Why do mutations appear more often with selective breeding?

Why do mutations appear more often with selective breeding?

A - They are selected for a desirable trait
B - Genetic diversity is increased
C - Desirable traits are only beneficial if mutations occur too
D - Genetic diversity is decreased
E - They will eventually disappear over time so they are not a problem


Answer: D - Genetic diversity is decreased
Genetic diversity is greatly decreased through the inbreeding process (breeding of closing related species) which mutations that are normally selected against will be selected.

Our modern corn was created through artificial selection from the ancestral plant

Our modern corn was created through artificial selection from the ancestral plant

A - Alfalfa
B - Chihuahua
C - Wheat
D - Teosinte


Answer: D - Teosinte

What is the main difference between natural selection and artificial selection?

What is the main difference between natural selection and artificial selection?

A - Individuals choose to adapt in natural selection but are forced to adapt in artificial selection
B - Artificial selection is a deliberate act by humans, while natural selection is a naturally occurring process
C - Artificial selection is a naturally occurring process, while natural selection is a deliberate act by humans
D - They are the same process and the names are interchangeable
E - Artificial selection can only occur after natural selection has occurred,. while natural selection can occur at any time


Answer: B - Artificial selection is a deliberate act by humans, while natural selection is a naturally occurring process

Which is NOT a trait that might be selected for through artificial selection?

Which is NOT a trait that might be selected for through artificial selection?

A - Decreased disease resistance
B - Accelerated growth
C - Faster running speeds
D - Increased growth rate


Answer: A - Decreased disease resistance
It is a breeding for desired traits only.

Artificial selection is also known as

Artificial selection is also known as

A - Out-breeding
B - Mutation breeding
C - Rapid evolution
D - Selective breeding
E - Natural selection


Answer: D - Selective breeding
ARTIFICIAL selection is when specific traits are deliberately selected for or against by humans.

What best describes natural selection?

What best describes natural selection?

A - Organisms with lighter coloration are more likely to survive and reproduce
B - Organisms best suited to the environment are more likely to survive and reproduce
C - Organisms that can willfully change to fir their environment are more likely to survive and reproduce
D - Organisms with darker coloration are more likely to survive and reproduce
E - Organisms best suited to their environment are less likely to survive and reproduce


Answer: B - Organisms best suited to the environment are more likely to survive and reproduce

What color of moth was most common before the Industrial Revolution?

What color of moth was most common before the Industrial Revolution?

A - Both the light and dark colored moths were common
B - The light-gray colored moth
C - The bright white moth
D - The brown moth with white spots
E - The dark-colored moth


Answer: B - The light-gray colored moth

What best describes directional selection?

What best describes directional selection?

A - Natural selection in the direction of one trait extreme to another
B - Natural selection for dark colors
C - Natural selection over short time periods
D - Natural selection of a blended trait somewhere in the middle of the extremes
E - Natural selection in the direction of both trait extremes


Answer: A - Natural selection in the direction of one trait extreme to another

How did the Industrial Revolution help the dark-colored moths become more common?

How did the Industrial Revolution help the dark-colored moths become more common?

A - It reduced predation on the light-colored moths
B - It lightened the trees, providing moths better camouflage
C - It c=decreased the number of birds in the environment so predation of moths was less
D - It blackened the trees, providing moths better camouflage
E - It actually increased predation on the dark-colored moths


Answer: D - It blackened the trees, providing moths better camouflage

Why is the peppered moth phenomenon uncommon?

Why is the peppered moth phenomenon uncommon?

A - Adaptations normally occur over very short periods of time
B - Moths can fly away to new environments where they re better camouflaged
C - Adaptations normally occur over very long periods of time
D - Moths rarely adapt to their environment


Answer: C - Adaptations normally occur over very long periods of time
Normally, adaptation occurs over thousands or millions of years, unless something changes about the environment.

What is true about random mutations?

What is true about random mutations?

A - They are always positive
B - They introduce new variation into a population
C - They make measuring variation possible
D - They are always negative
E - They remove variation from a population


Answer: B - They introduce new variation into a population
RANDOM MUTATIONS are changes in the nucleotide sequence of DNA and are critical components of evolution because they create genetic variation.

Genetic variability describes which of the following?

Genetic variability describes which of the following?

A - How likely a variation is to be hereditary
B - The potential for a characteristic to vary within a population
C - The amount of variation within a population
D - How harmful a mutation will be to an individual
E - The prevalence of random mutations within a population


Answer: B - The potential for a characteristic to vary within a population
GENETIC VARIABILITY is the potential for a characteristic to vary within a population, which can be measured. It is different from genetic variation because instead of measuring the actual variation it measures how the trait will vary. It is directly related to biodiversity and evolution because a population needs enough of it to adapt and evolve to environmental changes.

Why is evolution best described as an editing process?

Why is evolution best described as an editing process?

A - It creates "fitter" organisms
B - It selects for individuals with traits best suited for the future environment
C - It selects the best individuals
D - It selects for individuals that will be better able to adapt to environmental changes
E - It selects for individuals with traits best suited for the current environment


Answer: E - It selects for individuals with traits best suited for the current environment
Evolution is selecting the individuals with the traits that are best suited for the current environment.

What best describes genetic variation?

What best describes genetic variation?

A - The potential for a characteristic to vary within a population
B - The amount of variation in an individual's DNA
C - Naturally occurring genetic differences among individuals
D - The number of mutations within a population
E - A population that is genetically different from a nearby population


Answer: C - Naturally occurring genetic differences among individuals
GENETIC VARIATION measures the actual amount of variation in a population

Which is true about evolution?

Which is true about evolution?

A - It creates genetic variation
B - It occurs within a population
C - It occurs among individuals
D - It decreases genetic variability
E - It creates random mutations


Answer: B - It occurs within a population

A postzygotic __________ is a mechanism that reduces the viability or reproductive capacity of hybrid offspring.

A postzygotic __________ is a mechanism that reduces the viability or reproductive capacity of hybrid offspring.

A - Reproductive barrier
B - high hybrid infertility
C - low hybrid viability
D - hybrid infertility
E - Hybrid zygote abnormality


Answer: A - Reproductive barrier

A scientist mates a blue population of lizards with a red population of lizards. She observes that one out of ten hybrid offspring survive to adulthood compared to roughly, eight out of ten blue or red lizards. This is an example of

A scientist mates a blue population of lizards with a red population of lizards. She observes that one out of ten hybrid offspring survive to adulthood compared to roughly, eight out of ten blue or red lizards. This is an example of

A - Mechanical isolation
B - Hybrid zygote abnormality
C - Hybrid infertility
D - Low hybrid viability
E - Gametic isolation


Answer: D - Low hybrid viability
This is when the viability (ability to live) of the hybrid is significantly lower than the parents.

A farmer mates a goat and a sheep together. However, he finds he cannot use this hybrid animal to produce any new hybrids. This is an example of

A farmer mates a goat and a sheep together. However, he finds he cannot use this hybrid animal to produce any new hybrids. This is an example of

A - Hybrid infertility
B - Gametic isolation
C - Low hybrid viability
D - Mechanical isolation
E - Hybrid zygote abnormality


Answer: A - Hybrid infertility
This is when the hybrids are sterile.

A scientist mates two different organisms, She observes no offspring. A closer inspection reveals that the hybrid embryo does not develop properly. This is an example of

A scientist mates two different organisms, She observes no offspring. A closer inspection reveals that the hybrid embryo does not develop properly. This is an example of

A - Gametic isolation
B - Low hybrid viability
C - Hybrid infertility
D - Hybrid zygote abnormality
E - Mechanical isolation


Answer: D - Hybrid zygote abnormality
This is when the hybrid zygote fails to mature normally, normally this means they die during development.

Which of the following statements is true?

Which of the following statements is true?

A - A prezygotic reproductive barrier reduces the reproductive capacity of hybrid offspring
B - Both prezygotic and postzygotic mechanisms influence the speciation of a population
C - If two organisms can produce a viable hybrid, the parental organisms are not different species
D - Gametic isolation is a postzygotic reproductive barrier
E - Low hybrid viability is a form of prezygotic isolation


Answer: B - Both prezygotic and postzygotic mechanisms influence the speciation of a population
POSTZYGOTIC reproductive barriers occur after the zygote has formed, meaning they either reduce the viability or the reproductive capacity of the hybrid.
PREZYGOTIC reproductive barriers do not cause speciation since they happen before the zygote is formed.

