Quotes About Reproduction

One gene may be regarded as a unit that survives through a large number of successive individual bodies.

So, the question is: If greenflies and elm trees don't do it, why do the rest of us go to such lengths to mix our genes up with somebody else's before we make a baby? It does seem an odd way to proceed. Why did sex, that bizarre perversion of straightforward replication, ever arise in the first place? What is the good of sex?*

A male on the other hand can never get enough copulations with as many different females as possible: the word excess has no meaning for a male.

They have come a long way, those replicators. Now they go by the name of genes, and we are their survival machines.

A germ-line replicator (which may be active or passive) is a replicator that is potentially the ancestor of an indefinitely long line of descendant replicators. A gene in a gamete is a germ-line replicator. So is a gene in one of the germ-line cells of a body, a direct mitotic ancestor of a gamete.

The ESS has been rigorously defined (Maynard Smith 1974), but it can be crudely encapsulated as a strategy that is successful when competing with copies of itself.

If a program or strategy is successful, this means that copies of it will tend to become more numerous in the population of programs and will ultimately become almost universal. It will therefore come to be surrounded by copies of itself. If it is to remain universal, therefore, it must be successful when competing against copies of itself, successful compared with rare different strategies that might arise by mutation or invasion.

To recapitulate, the significance of the difference between growth and reproduction is that reproduction permits a new beginning, a new developmental cycle, and a new organism which may be an improvement, in terms of the fundamental organization of complex structure, over its predecessor.

When we talk of a program as 'doing better' or as being 'successful' we are notionally measuring success as capacity to propagate copies of the same program in the next generation: in reality this is likely to mean that a successful program is one which promotes the survival and reproduction of the animal adopting it.

The point about recurrent reproduction life cycles, and hence, by implication, the point about organisms, is that they allow repeated returns to the drawing board during evolutionary time.

Firstly, we could ban reproduction before a certain age, say forty. After some centuries of this the minimum age limit would be raised to fifty, and so on. It is conceivable that human longevity could be pushed up to several centuries by this means.

A DNA molecule in the germ-line of an individual who happens to die young, or who otherwise fails to reproduce, should not be called a dead-end replicator. Such germ-lines are, as it turns out, terminal. They fail in what may metaphorically be called their aspiration to immortality. Differential failure of this kind is what we mean by natural selection.

As I said, the active/passive distinction cuts across the germ-line/dead-end distinction. All four combinations are conceivable.

We should not seek immortality in reproduction.

Why did sex, that bizarre perversion of straightforward replication, ever arise in the first place? What is the good of sex?* This is an extremely difficult question for the evolutionist to answer.

From the viewpoint of this book an animal artefact, like any other phenotypic product whose variation is influenced by a gene, can be regarded as a phenotypic tool by which that gene could potentially lever itself into the next generation.

Phenotypic effects of genes, whether at the level of intracellular biochemistry, gross bodily morphology, or extended phenotype, are potentially devices by which genes lever themselves into the next generation, or barriers to their doing so. Incidental side-effects are not always effective as tools or barriers, and we do not bother to regard them as phenotypic expressions of genes, either at the conventional or the extended phenotype level.

Animals therefore go to elaborate lengths to find and catch food; to avoid being caught and eaten themselves; to avoid disease and accident; to protect themselves from unfavourable climatic conditions; to find members of the opposite sex and persuade them to mate; and to confer on their children advantages similar to those they enjoy themselves.

Kamikaze behaviour and other forms of altruism and cooperation by workers are not astonishing once we accept the fact that they are sterile. The body of a normal animal is manipulated to ensure the survival of its genes both through bearing offspring and through caring for other individuals containing the same genes.

Within each species some individuals leave more surviving offspring than others, so that the inheritable traits (genes) of the reproductively successful become more numerous in the next generation. This is natural selection: the non-random differential reproduction of genes.

The gene is the basic unit of selfishness.

It is important to understand that in the modern world we prefer the replica to the original because it gives us the greater frisson. I leave that word in French because I think you understand it well that way.

What we call beauty is perhaps the strength of our feeling of resistance to destructibility. Difficulty of reproduction is the yardstick of the degree of beauty.

This law of capitalistic society would sound absurd to savages, or even civilised colonists. It calls to mind the boundless reproduction of animals individually weak and constantly hunted down.24