Over millions of years, hominid species learned to use and create tools that became more complex over time. They eventually shaped stone into knives used for cutting, and they harnessed fire for light, heat, and cooking food. Which of the following best explains what effect this had on hominid evolution?

Question

anonymous · Answer

a. Hominid brain size decreased as life became easier with the advent of tools.
b. Hominid hands developed smaller thumbs as they developed finer tools.
c. Hominid tooth size decreased as they relied on cooked foods and tools for cutting.
d. Hominid front limbs became longer in proportion to the rest of their body.

anonymous · Answer

i think its either b or d

blues · Answer

Oh jeepers. I think it's C.

Because the tools were designed to suit the hands, I think it's unlikely that hands evolved to suit the tools. Also, I don't see why tool use would affect limb size.

But if the food were softer (from cooking) and the early humans could make it softer still by pounding it with rocks and cutting up with sticks (I assume, I really should not speculate about caveman cooking practices), it would remove the necessity for humans to have very big rugged teeth. They could get by with smaller ones instead and those genes eventually became widespread in the population...

anonymous · Answer

oh so the less you use it, you loss it?

blues · Answer

No, the less you need to use it, the less necessary it becomes.

Before tools, not being able to chew really tough food would put individuals at a competitive disadvantage. Small toothed individuals would be less able to eat so they wouldn't reproduce and pass on their small-toothed alleles so much - as a result, those alleles would not be common in the population.

But if that limiting factor wasn't a factor anymore (because now they can chop their food up before chewing it), they'd eat and compete and pass on their genes as well as the big toothed ones and those genes would gradually become more common.

anonymous · Answer

ohh i get it, thanks, so final answer is c?

blues · Answer

I think so. Never entirely sure though.