A zoo wants to assist two related endangered species with their reproduction and plans to directly implant the sperm into the female. Which type of isolation cannot be overcome this way?

A zoo wants to assist two related endangered species with their reproduction and plans to directly implant the sperm into the female. Which type of isolation cannot be overcome this way?

A - Temporal
B - Gametic
C - Behavioral
D - Spatial
E - Mechanical


Answer: B - Gametic
GAMETIC isolation is when sperm of one species cannot find, attach, or fuse with the egg of the other meaning no zygote is ever formed. (prezygotic barrier)

One species of sea urchin is able to mate with another, but fertilization is rarely successful. What is this an example of?

One species of sea urchin is able to mate with another, but fertilization is rarely successful. What is this an example of?

A - Spatial
B - Behavioral
C - Temporal
D - Mechanical
E - Gametic


Answer: E - Gametic
MECHANICAL isolation refers to the size or shape of the reproductive organs preventing successful mating.(prezygotic barrier)

Two species of plants that do not cross-pollinate are an example of ________ isolation because they flower at different times of the year.

Two species of plants that do not cross-pollinate are an example of ________ isolation because they flower at different times of the year.

A - Spatial
B - Behavioral
C - Temporal
D - Mechanical
E - Gametic


Answer: C - Temporal
TEMPORAL isolation refers to species that mate at different times of the year. (prezygotic barrier)

One way to overcome behavioral isolation that prevents animals from reproducing might be to ______.

One way to overcome behavioral isolation that prevents animals from reproducing might be to ______.

A - Clone the animals and raise them in a laboratory
B - Give the animals treats when they come near each other. thereby training them to accept each other
C - Keep the animals away from each other at all times, to reinforce the behavior
D - Let nature take its course
E - Use genetic engineering to create compatible DNA


Answer: B - Give the animals treats when they come near each other. thereby training them to accept each other. (prezygotic barrier)

Spatial isolation is the main reason why _______ do not mate.

Spatial isolation is the main reason why _______ do not mate.

A - Siberian and South China tigers
B - Red pandas and giant pandas
C - Sharks and dolphins
D - Sea urchins and sea horses
E - Wolves and house cats


Answer: A - Siberian and South China tigers
SPATIAL isolation refers to species not being able to mate because they live in different areas. (prezygotic barrier)

A population of lizards is split by an earthquake which leaves half of the population on an island and the other half on the tip of the peninsula. These lizards cannot swim. What type of speciation will occur?

A population of lizards is split by an earthquake which leaves half of the population on an island and the other half on the tip of the peninsula. These lizards cannot swim. What type of speciation will occur?

A - Parapatric speciation
B - Sympatric speciation
C - Peripatric speciation
D - Allopatric speciation


Answer: D - Allopatric speciation

Define speciation.

Define speciation.

A - It is the process by which two or more species converge to become one species
B - It is the process by which an independent evolutionary unit of organisms is forced into extinction
C - It is the process by which an ancestral species split into two or more new species
D - It is the process by which the characteristics of a cell or organism become more prevalent within a group of organisms


Answer: C - It is the process by which an ancestral species split into two or more new species
For speciation to occur the gene pool must be divided in some way.

Identify the factor that is responsible for allopatric speciation and NOT for sympatric speciation

Identify the factor that is responsible for allopatric speciation and NOT for sympatric speciation

A - Gene mutation
B - Physical barrier
C - Competition
D - mate choice


Answer: B - Physical barrier
ALLOPATRIC speciation is the dominant mode of speciation. It is speciation that occurs when a population is separated by a physical barrier. SYMPATRIC speciation is speciation that occurs without physical separates of the population.

Which of the following four statements about species is MOST accurate?

Which of the following four statements about species is MOST accurate?

A - Animals which look different are classified as different species
B - Animals which do not mate with each other or could mate with each other given the opportunity as members of the same species
C - Plants which cannot mate with each other because they are located too far apart are different species
D - Animals which become separated geographically become different species


Answer: B - Animals which do not mate with each other or could mate with each other given the opportunity as members of the same species
A SPECIES is an individual evolutionary unit. They are able to mate with each other and produce fertile offspring.

Polyploidy has contributed to which of the following patterns of speciation?

Polyploidy has contributed to which of the following patterns of speciation?

A - Allopatric speciation in plants
B - Sympatric speciation in animals
C - Sympatric speciation in plants
D - Allopatric speciation in animals


Answer: C - Sympatric speciation in plants
POLYPLOIDY is a characteristic of a cell or organism with more than two complete sets of chromosomes.

A situation in which two alleles of a gene are maintained in a population because heterozygotes are more fit than their homozygous counterparts are called

A situation in which two alleles of a gene are maintained in a population because heterozygotes are more fit than their homozygous counterparts are called

A - Balanced polymorphism
B - Directional selection
C - Stabilizing reaction
D - Heterozygote advantage


Answer: A - Balanced polymorphism
BALANCED POLYMORPHISM is a situation in which two alleles of a gene are maintained in a population because heterozygotes are more fit than their homozygous counterparts.

A scientist has observed animals in a particular habitat for some time. She notices that the slower gazelles tend ti fall victim to predators more frequently than faster ones. Over time, she notes that the gazelle herd on average runs faster. She is observing

A scientist has observed animals in a particular habitat for some time. She notices that the slower gazelles tend ti fall victim to predators more frequently than faster ones. Over time, she notes that the gazelle herd on average runs faster. She is observing

A - Disruptive selection
B - Directional selection
C - Balanced polymorphism
D - Heterozygote advantage


Answer: B - Directional selection
DIRECTED SELECTION is a type of natural selection in which individuals with a trait at one end of a phenotypic spectrum are most fit.

Some studies have shown that a single copy of the cystic fibrosis disease allele can confer resistance to tuberculosis to a person. This is an example of

Some studies have shown that a single copy of the cystic fibrosis disease allele can confer resistance to tuberculosis to a person. This is an example of

A - Heterozygote advantage
B - Gene dominance
C - Stabilizing selection
D - Disruptive selection


Answer: A - Heterozygote advantage
HETEROZYGOTE ADVANTAGE is a case in which the heterozygous genotype has a higher relative fitness than either homozygous genotype.

A scientist has observed animals in a particular habitat for some time. She notices that in a population of birds those with either short or long beaks can find more food than those with average sized beaks. Over time, she notices a higher proportion of birds in the population have either short or long beaks. She is observing:

A scientist has observed animals in a particular habitat for some time. She notices that in a population of birds those with either short or long beaks can find more food than those with average sized beaks. Over time, she notices a higher proportion of birds in the population have either short or long beaks. She is observing:

A - Disruptive selection
B - Heterozygote advantage
C - Balanced polymorphism
D - Directional selection


Answer: A - Disruptive selection
DISRUPTIVE SELECTION is a type of natural selection in which individuals at either end of a phenotypic spectrum are most fit.

Which of the following forces is LEAST likely to cause a new species to arise in a population?

Which of the following forces is LEAST likely to cause a new species to arise in a population?

A - Balanced polymorphism
B - incomplete dominance
C - Directional selection
D - Stabilizing selection


Answer: C - Stabilizing selection
STABILIZING SELECTION is a type of selection in which individuals in the middle of a phenotypic spectrum are most fit.

Which of the following is an example of convergent evolution?

Which of the following is an example of convergent evolution?

A - The bones in a human hand are similar to those in a dog's paw
B - Whales and fish both developed the ability to swim in the ocean
C - Prehistoric mammals thrive after the extinction of the dinosaurs
D - A spider develops a web that is better at catching insects
E - Finches in the Galapagos develop specialized beaks


Answer: B - Whales and fish both developed the ability to swim in the ocean
CONVERGENT evolution occurs when selective pressure results in the independent evolution of similar traits in two or more different organisms.

Which of the following is an example of a homologous structure or trait?

Which of the following is an example of a homologous structure or trait?

I. Leg bones of a human and leg bones of a penguin
II. Wing of a penguin and wing of a mosquito III. Beak of a penguin and beak of a duck


A - I, II, and III
B - II and III
C - I and II
D - II
E - I and III


Answer: E - I (Leg bones of a human and leg bones of a penguin) and III (Beak of a penguin and beak of a duck)
HOMOLOGOUS structures are shared between organisms which evolved from a common ancestor.

