Tuesday, October 16, 2012

"Going Backwards": Seed Babies and the Invisible Duplication Mechanism

One of the more fascinating things about growing sunflowers from seeds is that as the sprout shoots up out of the ground, it carries the seed along for the ride.  It's like a little helmet that helps the seed poke out of the dirt and then protects the first leaves that hide underneath it.  Eventually as the leaves get bigger, the seed "helmet" falls off.  All of the students were surprised to see the seed going on a ride, and it generated a lot of hypotheses about what's really happening with the seed.  One of the most intriguing hypotheses was D's idea about "Going Backward."

D: Going backward means the seed is going up and the flower will be at the bottom.
O: The inside part was the seed and the outside part was the protection.
Is this what normally happens to seeds?
T: No, birds eat them.
E: When it started to grow the seed was laying on it, and the seed (grew up with it).
K: When the flower head starts to get there then lots of other seeds come and birds come. I have a question…How would it feel if I were a seed?
N: The seed multiplies to form the sunflower head. Maybe there’s a seed at the bottom and a seed at the top.
D: You know how the seed opens. Maybe…the stem raises the seed up. 
What’s happening to the seed?
K: It’s growing (indicates that it’s going up).
What job is the seed performing?
T: I think the skin, the seed, never does fall off. At the top it’ll sprout and all the sunflowers will come from that. It’s going to be the bottom of the sunflower head.
K: I think it would be cool to be a seed because if you see the sprout it looks like a tunnel and then I’d say, “Oh, that looks like fun,” and go through.
D: You know what I think…something went wrong with the plant and it accidentally got duplicated with the duplication ray (giggles), and so there’s one seed on top and one on the bottom. 
D's letter to his seed:  Invisible Duplication Mechanism
How the seed sprouts, 
why the seed seems to stay on the top of the sprout, 
and how that sprout later produces more seeds 
certainly seems like a duplication mechanism 
is at work in the sunflower. 

What does duplication mean?
D: It means there are two of them.
Where’s the second one?
D One’s at the bottom and one’s at the top, because something went wrong and it was duplicated. 

Other students captured this idea in their own work:

L. notes that the seed is still on top of the sprout
"It's like a trampoline bringing the seed up."

"The sunflower grows up and the seed will pop off.  
The roots you can barely see because they're in the dark soil.  
When the seed pops off, the leaves will be under it."

No comments:

Post a Comment