Consider the following statements 1 Very small animals are found primarily in polar regions because ...........

Environment and Ecology Biodiversity

Consider the following statements:

1. Very small animals are found primarily in polar regions because they lose less heat owing to smaller surface areas.

2. Mammals are able to survive both in polar and desert ecosystems because they maintain stable body temperature.

Which of the statements given above is/are correct?

1 only

2 only

Both 1 and 2

Neither 1 nor 2

Statement 1 is not correct: Thermoregulation is energetically expensive for many organisms. This is particularly true for small animals like shrews and humming birds. Heat loss or heat gain is a function of surface area. Since small animals have a larger surface area relative to their volume, they tend to lose body heat very fast when it is cold outside; then they have to expend much energy to generate body heat through metabolism. This is the main reason why very small animals are rarely found in polar regions.
Statement 2 is correct: Some organisms are able to maintain homeostasis by physiological (sometimes behavioural also) means which ensures constant body temperature, constant osmotic concentration, etc. All birds and mammals, and a very few lower vertebrate and invertebrate species are indeed capable of such regulation (thermoregulation and osmoregulation). Evolutionary biologists believe that the ‘success’ of mammals is largely due to their ability to maintain constant body temperature and thrive whether they live in Antarctica or in the Sahara desert