Final answer:
Mammals living in the tropics generally have protruding structures compared to similar species living in the polar region in order to adapt to the different environmental conditions. Protruding structures help in increasing surface area for heat dissipation in tropical regions, whereas animals in polar regions have more compact body structures to minimize exposure to the cold.
Step-by-step explanation:
Mammals living in the tropics generally have protruding structures compared to similar species living in the polar region. This is because of the difference in environmental conditions and the need to adapt to those conditions. In tropical regions, the temperature is generally higher, so mammals living there need to dissipate heat more efficiently to avoid overheating. Protruding structures, such as large ears or nasal passages, help in increasing the surface area for heat dissipation.
On the other hand, in polar regions, the temperature is much colder, and mammals living there need to conserve heat to maintain their body temperature. They have adaptations like thick fur and a dense layer of fat to reduce heat loss. Having protruding structures that increase the surface area would actually lead to more heat loss, which is not beneficial in a cold environment. Therefore, mammals in polar regions have more compact body structures to minimize exposure to the cold.
For example, polar bears have a cylindrical body shape, thick blubber, and relatively small ears and nasal passages to minimize heat loss. In contrast, animals like elephants living in the tropics have large ears with a network of blood vessels that help cool their bodies in the heat.