Unit A Lesson 10: Asexual and Sexual Reproduction

 Learning Targets

Inquiry Question: What are the advantages and disadvantage of asexual versus sexual reproduction
Asexual and sexual reproduction have advantages and disadvantages, both helping and hurting the survival of a species.

At the end of this inquiry, you should be able to answer the following questions:

  • What are the disadvantages and advantages of sexual reproduction versus asexual reproduction?
  • What organisms reproduce sexually  and what organisms reproduce asexually?
Page 35 and 36 in your textbook will help you answer these questions about asexual and sexual reproduction.


Try It!

Advantages and Disadvantages of Asexual and Sexual Reproduction

There are advantages and disadvantages to everything in life! This is also the case for asexual reproduction and sexual reproduction.

  1. DOWNLOAD this practice worksheet "S9_UA_S2_L10_asexual_vs_sexual". If you prefer to use a Google Drive or PDF version of the worksheet, click here.

  2. Complete the chart with the information you learn as you work through this lesson.

  3. When you are satisfied with your responses you can check your work by clicking on the "SUGGESTED ANSWERS" button below.

Wait! Don't view the suggested answers first. This practice work is not for marks, it is meant to help you check your understanding. Check the answers AFTER doing the questions! Keep the practice worksheet for study purposes. If you don't understand something, contact your teacher!



Figure 1 – Bacteria reproduce by binary fission, a type of asexual reproduction.

Figure 2 – Birds, like all larger animals, reproduce sexually.

Asexual reproduction has several advantages.  For one, it is very fast.  For example, bacteria can reproduce very quickly and very soon will produce hundreds of thousands of offspring.  As well, asexual reproduction does not require mates.  This saves significant energy and time because a relationship need not be formed for offspring to be reproduced.

Asexual reproduction has several disadvantages. On the other side, the diversity of the organisms is very limited because all offspring are identical to the parents.  This makes organisms very susceptible to disease or other unfavourable changes in the environment.  For example:  If only one type of Lodge Pole Pine existed and it was very susceptible to disease then all Lodge Pole Pines would die because there would be no variation among them to fight the disease.

Sexual reproduction has several advantages. Sexual reproduction results in many variations as it is the product of the mixing of the genetic information of two organisms.  Genetic variation enables greater chances for survival during major environmental changes such as disease outbreaks. 

Sexual reproduction has several disadvantages. A disadvantage to sexual reproduction is that it can take much energy and time to find a mate.  Species that reproduce sexually produce fewer offspring because the process of developing offspring takes much more time and care.  A human baby takes nine months to develop and a baby elephant takes 22 months to develop – compare that to E. coli bacteria that multiply in seconds.  Furthermore, since sexual reproduction involves crossing the genetic material of two organisms, the chances of mutations are far greater.  Mutations are explained further in Section 3.

Watch

For a review of the advantages and disadvantages of asexual and sexual reproduction, watch "Asexual and Sexual Reproduction".

 
 
For a review on the disadvantages of sexual reproduction, watch the video "Sexual Reproduction Disadvantages".

Some organisms have the ability to reproduce both sexually and asexually by various methods. Most plants that reproduce with seeds (sexual reproduction) also have the ability to produce from cuttings, producing bulbs, or producing runners or suckers (asexual reproduction).

Aphids have the ability to produce live young on their own during the growing season,  but in the fall they lay eggs where males will fertilize the eggs and ensure fresh aphids in the spring.  This ensures they start a fresh year with high numbers in their populations.  Watch "Amazing! Aphid Cloning-Battle of the Animal Sexes" to learn more about the unique abilities of aphids.




Jellyfish and strawberry plants also have this extraordinary ability.  It is almost as if they have an insurance policy that guarantees to continue their species if they cannot find a mate.  They can reproduce on their own if they cannot find a mate... a fascinating way to ensure one’s genes are passed forward!