The problem with natural selection (at our house)
The problem is, we can't kill anything at our house. Metaphorically speaking, that is. I mean, usually, we don't kill things at our house, except maybe mosquitoes, if we can catch them, and an occasional fly. We do eat things that have been killed for us, though. And herein lies the problem. Nadia does not like the fact that some creatures get killed so that others may live.
If it was up to Nadia, natural selection would not exist, at least in the animal kingdom. She's OK with creatures eating plants. Although, perhaps if creation had been up to her, she would have invented a non-living source of nourishment for all, and we would all, plants and animals alike, go on merrily procreating in perpetuity.
But we don't. To represent this, we chose inanimate yellow and blue lego bricks. (BTW, lego's are great for all sorts of educational applications. If a book asks you to do something time consuming, like cutting out little squares, just look around and see if you can find enough legos instead. We usually can.)
As you can see, the yellow bricks were better camouflaged than the blue, and the blue ones were being "eaten" in greater numbers. Poor blue bricks! sighed Nadia. As sorry as she felt for the blue bricks, she could not pass up the fun of gobbling them up (she has a similar problem with chicken dinosaurs and meatballs).
So, eventually, most of the blue bricks were eaten, and the world looked like this:
This presented a bit of a problem for the predators. Only ones with the sharpest eyesight could compete for survival. The happy yellow bricks enjoyed a life of relative leisure, until Peter found a blue sheet:
The surviving blue bricks suddenly became the life of the party: everyone wanted to mate with them!
Once we got over the fact that we were eating lego bricks, this generated all kinds of interesting discussion:
- What are different ways legos, er... creatures can adapt?
- What is the advantage of adapting in a variety of ways to the same set of circumstances (eg. growing longer necks vs. climbing as trees get taller).
- If you're a predator, and you've been so successful in hunting a certain type of prey, that it has become rare, how might you adapt?
- If you are the well-adapted prey, and your less-well-adapted cousins have died off, what might you have to do to survive?
- What is the "value" of an individual's survival (think the lone blue lego) for the survival of the species?
- We also touched on the subject of mutations and changing patterns and/or colors, but that's a subject for another post.


Brilliant. We might have to borrow this activity. Anything that combines legos and evolution is good.
Posted by: kim | September 24, 2007 at 09:45 AM
ohh, I've used Legos for all sorts of manipulatives. I'll have to remember this one.
If you want a great micro-evolution lab using M&Ms, drop me a line. You have to be able to buy single colored M&Ms, but the kids get the idea real fast.
And enjoy eating the non-viable offspring!
Posted by: Meg L | September 24, 2007 at 02:00 PM
I wish I could take credit for this one, but it comes straight out of "How Nature Works", p. 22, I think. This is where I drew the line at cutting out squares. Legos, m&m's, cheerios, these all work for me. Thanks, y'all.
Posted by: Justyna | September 24, 2007 at 04:33 PM