Question

35. One selective force (or mixture of forces) limits the largest viable birth weight of a human baby, while another selective force limits the smallest viable birth weight of a baby. This is called .............. natural selection.

    a. Artificial
    b. Fictional c. Directional d. Disruptive e. Stabilizing

36. A population splits into two rather different populations. The two phenotypic extremes of the original population are favored over the more common central phenotype of the original population. This is called ............ natural selection.

    a. Artificial
    b. Fictional c. Directional d. Disruptive e. Stabilizing

37. What type of natural selection is thought to have caused long necks in giraffes?

    a. Artificial
    b. Fictional c. Directional d. Disruptive e. Stabilizing

38. Any change in the gene pool is called .......... a. Microevolution b. Macroevolution

Answer 1

1. Disruptive

In the given question, phenotypes with two extreme conditions are being selected, smallest and largest viable weight of the baby. It mean it is a disruptive or destabilizing selection.

2. Disruptive

(Same as 1)

3. Directional

Whenever only one type of phenotype is collected over all the other phenotypes, it is called as directional selection. In the given question one length of neck of Giraffe have been selected, that is the longest length.

4. Mircoevolution

Microevolution is the process which gives rise to different species whereas macroevolution is the process which give rise to the origin of new era of species. In short macroevolution occurs in a very large scale.

Note -

In case of stabilizing natural selection, individual having mean or intermediate phenotypes are selected.

You can see the graph of various natural selections below

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