A new mutation allows a cheetah to run faster and hunt down more prey than its slower counterparts. This mutation increased the _________ of the cheetah.

A new mutation allows a cheetah to run faster and hunt down more prey than its slower counterparts. This mutation increased the _________ of the cheetah.

A - Analogy
B - Equilibrium
C - Natural selection
D - Fitness
E - Homology


Answer: D - Fitness
Evolutionary FITNESS is the measurement of the ability of a trait to increase or decrease the relative contribution of offspring by an individual in the next generation. The better the trait the more offspring the individual will provide.

Which of the following is an example of analogous structures or traits?

Which of the following is an example of analogous structures or traits?

I. Leg bones of a human and leg bones of a penguin
II. Wing of a penguin and wing of a mosquito III. Beak of a penguin and beak of a duck

A - II
B - I and III
C - I and II
D - II and III
E. I, II, and III


Answer: A - II
ANALOGOUS traits refers to a trait that may be similar in appearance or purpose but which evolved independently in the two organisms in question.

A scientist notices several birds in the same area that are similar in appearance with the exception of different beak lengths. She observes that one type of bird with a particularly long beak can pick bugs out of holes in the ground, while the birds with shorter beaks cannot. The longer beak is an example of

A scientist notices several birds in the same area that are similar in appearance with the exception of different beak lengths. She observes that one type of bird with a particularly long beak can pick bugs out of holes in the ground, while the birds with shorter beaks cannot. The longer beak is an example of

A - Adaption
B - Convergent evolution
C - Analogy
D - Equilibrium
E - Homology


Answer: A - Adaption
An ADAPTATION is a trait that enhances the survival or reproductive success of an organism.

Consider a population of fish where the length of a given fish's dorsal spine is determined by a single gene, which is defined by two different alleles. The dominant A allele encodes a long dorsal spine and the recessive a allele encodes a short dorsal spine. The fish is diploid and reproduces sexually. If the number of AA individuals is 500, the number of Aa individuals is 200, and the number of aa individuals is 300, then is this population in equilibrium? Why or why not?

Consider a population of fish where the length of a given fish's dorsal spine is determined by a single gene, which is defined by two different alleles. The dominant A allele encodes a long dorsal spine and the recessive a allele encodes a short dorsal spine. The fish is diploid and reproduces sexually. If the number of AA individuals is 500, the number of Aa individuals is 200, and the number of aa individuals is 300, then is this population in equilibrium? Why or why not?

A - It is because the number of fish with short dorsal spines is larger than the number predicted by the Hardy-Weinberg equation
B - It is because the number of fish with short dorsal spines is smaller than the number predicted by the Hardy-Weinberg equation
C - It is not because the number offish with short dorsal spines is smaller than the number predicted by the Hardy-Weinberg equation
D - It is not because the number of fish with short dorsal spines is larger than the number predicted by the Hardy-Weinberg equation


Answer: D - It is not because the number of fish with short dorsal spines is larger than the number predicted by the Hardy-Weinberg equation

Consider a population of fish where the length of a given fish's dorsal spine is determined by a single gene, which is defined by two different alleles. The dominant A allele encodes a long dorsal spine and the recessive a allele encodes a short dorsal spine. The fish is diploid and reproduces sexually. If the number of AA individuals is 500, the number of Aa individuals is 200, and the number of aa individuals is 300, then what is the chance that I will catch a fish with a long dorsal spine from this population?

Consider a population of fish where the length of a given fish's dorsal spine is determined by a single gene, which is defined by two different alleles. The dominant A allele encodes a long dorsal spine and the recessive a allele encodes a short dorsal spine. The fish is diploid and reproduces sexually. If the number of AA individuals is 500, the number of Aa individuals is 200, and the number of aa individuals is 300, then what is the chance that I will catch a fish with a long dorsal spine from this population?

A - .6
B - .7
C - .4
D - .84


Answer: D - .84
To solve this problem you would use the Hardy-Weinberg equation: p^2+2pq+q^2=1

After observing a population of fish with interesting protective spines, a scientist decides to move two of the fish into a new pond to create a new population of fish to study the ability of the fish to survive a new set of predators. Which of the following evolutionary agents did the scientist introduce?

After observing a population of fish with interesting protective spines, a scientist decides to move two of the fish into a new pond to create a new population of fish to study the ability of the fish to survive a new set of predators. Which of the following evolutionary agents did the scientist introduce?

A - Natural selection
B - Mutation
C - People cannot introduce evolutionary agents
D - Founder effect


Answer: D - Founder effect
The FOUNDER EFFECT is a special form of population bottleneck (population size decreases significantly) in which a small group leaves the main population to form a new population.

Consider a population of fish where the length of a given fish's dorsal spine is determined by a single gene, which is defined by two different alleles. The dominant A allele encodes a long dorsal spine and the recessive a allele encodes a short dorsal spine. The fish is diploid and reproduces sexually. The number of AA individuals in this population is 500, the number of Aa individuals is 100, and the number of aa individuals is 400. If a new population was started with 10 AA, 20 Aa, and 10 aa fish, then what are the new allelic frequencies?

Consider a population of fish where the length of a given fish's dorsal spine is determined by a single gene, which is defined by two different alleles. The dominant A allele encodes a long dorsal spine and the recessive a allele encodes a short dorsal spine. The fish is diploid and reproduces sexually. The number of AA individuals in this population is 500, the number of Aa individuals is 100, and the number of aa individuals is 400. If a new population was started with 10 AA, 20 Aa, and 10 aa fish, then what are the new allelic frequencies?

A - 60% A and 40% a
B - 40% A and 60% a
C - 50% A and 50% a
D - 75% A and 25% a


Answer: C - 50% A and 50% a
To solve this problem you would use the equations:
p=B/B+b and q=b/B+b

How do losses of alleles in natural selection differ from losses of alleles in genetic drift?

How do losses of alleles in natural selection differ from losses of alleles in genetic drift?

A - In natural selection, alleles are lost if they do not confer a survival advantage, whereas in genetic drift alleles are lost if they do not confer an advantage in partner selection
B - In genetic drift. alleles are lost if they do not confer a survival advantage, whereas in natural selection alleles are lost if they do not confer an advantage in partner selection
C - In genetic drift, alleles are lost if they do not confer a survival advantage, whereas in natural selection the losses are random
D - In natural selection, alleles are lost if they do not confer a survival advantage, whereas in genetic drift the losses are random


Answer: D - In natural selection, alleles are lost if they do not confer a survival advantage, whereas in genetic drift the losses are random
GENETIC DRIFT is the random loss of individuals and the alleles they possess. This is why the populations need to be big, the bigger they are the more they can absorb the random loss of alleles without significant effect to the gene pool.

The coat color gene of a population of squirrels is defined by a dominant allele G, which encodes a gray coat, and a recessive allele g, which encodes a black coat. In a population, genetic typing reveals the genotypic distribution to be 50 GG, 30 Gg, and 20 gg. What is the allelic frequency of the G allele?

The coat color gene of a population of squirrels is defined by a dominant allele G, which encodes a gray coat, and a recessive allele g, which encodes a black coat. In a population, genetic typing reveals the genotypic distribution to be 50 GG, 30 Gg, and 20 gg. What is the allelic frequency of the G allele?

A - .70
B - .50
C - .60
D - .65


Answer: D - .65

The coat color gene of a population of squirrels is defined by a dominant allele G, which encodes a gray coat, and a recessive allele g, which encodes a black coat. In a population, genetic typing reveals the genotypic distribution to be 50 GG, 30 Gg, and 20 gg. If this population is in equilibrium, then what should the genotypic frequency of Gg squirrels in this population be?

The coat color gene of a population of squirrels is defined by a dominant allele G, which encodes a gray coat, and a recessive allele g, which encodes a black coat. In a population, genetic typing reveals the genotypic distribution to be 50 GG, 30 Gg, and 20 gg. If this population is in equilibrium, then what should the genotypic frequency of Gg squirrels in this population be?

A - .46
B - .42
C - .52
D - .55


Answer: A - .46

The coat color gene of a population of squirrels is defined by a dominant allele G, which encodes a gray coat, and a recessive allele g, which encodes a black coat. In a population, genetic typing reveals the genotypic distribution to be 50 GG, 30 Gg, and 20 gg. If this population is in equilibrium, then what should the genotypic frequency of GG squirrels in this population be?

