Question about Human Evolution...?

Question

Are human's today basically genetically the same as human's 1,000 years ago? 5,000 years ago? 10,000 years ago? 20,000 years ago?

People tend to believe the people today are superior in strength and intelligence but is this not only true because we have built opon the achievements of those before us? Is it not true that humans 1,000's of years ago were the same with the same capacity for intelligence. Human's have not evolved in hundreds of thousands of years. Is this not true? The only evolution has been in our technology and knowledge that has accumulated over time by learning from our predecessors, right? No technological knowledge is inate, just learned from those wh invented things and those who made them better. If humans today were put in a world with no technology would it not take them a similar rate to get back to the point that we are at now?

I know that we live longer and are taller but that is only a result of a better diet due to the connection of all parts of the world and access to lots of different forms of nutrition, not to mention health care as well.

Answer 1

Each generation is, on average, genetically slightly different from the previous one. The examples you cite such as height may have both a genetic and an environmental influence. But consider the increasing number of people with poor eyesight. In the days before spectacles such people would be a burden to the tribe and easy prey for predators. The gene pool is now full of people with a variety of inherited eyesight defects. You could therefore state that the average of all the human gene pool has moved towards poorer eyesight in the last 10,000 years. 10,000 years is the blink of an eye in an evolutionary timescale. Man has been evolving for around 8 million years - and even this is a tiny moment compared to the 3.5 billion years that life has existed.

Another similar change is that of birth weight. This again carries an environmental factor as well but the routine use of ceasarian births means that birth weight, shoulder width and brain size is no longer a limiting factor. In earlier times large babies would have died in childbirth along with their mothers. In effect the genetic tendency towards larger babies is now permitted by modern medicine and there may come a time when all humans will have to be born by ceasarian section in much the same way as broad-shouldered breeds of dog (eg. bulldog) are today. Whether this is reflected in an increased level of intelligence remains to be seen.

"Capacity for intelligence" is not an easy thing to measure. It may be loosely related to brain size but, to quote a well-known phrase, "it's not just size that counts but what you do with it". Neanderthal Man had a larger brain capacity than modern man but that didn't prevent his species becoming extinct in the face of competition from early homo sapiens.

Answer 2

I think you are mostly right. Humans of 1,000 and 5,000 years ago were just about as intelligent as we were, barring, perhaps brain damage caused by malnutrition or childhood diseases or whatever. 10,000 years ago you don't have a lot of evidence to go on because it's prehistoric, but what evidence there is seems to support the idea. Beyond that I don't know if you could be sure at all.

The growth of science and technology in the 'modern age' is more a matter of intellectual maturity. The 'enlightenment' of the 16th century had a lot to do with it, basically a collective decision by leading thinkers to go with observation and experiment to gather new knowledge rather than religious doctrine. But you could also say it started with Aristotle's attempts at systematizing knowledge. Ancient Egypt lasted for 3000 years, and they had brain surgery, dental transplants, developed an accurate calendar, etc. They were certainly smart enough to have invented the internal combustion engine (if they had known about iron!)

Answer 3

I would certainly agree with most of what you say. Anyone who thinks humans are a lot smarter now than they were 10,000 or 100,000 years ago should try to imagine what would happen to the average U.S. city dweller if all civilization and technology were taken away. Would that person be able to find any food in the wilderness? Or start a fire with a spark from two rocks? Build a shelter? Wander off from that shelter and be able to find his/her way back?

Think how panicky we get when someone gets lost in a forest. And, how, if they are missing for more than a week or so, we expect them not to be able to survive.

You are right about knowledge and technology being cumulative. Each generation builds on what came from the previous generation.

Answer 4

For one thing, humans aren't even genetically the same from generation to generation. Allele frequencies vary in response to environmental pressures. Although "microevolution" is a dirty word to some hardcore evolutionary biologists (because it's a darling of Creationists), the term can be applied to refer to these "small-scale" changes in allele frequency. No, it's not distinct from "macroevolution"...it's just part of the process.

The first modern Homo sapiens appeared on Earth some 200,000 years ago, although it's believed that the genes necessary for human speech didn't develop until about 130,000 years ago. After that landmark, its debatable as to whether there have been any sweeping genetic changes to the species, especially as far as intelligence goes. We can't travel back in time and administer IQ tests to cavemen, so we're stuck deducing their intelligence based on the tools they made and the paintings they did.

Answer 5

You've seen Avatar one to many times. "there's no denying" Actually, science DOES deny many of these things and denies them quite well. Dreams do NOT accurately predict future events, and even when they do it is usually a self-fulfilling prophesy ("I dreamed I was living in New York so I moved to New York") or one of a number of known outcomes ("I dreamed I got this job I was applying for" - yes, because getting it or not getting it were the only possible options). And while some people have anecdotes of not getting on a plane because they'd dreamed it would crash, there is not one verifiable, documented case of anyone waking up and writing down or informing officials in advance that a particular plane would crash PRIOR to the plane actually crashing. And Mentalists read body language, yes, a skill that is not supernaturally "connected" to other people in any way, but one that can be easily learned by anyone with the patience to do so (and easily deceived by those who want to do so). My advice is learn about statistics, probability, and coincidence because that's how much of the real world operates.

Answer 6

Are human's today basically genetically the same as humans

1000 years ago: yes
5000 years ago: yes
10,000 years ago: not quite
20,000 years ago: not quite

As a result of warfare, disease, accidents, and cultural selection, we've lost some of the alleles that were present in human populations long ago.

Conversely, there have been some mutations, resulting in new alleles now that were not present in earlier humanity.

Answer 7

your timescales are rather too short to measure evolutionary change (easier to see changes after millions of years)

if you look at our descendency you WILL see an increase
in brain size; you need go back as far as Neanderthal man)

comment:
(a whole generation of US citizens will not know anything about evolution as religious fanatics have banned
it from schools aided and abetted by Bush)