Question

Mammals of colder areas generally have shorter extremities in comparison to the tropical mammals.
The given statement conforms to which of the following rules?

• A. Jordan’s rule
• B. Bergman’s rule
• C. Darwin’s rule
• D. Allen’s rule

Answer 1

Answer: (D)

Allen's rule is an ecogeographical rule which was formulated by Joel Asaph Allen in 1877. It states that warm-blooded animals adapted to cold climates have shorter limbs and bodily appendages than animals adapted to warm climates in order to prevent loss of heat.
Bergman’s Rule: Warm-blooded animals (birds and mammals) have larger body sizes in a cold climate than in hotter areas.
Rensch’s Rule: In a colder climate, birds possess narrow and acuminate wings as compared to broader wings of birds found in water areas.
Jordan’s Rule: As the temperature is lowered, some fishes possess a larger size with a larger number of vertebrae.