What happens to the retina and optic nerves in deep sea fish that are blind?
I heard that first-born males are more likely in younger couples who have sex frequently, because male sperm are more likely to reach the egg just after ovulation. Is there any truth to this, and if so, how is sex ratio maintained?
I have noticed that man made machines are full of spinning parts such as cogs, wheels, turbines etc but as far as I know no living thing has ever evolved the wheel or anything remotely similar. Is this so and if so why?
There are certain kinds of food that I like and some that I dislike, just like everybody else. But from an evolutionary standpoint, it seems like we shouldn't be turning our noses up at anything that helps us survive, nor should we have differing tastes than other people living in the same environment. Why would we develop a distaste for certain foods?
Please explain the mechanism by which a species that is drifting genetically to become a new species reorganizes its DNA on its chromosomes, creating a new number of chromosomes or putting the information in a new arrangement.
Where do new genes come from? It is one case where genes turn on or off, resulting in black or white fur, or where say slightly longer necks are favored over short ones. These changes are based on existing genes. What about the case of completely novel features? How do you go from a bacterium without any concept of arms and legs, teeth, etc. and lacking genes for these, to macroscopic animals having these genes. Macroscopic animals of course descended from single celled organisms. How do you get a gene (or group of genes) for an eye or a pancreas? What sort of mutation can give me a new, useful gene?
How do scientists learn about plants that are extinct?
Can you explain the genetics and evolution of skin color? Is skin color useful for grouping people into ethnic groups?
In almost every study that I have seen, brunets are preferred over blonds. Why?
Generally, members of a species have different DNA makeup from other species. However, as I understand it, chromosomal DNA is difficult, if not impossible, to get from ancient fossilized remains, so most paleontologists rely on structures to indicate whether speciation has occurred when such remains are analyzed.