Freethought & Rationalism Archive

07-16-2003, 07:31 AM

Quote:

Survival of the Fittest. The Evolutionist's mantra. IF this is all about the Survival of the Fittest, then the worms that lost their "maleness" would no longer be the fittest. Obviously those worms that could give AND receive DNA information would be the ones with the edge. So why is it that the one that was NOT the fittest suddenly is the norm for all of higher biology? It totally goes against the whole backbone of evolution. Hermaphrodites should be the norm, because they have the advantage.

I think this garbage proves that this person has only the sketchiest understanding of natural selection.

lpetrich · 07-16-2003, 08:11 AM

I think that the key to this conundrum is how easily individuals can find each other, because a random encounter has 0.5 probability of being the opposite sex.

There are two ways out of that conundrum: make multiple encounters more likely and increase the probability by some sort of advertisement (visual, audio, olfactory). The first is a feasible strategy for those that live in close proximity, while the second is often implemented with pheromones and the like.

But if neither can easily be satisfied (unlikely to meet, long-range advertisement impractical), then it's safest to be both sexes. Which is the case for land snails and earthworms.

Interestingly, deep sea anglerfish may face a similar difficulty in finding partners; that has been proposed for why male DSA's often attach themselves to female ones.

MortalWombat · 07-16-2003, 08:55 AM

Quote:

Originally posted by lpetrich
A cell "gains" or "loses" chromosomes by existing chromosomes splitting or fusing. This suggests that those chromosomes can still match with the originals -- at first.

But if the chromosomes start becoming too different in structure, "hybrid sterility" can indeed result. Resulting in the splitting of one species into two.

Even different species with different chromosome numbers can mate to produce fertile offspring in some cases. Domestic horses, with 64 chromosomes, when mated with donkeys, with 62 chromosomes, produce (normally) sterile mule offspring. However, domestic horses can also mate with the Przewalski Horse (or Asiatic wild horse), which has 66 chromosomes, to produce fertile offspring. Source.

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07-16-2003, 08:11 AM	#32
lpetrich Contributor Join Date: Jul 2000 Location: Lebanon, OR, USA Posts: 16,829	I think that the key to this conundrum is how easily individuals can find each other, because a random encounter has 0.5 probability of being the opposite sex. There are two ways out of that conundrum: make multiple encounters more likely and increase the probability by some sort of advertisement (visual, audio, olfactory). The first is a feasible strategy for those that live in close proximity, while the second is often implemented with pheromones and the like. But if neither can easily be satisfied (unlikely to meet, long-range advertisement impractical), then it's safest to be both sexes. Which is the case for land snails and earthworms. Interestingly, deep sea anglerfish may face a similar difficulty in finding partners; that has been proposed for why male DSA's often attach themselves to female ones.

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