aartadventure
aartadventure t1_jac3zfp wrote
Reply to comment by zakabog in Why does temperature determine the sex of certain egg laying animals like crocodiles? by insink2300
It could be that most mutations do nothing bad, or that they end up being harmful in time, such as cancer. Here is one paper on the topic:
https://www.sciencedaily.com/releases/2022/06/220608112504.htm
And yes, that was my point. Evolution tends to work slowly, over millions of years, due to the low chance of a beneficial mutation occurring, and then also being selected for in a given environment. And, since environments change, what was once beneficial, may end up becoming harmful over time.
aartadventure t1_jabnn6o wrote
Reply to comment by atred in Why does temperature determine the sex of certain egg laying animals like crocodiles? by insink2300
Most mutations are not good, or downright lethal, leading to miscarriage, cancer and other awful outcomes. Especially in multicellular organisms, advantageous mutations occur quite rarely. That organism also has to be lucky enough to survive long enough to reproduce (you might have an incredibly advantageous mutation but just be unlucky and get struck by lightning before you reproduce for example). It may be something more akin to flipping 50 or 100 heads in a row.
aartadventure t1_jabnb5b wrote
Reply to comment by Tiny_Rat in Why does temperature determine the sex of certain egg laying animals like crocodiles? by insink2300
Even recessive traits are selected for in the natural environment over time. However, they remain recessive for various reasons. This could include the recessive trait being advantageous in certain circumstances, but not others. Or that is only an advantage if other traits are also expressed at the same time. Many times a recessive trait can be an advantage but exacts a biological cost as well. If these traits remain recessive, evolutionary pressures cause them to become more common in the "required" circumstances, while allowing them to swiftly become less common when the environment is not suitable for that trait.
aartadventure t1_ixbfduk wrote
Reply to AskScience AMA Series: I'm a wildlife filmmaker who's spent years tracking and filming the endangered ocelot population in Texas. Ask me anything! by AskScienceModerator
I don't live in the USA, but good luck, and thank you for your efforts. A shame people don't value other species as much as oil and money.
aartadventure t1_jbjbyex wrote
Reply to Is there a fertile creature with an odd number of chromosomes? by TheBloxyBloxGuy
The most crazy examples of animals are usually parthenogenetic insects. And in the distant future, even human males may lose their Y chromosome (although another chromosome would need to take over). Here is a case study featuring the spiny rat: https://greekreporter.com/2022/11/30/rat-without-y-chromosome-human-genetic-future/