Bio 200 EXAM QUESTIONS WITH COMPLETE
SOLUTIONS!!/GRADE A+ GUARANTEED
SATISFACTION
What does the Hardy-Weinberg principle state? - ANSWER-If only Mendelian segregation and
recombination are occurring then the allele and genotype frequency in a population will remain
constant generation to generation.
Punnett's squares used at population level: - ANSWER-prove the Hardy-Weinberg principle
A population is in Hardy-Weinberg Equilibrium if: - ANSWER--it meets the 5 conditions
AND
-its genotypes match the correct proportions
((p^2)+(2pq)+(q^2)=1)
If a population is NOT in Hardy-Weinberg Equilibrium, then: - ANSWER-Evolution is occurring
1. Genotype frequency vs. 2. Allele frequency: - ANSWER-1. ((p^2)+(2pq)+(q^2)=1)
2. (p+q)=1
Genetic change can be caused by: - ANSWER--Natural Selection
-Genetic Drift (change due to random chance)
-Gene Flow (movement in or out of a population)
Two common situations where you get small populations through genetic drift are: - ANSWER-1.
Founder Effect (New population has different ratios than the source)
2. Bottleneck Event (change after drastic decline in population; usually after natural disaster)
*ex. Greater Prairie Chicken pop. decline
Two dangers of the founder effect and the bottleneck event: - ANSWER--Can lead to losing certain
alleles (and thus genetic variation)
,-Can allow harmful recessive alleles to increase.
What affect does gene flow have on natural selection? - ANSWER--it can undo or enhance natural
selection
What is the only type of genetic change that is adaptive? - ANSWER-Natural Selection
How is natural selection measured? - ANSWER--by Relative Fitness
What is relative fitness? - ANSWER-the contribution to the gene pool of the next generation compared
to other individuals in the population.
The environment acts on ____ directly, and ____ indirectly. - ANSWER-phenotype; genotype
Types of Natural Selection: - ANSWER--Directional (favors one side or the other; moves curve up and
down graph)
-Disruptive (favors the extremes; creates two humps)
-Stabilizing (favors the average; creates smaller range)
-Balancing (Include the heterozygote advantage and frequency dependence)
Sexual Selection: - ANSWER--involves traits related to mating
(ex. peacock feathers)
-these traits are usually an "honest" signal of quality (if has trait= "good genes")
Heterozygote Advantage: - ANSWER--occurs when both types of homozygote have a lower level of
fitness
-preserves genetic variation
Frequency Dependent Selection: - ANSWER--not based on the trait itself but how common the trait is
-which phenotype is better/favored changes continuously depending on which is more common
, (ex. the right/left mouthed fish)
True/False: The perfectly adapted organism can evolve. - ANSWER-False
Limits to Natural Selection (aka: why the perfectly adapted organism cannot evolve): - ANSWER-1.
Selection only acts on variation that exists, and not all variations exist
2. Genetic possibilities can be limited by historical constraints
3. The speed at which change can happen is limited by the selection time (how long it takes for many
generations to occur; ex. elephants vs. fruit flies)
4. Certain trade-offs need to be made (ex. bone density for speed; compromises for best possible trait
which is not always ideal)
5. Random chance
6. The environment is not necessarily constant
Biological Species Concept: - ANSWER--Defines a species as all organisms that can produce viable
offspring with each other (viable offspring must be able to survive to adulthood and reproduce.)
*Different species also should not be able to produce viable offspring with different groups
-Depends on reproductive isolation (includes prezygotic and postzygotic barriers to reproduction)
Prezygotic barriers to reproduction: - ANSWER--prevent fertilization= no formation of zygote
Postzygotic barriers to reproduction: - ANSWER--zygote cannot become fully fledged adult
The 5 types of Prezygotic Barriers: - ANSWER-1. Habitat Isolation
2. Temporal Isolation (Night/Day/Seasonal)
3. Behavioral Isolation
(1-3 = No mating takes place)
4. Mechanical Isolation
5. Gametic Isolation
(4 & 5 = no fertilization)
SOLUTIONS!!/GRADE A+ GUARANTEED
SATISFACTION
What does the Hardy-Weinberg principle state? - ANSWER-If only Mendelian segregation and
recombination are occurring then the allele and genotype frequency in a population will remain
constant generation to generation.
