13.2. Simulating Evolution¶
We start with a simple model that demonstrates a basic form of evolution. According to the theory, the following features are sufficient to produce evolution:
Replicators: We need a population of agents that can reproduce in some way. We’ll start with replicators that make perfect copies of themselves. Later we’ll add imperfect copying, that is, mutation.
Variation: We need variability in the population, that is, differences between individuals.
Differential survival or reproduction: The differences between individuals have to affect their ability to survive or reproduce.
To simulate these features, we’ll define a population of agents that represent individual organisms. Each agent has genetic information, called its genotype, which is the information that gets copied when the agent replicates. In our model, a genotype is represented by a sequence of N binary digits (zeros and ones), where N is a parameter we choose.
To generate variation, we create a population with a variety of genotypes; later we will explore mechanisms that create or increase variation.
Finally, to generate differential survival and reproduction, we define a function that maps from each genotype to a fitness, where fitness is a quantity related to the ability of an agent to survive or reproduce.
- Replicators
- Correct, they needed a population of agents that could reproduce in some way, and they used replicators that make perfect copies of themselves.
- Variations
- Correct, we need variability in the population, that is, differences between individuals.
- Fitness
- Sorry this is a way to define one of the features.
- Differential survival or reproduction
- Correct, the differences between individuals have to affect their ability to survive or reproduce.
- Genotype
- This is what is needed to produce one of the three.
Q-1: Evolution needs three things to be present, what are those three things?