Question

By the process of artificial selection of evolution, which of the following is developed for sterile flowers?
A. Broccoli
B. Cauliflower
C. Kohlrabi
D. Kale

Answer 1

Hint: Artificial selection is also known as selective breeding. The process is undertaken by humans to grow specific phenotypes that can be reproduced by sexual reproduction. It can be done in both plants and animals. Artificial selection can give rise to new breeds, races, varieties or strains.

Complete answer:
Artificial selection is the procedure of creating new strains, varieties or breeds of plants and animals that can be utilized by humans for commercial uses and as food.
Artificial selection in plants has given rise to many vegetables that we consume daily. A classic example of artificial selection in plants is demonstrated by the cabbages.
Brassica oleracea is the wild cabbage present in nature. This is a tall biennial plant and is tolerant to salt and lime. The leaves of this particular species are thicker and fleshier than the other species of the genus which led to extensive domestication of the wild cabbage. This resulted in new varieties of the species within a very short span of time. Preference for leaves, buds, stem, inflorescence of the wild cabbage has led to development of many varieties through artificial selection.

The preferences have affected the cultivation of cabbages in the following ways:
-Preference for leaves led to the selection of plants with exceptionally large leaves and planting the seeds of that particular plant every year. This has given rise to kale.
-Within kale, plants with bunched leaves and terminal buds were preferred over others. This led to the evolution of cabbages.
-Again, within the plants with flattened stems were selected and cultivated leading to evolution of kohlrabi.
-Certain populations consumed immature inflorescence of these plants. The selective breeding for inflorescence led the evolution of cauliflowers – for sterile flowers and broccolis – for stems and flowers.
Hence it can be concluded that cauliflowers have evolved through the process of artificial selection with a preference for sterile flowers.

Hence, the correct answer is option (B).

Note: Artificial selection is man made selection, that is breeding a plant or animal for desired characteristics. In plants, these characters are known as cultivars, while in animals it is known as breeds. Artificial selection gives rise to populations with better yields, better ornamentation in plants and better wool or meat quality in animals.