Starting conditions	Simple bonds form	Cell walls and replication	Population dominance

MOLYPOLY LINKS

GENETIC ALGORITHMS

Robby the Robot

Robby starts with population of random genes with each gene containing a stragegy for picking up the cans.  Robby is a pretty dumb robot:  he can't see beyond the square he's sitting on, he can't count squares, he has no memory, and he doesn't even know there's a can in his square until he tries to pick it up.  Robby gets 10 points for every can he picks up, but he loses points for crashing into a wall (-5) or trying to pick up a can when there isn't one (-1).  Since there's a 50/50 random chance that a square has a can and there are 10x10=100 squares, then there should be about 50 cans to pick up.  At 10 points apiece and with no penalty points, the best Robby can score is 500. 

In one generation, Robby collects the cans and the simulator keeps track of his score (fitness) for each strategy (gene) in the population.  When all of the genes have been scored, the collection of genes in the population becomes the basis for a new generation.  Here's how they are combined:  a pair of genes is randomly selected, but the chance of selection is better for genes with higher fitness scores.  Each member of the pair of selected genes is split at some random location and rejoined, taking a piece from each parent gene to produce a new combined gene to be added to the next generation's population.  Just to make things interesting, a random mutation is introduced at this time.  Once a new generation is created, Robby picks up cans using the evolved strategy, scores each gene, and the whole process repeats.  As each generation is built from the previous genetic population, genes with the best scores have the greatest chance of remaining in the gene pool.  Robby starts with completely random genes initially, and he usually does so badly that he has a negative score!  But as Robby's strategy evolves, his score gradually improves and approaches the theoretical best score of 500.  Dr. Mitchell reports that her Robby got as high as 483 which is pretty close to optimal... so far, I'm only getting 300, but I probably still have bugs in my code. :)

ORIGIN OF LIFE PRESENTATION

NEW DEVELOPMENTS

Scientific American Article

• Researchers have found a way that the genetic molecule RNA could have formed from chemicals present on the early earth.
• Other studies have supported the hypothesis that primitive cells containing molecules similar to RNA could assemble spontaneously, reproduce and evolve, giving rise to all life.
• Scientists are now aiming at creating fully self-replicating artificial organisms in the lab­oratory—essentially giving life a second start to understand how it could have started the first time.

Self-Replication

Not content with achieving one hallmark of life in the lab, Joyce and Lincoln sought to evolve their molecule by natural selection. They did this by mutating sequences of the RNA building blocks, so that 288 possible ribozymes could be built by mixing and matching different pairs of shorter RNAs. What came out bore an eerie resemblance to Darwin's theory of natural selection: a few sequences proved winners, most losers. The victors emerged because they could replicate fastest while surrounded by competition, Joyce says. 

Alternative Life Forms