All of hnowak's Comments + Replies

hnowak70

Yes, but the distinction between gametes had to evolve first from asexual, i.e., undifferentiated reproduction, while hermaphroditism requires some added complexities, as it has to combine both sexes in a way that works. And as long as divided sexes work well enough, there isn't much selection pressure to go that route.

As for why this is more common in plants, I'm intuitively guessing that there are a bunch of issues involved that I'm not familiar with either. But a major driver is probably that (land) plants are sessile and tend to require some space for ... (read more)

5Yoav Ravid
Unless they're slow and uncommon as snails, in which case the cost of looking for a new mate might be high enough that developing hermaphroditeness was worth it. 
hnowak130

My take is that it boils down to increasing the probability of fertilization, primarily in our early eukaryotic ancestors, in which sexual reproduction first evolved.

On the level of gametes (the reproductive cells), it's about the difference between isogamy (gametes being the same) and anisogamy (involving a larger and a smaller gamete, which are then by definition are the female egg cell and male sperm cell). The egg cells provide almost everything the eventual zygote needs to develop, while the main role of the sperm cell is to transport a set of genes t... (read more)

Yeah, this is pretty much the explanation I'm familiar with.

  • Gametes evolve, and two members of a species have to combine their gametes to reproduce
  • But having the same gamete that is both capable of moving out of the body and has the machinery for developing the embryo is inefficient.
  • So a division of labor evolves, where one gamete evolves to be easy to transfer (which causes it to be very small, which allows the production of much more of it), and one gamete evolves to receive the other gamete and have all the machinery required to create an embryo.
  • All oth
... (read more)
3Richard_Ngo
Interesting! I don't think this answers the question of "why not hermaphrodites" though. A hermaphrodite can produce two different types of gametes, large and small (I assume this is what trees do). 
hnowak10

Thanks for the encouragement.

I've come across your work, but have to admit that I've only read parts of it so far. I'm still in the process of catching up to the state of the art.

hnowak10

Probably too late, but I wanted to submit this:

https://www.lesserwrong.com/posts/8JQQLkqjTPka9mJ4K/belief-alignment