Punnett's squares used at population level: - ANSWER-prove the Hardy-Weinberg principle
A population is in Hardy-Weinberg Equilibrium if: - ANSWER--it meets the 5 conditions
AND
-its genotypes match the correct proportions
((p^2)+(2pq)+(q^2)=1)
If a population is NOT in Hardy-Weinberg Equilibrium, then: - ANSWER-Evolution is occurring
1. Genotype frequency vs. 2. Allele frequency: - ANSWER-1. ((p^2)+(2pq)+(q^2)=1)
2. (p+q)=1
Genetic change can be caused by: - ANSWER--Natural Selection
-Genetic Drift (change due to random chance)
-Gene Flow (movement in or out of a population)
Two common situations where you get small populations through genetic drift are: - ANSWER-1.
Founder Effect (New population has different ratios than the source)
2. Bottleneck Event (change after drastic decline in population; usually after natural disaster)
*ex. Greater Prairie Chicken pop. decline
Two dangers of the founder effect and the bottleneck event: - ANSWER--Can lead to losing certain
alleles (and thus genetic variation)
,-Can allow harmful recessive alleles to increase.
What affect does gene flow have on natural selection? - ANSWER--it can undo or enhance natural
selection
What is the only type of genetic change that is adaptive? - ANSWER-Natural Selection
How is natural selection measured? - ANSWER--by Relative Fitness
What is relative fitness? - ANSWER-the contribution to the gene pool of the next generation compared
to other individuals in the population.
The environment acts on ____ directly, and ____ indirectly. - ANSWER-phenotype; genotype
Types of Natural Selection: - ANSWER--Directional (favors one side or the other; moves curve up and
down graph)
-Disruptive (favors the extremes; creates two humps)
-Stabilizing (favors the average; creates smaller range)
-Balancing (Include the heterozygote advantage and frequency dependence)
Sexual Selection: - ANSWER--involves traits related to mating
(ex. peacock feathers)
-these traits are usually an "honest" signal of quality (if has trait= "good genes")
Heterozygote Advantage: - ANSWER--occurs when both types of homozygote have a lower level of
fitness
-preserves genetic variation
Frequency Dependent Selection: - ANSWER--not based on the trait itself but how common the trait is
-which phenotype is better/favored changes continuously depending on which is more common
, (ex. the right/left mouthed fish)
True/False: The perfectly adapted organism can evolve. - ANSWER-False
Limits to Natural Selection (aka: why the perfectly adapted organism cannot evolve): - ANSWER-1.
Selection only acts on variation that exists, and not all variations exist
2. Genetic possibilities can be limited by historical constraints
3. The speed at which change can happen is limited by the selection time (how long it takes for many
generations to occur; ex. elephants vs. fruit flies)
4. Certain trade-offs need to be made (ex. bone density for speed; compromises for best possible trait
which is not always ideal)
5. Random chance
6. The environment is not necessarily constant
Biological Species Concept: - ANSWER--Defines a species as all organisms that can produce viable
offspring with each other (viable offspring must be able to survive to adulthood and reproduce.)
*Different species also should not be able to produce viable offspring with different groups
-Depends on reproductive isolation (includes prezygotic and postzygotic barriers to reproduction)
Prezygotic barriers to reproduction: - ANSWER--prevent fertilization= no formation of zygote
Postzygotic barriers to reproduction: - ANSWER--zygote cannot become fully fledged adult
The 5 types of Prezygotic Barriers: - ANSWER-1. Habitat Isolation
2. Temporal Isolation (Night/Day/Seasonal)
3. Behavioral Isolation
(1-3 = No mating takes place)
4. Mechanical Isolation
5. Gametic Isolation
(4 & 5 = no fertilization)
