The Big Idea: The Selfish Gene says that all forms of life on Earth begin with genes, and that the purpose of life is to make sure those genes survive.
Any form of life anywhere in the universe must begin with some type of replicating molecule.
Genes are like a blueprint for the bodies they create and inhabit. Genes can’t control their bodies directly, so they create structures like the brain and muscles to coordinate and execute all of the many processes required for life.
All biology should be considered from the perspective of genes.
A population of altruistic individuals can be easily exploited by a selfish one.
The explanation for altruistic behavior is gene selection. The key to understanding gene selection is recognizing that close relatives, by definition, share many of the same genes.
There is a ratio of selfish to altruistic animals where the population will be stable. This is called the Evolutionarily Stable Strategy (ESS).
Competition for finite resources extends to family members, including the struggle between parents and their children for exactly what proportion of the resources each child should get.
There should also be severe conflicts of interest between mates.
There are benefits to two conflicting mating situations: staying with your partner for as long as possible, and abandoning them with the child before being abandoned yourself.
For mates, many species of animals have long, intricate courtships to get both the male and female heavily involved before they actually reproduce.
Many types of animals move, or even live, together in groups. Some advantages of this are obvious.
Acts of animal altruism may ultimately be an act of selfishness—in fact, considering the selfish gene theory, it must be.
If the replicator unit of biology is the gene, then the replicator unit of ideas could be called the meme.
Culture and memes don’t seem to have any inherent survival value. It’s more likely that they’re side effects of group-focused evolutionary traits such as those discussed at the beginning of this section.
Organisms don’t replicate themselves at all (except in the relatively rare case of asexual reproduction). Given that the “purpose” of life is replication, it seems clear that organisms are tools that genes use to replicate themselves.
organisms don’t have to exist. They exist on Earth because that’s what evolution happened to favor in this particular environment.
Replication is both the beginning and the purpose of life.