Lesson 5 — Variation in Reproductive Strategies


Lesson Summary

In this lesson, you considered how various organisms fashion their life cycles. Each cycle balances the speed and ease of mitosis with the variety and change of meiosis. Earlier, you learned how those processes result in cells for growth or for gamete cells for reproduction. Now, you can relate those processes to the various reproductive cycles of organisms.

This lesson presented these focusing questions:

  • What are the advantages or disadvantages of various reproductive strategies?
  • Why do organisms vary their reproductive strategies?

Organisms can reproduce quickly and effectively with mitosis and asexual reproduction. The resulting offspring may dominate a habitat, and the whole species will benefit by a sheer growth in numbers. However, the entire population is genetically identical. Therefore, they may all be susceptible to a virus or disease and experience rapid death.

Many organisms include a part of their life cycle that requires meiosis and sexual reproduction. This increases genetic variability and allows for offspring that are different from their parents. Some of these organisms may not be susceptible to a disease or a change in the environment that hurts the general population. These organisms will live to reproduce again.

Some organisms can change their strategies depending on conditions. This allows for the best of both reproductive worlds. When conditions are favourable, mitotic or asexual reproduction can help colonize an area quickly. However, when the conditions become unfavourable, meiosis or sexual reproduction allows for genetic variation that will help the species survive.

Throughout this section, you have studied about cell growth, repair, and reproduction. By understanding the life cycle of your cells, you have gained insight into how your own body renews itself over the course of your lifetime. As you get older, you will understand the differences between combating the signs of aging and actually keeping your cells in a healthy cell cycle of growth and repair. You have a better understanding of how cancer can lead to serious health concerns and how various treatments show promise in combating this disease. By examining emerging technologies involved in cell research, you are now prepared better to help society guide scientists in setting limits or guidelines for new research aimed at combating serious illness and disease.

Assignment

Complete the Lesson 5 set of questions in Assignment 5B and Assignment 5C