The coat color gene of a population of squirrels is defined by a dominant allele G, which encodes a gray coat, and a recessive allele g, which encodes a black coat. In a population, genetic typing reveals the genotypic distribution to be 50 GG, 30 Gg, and 20 gg. If this population is in equilibrium, then what should the genotypic frequency of GG squirrels in this population be?

A - .52
B - .42
C - .44
D - .55


Answer: B - .42

The coat color gene of a population of squirrels is defined by a dominant allele G, which encodes a gray coat, and a recessive allele g, which encodes a black coat. In a population, genetic typing reveals the genotypic distribution to be 50 GG, 30 Gg, and 20 gg. If this population is in equilibrium, then what should the genotypic frequency of gg squirrels in this population be?

The coat color gene of a population of squirrels is defined by a dominant allele G, which encodes a gray coat, and a recessive allele g, which encodes a black coat. In a population, genetic typing reveals the genotypic distribution to be 50 GG, 30 Gg, and 20 gg. If this population is in equilibrium, then what should the genotypic frequency of gg squirrels in this population be?

A - .35
B - .12
C - .15
D - .22


Answer: B - .12
Genotypic frequency is calculated with the equation: (p^2 + 2pq + q^2 = 1

The coat color gene of a population of squirrels is defined by a dominant allele G, which encodes a gray coat, and a recessive allele g, which encodes a black coat. In a population, genetic typing reveals the genotypic distribution to be 50 GG, 30 Gg, and 20 gg. What is the allelic frequency of the g allele?

The coat color gene of a population of squirrels is defined by a dominant allele G, which encodes a gray coat, and a recessive allele g, which encodes a black coat. In a population, genetic typing reveals the genotypic distribution to be 50 GG, 30 Gg, and 20 gg. What is the allelic frequency of the g allele?

A - .40
B - .30
C - .35
D - .25


Answer: C - .35
Allelic frequency is calculated with the equation:
q = b/B+b and p = B/B+b
p is often used to represent dominant alleles and q is used for recessive alleles

Why do scientists use the Hardy-Weinberg equation?

Why do scientists use the Hardy-Weinberg equation?

A - To study the genotypic frequency in a genetic cross
B - To study the genotypic frequency in a population
C - To study the number of alleles associated with a gene
D - To study the phenotypic ratios in a dihybrid cross


Answer: B - To study the genotypic frequency in a population
The equation can tell you whether or not an evolutionary agent is affecting a population, the allele frequency in a population should not change if there is no evolutionary agents.

Select the statements about Hardy-Weinberg equilibrium that are true.

Select the statements about Hardy-Weinberg equilibrium that are true.

I. Hardy-Weinberg equilibrium is often found in the wild.
II. The allele frequency of a population in Hardy-Weinberg equilibrium does not change. III. The Hardy-Weinberg equation predicts the evolutionary agent affecting a population.


A - I and III
B - I and II
C - I, II, and III
D - II and III


Answer: D - II and III
The Hardy-Weinberg equation can be used to determine whether or not the genetic makeup of a population is changing. The necessary criteria for a population are difficult to come by naturally.

Which of the following criteria must be met for Hardy-Weinberg equilibrium?

Which of the following criteria must be met for Hardy-Weinberg equilibrium?

I. Beneficial trait II. Non-random mating III. Large population size
A - II and III
B - III
C - I, II, and III
D - I and II


Answer: B - III
The prerequisites for a population:
1) Random mating
2) Large population size
3) No migration between populations
4) No mutations
5) No natural selection

Using the criteria outlined in the Hardy-Weinberg equilibrium, determine which of the following populations can be balanced.

Using the criteria outlined in the Hardy-Weinberg equilibrium, determine which of the following populations can be balanced.

A - A population of parrots that was reduced in size by 90% due to natural disaster
B - A population of fish experiencing a dramatic increase in mutation rate due to toxic dumping in their habitat
C - A population of squirrels isolated on a remote island from other squirrel communities
D - A population of moths in which the mortality rate of lighter colored moths is much higher than darker ones


Answer: C - A population of squirrels isolated on a remote island from other squirrel communities
The Hardy-Weinberg equation describes genotypic frequency in a population. The equation can only be applied if the prerequisites of a population are met.

The study of the allelic, genotypic, and phenotypic variation within a population is referred to as _______.

The study of the allelic, genotypic, and phenotypic variation within a population is referred to as _______.

A - Phenotypic genetics
B - Genotypic genetics
C - Population genetics
D - allelic genetics


Answer: C - Population genetics

What are homologous genes?

What are homologous genes?

A - Genes that are different between organisms
B - Genes that are similar between organisms
C - Genes that accumulate change at constant rates
D - Genes that change over time
E - All of an organisms genetic information


Answer: B - Genes that are similar between organisms
HOMOLOGOUS GENES are genes between two organisms that are similar in the same locations.

Which best describes the general rate of evolution?

Which best describes the general rate of evolution?

A - It takes at least 6.5 million years for a new species to form
B - On average it takes 6.5 million years for a new species to form
C - We do not know how long it takes for a new species to form
D - It takes no more than 4,000 years for a new species to form
E - It takes no more than 40 million years for a new species to form


Answer: B - On average it takes 6.5 million years for a new species to form
IT takes such a long time for populations to evolve because the changes occur slowly over many generations. It does not always happen at this rate but as quickly as 4,000 years or as slow as 40 million years.

Which is NOT true about the fossil record?

Which is NOT true about the fossil record?

A - It is a complete record
B - It provides information about evolution on Earth
C - None are correct
D - It is an incomplete record
E - It is layered in order from oldest to youngest


Answer: A - It is a complete record
The order that fossils occur in the ground allows us to make a timeline but sometimes species seem to gradually evolve and other times they seem to appear out of no where.

Punctuated equilibria describes which phenomenon?

Punctuated equilibria describes which phenomenon?

A - Sudden appearance of species followed by long periods of little change
B - Long periods of constant change
C - Sudden appearances of species followed by short periods of rapid change
D - Sudden disappearance of species after much change has occurred
E - Changes that only occur at regular time intervals


Answer: D - Sudden disappearance of species after much change has occurred
PUNCTUATED EQUILIBRIA is the hypothesis that evolutionary development is marked by isolated episodes of rapid speciation between long periods of little or no change. This normally happens in remote location or from a small, isolated population.

What is a genome?

What is a genome?

A - The number of nucleotides in an organism's DNA that change over time
B - The part of an organisms genetic information that matches other organisms
C - The rate of genetic change
D - The order of fossils in the fossil record
E - All of an organism's genetic information


Answer: E - All of an organisms genetic information
An organisms GENOME accumulates change at constant rates which allows for the comparison of different organisms to determine evolutionary relationships.

Which does NOT provide evidence for evolution?

Which does NOT provide evidence for evolution?

A - Comparative anatomy
B - Bio-geography
C - Molecular biology
D - Climatology
E - Paleontology


Answer: D - Climatology
MOLECULAR BIOLOGY uses biological changes at the molecular level to describe the evolution of organisms.

Which field would best describe why penguins and polar bears are not found in the same regions of Earth?

Which field would best describe why penguins and polar bears are not found in the same regions of Earth?

A - Homology
B - Molecular biology
C - Paleontology
D - Bio-geography
E - Comparative anatomy


Answer: D - Bio-geography
BIO-GEOGRAPHY tells how species are distributed geographically, which helps to understand how similar environments do not always support the same species.

Comparative anatomy is useful for all but which if the following?

Comparative anatomy is useful for all but which if the following?

A - Homologous features in adults
B - Very closely related species
C - Homologous features in embryos
D - Very distantly related species
E - All are correct


Answer: D - Very distantly related species
COMPARATIVE ANATOMY allows us to visually compare the homology of organisms which shows how different environmental demands may lead to similar structures but different functions.

Paleontology is the study of

Paleontology is the study of

A - Fossils and the fossil record
B - Species distribution across Earth
C - Homologous structures
D - Homologous DNA
E - Embryos


Answer: A - Fossils and fossil records
PALEONTOLOGY is important to the support and understanding of evolution. This is the study of prehistoric like, including fossils, footprints, and past climate events.

How does the fossil record support evolution?

How does the fossil record support evolution?

