BIO 173 Final Exam Questions and All
Correct Answers 2025-2026 Version.
What is the major fitness cost of sexual reproduction compared to asexual reproduction for
females?
Describe at least 2 other costs of sexual reproduction.
Describe 3 hypotheses for why almost all animal species have sexual reproduction as part of
their life cycles despite this cost. - Answer For females, sexual reproduction requires much of
their energy, resources, and ultimately decreases their fitness by 50%. It also often does not
produce as man y viable offspring since fewer offspring are born and can be male or female.
Asexual reproduction, however, allows the female to maintain their fitness and resources as
more offspring are produced that can also asexually reproduce since they all must be females.
Sexually transmitted disease, cost of courtship, and sexual conflict.
Sexual reproduction allows for greater genetic diversity.
Sexual reproduction can reduce competition among offspring
??
Define asexual reproduction and sexual reproduction.
What are the two most common types of asexual reproduction in animals? - Answer Asexual
reproduction is the production of offspring that are genetically identical to the single parent
that made it. Sexual reproduction is the fusion of gametes (sperm and egg) to create genetically
different offspring.
The most common types of asexual reproduction in animals are fission (an animal divides itself
into multiple identical individuals) and budding (organisms develops a growth or bud on itself).
Describe an example of a counter-current system in animal physiology and state what substance
is transferred between flows in your example.
Draw a cartoon illustrating the how the relative concentration or quantity of this substance
varies along each of the two flows.
How would the transfer of this substance differ in a CONcurrent system?
A drawing of the concurrent system
may help you illustrate this. - Answer An example of a counter current system would be the
blood flow in a birds feet. Heat is transferred as warm blood coming from the body flows
adjacent to cool blood flowing back into the body. As the blood reaches the foot it decreases in
heat hit rather than lose it, it's is transferred to the adjacent vein.
In a concurrent system, the blood coming from the body and coming back into the body would
,How do the physical properties of water create challenges for gas exchange by aquatic animals?
- Answer Water can hold more oxygen in cold temperatures, while warmer water holds less
oxygen due to the increased movement of the H2O molecules. Therefore, aquatic animals,
mostly ectotherms, rely on external temperatures to carry out metabolism. So an increase in
water temp. would increase respiration rates but not provide enough oxygen for the organism.
Water also allows gases to move much slower than if it were diffusion through the air.
Why does the complexity of digestive, respiratory, and excretory systems tend to increase with
animals' size? - Answer As the animal increases in body size, they become less dependent on
diffusion (as it takes too long), and instead rely on more complex organ systems for gas
exchange, circulation, and the providing of nutrients.
Explain how each of the following affect animals' ability to acquire oxygen and expel wastes
through diffusion:
body size, metabolic rate, skin permeability, terrestrial vs. aquatic habitat. - Answer Body size:
Larger animals need more complex organ systems to maintain metabolism and exchange
nutrients with their environment.
Metabolic rate: Organisms that metabolize faster, need more complex organ systems to take in
more oxygen.
Skin Permeability: Exchange of nutrients through diffusion in and out of the body
(permeable/impermeable membrane)
Terr. vs Aqua Habitat: Aquatic animals can avoid diffusion because gasses diffuse quicker in air,
but terrestrial have an impermeable membrane which prevents them from drying out.
Define homeostasis.
List 5 conditions for which at least some animals are homeostatic regulators, and describe an
example of how an animal regulates this condition.
For each of the conditions you listed, do you think most plants are regulators or conformers? -
Answer Homeostasis is a state of equilibrium that an organism tries to maintain in order to
function as best and efficiently as possible.
- Increase in Temperature: Panting/sweating
- Water Loss: Osmoregulation/drink H2O
- Decrease in Temperature: Shivering
- Carbon Dioxide Levels: Increased breathing
- Increased Glucose: Release of insulin, storing of glycogen
Plants are conformers.
, c. The metabolic rate (rate of cellular respiration per g animal tissue)
d. The TOTAL oxygen consumption
e. Gut complexity
f. Food consumed daily/body mass - Answer b. Total surface area of the respiratory
membrane,
e. Gut complexity
(Increase with body size)
Define sensation and perception. In what part of the nervous system does each of these take
place? - Answer Sensation is the conversion of stimuli into change in membrane potential that
changes frequency of action potentials. Perception is the how the information that we observe
it interpreted by neurons.
Sensation takes place in the peripheral nervous system, perception takes place in the central
nervous system.
Define a stimulus. - Answer A stimulus is a form of energy that creates a detectable change in
the physical or chemical structure of an organism's internal or external environment.
What is the role of each of the following in generating a muscle contraction:
actin, myosin, tropomyosin, Ca++, sarcoplasmic reticulum - Answer Actin: Thin filaments
proteins that form microfilaments in the muscle, when bound to myosin causes muscle
contraction.
Myosin: Thicker filament structural and motor protein that interacts with actin filaments to
cause muscle contraction.
Tropomyosin: The regulatory protein that blocks the myosin-binding sites on actin molecules
which ends muscle contraction, not found in smooth muscle.
Ca++: Regulates the binding of actin and myosin and contraction of muscles by binding to
troponin, and stimulates the release of acetylcholine into the synaptic cleft.
Sarcoplasmic reticulum: Action potential travels down t-tubules in the SR to signal the muscle to
contract, store Ca+ when the muscles are at rest but changes cause the release of Ca++
Correct Answers 2025-2026 Version.
