Today I Learned (TIL)

6594 readers

2 users here now

You learn something new every day; what did you learn today?

/c/til is a community for any true knowledge that you would like to share, regardless of topic or of source.

Share your knowledge and experience!

Rules

Information must be true
Follow site rules
No, you don't have to have literally learned the fact today
Posts must be about something you learned

founded 2 years ago

MODERATORS

[email protected]

131

TIL about Tetrachromacy, a condition which lets you see more colors. Normal people can see about 1 million colors, while tetrachromats may see up to 100 million. Up to 12% of women may have it. (www.healthline.com)

submitted 11 months ago by [email protected] to c/[email protected]

22 comments fedilink hide all child comments

you are viewing a single comment's thread
view the rest of the comments

[–] [email protected] 20 points 11 months ago (1 children)

Cool! I had never heard about this theory for explaining color blindness.

[–] givesomefucks 21 points 11 months ago (1 children)

There's very few things that are a flat negative evolutionarily.

Like sickle cell, in most of the world it's a significant disease. But if you live somewhere with malaria before modern medicine, then for 99.9999% of human existence, you'd be dead at a young age without sickle cell in those places.

Or how appendix bursting was worth the risk of retaining gut bacteria. Once we got clean water, the adaption of not having an appendix started to spread. Until modern surgery took out the negative evolutionary pressure so humans will be stuck with appendixes for ever now.

[–] Anamnesis 3 points 11 months ago* (last edited 11 months ago)

I'm heterozygous for cystic fibrosis. It fucked my plans for having kids, cause I don't have vas deferens. (Most people who are heterozygous don't have any problems, but some men do with fertility). But apparently heterozygous people are more resistant to cholera and dysentery, since our cells hold onto water easier.