Santalum

That 's confusing cause and effect. WE started wearing animal skins because we became hairless. We did not become hairless because we started wearing animal skins.

I thought the general consensus was that they were not a homogeneous group of animals as far as warm/cold bloodedness. Some were largely cold blooded and some were incompletely warm blooded. In either case I would presume large size and heat retention would still be of some advantage. As they evolved they became increasingly efficient endotherms until we ended up with the bird like and mammal like reptiles.

The is a whole new branch of genetics dedicated to this called epigenetics. Various chemicals proteins can bind to the initiator, promoter and enhancer regions of a gene and thus alter how those genes are expressed. This is believed to be the underlying cause of some human diseases, including some cancers. So it is quite possible that a smoker, for example, can pass on their increased risk of lung cancer to their children. Because your DNA, complete with all the attached chemicals and proteins can be passed on to your children.

He is right. Even the most powerful of our nuclear bombs would not come any where near being able to penetrate the crust to the magma chamber in order to relieve the pressure and there is most likely vastly more pressure in the magma chamber than could be relieved by a small hole that could hypothetically be produced by a nuclear weapon;

With the megafauna versus contemporary mammals one theory it that hunting pressure from humans has resulted in dwarfing as humans nearly always target larger animals because the meat goes further. Over generations this puts selective pressure against the largest of the individuals of a species and for smaller individuals. Also larger animals require more food and this is an evolutionary disadvantage in hard times such as droughts etc. This has certainly also been a factor in the dwarfing of Australian mammals. With dinosaurs there was selective pressure among sauropod species was for larger individuals since they retain heat for longer, an advantage for cold blooded animals, and larger animals can contain larger stomachs to process larger amounts of poor nutritional quality vegetation. Then large sauropods can only be predated upon by larger carnovores.

Raised CO2 levels will not make plant growth more prolific to the extent your are obviously assuming. http://www.newscientist.com/article/dn11655-climate-myths-higher-co2-levels-will-boost-plant-growth-and-food-production.html

Why didin't you just engage the services of Mrs Palmer and her five daughters?

Probably at about the same time that our ancestors became persistence hunters and evolved sweat glands. I believe we are unique in the animal kingdom in having seat glands in our skin that enables us to cool ourselves while still running. All or most other animals have to stop in order to pant or throat flutter etc, as sweat glands would simply not work in a full coat of fur or feathers. Sweat glands give us a major evolutionary edge over them when it comes to hunting and sweat glands are probably genetically linked to hairlessness.