What is the major fitness cost of sexual reproduction compared to asexual reproduction for
females?
Describe at least 2 other costs of sexual reproduction.
Describe 3 hypotheses for why almost all animal species have sexual reproduction as part of
their life cycles despite this cost. - Answer For females, sexual reproduction requires much of
their energy, resources, and ultimately decreases their fitness by 50%. It also often does not
produce as man y viable offspring since fewer offspring are born and can be male or female.
Asexual reproduction, however, allows the female to maintain their fitness and resources as
more offspring are produced that can also asexually reproduce since they all must be females.
Sexually transmitted disease, cost of courtship, and sexual conflict.
Sexual reproduction allows for greater genetic diversity.
Sexual reproduction can reduce competition among offspring
??
Define asexual reproduction and sexual reproduction.
What are the two most common types of asexual reproduction in animals? - Answer Asexual
reproduction is the production of offspring that are genetically identical to the single parent
that made it. Sexual reproduction is the fusion of gametes (sperm and egg) to create genetically
different offspring.
The most common types of asexual reproduction in animals are fission (an animal divides itself
into multiple identical individuals) and budding (organisms develops a growth or bud on itself).
Describe an example of a counter-current system in animal physiology and state what substance
is transferred between flows in your example.
Draw a cartoon illustrating the how the relative concentration or quantity of this substance
varies along each of the two flows.
How would the transfer of this substance differ in a CONcurrent system?
A drawing of the concurrent system
may help you illustrate this. - Answer An example of a counter current system would be the
blood flow in a birds feet. Heat is transferred as warm blood coming from the body flows
adjacent to cool blood flowing back into the body. As the blood reaches the foot it decreases in
heat hit rather than lose it, it's is transferred to the adjacent vein.
In a concurrent system, the blood coming from the body and coming back into the body would
,How do the physical properties of water create challenges for gas exchange by aquatic animals?
- Answer Water can hold more oxygen in cold temperatures, while warmer water holds less
oxygen due to the increased movement of the H2O molecules. Therefore, aquatic animals,
mostly ectotherms, rely on external temperatures to carry out metabolism. So an increase in
water temp. would increase respiration rates but not provide enough oxygen for the organism.
Water also allows gases to move much slower than if it were diffusion through the air.
Why does the complexity of digestive, respiratory, and excretory systems tend to increase with
animals' size? - Answer As the animal increases in body size, they become less dependent on
diffusion (as it takes too long), and instead rely on more complex organ systems for gas
exchange, circulation, and the providing of nutrients.
Explain how each of the following affect animals' ability to acquire oxygen and expel wastes
through diffusion:
body size, metabolic rate, skin permeability, terrestrial vs. aquatic habitat. - Answer Body size:
Larger animals need more complex organ systems to maintain metabolism and exchange
nutrients with their environment.
Metabolic rate: Organisms that metabolize faster, need more complex organ systems to take in
more oxygen.
Skin Permeability: Exchange of nutrients through diffusion in and out of the body
(permeable/impermeable membrane)
Terr. vs Aqua Habitat: Aquatic animals can avoid diffusion because gasses diffuse quicker in air,
but terrestrial have an impermeable membrane which prevents them from drying out.
Define homeostasis.
List 5 conditions for which at least some animals are homeostatic regulators, and describe an
example of how an animal regulates this condition.
For each of the conditions you listed, do you think most plants are regulators or conformers? -
Answer Homeostasis is a state of equilibrium that an organism tries to maintain in order to
function as best and efficiently as possible.
- Increase in Temperature: Panting/sweating
- Water Loss: Osmoregulation/drink H2O
- Decrease in Temperature: Shivering
- Carbon Dioxide Levels: Increased breathing
- Increased Glucose: Release of insulin, storing of glycogen
Plants are conformers.
, c. The metabolic rate (rate of cellular respiration per g animal tissue)
d. The TOTAL oxygen consumption
e. Gut complexity
f. Food consumed daily/body mass - Answer b. Total surface area of the respiratory
membrane,
e. Gut complexity
(Increase with body size)
Define sensation and perception. In what part of the nervous system does each of these take
place? - Answer Sensation is the conversion of stimuli into change in membrane potential that
changes frequency of action potentials. Perception is the how the information that we observe
it interpreted by neurons.
Sensation takes place in the peripheral nervous system, perception takes place in the central
nervous system.
Define a stimulus. - Answer A stimulus is a form of energy that creates a detectable change in
the physical or chemical structure of an organism's internal or external environment.
What is the role of each of the following in generating a muscle contraction:
actin, myosin, tropomyosin, Ca++, sarcoplasmic reticulum - Answer Actin: Thin filaments
proteins that form microfilaments in the muscle, when bound to myosin causes muscle
contraction.
Myosin: Thicker filament structural and motor protein that interacts with actin filaments to
cause muscle contraction.
Tropomyosin: The regulatory protein that blocks the myosin-binding sites on actin molecules
which ends muscle contraction, not found in smooth muscle.
Ca++: Regulates the binding of actin and myosin and contraction of muscles by binding to
troponin, and stimulates the release of acetylcholine into the synaptic cleft.
Sarcoplasmic reticulum: Action potential travels down t-tubules in the SR to signal the muscle to
contract, store Ca+ when the muscles are at rest but changes cause the release of Ca++
