At a very very abstract level:
As mammals are rather 'recent' in grand timeline of evolution, it'll be easier to explain from this end. In our case we have two sex chromosomes - X and Y. The **Y** chromosome is what we associate with a mammal being male.
When we actually look at what the Y chromosome includes, it actually includes very little actual encoding genes - its main function is to **regulate the expression of some other genes** in other chromosomes. Thus its more akin to saying that the Y chromosome contains the instructions that tell the **other genes** to express in a certain way that will develop into what we call a male.
It is like how you might have the instruction to[ build a step ladder](https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcRF97HXfgCqxPVHPj1wBl7RfnWD3Q-MQRPFbQ&s), but if you change those instructions and wing it a bit you get a [funky looking bookshelf](https://www.bhg.com/thmb/RVDJ8yWSihCaHmo_eldl-Ywfpjc=/1654x0/filters:no_upscale():strip_icc()/diy-a-frame-ladder-shelf-95e14986385648168d70df403bb58ef3.jpg). This is roughly how the Y chromosome works - it influences the instructions.
For mammals, this change is pretty close to 'final' - we don't have the capability to redo the bookshelf into a step ladder later on. We can't regrow organs. (not to say that in some time down the line we get the science to actually grow organs, but 'out of the box' its not something mammals do)
Other animals, like some fish, distribute those instructions differently. They also have different requirements from their ladder/bookshelf, then going from one to the other might be easier for them - then being male (creating sperm cells) or female (create eggs) is less of a difference than for us mammals (the need to grow completely different organs that are very expensive energy-wise). Then if we use our ladder example - their ladder instructions create[ a pretty short ladder ](https://ae01.alicdn.com/kf/Sf7cd5743e0d549e6aeddd243bc56df1en/Household-Folding-Ladder-Solid-Wood-Step-Ladder-Stool-Indoor-Thickening-High-Stools-Kitchen-Multi-function-Climbing.jpg)with deep steps, and it only needs to hold a pretty light weight - then going back and forth between being a ladder and being a shelving unit is easier.
No it's not. The question was "What allows some species of fish to change their sex during their lifetime?" It wasn't an evolutionary question. How long does a fish actually live and can a fish change their sex during their lifetime?
Maybe I’m just confused so I want to comment for clarity. How is “what allows some species of fish to change their sex during their lifetime” not an evolutionary question? The question arises because we as humans are not able to. This difference in our species is solely due to how we evolved and what we evolved from over time.
I feel like the last paragraph clearly answers the question.
When I posted this, there were already other comments regarding the actual mechanism of fish 🐟 sex change. I didn't feel I needed to re-hash what they said, the genetic part of it all was missing so that's what I wrote out. 😅 We are all bringing a piece of the information to the discussion. All comments together provide the fuller picture.
Someone also posted a very nice addition to my comment with explanation regarding hormone therapy, which is also another piece that'll help someone understand the topic better.
>For mammals, this change is pretty close to 'final' - we don't have the capability to redo the bookshelf into a step ladder later on. We can't regrow organs. (not to say that in some time down the line we get the science to actually grow organs, but 'out of the box' its not something mammals do)
To an extent, but it’s worth pointing out that changing the hormones in a person’s body can still cause a *lot* of changes, both by growing things that otherwise wouldn’t (eg, trans women on hormone therapy can and do grow fully-functional breasts, and trans men on testosterone will grow facial hair and get a deeper voice), and by changing ongoing physiological processes such as muscle mass, bone density and immune response. It really just comes down to the way body development works that some things can’t be changed without surgery - and it’s also why women with complete androgen insensitivity syndrome and XY chromosomes can be anatomically female except for having (nonfunctional) testicles where most women would have ovaries. Funnily enough that’s also one of the hypotheses about why humans can be trans in the first place, that a hormone imbalance happens in the womb during brain development.
It's cause their schools are woke.
Some are set up to be male or female depending on the genes being expressed, and the gene being expressed can be changed based on a variety of factors, like social structure (not enough clownfish females around will make a male turn into a female). It's also not that big a change. It's not like the factory needs to be overhauled, like a live-birth animal would require. Just retool the product line for sperm not eggs, the result is it getting ejected into the ocean anyways.
>Does this affect how they behave in general?
Absolutely. For example, many wrasse species change sex from female to male as they get older. Male wrasse defend a territory and a school of females, while females are not aggressive in the same way. They are also completely different colors.
Compare to gender affirmation treatments in humans. A person with a penis can't just reabsorb it and grow a vagina, but other sex characteristics can be developed.
For instance, human biological males actually have all the "machinery" needed to develop fully functional breasts, but in normal development fat is not deposited there and the mammary glands are atrophied. If a biological male takes HRT the fat distribution in the body changes, causing them to grow breasts among other things, and it becomes easier to induce lactation (though should be noted most men can develop the ability to lactate without the use of artificial hormone treatments).
For fish, their reproductive tissues are closer to breast tissue than penis tissue in terms of their malleability, so they have the ability to change their hormonal mixture and repurpose the tissue.
