Chapter 50 Lecture Enrichment Ideas
Discuss the process of internalization of reproduction as a requirement for life on land, and examine the shelled eggs of reptiles and birds, the egg cases of insects, and the internal development of the fetus in mammals. Discuss how each is adapted to prevent desiccation.
Using a diagram, follow the path of sperm from its development in the testes to its release during ejaculation; discuss the additions of glandular secretions along the way.
Note that when the sperm enters the egg, only the nuclear material and not the mitochondria mid-piece or tail enter. Thus, all of a person's mitochondria were inherited from his/her mother.
Using a diagram, follow the path of the egg as it develops in the ovary and is released. Describe what happens to the egg if fertilized or if unfertilized.
Twins occur in one out of 80 births in the U.S. but with more frequency in the tropics where lifespan is much shorter, and with less frequency in northern regions where lifespan has been longer. And age of first menstruation (menarche) is lower in the tropics, higher in Norway, etc. Discuss the physiological basis and the evolutionary implications of this.
Discuss the methods of birth control and how they function, including the barrier method, spermicide, hormonal control (the pill or implants), and new male pills and female condoms; samples are often available from local health agencies.
STDs have been epidemic in the U.S. Normalizing discussion of this topic can go a long way to make students more comfortable with the topic.
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