GC: Can you explain why defining sex as the different sized gametes (egg and sperm) is not conflating sexual dimorphism with sex, because I think it is conflating? And can you tell me why sex is binary and is not a bimodal distribution?

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    [–]Juniperius 15 insightful - 1 fun15 insightful - 0 fun16 insightful - 1 fun -  (0 children)

    A sperm isn't just a smaller egg, and an egg isn't just a larger sperm. They are entirely different types of cells. An egg has a nucleus, mitochondria and other organelles, everything it needs to be a whole cell. It can live forty years in the ovary before emerging to become a new person. It's very nearly a single-cell organism in its own right. A sperm is just a bit of dna wrapped in a membrane. It has no substructures except for the tail. It doesn't process its own energy. It lives only a few hours. It's like comparing a virus to an amoeba. This isn't a matter of dimorphism because you are not talking about things that are just a different shape, size, color, or other superficial characteristic (morph = shape, form) but things that are entirely, fundamentally different orders of being.

    [–]kwallio 10 insightful - 1 fun10 insightful - 0 fun11 insightful - 1 fun -  (3 children)

    Like the first poster says, you have it back to front. The sex is defined as gamete size, you can have animals with no sexual dimorphism where the sexes are identical and can't be told apart (I own one of these, an angelfish) or have sexes where there is a large size difference (anglerfish). The size difference in gametes is NOT the result of sexual dimorphism, I think you need to become educated on sexual dimorphism because its not always about size (males can have different color feathers but be the same size like in some birds). Its just an observational difference between the sexes.

    [–]MezozoicGaygay male 7 insightful - 1 fun7 insightful - 0 fun8 insightful - 1 fun -  (1 child)

    Some animals have it reversed, females are much bigger and stronger than males.

    [–]kwallio 5 insightful - 1 fun5 insightful - 0 fun6 insightful - 1 fun -  (0 children)

    Yes thats true. In fact females being larger is more typical than the reverse.

    [–]kwallio 4 insightful - 1 fun4 insightful - 0 fun5 insightful - 1 fun -  (0 children)

    Also wouldn't your idea of size = size of gamete kinda fail in species in which the males are larger? I mean you can observe which cell is larger pretty easily.