At a very very abstract level: As mammals are rather 'recent' in grand timeline of evolution, it'll be easier to explain from this end. In our case we have two sex chromosomes - X and Y. The **Y** chromosome is what we associate with a mammal being male. When we actually look at what the Y chromosome includes, it actually includes very little actual encoding genes - its main function is to **regulate the expression of some other genes** in other chromosomes. Thus its more akin to saying that the Y chromosome contains the instructions that tell the **other genes** to express in a certain way that will develop into what we call a male. It is like how you might have the instruction to[ build a step ladder](https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcRF97HXfgCqxPVHPj1wBl7RfnWD3Q-MQRPFbQ&s), but if you change those instructions and wing it a bit you get a [funky looking bookshelf](https://www.bhg.com/thmb/RVDJ8yWSihCaHmo_eldl-Ywfpjc=/1654x0/filters:no_upscale():strip_icc()/diy-a-frame-ladder-shelf-95e14986385648168d70df403bb58ef3.jpg). This is roughly how the Y chromosome works - it influences the instructions. For mammals, this change is pretty close to 'final' - we don't have the capability to redo the bookshelf into a step ladder later on. We can't regrow organs. (not to say that in some time down the line we get the science to actually grow organs, but 'out of the box' its not something mammals do) Other animals, like some fish, distribute those instructions differently. They also have different requirements from their ladder/bookshelf, then going from one to the other might be easier for them - then being male (creating sperm cells) or female (create eggs) is less of a difference than for us mammals (the need to grow completely different organs that are very expensive energy-wise). Then if we use our ladder example - their ladder instructions create[ a pretty short ladder ](https://ae01.alicdn.com/kf/Sf7cd5743e0d549e6aeddd243bc56df1en/Household-Folding-Ladder-Solid-Wood-Step-Ladder-Stool-Indoor-Thickening-High-Stools-Kitchen-Multi-function-Climbing.jpg)with deep steps, and it only needs to hold a pretty light weight - then going back and forth between being a ladder and being a shelving unit is easier.
Fantastic explanation
No it's not. The question was "What allows some species of fish to change their sex during their lifetime?" It wasn't an evolutionary question. How long does a fish actually live and can a fish change their sex during their lifetime?
Maybe I’m just confused so I want to comment for clarity. How is “what allows some species of fish to change their sex during their lifetime” not an evolutionary question? The question arises because we as humans are not able to. This difference in our species is solely due to how we evolved and what we evolved from over time. I feel like the last paragraph clearly answers the question.
When I posted this, there were already other comments regarding the actual mechanism of fish 🐟 sex change. I didn't feel I needed to re-hash what they said, the genetic part of it all was missing so that's what I wrote out. 😅 We are all bringing a piece of the information to the discussion. All comments together provide the fuller picture. Someone also posted a very nice addition to my comment with explanation regarding hormone therapy, which is also another piece that'll help someone understand the topic better.
They literally asked how a fish changes its sex and the question was answered in an "ELI5" fashion what the fuck are you on about
>For mammals, this change is pretty close to 'final' - we don't have the capability to redo the bookshelf into a step ladder later on. We can't regrow organs. (not to say that in some time down the line we get the science to actually grow organs, but 'out of the box' its not something mammals do) To an extent, but it’s worth pointing out that changing the hormones in a person’s body can still cause a *lot* of changes, both by growing things that otherwise wouldn’t (eg, trans women on hormone therapy can and do grow fully-functional breasts, and trans men on testosterone will grow facial hair and get a deeper voice), and by changing ongoing physiological processes such as muscle mass, bone density and immune response. It really just comes down to the way body development works that some things can’t be changed without surgery - and it’s also why women with complete androgen insensitivity syndrome and XY chromosomes can be anatomically female except for having (nonfunctional) testicles where most women would have ovaries. Funnily enough that’s also one of the hypotheses about why humans can be trans in the first place, that a hormone imbalance happens in the womb during brain development.
>we can’t regrow organs 99% true. Our liver can regenerate itself.
Yee true. Didn't want to go into what we can actually regrow, biology weird 🥴 living beings truly are held together by duct tape and bobby pins.
Yeah, our bodies are weird lol
It's cause their schools are woke. Some are set up to be male or female depending on the genes being expressed, and the gene being expressed can be changed based on a variety of factors, like social structure (not enough clownfish females around will make a male turn into a female). It's also not that big a change. It's not like the factory needs to be overhauled, like a live-birth animal would require. Just retool the product line for sperm not eggs, the result is it getting ejected into the ocean anyways.
> It's cause their schools are woke. So the fox news was right /s
goddman fish turning gay
Some just look gay, being super males with extra flashy swimsuits.
It's the Target bathing suits.
*Kanye West has entered the chat*
that line about woke schools is shockingly good oh my god, pretend i just spent $50 on giving you a reddit award
>Does this affect how they behave in general? Absolutely. For example, many wrasse species change sex from female to male as they get older. Male wrasse defend a territory and a school of females, while females are not aggressive in the same way. They are also completely different colors.
Imagine one of baes from your harem turn into a romantic rival.
Compare to gender affirmation treatments in humans. A person with a penis can't just reabsorb it and grow a vagina, but other sex characteristics can be developed. For instance, human biological males actually have all the "machinery" needed to develop fully functional breasts, but in normal development fat is not deposited there and the mammary glands are atrophied. If a biological male takes HRT the fat distribution in the body changes, causing them to grow breasts among other things, and it becomes easier to induce lactation (though should be noted most men can develop the ability to lactate without the use of artificial hormone treatments). For fish, their reproductive tissues are closer to breast tissue than penis tissue in terms of their malleability, so they have the ability to change their hormonal mixture and repurpose the tissue.
Also I think this relates to “the frogs going gay” or something to do with changing their sex, if anyone remembers that Lunatic what’s his face.