Consider the following statements: Very small animals are found ...
Explanation:
The correct answer is option 'B' - 2 only. Let's analyze each statement:
Statement 1: Very small animals are found primarily in polar regions because they lose less heat owing to smaller surface areas.
This statement is incorrect. While it is true that smaller animals have a larger surface area to volume ratio, which can increase heat loss, it does not necessarily mean that very small animals are found primarily in polar regions. The distribution of animals is influenced by various factors such as food availability, competition, and environmental conditions. Polar regions are characterized by extreme cold temperatures, and while some small animals may have adaptations to survive in such environments, their presence is not solely determined by their surface area to volume ratio.
Statement 2: Mammals are able to survive both in polar and desert ecosystems because they maintain stable body temperature.
This statement is correct. Mammals are endothermic animals, meaning they can generate and regulate their body heat internally. This ability to maintain a stable body temperature allows mammals to survive in diverse ecosystems, including polar regions and deserts. In polar regions, mammals have adaptations such as thick fur, blubber, and small extremities to minimize heat loss. In deserts, mammals have adaptations such as efficient water conservation mechanisms, nocturnal behavior, and tolerance to high temperatures. These adaptations enable mammals to thrive in extreme environments and maintain their body temperature within a narrow range.
In conclusion, only statement 2 is correct. Very small animals are not found primarily in polar regions due to their smaller surface area. Mammals, on the other hand, are able to survive in both polar and desert ecosystems because they can maintain a stable body temperature.
Consider the following statements: Very small animals are found ...
- 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.