Taxonomy (Biology) Part-II

Total Questions: 50

31. Which of the following has the largest brain in proportion to its body size? [U.P.P.C.S. (Pre) 2017]

Correct Answer: (a) Ant
Solution:The largest brain belongs to the sperm whale: about 7 kg (17.5 pounds). The blue whale, the largest animal on the planet, being twice longer and thrice heavier, has a brain weighing about 5 kg (12.5 pounds).

Human brain has an average weight of about 2.7 pounds (1.2 kg), variations between 1.1 and 1.4 kg being considered normal. Our brain represents about 1.5-2% of our weight.

The largest brain of terrestrial animals is that of elephant: about 10.5 pounds (4.78 kg). Still, the brain of the elephant makes less than 0.1% of its body weight. Ant has the largest brain in proportion to its body size.

32. When ants bite, they inject: [I.A.S. (Pre) 1999]

Correct Answer: (c) Formic acid
Solution:

The acid produced by ants is called formic acid. Chemically, it is a simple carboxylic acid. When ants bite, they inject this acid. Formic acid, also known as methanoic acid, is the simplest carboxylic acid with the chemical formula HCOOH.

Ants use formic acid as a component of their venom, which they inject into their prey or enemies to defend themselves or to subdue their prey. Carboxylic acids are organic compounds characterized by a carboxyl group (-COOH), which is present in formic acid.

33. Certain species of which one of the following organisms are well known as cultivators of fungi? [I.A.S. (Pre) 2022]

Correct Answer: (a) Ant
Solution:

Many species of ants are well known as cultivators of fungi. The ant-fungus mutualism is a symbiosis seen between certain ants (tribe Attini) and fungal species, in which ants actively cultivate fungus much like humans farm crops as a food source.

The leafcutter ant is a well-known example of this symbiosis. They are known to farm fungus in the Americas and the Caribbean. However, ants are not the only ground-dwelling arthropods which have developed symbioses with fungi. A mutualism with fungi is also noted in some species of termites in Africa.

34. Consider the following statements about mosquitoes: [U.P. R.O./A.R.O. (Pre) 2016]

  1. Only males suck blood
  2. Only females suck blood
  3. Females suck plant juices
  4. Males have bigger wings than females
  5. Females have bigger wings than males
    Of these:
Correct Answer: (d) Only 2 and 5 are correct.
Solution:Only female mosquitoes suck the blood of warm-blooded vertebrate birds and mammals and live on them as an ectoparasite. The male mosquitoes do not suck blood, they survive by feeding on flowers and fruit juices.

Occasionally, females may also suck juices. Generally, female mosquitoes are larger than male mosquitoes. That is why option (d) is the correct answer.

35. Which one of the following animals stores water in the intestine? [I.A.S. (Pre) 1994]

Correct Answer: (b) Camel
Solution:Camels have some special abilities which enable it to walk for a long distance over sandy desert hills when there is neither water nor vegetation. That is why it is called 'The Ship of the Desert'.

They have broad, flat, leathery pads with two toes on each foot. Their breathing rate is very slow. A camel can drink more than 100 liters of water at once and they store it in their intestine for future needs.

36. Which of the following animals can live for the longest duration without drinking water? [U.P.P.C.S. (Pre) 2018]

Correct Answer: (d) Kangaroo rat
Solution:Among the given animals, Kangaroo rat can live for the longest duration without drinking water. The Kangaroo rat is a rodent native to the desert areas of North America.

The Kangaroo rat adapted to live in the desert climate because it produces the most concentrated urine in all mammals. Their kidneys concentrate the urine so much that it becomes almost solid.

37. Which among the following animals excretes solid urine? [U.P. P.C.S. (Mains) 2017]

Correct Answer: (a) Kangaroo rat
Solution:Among the given animals, Kangaroo rat can live for the longest duration without drinking water. The Kangaroo rat is a rodent native to the desert areas of North America.

The Kangaroo rat adapted to live in the desert climate because it produces the most concentrated urine in all mammals. Their kidneys concentrate the urine so much that it becomes almost solid.

38. In which one of the following kinds of organisms is the phenomenon found wherein the female kills the male after copulation? [I.A.S. (Pre) 2008]

Correct Answer: (c) Spider 
Solution:Spider cannibalism is the act of a spider consuming all or part of another individual of the same species as food. In the majority of cases, a female spider kills and eats a male spider before, during or after copulation. But the strong male spider escapes and again copulates.

39. King Cobra is the only snake that makes its own nest. Why does it make its nest? [I.A.S. (Pre) 2010]

Correct Answer: (c) It is an oviparous snake and lays its eggs in the nest and guards the nest until they are hatched
Solution:The king cobra is unusual among snakes in such a way that the female king cobra is a very dedicated parent. She makes a nest for her eggs, scraping up leaves and other debris into a mound in which to deposit them and remains in the nest until the young hatch. A female usually deposits 20 to 40 eggs into the mound, which acts as an incubator.

40. The only snake that builds a nest is: [I.A.S. (Pre) 1995]

Correct Answer: (b) King Cobra
Solution:The king cobra is unusual among snakes in such a way that the female king cobra is a very dedicated parent. She makes a nest for her eggs, scraping up leaves and other debris into a mound in which to deposit them and remains in the nest until the young hatch. A female usually deposits 20 to 40 eggs into the mound, which acts as an incubator.