A - It creates a timeline of evolutionary events from oldest to youngest
B - It layers fossils from youngest at the bottom to the oldest at the top
C - It preserves each change a species experiences as it evolves
D - It shows that island species are related to other island species
E - It perfectly preserves organisms from each time period


Answer: A - It creates a timeline of evolutionary events from oldest to youngest
The FOSSIL RECORD shows the sequence of historical changes in organisms that visually allows us to see how organisms evolved over time. Not all prehistoric animals fossilized so its impossible to know everything

Which of the following is an example of natural selection?

Which of the following is an example of natural selection?

I. Albino animals are rare in nature because they are easy for predators to find. II. The fastest gazelle is least likely to be eaten by a lion. III. The gorilla that is strong enough to become alpha male is the most likely to pass on his genes.


A - I and III
B - I and II
C - I, II, and III
D - II and III
E - III


Answer: C - I, II, and III
Natural selection is the agent which determines a differential rate of reproduction

The study of the genetic variation within a population is known as

The study of the genetic variation within a population is known as

A - Lamarkian genetics
B - Population genetics
C - population dynamics
D - Natural selection



Answer: B - Population genetics

Which of the following is NOT a principle of Darwin's theory of evolution?

Which of the following is NOT a principle of Darwin's theory of evolution?

A - An individual can evolve
B - Individuals with different genotypes may pass on their traits at different rates to the next generation
C - Some traits give an individual a better chance of survival
D - A population consists of individuals with different genotypes
E - traits are heritable


Answer: A - An individual can evolve
Principles of Darwin's Theory:
1) Populations, not individuals, evolve
2) Evolution is possible because genetic variation already exists within a population
3) Individuals with different genotypes in the population survive and reproduce at different rates (natural selection)

Which of the following statements does not represent the idea of acquired characteristics?

Which of the following statements does not represent the idea of acquired characteristics?

I. A body builder develops stronger muscles during the course of his life, so his son will be strong as well. II. A cat that lost its tail will produce offspring with shorter tails.
III. Neck length in a giraffe population increased over time since taller giraffes had a competitive advantage over shorter giraffes.


A - I and III
B - III
C - I and II
D - I
E - II


Answer: B - III Neck length in a giraffe population increased over time since taller giraffes had a competitive advantage over shorter giraffes.
ACQUIRED CHARACTERISTICS is also known as Lamarckian inheritance. It is the idea that characteristics an organism acquires during it's lifetime can be passed on to its offspring. The need for a trait drives the evolution of that trait.

_________ can be defined as a change in a characteristic within a population over time.

_________ can be defined as a change in a characteristic within a population over time.

A - Lamarckian inheritance
B - Natural selection
C - Evolution
D - Creationism


Answer: C - Evolution
This is a basic definition

Sea turtles lay hundreds of eggs with the hope that a few of their offspring will survive to adulthood. This is an example of which type of survivor-ship curve?

Sea turtles lay hundreds of eggs with the hope that a few of their offspring will survive to adulthood. This is an example of which type of survivor-ship curve?

A - Type III
B - Type II
C - Type I
D - Type IV


Answer: A - Type III
TYPE III shows species where few individuals will live into adulthood and die as they get older because morality is increased during early life.

What is a survivor-ship curve?

What is a survivor-ship curve?

A - A scientific analysis on the highest cause of death among various species
B - A graph that measures the proportion of human life span related to geographical location
C - A scientific analysis of the likelihood of death in various species
D - A graph that measures the proportion of individuals in a given species that are alive at different ages

Answer: D - A graph that measures the proportion of individuals in a given species that are alive at different ages.

Small mammals, such as rabbits, have many predators and are often hunted by humans and killed on the roadways. they often die at various ages. This is an example of which type of survivor-ship?

Small mammals, such as rabbits, have many predators and are often hunted by humans and killed on the roadways. they often die at various ages. This is an example of which type of survivor-ship?

A - Type IV
B - Type III
C - Type I
D - Type II


Answer: D - Type II
TYPE II shows a roughly constant mortality rate for the species throughout their life.

Elephants have a high probability of living into middle age and adulthood. After becoming adults, their chances of dying increase greatly. Which type of survivor-ship curve depicts an elephant's life?

Elephants have a high probability of living into middle age and adulthood. After becoming adults, their chances of dying increase greatly. Which type of survivor-ship curve depicts an elephant's life?

A - Type II
B - Type III
C - Type I
D - Type IV


Answer: C - Type I
TYPE I shows individuals that have a high probability of surviving through early and middle life, but the amount living into old age is decreased.

There are _____ types of survivor-ship curves.

There are _____ types of survivor-ship curves.

A - 2
B - 5
C - 3
D - 4


Answer: C - 3
They are called Type I, Type II, and Type III.

What is a fate map?

What is a fate map?

A - A specific set of genes that gives step by step directions to a cell so that is differentiates correctly
B - A specific route that many cells take in the embryo during differentiation in order to form more complex structures
C - A diagram that shows the average lifespan of cells from various organs and tissues throughout the body
D - none of these
E - A diagram that shows the developmental fate of various cells from an early stage embryo


Answer: E - A diagram that shows the developmental fate of various cells from an early-stage embryo
Embryologist Walter Vogt developed a method to label a small number of cells with dye to track what they developed into. A FATE MAP is a diagram that shows the developmental fate of various cells from an early-stage embryo.

Being able to activate expression of a fluorescent protein when a specific gene is expressed has been most useful for fate mapping in which of the following organisms?

Being able to activate expression of a fluorescent protein when a specific gene is expressed has been most useful for fate mapping in which of the following organisms?

A - C. elegans
B - Frogs
C - Chickens
D - Humans
E - Mice


Answer: E - Mice
Scientists use genetically engineered mice that self-label any gene they choose and those cells' progeny. They are then used to create fate maps for mammals that were not possible before.

From which of these organisms have scientists created the most complete and detailed fate map?

From which of these organisms have scientists created the most complete and detailed fate map?

A - C. elegans
B - Mice
C - Frogs
D - Humans
E - Zebra fish


Answer:
R - Chickens
A - C. elegans
This is because it is so small and its body plan is so precise and uniform.

What is a somatic cell?

What is a somatic cell?

A - A cell that can still become any cell type
B - A cell that has already differentiated
C - A non-reproductive cell
D - A cell that is in the process of differentiation
E - A cell that is found only in C. elegans


Answer: C - A non-reproductive cell

Out of all the following organisms, which one would you expect to have the least complete and detailed fate map?

Out of all the following organisms, which one would you expect to have the least complete and detailed fate map?

A - Humans
B - Chickens
C - Zebra fish
D - C. elegans
E _Frogs
F - Mice


Answer: A - Humans

Which extra-embryonic membrane functions to remove waste from the embryo in n=both birds and mammals?

Which extra-embryonic membrane functions to remove waste from the embryo in n=both birds and mammals?

A - The amnion
B - None of them
C - The allantois
D - The chorion
E - The yolk sac


Answer: C - The allantois
The ALLANTOIS is the sac-like membrane that removes waster from the embryo. In birds, the embryo grows so does this membrane, causing it to eventually press against the chorion, allowing for exchange of oxygen and carbon dioxide to the outside of the shell and as a disposal site for uric acid.

What is the biggest difference between a liver cell and a brain cell?

What is the biggest difference between a liver cell and a brain cell?

A - Their shape
B - Their gene expression
C - The genes that they have
D - Their size
E - Where they are located


Answer: B - Their gene expression
GENE EXPRESSION is the formation of a protein encoded by a particular gene.

Which of the following is NOT a true statement about transcription factors?

Which of the following is NOT a true statement about transcription factors?

A - Transcription factors are key regulators of gene expression
B - A transcription factor binds to a specific DNA sequence
C - Transcription factors can be activated by signalling pathways which themselves are activated by signalling molecules
D - It usually takes three or more transcription factors working together to initiate transcription of a gene
E - All of these


Answer: E - All of these

The process by which a cell becomes a functional, mature cell of a specific type is known as

The process by which a cell becomes a functional, mature cell of a specific type is known as

A - Binding
B - Transcription
C - Signaling
D - Differentiation
E - Expression


Answer: D - Differentiation

What is a ligand?

What is a ligand?

A - A protein that makes a connection between two cells
B - A protein that binds to a specific DNA sequence
C - A molecule that binds to a receptor
D - A molecule that binds two proteins together
E - A DNA sequence that is necessary for transcription


Answer: C - A molecule that binds to a receptor
LIGANDS are molecules that bond to a receptor.

The transcription of the following genes is regulated by the following combinations of binding sites.

The transcription of the following genes is regulated by the following combinations of binding sites.

