Analogy of Squirrel Island
ANALOGY OF SQUIRREL ISLAND
An isolated chain of islands known as the squirrel islands exists in the Pacific Ocean.The island group consists of three separate islands named A, B, and C.The three islands are each 5 miles apart.See diagram below.
The islands support various wildlife including a population of 10,000 squirrels per island.Although the island group is isolated, there is a bit of mixing of squirrels between islands.Occasionally a very ambitious squirrel will swim from one island to another in search of a better life.It is rare—but it does happen.
One day, on island B, a squirrel was born that was named Chip by his parents. Chip looked like all the other squirrels on the island on the surface but was actually a mutant.
CHIPS – the mutantsNORMALS- the non mutants
When Chip was just a one-celled embryo, one base a “T” in his DNA was changed to a “C”.The change happened in a gene that coded for an electron transport chain enzyme.This mutation is carried in all cells of his body.The mutation has both positive and negative effects on chip.
— On the down side, Chip still makes the ETC enzyme but it has a slightly different shape and doesn’t work as well.This means that his ETC won’t generate a hydrogen ion gradient as quickly as the normal squirrels.He has to consume more glucose than other squirrels in order to make the same amount of ATP.The result is that Chip and all of his descendants when he has them will have to eat 5 nuts a day in order to survive, while the normal squirrels have to only consume 4 nuts a day to survive.
