Most skin cancer is deadly after the age of 45 see above...

Most skin cancer is deadly after the age of 45 (see above). Thus, the evolution of melanin variation across human populations was likely driven as... (check all that are correct) Question 4 options: Prevent the degradation on folate (vitamin B9) in lower-latitude human populations and the resulting reduction on reproductive output via folate-deficiencies. Increase the skin exposure to UVB radiation and the resulting increase production of Vitamin D in our skin for human populations at higher latitudes. Protection against UV caused skin cancer Protect populations against skin parasites in tropical latitudes

Transcript

00:01 Hello students, the question says that they have to describe these selective pressures for the production of lightly pigmented skin in the areas with low uv radiation.

00:18 Indigenous populations in low uv environments, they tend to have the lighter skin tones.

00:30 One hypothesis is that in low uv environment, the selective pressure for the dark skin is low.

00:40 Instead, there are selective pressure for lighter skin which absorbs more uv radiation since uv is needed for vitamin d production.

00:52 Light can provide better absorption qualities of ultraviolet radiation.

00:57 This helps the body to synthesize more amount of vitamin d.

01:04 This is the answer for first question.

01:07 Following this, we have our second question.

01:09 We have to describe the evolutionary interplay between folate.

01:15 And vitamin d.

01:20 Vitamin d and folate are both recognized for their evolutionary importance in healthy pregnancy as well as early childhood development.

01:34 A higher level of melanin, it allows normal folate synthesis by absorbing the uv rays and can allow normal gestation.

01:47 Essentially, evolution allowed for the feature that would allow healthy and successful represents.

01:53 Production.

01:54 Conversely, lightly pigmented population in high uvr environments may be at a risk of deleterious vascular effects of uvr.

02:04 Therefore, induced foliate degradation happens...

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