Question

(a)Explain giving examples how artificial selection has helped in formation of newer varieties of cauli flower. (b)List the steps involved in formation of new species. (c) how different races of humans belong to the same species?

Answer 1

Ans a) Artificial selection is done by selecting individuals that show desired phenotypes and then these individuals are bred artificially in order to generate new plants/ animals with improved characters.
For e.g. Early farmers cultivated wild cabbage or Brassica oleracea . This wild cabbage was developed into many varieties such as cabbage, broccoli, kohlrabi, cauliflower, kale, and Brussels by artificial selection and breeding.

Ans b). We cannot say that organisms follow any particular path or steps for speciation. It is a gradual process. Various factors can act simultaneously thus charting of particular steps of speciation is not feasible. For any speciation to occur, variations ( which arise due to many reasons) need to be accumulated through restriction to gene flow which itself occurs through many ways .

Ans c). Different races of humans regardless of their skin colour and other features belong to a single species called Homo sapiens. All human beings evolved from primates in Africa.They have more than enough similarities to classify them as same species and they differ only in a few traits like skin colour and some other minor genetic sequence.