Battle of bills
adapté de la séquence "Une belle prise de bec" de "la main à la pâte"
Step 1 : Adaptation
Observation :
There is a link between the shapes of the beaks and the food found in the birds' environment.
Hypothesis :
What if the Galapagos finches had evolved to have better chances at surviving in their different environments ?
Step 2 : Variability
Observations :
There are variations within the same species. In this sample : medium-sized beaks are the most numerous (from 9.5 mm to 11 mm). These are hereditary traits
Hypothesis :
If beak length is hereditary, medium-sized beaks will be passed on to the next generation in greater numbers.
Step 3 : Selection
In order to see whether Darwin's hypothesis can actually explain the evolution of living creatures and the appearance of various beak shapes in the Galapagos, you are going to make a modelling.
The finches and their beaks are represented by :
dissecting forceps
wooden pegs
pliers
Food is represented by :
semolina
beans
vermicelli
Battles are going to take place between different types of beaks on diffent islands.
We'll see how things are evolving !
You must transfer seeds / beans from the "environment" plate to your "stomach" plate with one of the tools.
Competitions will take place between 4 pupils.
+ 1 naturalist who will take notes
Modelling
One round = finches life span ( they reproduce and die ).
Next round = new generation
The finch population remains the same. (4 birds per island)
The bird with the smallest score dies without offsprings.
The winner reproduces best and has 2 offsprings.
Birds in the 2nd and 3rd position have one offspring each.
Observing
The naturalists write down their observations
They can count or use scales.
We will compare the data once the modelling is over.
Prep battle # 1
The finches are still on the continent.
There is only one type of food : vermicelli.
There is only one type of beak : dissecting forceps
Observations
Prep battle # 2
Changes have occured in the finch population
There is still only one type of food : vermicelli.
But there are 3 types of beaks:
2 dissecting forceps 1 cloth peg 1 pair of pliers
Observations
Battle # 3
The finches have migrated to the Galapagos.
Each group represents an island.
There are 3 types of beaks.
but ...
Food is different on every island !
Let's see what happens !
adapté de la séquence "Une belle prise de bec" de "la main à la pâte"