EvoWiki is now a project of the
We are moving all content to RationalWiki.
See the for details! .
The Earth's biota contains numerous conflicting designs; one organism has features that cause trouble for another one, and vice versa. A very common form of conflict is predator-prey and parasite-host relationships, where the predators and parasites attempt to live off of the prey and hosts, while the prey and hosts try to keep that from happening. There are also conflicts between members of the same species, like conflicts over resources like food and mates, conflicts between the sexes, etc.
Predator-prey and parasite-host relationships are often chained; here is a simple example:
- Wolbachia bacteria
- Deer eat grass
- Wolves eat deer
- Fleas suck wolves' blood
- Wolbachia bacteria live inside of fleas' cells
- Bacteriophages induce bacteria to make more copies of them
- Grass has phytoliths, tiny silica grains that abrade teeth.
- Deer have big cheek teeth for grinding up grass.
- Deer have forward-to-sideways-pointing eyes and ears, because wolves can approach them from any direction.
- Wolves have forward-pointing eyes and ears, because that's the direction in which they approach deer. They also have teeth that are convenient for cutting and slicing meat.
- Wolves scratch themselves to get rid of fleas.
- Fleas have mouthparts that can pierce skin, enabling them to suck blood.
- Fleas have an immune system that attacks wayward bacteria.
- Wolbachia bacteria hide inside of fleas' cells, thus avoiding fleas' immune systems.
- Bacteria have "restriction enzymes" for snipping up stray nucleic-acid strands, like bacteriophage genomes
- Bacteriophages imitate their hosts' genetic material, inducing their hosts to make copies of them without snipping them up
Note that the predators and parasites look lovingly designed for living off of their prey and hosts, while the prey and hosts look lovingly designed to thwart their predators and parasites. If these features were the result of design, then this raises curious questions about the motivations of the designer(s) responsible. Is there one designer with a multiply-split personality? Or are there a multitude of designers, at least one each for grass, deer, wolves, fleas, Wolbachia bacteria, and bacteriophages?
Continuing further, conflicts between individuals of the same species seem maladaptive and wasteful. In many species, males fight each other for access to females, when one might expect them to prefer to fight their "real" enemies. Also in many species, females prefer males with flashy and troublesome features, like brightly-colored feathers that effectively paint targets on their owners. Among some predatory insects, females only mate with males that bring them some prey -- and fly off before completion if the prey is not enough. And among lions and langur monkeys, a male who has driven another male from a group of females will kill all the babies.
However, all these features are readily explicable by Richard Dawkins's concept of the Selfish gene; Charles Darwin himself had noted that no organism has features that only benefit others. Predators and parasites try to nourish themselves, while prey and hosts try to survive in good health. Males compete with each other because they have relatively small contributions to the next generation, meaning that they can afford competing with each other. Females like males with flashy and troublesome features, because such features indicate potential mates that have successfully evaded predators and parasites. And they may like males that can catch big prey. And males that practice infanticide after driving off rival males help themselves become fathers and hinder the fatherhood of the driven-off males.