Background: Consider the antlers of the Irish elk, (often supposed to be far too large; in deer antler size has an allometric relationship to body size). Obviously, antlers serve positively for defence against predators, and to score victories in the annual rut. But they are costly in terms of resource. Their size during the last glacial period presumably depended on the relative gain and loss of reproductive capacity in the population of elks during that time. As another example, camouflage to avoid detection is destroyed when vivid coloration is displayed at mating time. Here the risk to life is counterbalanced by the necessity for reproduction.Stream-dwelling salamanders, such as Caucasian salamander or Gold-striped salamander have very slender, long bodies, perfectly adapted to life at the banks of fast small rivers and mountain brooks. Elongated body protects their larvae from being washed out by current. However, elongated body increases risk of desiccation and decreases dispersal ability of the salamanders; it also negatively affects their fecundity. As a result, fire salamander, less perfectly adapted to the mountain brook habitats, is in general more successful, have a higher fecundity and broader geographic range.

Situation: John is a biologist. Last summer, he was studying the evolution of two different salamander species, species A and species B. Species A salamander was Gold-striped salamander while species B salamander was fire salamander. He found it interesting that they took different approaches to adapt to different habitats.

Question: Which species would do better in mountain brooks, species A or species B?
Answer: species A

Situation: John is a biologist. Last summer, he was studying the evolution of two different salamander species, species A and species B. Species A salamander was Gold-striped salamander while species B salamander was fire salamander. He found it interesting that they took different approaches to adapt to different habitats.

Question: Which species would do worse in mountain brooks, species A or species B?
Answer: species B

Situation: John is a biologist. Last summer, he was studying the evolution of two different salamander species, species A and species B. Species A salamander was Gold-striped salamander while species B salamander was fire salamander. He found it interesting that they took different approaches to adapt to different habitats.

Question: Would species A do better or worse in mountain brooks than species B?
Answer: better

Situation: John is a biologist. Last summer, he was studying the evolution of two different salamander species, species A and species B. Species A salamander was Gold-striped salamander while species B salamander was fire salamander. He found it interesting that they took different approaches to adapt to different habitats.

Question: Would species B do better or worse in mountain brooks than species A?
Answer: worse

Situation: John is a biologist. Last summer, he was studying the evolution of two different salamander species, species A and species B. Species A salamander was Gold-striped salamander while species B salamander was fire salamander. He found it interesting that they took different approaches to adapt to different habitats.

Question: Which species would have larger habitat, species A or species B?
Answer: species B

Situation: John is a biologist. Last summer, he was studying the evolution of two different salamander species, species A and species B. Species A salamander was Gold-striped salamander while species B salamander was fire salamander. He found it interesting that they took different approaches to adapt to different habitats.

Question: Which species would have smaller habitat, species A or species B?
Answer: species A

Situation: John is a biologist. Last summer, he was studying the evolution of two different salamander species, species A and species B. Species A salamander was Gold-striped salamander while species B salamander was fire salamander. He found it interesting that they took different approaches to adapt to different habitats.

Question: Would species A have larger or smaller habitat than species B?
Answer: smaller

Situation: John is a biologist. Last summer, he was studying the evolution of two different salamander species, species A and species B. Species A salamander was Gold-striped salamander while species B salamander was fire salamander. He found it interesting that they took different approaches to adapt to different habitats.

Question: Would species B have larger or smaller habitat than species A?
Answer: larger

Situation: John is a biologist. Last summer, he was studying the evolution of two different salamander species, species A and species B. Species A salamander was Gold-striped salamander while species B salamander was fire salamander. He found it interesting that they took different approaches to adapt to different habitats.

Question: Which species would be more successful in reproduction, Species A or species B?
Answer: species B

Situation: John is a biologist. Last summer, he was studying the evolution of two different salamander species, species A and species B. Species A salamander was Gold-striped salamander while species B salamander was fire salamander. He found it interesting that they took different approaches to adapt to different habitats.

Question: Which species would be less successful in reproduction, Species A or species B?
Answer: species A