Given the loss of childbearing ability and negative health effects associated with menopause, there is cause to question why it exists given that evolution usually selects against most negative health effects and reduced fertility. Appraise and compare
the two possible explanations covered in this section.
What will be an ideal response?
One hypothesis is that human females are simply following the same pattern seen in some other mammalian species. That is, menopause comes at a point in the female life span when she will have time to raise one last offspring to the point of independence from maternal care. This helps to ensure that offspring will not be born so late in life that the mother will not be around to offer nourishment and protection. Menopause only seems to come earlier in the life span than it does in other mammalian species because of relatively recent improvements in the human life span. Another possibility, the "grandmother hypothesis," suggests that postmenopausal women may improve the reproductive success of their children with additional care for both her children and grandchildren.
You might also like to view...
In mammalian cells, the mRNA sequence elements that target the mRNA for rapid degradation are called:
A. AU-rich elements. B. upstream open reading frames. C. age responsive elements. D. enhancers.
Which of the following is NOT found in a
chloroplast?
a. a single outer membrane b. DNA c. ribosomes d. stroma e. thylakoids
You are a young scientist who has just learned about one of the hot topics in microbiology, biofilms. One aspect of the interest in biofilms is that the microbes living within biofilms appear to behave and function differently from their counterparts not
living in a biofilm. Devise a way to explore the idea. (Do not focus on the technical details of how this might be accomplished.) What will be an ideal response?
Which of the following statements about the cell cycle is correct?
A. During G2 phase, the cell grows and copies its chromosomes in preparation for cell division. B. The cell cycle is a sequence of replications and divisions that produces a new cells. C. In actively dividing cells, the S and G2 phases are collectively known as interphase. D. When the S phase of the cell cycle is finished, a cell has twice as many chromatids as the number of chromosomes in the G1 phase. E. The phases of the cell cycle are G1, S, and M phases.