- Gene 1 is regulated by binding sites A, B and D
- Gene 2 is regulated by binding sites A, D and F
- Gene 3 is regulated by binding sites B, C and D
-Gene 4 is regulated by binding sites B, D and E
-Gene 5 is regulated by binding sites A, D and E.
If transcription factors TF-A, TF-B, TF-D and TF-E are all active in the cell, which genes will be transcribed?


A - Genes 1, 3, and 4
B - Genes 1 and 4
C - Genes 1 and 5
D - Genes 1, 4 and 5
E - Genes 2 and 3


Answer: D - Genes 1, 4 and 5

What is a protease?

What is a protease?

A - A protein that inhibits receptors and other proteins
B - A protein that degrades other proteins
C - An enzyme that aids in the synthesis of new proteins
D - A protein that directs the differentiation of cells
E - A molecule that is used to send signals between different cells



Answer: B - A protein that degrades other proteins

Which of the following contribute to the formation of the concentration gradient of BMP-4 in the frog embryo?

Which of the following contribute to the formation of the concentration gradient of BMP-4 in the frog embryo?

I. BMP-4 is produced in the ventral portion of the embryo
II. Chordin is produced in Spemann's Organizer III. Chordin inhibits BMP-4 IV. Xolloid is produced in the ventral portion of the embryo. V. Xolloid degrades chordin.


A - I
B - I, II, and IV
C - I, III, V
D - I, II, and III
E - I, II, III, IV, and V


Answer: E - I, II, III, IV, and V
Xolloid helps to sharpen the concentration gradient of BMP-4 activity by degrading chordin in the ventral part of the embryo, where BMP-4 levels are already high. The gradient is set up along the dorsoventral axis.

Which of the following statements is true about the chordin?

Which of the following statements is true about the chordin?

A - It is produced in Spemann's organizer and inhibits Xolloid
B - It is produced in Spemann's organizer and inhibits BMP-4
C - It is produced in Spemann's organizer and is inhibited by BMP-4
D - It is produced in the ventral portion of the embryo and inhibits BMP-4
E - It is produced in the ventral portion of the embryo and is inhibited by BMP-4


Answer: B - It is produced in Spemann's organizer and inhibits BMP-4
Chordin is produced in Spemann's organizer.

When chordin binds to BMP-4, what effect does this have on the BMP-4 concentration gradient?

When chordin binds to BMP-4, what effect does this have on the BMP-4 concentration gradient?

A - It sharpens the concentration gradient by degrading BMP-4 that diffuses to the dorsal half of the embryo.
B - It destroys the concentration gradient by degrading almost all BMP-4.
C - It sharpens the concentration gradient by inhibiting BMP-4 that diffuses to the dorsal half of the embryo.
D - It spreads out the concentration gradient by inhibiting BMP-4 activity where BMP-4 concentrations are highest.
E - It spreads out the concentration gradient by degrading BMP-4 where its concentrations are highest.


Answer: C - It sharpens the concentration gradient by inhibiting BMP-4 that diffuses to the dorsal half of the embryo.
Chordin inhibits BMP-4 activity in the dorsal part of the embryo.

Xolloid is a(n)

Xolloid is a(n)

A - Protease
B - Nucleic acid
C - Inhibitor
D - Receptor
E - Signaling molecule


Answer: A - Protease
Xolloid is a protease which degrades chordin and it sharpens the concentration of BMP-4. It is produced in the ventral portion of the embryo and is not effective in the dorsal side because chordin is so abundant.

Which of the following is true about Spemann's experiments with 2-cell-stage embryos?

Which of the following is true about Spemann's experiments with 2-cell-stage embryos?

A - The experiments resulted in embryos with two sets of body axes and structures.
B - The experiments resulted in embryos with two sets of body axes and structures.
C - All of the cells could only form the ventral side of the embryo.
D - Some of the cells formed complete, half-sized embryos, but some of them only formed the ventral side of the embryo.
E - All of the cells formed complete, half-sized embryos.


Answer: D - Some of the cells formed complete, half-sized embryos, but some of them only formed the ventral side of the embryo.
In some cases, both of the separated cells produced fully-formed, half-sized embryos, but in others, one cell would form a complete half-sized embryo, and the other would form only the ventral half of the embryo.

Which of the following is not an organizer?

Which of the following is not an organizer?

A - Spemann's organizer
B - The dorsal lip
C - The ventral side of the gastrula
D - The node
E - Hensen's node


Answer: C - The ventral side of the gastrula

Which of the following refers to the underbelly side of an animal?

Which of the following refers to the underbelly side of an animal?

A - Ventral
B - Posterior
C - Anterior
D - Dorsal
e - Sagittal


Answer: A - Ventral
Dorsal = back side
Ventral = underbelly side
Anterior = head
Posterior = tail

What is "the node"?

What is "the node"?

A - The part of the embryo that will eventually become the brain
B - None of these
C - The center of the developing embryo
D - The mammalian equivalent of Spemann's organizer
E - The bird equivalent of Spemann's organizer


Answer: D - The mammalian equivalent of Spemann's organizer
The NODE is the term for the mammalian organizer that organizes body structures and axes. The bird equivalent is Hensen's node.

How were Spemann and Mangold able to tell that the organizer was directing cells of the host embryo to change their fates?

How were Spemann and Mangold able to tell that the organizer was directing cells of the host embryo to change their fates?

A - They assumed that all cells were dividing at the same rate and therefore some cells from the host embryo had to change their fate; otherwise there just wouldn't be enough cells.
B - They sequenced the DNA from different cells so that they could tell the host cells from the graft cells based on genotype.
C - They carefully observed the embryos differentiating under the microscope and kept track of which cells became what
D - They injected the graft cells with a dye to mark them and their progeny
E - The host cells and the graft cells had different pigmentation


Answer: E - The host cells and the graft cells had different pigmentation

After gastrulation has occurred, the inner layer of cells is called what?

After gastrulation has occurred, the inner layer of cells is called what?

A - The mesoderm
B - The ICM
C - The endoderm
D - The epiblast
E - The ectoderm


Answer: C - The endoderm

Why doesn't the outer layer of cells in the mammalian blastocyst become the ectoderm during mammalian gastrulation?

Why doesn't the outer layer of cells in the mammalian blastocyst become the ectoderm during mammalian gastrulation?

A - All the cells in the layer die
B - It become the endoderm
C - It becomes the placenta
D - The outer layer is shed when the blastocyst hatches out of the zona pellucida
E - It becomes the mesoderm


Answer: C - It becomes the placenta
The outer layer becomes the mammalian placenta so the ICM has to form the three germ layers.

What is the main purpose of gastrulation?

What is the main purpose of gastrulation?

A - None of these
B - Formation of the gut tube
C - Formation of the primary germ layers
D - Formation of the primitive mouth


Answer: C - Formation of the primary germ layers
GASTRULATION is the process that results in the formation of three distinct germ layers in the early embryo.

In this drawing of a frog gastrula, which letter corresponds to the ectoderm?

In this drawing of a frog gastrula, which letter corresponds to the ectoderm?

A - A
B - E
C - C
D - B
E - D


Answer: A - A

The heart, blood vessels, blood cells, skeleton, kidneys, spleen, and muscles are all tissues or organs that arise from what primary germ layer?

The heart, blood vessels, blood cells, skeleton, kidneys, spleen, and muscles are all tissues or organs that arise from what primary germ layer?

A - The mesoderm
B - The ectoderm
C - The inner cell mass or ICM
D - The endoderm
E - The epiblast


Answer: A - The mesoderm
The ECTODERM will form the nervous system, the epithelial cells of the mammary glands, the lens of the eyes, hair, pigment cells and the epidermis of the skin. The MESODERM will form skeletal muscle, smooth muscle, the heart, blood vessels, blood cells, kidney, spleen, fat cells, the skeleton, most connective tissues and most of the urogenital system. The ENDODERM will form the entire epithelial lining of the gastrointestinal tract, as well as the liver, pancreas, gall bladder, thyroid, the epithelial lining of the trachea and the respiratory surface of the lungs.

Which of the following is crucial for proper development of a baby's lungs?

Which of the following is crucial for proper development of a baby's lungs?

A - The yolk sac
B - Amniotic fluid
C - The amnion
D - The chorion
E - The allantois


Answer: B - Amniotic fluid
AMNIOTIC FLUID is found within the amnion (surrounds the developing embryo) serves as a liquid cushion and is necessary for ordinary development of lungs and limbs.

