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10.6

Exercises for Chap. 10

Evolution Tasks

Task 10.1

Describe what is meant by evolution. Also elaborate on different mechanisms of speciation.

Task 10.2

Eigen’s ball games simulate evolution:

A chessboard, at least two colors of game pieces, and two octahedron cubes are needed.

Additional information and game instructions can be found in Eigen and Winkler (1975).

Game variant normal evolution:

If a die roll hits a color but no square is empty, that piece is removed from the game. If,

on the other hand, a die roll hits the piece and a square is empty, then that colour is also

placed in the previously empty square.

Just observe what happens when you’ve rolled a total of about 64 times (hitting each

square once on average) or when you’ve rolled a total of about 700 times (an afternoon,

worth it). Feel free to try multiple colors as well.

Task 10.3

For advanced players:

Interpret the observations obtained in terms of neutral evolution, directed evolution,

“survival of the fittest”.

Task 10.4

Hypercycle evolution:

Same playing field, but four colors. Two always form a tandem of information store and

replicating enzyme (a so-called “hypercycle” is such a tandem of enzyme and information

store). Now play the game according to the rule so that whenever a DNA (blue or red

chips) is hit and a square is free, it makes the corresponding enzyme (yellow or green

chips). Whenever an enzyme is hit and a field is free, the corresponding DNA is polymer­

ized (so if yellow, the blue DNA; such a chip into the field or if green enzyme then the red

DNA). Whenever all fields are occupied, a color is randomly thrown out by an octahe­

dron roll.

Question: What happens now in the game, which tandem wins and how fast? Also test

whether it is now easier or more difficult (compared to game 10.2) for a tandem to grow

up. To understand this, let a rare tandem compete against a dominant tandem that has

already occupied many fields.

10.6  Exercises for Chap. 10