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Evolution/Human evolution & intelligence


Hi there,

My name is Samantha and I'm interested in finding out why humans evolved to have intelligence and why our ancestors - apes, chimps, monkeys fail to evolve the same way we did.

1. Can you give me a brief summary of how evolution works and how our ancestors evolved from apes to having human intelligence?

2. Can evolution/science answer why only humans evolved to have intelligence?  

It's a little bit like why lions are the ones to evolved to have prides, where leopards, cheetahs who are much weaker hunt and defend for themselves

How evolution works...

In brief, it works thru mutations and natural selection....

Mutations are changes that occur in each generation in every single living organism on this planet...from viruses to humans, from flowers to trees, from hummingbirds, to eagles....each generations has within its genome a change relative to its parents.  Some of the changes result in no change in the structure or behavior  of the animal, the way it thinks, etc.  Then some of these changes... all called "mutations" are deadly.... two headed calves, two headed snakes, organisms born with no brain, heart outside the body, etc.  And these lead to early deaths in these organisms, and
thus the end of that mutation for that particular generation.  But since mutations in every living thing happen all the time, down the road, it will again crop up.  When a mutation is a really good one, it gives that animals or plant someone of an edge over the others.  And in 40 or so generations, individuals carrying it, will be the dominant species in that plant or animals.  And thus this is the way that we have such varieties in, say birds, or flowers or any other living thing, since if we choose to walk backwards in time, we are all related.... every living thing has some of the same sets of genes as does every other living thing.  You have the same series of genes that an oak tree has.  You have even more of what a scorpion has, and even more what all mammals have, and by the time you are into primates.... humans are primates..... humans share 98% of the genes as chimps, our closest living relative.

2.  Sure.  Again, using this same explanation.  However, intelligence isn't necessarily a good thing.  What if every creature on this planet were as smart as humans?  We as a species change our environment more than any other animal, and so far all we have produced is over populations, huge wars,  smog, filth, over-fished the seas, poisoned oceans, corporations allowed to  spew filth into our atmosphere, and now we are into global warming, the melting of the ice caps, and flooding of our coastal areas.  Intelligence has come with a tremendous price to our planet.

Why are we, as humans smarter than other animals? Because those mutations that created that intelligence helped the species survive, just as eagles that developed greater eyesight, helped it survive, or birds that developed huge wings assisted it in survival.  IF THE MUTATION IS BENEFICIAL, THE ANIMAL CARRYING IT SURVIVES, TO PASS IT ON TO THE NEXT GENERATION.  IF THE MUTATION IS DELETERIOUS, THE ANIMAL NEVER MAKES IT TO ADULTHOOD, AND THAT MUTATION DIES WITH THE ANIMALS THAT CARRIES IT........AT LEAST FOR THAT ANIMAL, THAT MUTATION, AT THAT TIME.  So the beginning of higher intelligence began with a slight mutation of hominid intelligence 4 or 5 million years ago.

In a way, the evolution of intelligence is the same as the evolution of any other trait or organization that animals make.  Lions evolved into prides because it was advantageous to their survival, but being a lone hunter has advantages too.... you get all the meat, you don't have to share.  There are no fights between you and other members of a pride, so injury is less.  And as lone hunters, mutations occurred with them too.... more spots for blending into the environment, faster speed, better eyesight.

All changes in all plants and animals over the millions of years that life has existed, have produced so many now separate species, (where they cannot interbreed) as to be staggering, but all of this diversity  rests on the simple idea of mutations, and natural selection.


Write if something is not clear.

Elisabeth Dewald


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Elisabeth DeWald


I've been a public school teacher for 26 years. My major was history, but along the way, picked up minors in math, biology, zoology, and other life sciences. My whole life has been on one side of the desk or the other. Husband and Dad were both MDs so science and medicine was a natural for me. My dad once told me that I knew more medicine than most doctors. I can easily answer almost any life science question, most history questions, and lots of medical questions.


Taught math,history, science, geology, chemistry, biology in a public school setting

None at the present time


Majored in history in college, minored in all those subject mentioned. Masters degree in education. Grad courses, but no degree in religious studies, U of Chicago, Divinity School.

Awards and Honors
Award at my one of my colleges of Best Student, in History as a year end award.

Past/Present Clients
I tutored for two years in math. Math however, if not used daily fades. My area of competency is in honors first year algebra, at this point.

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