Mixing the Gene Pool

OBJECTIVE: The student shall demonstrate their understanding of the reasons for and against sexual reproduction by classroom participation, lab reports and answers to the implication questions.

PURPOSE: Both sea urchins and humans are sexual beings. Why? What is the advantage of taking half of your kind out of reproduction (the males)? Sexual reproduction mixes the genes up more than is possible with asexual reproduction. This allows for greater diversity in a short period of time. This can lead to a greater likelihood of at least a few individuals being resistant to a new predator, parasite, or disease.

SET: What are males good for? They can't have kids. They eat too much and hog other resources too. And, many organisms do just fine without them.



STRUCTURED PRACTICE: This lesson is best done first entirely as structured practice, with the instructor manipulating the game pieces. Ask questions at every "generation" to help understanding.

GUIDED PRACTICE: Have them do the GAME in small groups. Only needed if you feel your students are not getting it. Often students will get something more easily that they themselves are the major participants. Can also go over the Implication Questions in class, after they have had a chance at answering them.

CLOSURE: We have seen that there just might be some justification for keeping the males around, but only if they behave themselves. Next we will study how complex the duplication and separation of genetic material becomes for sexual organisms as they use a process we call MEIOSIS.

INDEPENDENT PRACTICE: none specified, but of course can include questions pertaining to this lesson on exams.