the functions of the _____ gene is to encode a protein that is a transcription factor controlling expression of genes involved in the development in the eye of rodents, humans, and other animals
pax6 gene
All of the following are species concepts that have been proposed by evolutionary biologists EXCEPT: evolutionary lineage concept ecological species concept physiological species concept general lineage concept biological species concept
physiological species concept
A category of reproductive isolating mechanisms called ______ isolating mechanisms block the development of a viable and fertile individual after fertilization has taken place.
post zygotic
A category of reproductive isolating mechanisms called _____ isolating mechanisms prevent the formation of a zygote and include gametic or mechanical isolation.
prezygoic
Isolating mechanisms that prevent reproductive attempts or make it unlikely that reproductive attempts will be successful are referred to as:
prezygotic reproductive isolating methods
Consider a gene that segregates two alleles, A and a, with allele frequencies given by p and q, respectively. The frequency of the aa genotype will be ______ if the population is in Hardy-Weinberg equilibrium.
q2
frequency of the genotype rr
q2
For a population to be in Hardy-Weinberg equilibrium, mating must be: nonrandom random only between the most fit individuals in the population
random
One of the assumptions of the Hardy-Weinberg equation is that mating is ______
random
In genetic drift, allele frequencies change due to random chance. the influx of alleles from a neighboring population. increased reproductive success. natural selection.
random chance
The likelihood that an individual will contribute fertile offspring to the next generation is called _____ success.
reproductive
The biological species concept relies mainly on: the presence of analogous traits to define a species comparative biochemical analysis to define a species morphological differences to define a species reproductive isolation to define a species
reproductive isolation to define a species
How could a change in chromosome number lead to speciation? Behavioral isolation would result due to the effects of behavioral genes. Reproductive isolation would result due to hybrid sterility. Geographical isolation would result due to genes that underlying adaptions.
reproductive isolation would result due to hybrid sterility
Neutral variation describes changes in genes and proteins that do not affect reproductive success. heritable traits. visible phenotypes.
reproductive success. Neutral variation does affect heritable traits; however, they are not traits that affect reproductive success. visible phenotypes. Reason: Neutral variation may act on a trait with a visible phenotype; however, they are not phenotypes that affect reproductive success.
hybrid breakdown
results when a hybrid is able to produce offspring with other hybrids, but subsequent generations harbor deleterious genetic abnormalities. (offspring of hybrids are week or infertile)
Hox genes
series of genes that controls the organs and tissues that develop in various parts of an embryo
A significant difference in the appearance of the two sexes within a species is called_____ _____ and is often the result of sexual selection.
sexual dimorphism
Sexual selection can lead to a significant difference in appearance between the two sexes, which is called sexual dimorphism. intersexual fitness. a sex-linked trait. balanced fitness.
sexual dimorphism - example a brightly colored male peacock vs a dull brown female peacock
A group of related organisms that share a distinct set of attributes, are genetically related, and share an evolutionary history are called a(n)
species
general lineage species concept
species are metapopulations that exchange alleles frequently enough to comprise the same gene pool a population of independently evolving lineage
What type of speciation does not require a geographic barrier?
sympiatric
If two sympatric species of trees release pollen at different times of the year, what type of prezygotic isolation keeps these two species reproductively isolated? temporal behavioral ecological gametic
temporal
adaptive radiation example
the
The frequency of a gamete carrying a particular allele is the same as the genotype frequency in the population. the allele frequency in the population. the total number of alleles in the population. the number of that particular allele in a population.
the allele frequency in a population
A dramatic reduction in population size due to a natural disaster or destruction of habitat and the resulting change in the allele frequencies of the new population is called the founder effect. negative frequency-dependent selection. directional selection. the bottleneck effect.
the bottleneck effect.
Which concept defines a species based on the separate evolution of groups of organisms over time?
the evolutionary lineage concept
Which concept defines a species based on the separate evolution of groups of organisms over time? The evolutionary lineage species concept The biological species concept The general lineage species concept The ecological species concept
the evolutionary lineage concept
The hox gene controls differentiation in the body - what does this mean?
the hox gene controls which organ develops where
What is reproductive success? the likelihood of finding a suitable mate fertilization the likelihood of contributing fertile offspring to the next generation the likelihood of being selected by a potential mate
the likelihood of contributing fertile offspring to the next generation
The selective pressures for eyes to allow more light and have more visual acuity resulted from the duplication and changes to which gene?
the pax6 gene
Which of the following statements about Hox genes is TRUE? They have a constant arrangement in all animals but differ in number They differ in number and arrangement in various animals They have a constant number in all animals but differ in arrangement They have a constant number in vertebrates and a constant arrangement in invertebrates
they differ in number and arrangement in various animals
Pax6 gene
transcription factor involved in programming eye development.
True or false: The biological species concept proposes that the members of a species are reproductively isolated.
true
True or false: The more complicated an organism the more hox genes it will possess - so, a human would have more hox genes than in the body plan of a sponge which is simpler
true
True or false: Due to genetic drift, alleles with high fitness tend to become fixed in populations, and alleles with lower fitness tend to become lost.
true Reason: Genetic drift may lead to the fixation or loss of any allele. It does not select for alleles based on fitness.
True or false: Heterochrony involves changes in growth rates that may lead to the differences in morphological characteristics observed in members of different species.
true Reason: Heterochrony is the result of differences in growth rates that occur during different times of development, leading to the differences in skull shape observed in chimps and humans, for example.
True or false: Morphology may be influenced by genetic variation that influences the relative growth rates of the body during development.
true the heterochrony of human skulls vs chimpanzee skulls - humams have larger craniums and chimps have larger jaws. This is due to difference of developmental timing of skulls.