Which extra-embryonic membrane is used by mammals to form part of the placenta?

Which extra-embryonic membrane is used by mammals to form part of the placenta?

A -The yolk sac
B - The chorion
C - The allantois
D - The amnion
E - None of them


Answer: B - The chorion

Which of the following is NOT a true statement about the placenta?

Which of the following is NOT a true statement about the placenta?

A - It is an organ that is found in all species
B - It attaches the fetus to the uterine wall
C - It provides nutrients to the fetus
D - It allows the fetus to transfer waste products to the mother's bloodstream


Answer: A - It is an organ that is found in all species

Which of the four extra-embryonic membranes maintains the same form and functions in birds and mammals?

Which of the four extra-embryonic membranes maintains the same form and functions in birds and mammals?

A - The amnion
B - The allantois
C - The yolk sac
D - The chorion
E - None of them


Answer: A - The amnion

Which extra-embryonic membrane has a well-developed vascular structure that contributes to the vascular system of the developing mammalian embryo?

Which extra-embryonic membrane has a well-developed vascular structure that contributes to the vascular system of the developing mammalian embryo?

A - The chorion
B - None of them
C - The allantois
D - The amnion
E - The yolk sac


Answer: E - The yolk sac
The YOLK SAC in the mammals doesn't contain any yolk, but maintained a well-developed vascular system and contributes to the vascular system of the embryo.

The embryonic-derived portion of the placenta is called

The embryonic-derived portion of the placenta is called

A - Chorion
B - Fetus
C - Blastocyst
D - Trophoblasts


Answer: A - Chorion
The chorion is the embryonic-derived portion of the placenta. It is composed of fetal blood vessels and trophoblasts which are organized into finger-like structures called chorionic villi. The chorionic villi are surrounded by the intervillous space, which is the part of the placenta surrounding the chorionic villi that contains maternal blood.

Which of the following contains mostly maternal cells?

Which of the following contains mostly maternal cells?

A - The intervillus space
B - The chorionic villi
C - The capillaries within the chorionic villi
D - The umbilical cord


Answer: A - The intervillus space

Which part of the mammalian blastocyst will eventually become the embryo itself and its surrounding membranes?

Which part of the mammalian blastocyst will eventually become the embryo itself and its surrounding membranes?

A - The ICM
B - The blastula
C - The morula
D - The trophoblast cells


Answer: A - The ICM
The ICM are the internal cells of the morula that will eventually become the embryo itself. The external cells are the trophoblast cells which play a key role in the implantation of the embryo into the uterine wall, when it will become the chorion or placenta.

Which of the following is a true statement?

Which of the following is a true statement?

A - Oxygen diffuses from the maternal blood in the intervillous space, through trophoblasts in the chorionic villi, and into the fetal bloodstream.
B - Waste products from the fetus diffuse out of capillaries in the chorionic villi and into the umbilical vein, which carries them back to the mother who will be able to remove them from her blood.
C - Maternal blood is supplied to the fetus through the umbilical cord.
D - Nutrients diffuse from the maternal blood in the umbilical cord, through trophoblasts in the chorionic villi, and into the fetal bloodstream.


Answer: A
Maternal blood flows from the mother's circulatory system, through the intervillous space and then re-enters the mother's blood vessels. Fetal blood flows from the fetus into two main arteries in the umbilical cord, through the capillary network of the chorionic villi and is returned to the fetus by the umbilical vein. The maternal blood that enters the placenta is nutrient and oxygen rich.

Mary is pregnant and is telling you about how she is worried that her baby is floating around in her uterus with noting holding him in place. Which of the following would be most helpful to tell Mary about in order to ease her worries?

Mary is pregnant and is telling you about how she is worried that her baby is floating around in her uterus with noting holding him in place. Which of the following would be most helpful to tell Mary about in order to ease her worries?

A - Her blood and the baby's blood work together
B - Trophoblasts form columns of cells that anchor the fetus to the uterine wall
C - The placenta is keeping her baby nourished
D - The umbilical cord is attached to both the fetus and the mother


Answer: B - Trophoblasts form columns of cells that anchor the fetus to the uterine wall
The PLACENTA has three jobs:
1) Attach the fetus to the uterine wall
2) Provide nutrients to the fetus
3) Allow the fetus to transfer waste products to the mother's blood

Which of the following is an important function of the zona pellucida?

Which of the following is an important function of the zona pellucida?

A - Provide proteins which bind to the extracellular matrix of the uterine wall and allow the blastocyst to attach
B - Protect the blastocyst from proteases that would break the blastocyst apart
C - None of these are functions of the zona pellucida
D - Prevent the blastocyst from attaching to the wall of the fallopian tube
E - Provide proteases which will digest the extracellular matrix of the uterine wall


Answer: D - Prevent the blastocyst from attaching to the wall of the fallopian tube
The ZONA PELLUCIDA is a layer of extracellular matrix surrounding the mature oocyte, fertilized zygote and pre-implantation blastocyst. It surrounds the developing embryo during its journey through the fallopian tubes and prevents it from implanting prematurely to the wall of the fallopian tube.

Which of the following best describes what can be found in chorionic villi?

Which of the following best describes what can be found in chorionic villi?

A - Fetal blood vessels
B - Fetal blood vessels and maternal blood
C - Trophoblasts
D - Maternal blood
E - Fetal blood vessels and trophoblasts


Answer: E - Fetal blood vessels and trophoblasts
The CHORIONIC VILLI are finger-like structures of the placenta composed of embryo-derived trophoblasts that become surrounded by maternal blood (intervillus space).

When do trophoblasts do after the blastocyst attaches to the uterine wall?

When do trophoblasts do after the blastocyst attaches to the uterine wall?

A - They do all of these
B - They invade deeper into the uterine wall
C - They encounter and surround maternal blood vessels
D - They divide and multiply in number
E - They form the chorionic villi


Answer: A - They do all of these
As the blastocyst implants, the trophoblasts that make up the outer layer of cells multiply in number and invade deeper into the uterine wall

When and how does the blastocyst use proteases?

When and how does the blastocyst use proteases?

A - The blastocyst uses proteases to hatch from the zona pellucida when it reaches the uterus, and then it uses proteases again to digest the extracellular matrix of the uterine wall which allows the blastocyst to bury itself in the uterine wall.
B - The blastocyst uses proteases to degrade proteins which would allow it to attach to the wall of the fallopian tube.
C - The blastocyst uses proteases to hatch from the zona pellucida when it is in the fallopian tube.
D - The blastocyst uses proteases to digest the extracellular matrix of the uterine wall which allows the blastocyst to bury itself in the uterine wall.
E - The blastocyst uses proteases to hatch from the zona pellucida when it reaches the uterus.


Answer: A. Once the blastocyst reaches the uterus, it uses a protein digesting enzyme, or protease, to make a hole in the surrounding zona pellucida. It then squeezes through the hole to hatch out of the zona pellucida. Proteins on the outer surface of the blastocyst bind to the extracellular matrix of the uterine wall and allow the blastocyst to attach. Once attached, the blastocyst secretes a number of different proteases that digest the extracellular matrix of the uterus and allow the blastocyst to bury itself in the uterine wall.

Which of the following statements is true about the intervillous space?

Which of the following statements is true about the intervillous space?

A - The blood in the intervillous space is in direct contact with embryonic trophoblast cells
B - It is not lined by endothelial cells
C - It is filled with maternal blood
D - The intervillous space is formed by the fusion of maternal blood vessels and spaces between fetal trophoblasts
E - All of these are true statements about the intervillus space


Answer: E - All of these are true statements
The blood-filled sinuses expand and the trophoblasts form finger-like structures called chorionic villi. These finger-like structures of the placenta composed of embryo-derived trophoblasts become surrounded by maternal blood in what is now called the INTERVILLUS SPACE.

The structure within the ovary in which a primary oocyte grows and develops is called the

The structure within the ovary in which a primary oocyte grows and develops is called the

A - Follicle
B - Egg
C - Ovum
D - Polar body


Answer: A - Follicle

Which of the following is the last stage of mammalian development to occur before implantation in the uterus?

Which of the following is the last stage of mammalian development to occur before implantation in the uterus?

