Question 1 · 8.1 Responses to the Environment
Which type of learning occurs during a brief critical period early in life, as when goslings follow their mother?
- A Habituation
- B Operant conditioning
- C Fixed action pattern
- D Imprinting
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D — Imprinting is learning that can happen only during a short window early in life, when young animals such as goslings form a lasting attachment to the first suitable moving object they see. A fixed action pattern is fully innate, while imprinting requires the gosling to learn which object to follow.
Question 2 · 8.2 Energy Flow Through Ecosystems
In a desert where insects are scarce for months at a time, a 50-g insect-eating lizard survives in habitats where a 50-g insect-eating mouse starves. Which difference best explains this?
- A The lizard makes more body heat per gram, which keeps it active through lean months
- B The lizard absorbs energy from sunlight through its skin to make up for missing food
- C The lizard spends little energy holding its body temperature, so reserves last longer
- D The lizard assimilates all of the food it eats, so none of that energy is lost as heat
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C — The mouse is an endotherm: it spends most of its energy budget generating metabolic heat to keep its body temperature high and constant, so it must eat often. The lizard is an ectotherm whose body temperature follows its surroundings, so its maintenance cost is a small fraction of the mouse's. The same fat reserve therefore covers the lizard's needs for far longer between meals. Basking warms the lizard but supplies no chemical energy, and like every animal it still releases most assimilated energy as heat.
Question 3 · 8.3 Population Ecology
Which trait is typical of a K-selected species?
- A Many small offspring that receive no parental care
- B Few offspring, each receiving much parental care
- C Early maturity followed by a short life span
- D Rapid population growth in unstable habitats
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B — K-selected species live in stable environments near carrying capacity and invest heavily in a few offspring, as elephants and humans do. Many small offspring, early maturity, and fast growth in unstable habitats are r-selected traits.