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Which adaptation helps an animal blend into its surroundings?
A. Migration
B. Camouflage
C. Hibernation
D. Echolocation
B. Camouflage
What structure do most fish use for gas exchange?
A. Lungs
B. Tracheae
C. Gills
D. Kidneys
C. Gills
An animal that is primarily active at night is described as:
A. Diurnal
B. Nocturnal
C. Aquatic
D. Sessile
B. Nocturnal
Compared with sea level, high-altitude environments generally have:
A. More available oxygen
B. Lower oxygen partial pressure
C. No atmospheric oxygen
D. Higher water pressure
B. Lower oxygen partial pressure
What is blubber?
A. A respiratory organ
B. A type of muscle
C. A thick layer of fat that provides insulation and energy storage
D. Frozen skin
C. A thick layer of fat that provides insulation and energy storage
Why can camouflage increase an animal's fitness?
A. It always makes the animal stronger.
B. It prevents mutations.
C. It can help the animal avoid predators or capture prey.
D. It causes the animal to reproduce asexually.
C. It can help the animal avoid predators or capture prey.
Why do fish continuously move water across their gills?
A. To digest their food
B. To obtain oxygen and remove carbon dioxide
C. To increase body temperature
D. To produce blood cells
B. To obtain oxygen and remove carbon dioxide
Why are many desert animals nocturnal?
A. Nights contain more oxygen.
B. Predators cannot see at night.
C. Cooler nighttime temperatures reduce overheating and water loss.
D. Their body temperature must reach freezing.
C. Cooler nighttime temperatures reduce overheating and water loss.
Why can producing more red blood cells help an animal living at high altitude?
A. Red blood cells digest food.
B. They produce oxygen.
C. They increase the blood's oxygen carrying capacity.
D. They decrease heart activity.
C. They increase the blood's oxygen carrying capacity.
Why do many cold-climate mammals have relatively compact bodies and smaller extremities?
A. To increase heat loss
B. To increase surface area
C. To reduce heat loss by lowering surface area to volume ratio
D. To prevent cellular respiration
C. To reduce heat loss by lowering surface area to volume ratio
A wildfire darkens the forest floor. Dark colored mice are less visible to predators than light colored mice. Over many generations, what process could make dark fur more common?
A. Genetic engineering
B. Natural selection
C. Hibernation
D. Acclimation
B. Natural selection
A marine bony fish constantly loses water to its salty environment. Which response helps maintain homeostasis?
A. Producing large amounts of dilute urine
B. Never drinking water
C. Drinking seawater and actively removing excess salts
D. Allowing its cells to continuously lose water
C. Drinking seawater and actively removing excess salts
A desert rodent produces a very small amount of highly concentrated urine. What is the main advantage?
A. Increasing heat production
B. Conserving body water
C. Increasing oxygen uptake
D. Removing more glucose
B. Conserving body water
A mammal population has lived at high altitude for thousands of generations. Which inherited trait would most likely be advantageous?
A. Reduced ability to transport oxygen
B. More efficient oxygen uptake and delivery
C. Complete loss of hemoglobin
D. Smaller lungs with less surface area
B. More efficient oxygen uptake and delivery
Arctic foxes with thicker winter fur survive severe winters and reproduce more successfully. If fur thickness is heritable, what could happen over generations?
A. Every fox will intentionally grow thicker fur.
B. Alleles contributing to thicker fur may increase in frequency.
C. All genetic variation will disappear immediately.
D. The foxes will become a different species in one generation.
B. Alleles contributing to thicker fur may increase in frequency.
Two squirrel populations become separated by a canyon and cannot interbreed. After thousands of generations, they become reproductively isolated. What has most likely occurred?
A. Mutualism
B. Gene flow
C. Allopatric speciation
D. Artificial selection
C. Allopatric speciation
Why is countercurrent exchange in fish gills highly efficient?
A. Blood and water move in the same direction.
B. Fish store oxygen inside their scales.
C. Opposite flow maintains an oxygen diffusion gradient across the gill.
D. Gills actively pump oxygen directly into red blood cells.
C. Opposite flow maintains an oxygen diffusion gradient across the gill.
A desert jackrabbit has extremely large ears containing many blood vessels. During hot conditions, how can these ears contribute to homeostasis?
A. They store water.
B. They decrease oxygen consumption.
C. They increase heat transfer from blood to the environment.
D. They prevent all evaporation.
C. They increase heat transfer from blood to the environment.
A high-altitude mammal has hemoglobin with moderately greater oxygen affinity than a related sea-level species. What advantage could this provide?
A. It prevents cellular respiration.
B. It removes carbon dioxide from the atmosphere.
C. It improves oxygen loading when environmental oxygen availability is low.
D. It eliminates the need for breathing.
C. It improves oxygen loading when environmental oxygen availability is low.
Sea ice begins melting earlier each year. Which change could natural selection potentially favor in a predator that historically hunts from sea ice?
A. Traits that make alternative food impossible to use
B. Heritable traits that improve survival or feeding under reduced ice conditions
C. Traits that increase dependence on sea ice
D. Any mutation occurring during the animal's lifetime
B. Heritable traits that improve survival or feeding under reduced ice conditions
A mutation makes a forest bird much harder for predators to see but also makes the bird less attractive to mates. Why might the mutation NOT become common?
A. Beneficial mutations cannot be inherited.
B. Predators determine all evolutionary change.
C. Increased survival may be outweighed by decreased reproductive success.
D. Natural selection only acts on harmful mutations.
C. Increased survival may be outweighed by decreased reproductive success.
Ocean warming raises a fish's metabolic rate while simultaneously decreasing dissolved oxygen in the water. What problem is most likely?
A. The fish will obtain more oxygen than necessary.
B. Osmoregulation will completely stop.
C. Oxygen demand may increase while oxygen availability decreases.
D. The fish will automatically develop lungs.
C. Oxygen demand may increase while oxygen availability decreases.
A desert becomes progressively hotter and drier for hundreds of generations. Which population would natural selection most likely favor?
A. Animals that require more water
B. Animals that are active during the hottest afternoon hours
C. Animals possessing heritable traits that improve heat tolerance and water conservation
D. Animals that acquire useful mutations because they need them
C. Animals possessing heritable traits that improve heat tolerance and water conservation
Why could an EXTREMELY high hemoglobin affinity for oxygen actually become harmful?
A. Hemoglobin would destroy oxygen.
B. The animal could no longer inhale.
C. Hemoglobin might bind oxygen effectively but release it poorly to tissues.
D. Blood would stop circulating.
C. Hemoglobin might bind oxygen effectively but release it poorly to tissues.
Why might natural selection NOT simply produce animals with the maximum possible amount of insulation?
A. Insulation never affects temperature.
B. Natural selection always produces intermediate traits.
C. Biological traits involve trade offs; excessive insulation could cause overheating or require additional energy.
D. Animals cannot inherit insulation-related traits.
C. Biological traits involve trade offs; excessive insulation could cause overheating or require additional energy.