Biology : Taxonomy Part-IV

Total Questions: 40

11. Consider the following statements: [U.P. Lower Sub. (Pre) 2013]

  1. Weeping jelly is due to an excess of acid.
  2. Biofertilizer most suited to sugarcane are rhizobium.
  3. Plants grown in salt water are called halophytes.
  4. Dormancy breaking hormone is cytokinin.
    Which of these statements are correct?
Correct Answer: (d) Only 4 and 1
Solution:Weeping jelly is most often caused by an excess of acid in the fruit or recipe in general. So statement 1 is correct. Acetobacter diazotrophicus is more suitable for sugarcane crop than other biofertilizers. Therefore statement 2 is incorrect. A halophyte is a plant that grows in waters of high salinity, therefore, statement 3 is also wrong. Dormancy in some seeds is broken by treating them with hormones such as gibberellins and cytokinin. So statement 4 is correct.

12. Work as intermediaries between biotic and abiotic components : [U.P. R.O./A.R.O. (Mains) 2017]

Correct Answer: (c) Producers
Solution:Producers or autotrophs are the intermediaries between biotic and abiotic components of the environment.

Consumers:

Organisms that cannot make their own food and must consume other organisms. They are heterotrophs. Consumers can be further categorized into herbivores (eat plants), carnivores (eat meat), omnivores (eat both), and parasites.

Decomposers:

Organisms that break down dead organic matter, returning nutrients to the ecosystem. They are essential for nutrient cycling.

13. Which of the following is not correctly matched : [U.P.P.C.S. (Pre) 2000]

Correct Answer: (d) Herbivore  - Secondary consumer
Solution:Autotrophs are the producers in a food chain such as plants on land or algae in water, in contrast to heterotrophs as consumers of autotrophs. Saprotroph, a term used for organisms which obtain nutrients from dead organic matter (this term commonly applies to fungi). A herbivore is an animal anatomically and physiologically adapted to eating plant material (for example foliage) for the main component of its diet. More generally, herbivores feed on autotrophs and are known as primary consumers. Thus, option (d) is not correctly matched.

14. Trophic level-I includes : [M.P. P.C.S. (Pre) 2016]

Correct Answer: (d) Green plants
Solution:Trophic level-I includes all autotrophs which synthesize their food by themselves. All green plants belong to this trophic level. Organisms of trophic level-I usually utilize the radiant energy of the sun to synthesize their organic molecules.

Herbivores are animals that eat plants, placing them at the second trophic level as they consume the primary producers.

Carnivores eat other animals, which means they are at a higher trophic level than green plants.

Omnivores eat both plants and animals, so they are also at a higher trophic level than green plants.

15. Consider the following kinds of organisms: [I.A.S. (Pre) 2021]

  1. Copepods
  2. Cyanobacteria
  3. Diatoms
  4. Foraminifera

Which of the above are primary producers in the food chains of oceans?

Correct Answer: (b) 2 and 3
Solution:Copepods are a group of small crustaceans found in nearly every freshwater and saltwater habitat. Copepods are major zooplankton. Some of the larger species are predators of their smaller relatives. Many benthic copepods eat organic detritus or the bacteria that grow in it. Many copepods (e.g., fish lice like the Siphonostomatoida) are parasites, and feed on their host organisms.
Cyanobacteria, also called bluegreen algae, are microscopic organisms found naturally in all types of water. Cyanobacteria are important primary producers and form a part of the phytoplankton. They use photosynthetic pigments, such as carotenoids, phycobilins, and various forms of chlorophyll, which absorb energy from light.
Diatom refers to any member of a large group comprising several genera of algae, specifically microalgae, found in the oceans, waterways and soils of the world. They are especially important in oceans, where they contribute an estimated 45% of the total oceanic primary production of organic material.
Foraminifera are amoeba-like, single-celled protists (very simple micro-organisms). They are characterized by streaming granular ectoplasm for catching food and other uses, and commonly an external shell (called a "test") of diverse forms and materials.

16. Fishes survive under the frozen lake, because— [U.P.P.S.C. (GIC) 2010]

Correct Answer: (c) Water does not freeze near the bottom
Solution:Lakes and rivers are frozen when the outer temperature decreases below the freezing point in winters. But only the upper layer freezes in this condition. Water remains in liquid form below the upper layer. So fishes and other aquatic creatures can survive even in a frozen lake.

17. After bringing out of water fishes die, because— [39th B.P.S.C. (Pre) 1994]

Correct Answer: (c) They cannot breathe
Solution:Fishes respire with the help of their gills. Gills can readily absorb the oxygen dissolved in water. When fishes are taken out of water, the supply of oxygen to the gills is cut as their gills cannot absorb the oxygen present in the atmosphere. Hence, they die after sometime.

18. Fish generally breathe through— [Uttarakhand P.C.S. (Mains) 2006]

Correct Answer: (c) Gills 
Solution:Fishes respire with the help of their gills. Gills can readily absorb the oxygen dissolved in water. When fishes are taken out of water, the supply of oxygen to the gills is cut as their gills cannot absorb the oxygen present in the atmosphere. Hence, they die after sometime.

19. Redness in apple is due to— [U.P.P.C.S. (Mains) 2002]

Correct Answer: (a) Anthocyanin
Solution:Red apples get their color from anthocyanin pigment. These pigments are water-soluble and found in the vacuole of cells within the apple's skin. While anthocyanins are the main cause of red color, other factors also play a role, including the cultivar of the apple, light exposure, and the ripeness of the fruit. Light, especially blue-violet and UV light, is crucial for anthocyanin production. Warmer temperatures can suppress anthocyanin synthesis.

20. Which of the following accounts for the red colour of tomato? [U.P.P.C.S. (Mains) 2016]

Correct Answer: (d) Lycopene
Solution:The red colour of tomato (Lycopersicon esculentum) fruit is due to the carotenoid pigment lycopene. The red colour formation in the apple skin is due to the formation of anthocyanin pigments. The red-orange colour of carrot is due to the pigment β-Carotene.