A - Morula
B - Ovum
C - Blastocyst
D - Zygote


Answer: C - Blastocyst
The BLASTOCYST is the last stage of mammalian development before implantation. It is the specialized mammalian blastula (occurs after the trophoblast cells secrete fluid into the middle of the morula forming a hollow ball of cells) that contains the two different cell types (the trophoblast cells and the cells of the ICM).

Which embryonic stage consists of a solid, compact mass of sixteen or more cells?

Which embryonic stage consists of a solid, compact mass of sixteen or more cells?

A - The morula
B - The blastocyst
C - The blastula
D - The ICM


Answer: A - The morula
The MORULA comes after the zygote has divided several times, and is an embryonic stage consisting of a solid, compact mass of 16 or more cells. When it reaches the 64 cell stage, the internal and external cells become separate lineages.

How does cleavage differ from normal mitosis?

How does cleavage differ from normal mitosis?

A - The growth phases between divisions is faster
B - There are no growth phases between divisions
C - It occurs faster than normal mitosis
D - It occurs slower than normal mitosis


Answer: B - There are no growth phases between divisions
The zygote is rapidly dividing without growing to become multi-cellular, where in mitosis there is a growth period.

Which of the following is NOT a factor that makes studying in human development difficult?

Which of the following is NOT a factor that makes studying in human development difficult?

A - The small size of the early human embryo
B - The brief gestational time of humans
C - Ethical limitations on human research
D - Human embryos develop inside the mother


Answer: B - The brief gestational time of humans
The gestational period in humans is long, which slows down the pace of research and normally hum,ans only create one or two at a time.

The following image shows a diagram of spermatogenesis, the process by which male gametes, known as sperm, are created. How is the process different from oogenesis?

The following image shows a diagram of spermatogenesis, the process by which male gametes, known as sperm, are created. How is the process different from oogenesis?

A - The result of spermatogenesis is only one gamete, while the result of oogenesis is four gametes.
B - Spermatogenesis is the production of gametes through mitosis, while oogenesis is the production of gametes through meiosis.
C - The result of oogenesis is only one gamete, while the result of spermatogenesis is four gametes
D - Oogenesis is the production of gametes through mitosis, while spermatogenesis is the production of gametes through meiosis.


Answer: C - The result of oogenesis is only one gamete, while the result of spermatogenesis is four gametes
The chromosomes are divided evenly into two daughter cells but the cytoplasm isn't. The secondary oocyte is divided again, unevenly resulting in only one usable oocyte.

Which of these cells only exists in the fallopian tubes?

Which of these cells only exists in the fallopian tubes?

A - Oogonium
B - Secondary oocyte
C - Ovum
D - Primary oocyte


Answer: C - Ovum
Since the second meiotic division does not occur until fertilization, creation of the ovum only occurs at fertilization which happens in the fallopian tube, and very soon thereafter, the zygote begins cell division before it to the uterine wall, so the ovum is a very short-lived stage in oogenesis that only exists in the fallopian tubes. Secondary oocytes are found in the fallopian tubes, but they also exist in the ovaries just before ovulation.

In humans, when are primary oocytes made?

In humans, when are primary oocytes made?

A - Sometime between birth and the girl's second birthday
B - Throughout a women's like until menopause
C - When the female is still a fetus
D - During puberty


Answer: C - When the female is still a fetus
All of the oogonia that a female will have are created 1-2 months before she is born, most of the 7 million will die and surviving ones enter meiosis I (but freeze in prophase I) and become primary oocytes.

During oogenesis, when does the first meiotic division take place?

During oogenesis, when does the first meiotic division take place?

A - Just before ovulation
B - One to two months before a human female is born
C - Upon fertilization by a sperm
D - At about mid-gestation of the fetus


Answer: A - Just before ovulation

Which of the following is a somatic cell?

Which of the following is a somatic cell?

A - Spermatogonium
B - Sperm cell
C - Spermatid
D - Spermatocyte
E - Sertoli cell


Answer: E - Sertoli cell
SERTOLI CELLS are somatic cells that line the seminiferous tubules that support and provide nutrients to the various sperm precursors.

What is the function of the acrosome?

What is the function of the acrosome?

A - Penetrate the outer layers of the ovum
B - Incorporate the sperm DNA into the nucleus of the ovum
C - To protect the nucleus
D - Provide energy to the sperm for swimming
E - Make sure that the chromosome divide evenly


Answer: A - Penetrate the outer layers of the ovum

Forty sperm are made by the end of spermatogenesis. How many spermatogonium entered meiosis?

Forty sperm are made by the end of spermatogenesis. How many spermatogonium entered meiosis?

A - 8
B - 10
C - 4
D - 20
E - 1


Answer: B - 10
SPERMATOGOIUM are the first precursor cells, it turns into a primary spermatocyte when it enters mitosis, which divides into two secondary spermatocytes. These will then divide creating four.

Which of the following is true about sperm?

Which of the following is true about sperm?

A - They are haploid and have one copy of each chromosome
B - They are diploid and have two copies of each chromosome
C - They are haploid and have two copies of each chromosome
D - They are diploid and have one copy of each chromosome
E - They are tetraploid and have four copies if each chromosome


Answer: A - They are haploid and have one copy of each chromosome

What are the three basic components of a functional mature sperm cell?

What are the three basic components of a functional mature sperm cell?

A - An acrosome, a flagellum, and mitochondria
B - Mitochondria, a flagellum, and a nucleus
C - A flagellum, a nucleus, and an acrosome
D - A nucleus, mitochondria. and an acrosome
E - A nucleus, cytosol, and a flagellum


Answer: C - A flagellum, a nucleus, and an acrosome
They contain a NUCLEUS with the haploid genome, the ACROSOME forms a cap over the nucleus, and FLAGELLUM us used for locomotion.

In the early embryo, how are the positions of the mesoderm and endoderm different?

In the early embryo, how are the positions of the mesoderm and endoderm different?

A - The mesoderm is the outermost layer of the cells, while the endoderm is the innermost layer
B - The mesoderm is the innermost layer of the cells, while the endoderm is the middle layer
C - The mesoderm is the middle layer of the cells, while the endoderm is the innermost layer
D - The mesoderm is the innermost layer of the cells, while the endoderm is the outermost layer


Answer: C - The mesoderm is the middle layer of the cells, while the endoderm is the innermost layer
The ENDODERM is the outermost layer of cells. The MESODERM is the middle layer. The ENDODERM is in the innermost layer.

Select the statement that is TRUE about animal reproduction and development.

Select the statement that is TRUE about animal reproduction and development.

A - Animals that reproduce asexually are called hermaphrodites
B - Some multi-cellular organisms can reproduce by both sexual and asexual reproduction
C - Developmental biologists mainly study human development
D - Organogenesis begins immediately after fertilization


Answer: B - Some multi-cellular organisms can reproduce by both sexual and asexual reproduction

Which of the following describes a zygote?

Which of the following describes a zygote?

A - A multi-cellular embryo
B - An embryo that has the three primary germ layers
C - A fertilized ovum
D - An embryo that is in the process of organogenesis


Answer: C - A fertilized ovum

Which axis organizes the body from head to tail?

Which axis organizes the body from head to tail?

A - The anteroposterior axis
B - The dorsoventral axis
C - The cerebrospinal axis
D - The left-right axis


Answer: A - The anteroposterior axis


The ANTERPOSTERIOR organizes from head to tail. The DORSOVENTRAL organizes from back to belly. The LEFT-RIGHT organizes from left to right.

Select the set of event, in chronological order, as they occur during sexual reproduction in multi-cellular animals.

Select the set of event, in chronological order, as they occur during sexual reproduction in multi-cellular animals.

A - Fertilization, cleavage, gametogenesis, formation of the three primary germ layers, organogenesis

B - Gametogenesis, cleavage, fertilization, formation of the three primary germ layers, organogenesis

C - Gametogenesis, fertilization, cleavage, formation of the three primary germ layers, organogenesis

D - Gametogenesis, fertilization, cleavage, organogenesis, formation of the three primary germ layers





Answer: C - Gametogenesis, fertilization, cleavage, formation of the three primary germ layers, organogenesis

SEXUAL reproduction is when two parents produce offspring with unique combinations of genes from both parents.

Series of events:

1) Gametogenesis - formation of gametes

2) Fertilization - sperm and egg unite

3) Establishment of three major body axes

4) Cleavage - zygote rapidly divides to become multi-cellular

5) Formation of three germ layers

6) Organogenesis - formation of organs