UnitedIssues U.S. Political Debates - Debate

"If humans are a distinctly different species from other animals (and evolution took place), then wasn't there once a point where there were only two humans?"

Original Opinion by JamesBufkin (25)

If you want the short and sweet answer and don't feel like hearing all the details then the answer is no. If you're intrigued then feel free correct my mistakes (if I make any), and discuss other evolutionary topics related to humans.

Now, onto the subject matter. Basically, as all the evidence shows, evolution did in fact take place. (There's almost no point in arguing about whether or not it took place, so if you wish to, you may make another debate specifically about that.) This, to some people, means that humans must have a direct line of ancestors all the way to the first humans. This is mostly true, but some go further in saying that there must have been two "first" humans that spawned the rest of the species. This is wrong for a couple of reasons and I shall start with the first which is that evolution is not a clean process.

Whenever a new species is formed due to evolution it is actually not really noticeable because the changes which lead to new species are so small that only long amounts of time (tens or hundreds of thousands of years) can determine the defining line between two species. In human evolution our closest living relatives are chimpanzees, from whom we "split" about 6 million years ago. When people hear this they usually don't understand that we were still approximately the same species as that which led to chimpanzees for several thousand (if not more) years. During this time there was much interbreeding between the species as they constantly became more distinct. Eventually interbreeding probably produced either no offspring or sterile offspring closing the link between humans and chimps. The remaining human species then began a different journey through time that would later lead to us. This time period when genetic material is able to cross between the species allows for the slow procession of one or more species from another and the continued existence of the original species as well (Though those species won't necessarily survive!). This is what I mean by evolution not being a clean process. It relates to the "first" humans idea because it shows that the species as a whole is able to change from the original and other offshoots without requiring two new distinctly different(from the original) creatures to come out of nowhere and breed to make a new species.

Another reason why the "first" humans idea is wrong is due to the slow nature of evolution. Though dramatically intertwined with the first reason I gave the slow nature of the evolutionary process has more to offer in this line of thinking. Because species evolve based on the process of natural selection, that is to say they slowly change over time whenever a beneficial mutation comes about (though not all benefits survive). The mutation usually benefits when it prevents the organism from dying in whatever circumstances it happens to find itself, and this allows the genetic code for the benefit to be passed on to the next generation. Evolution takes a long, long time, and because of this populations of organisms for the most part evolve together combining mutations but keeping enough genetic diversity so as not to create too many inbreds. (I'll quickly explain the biggest issues of inbreeding here. The problem with inbreeding is that it magnifies the mutations of close relatives in a species. If two chimpanzees that were brother and sister were to have a child (though I've never heard of it happening) it would be, for the most part, normal except it might have some exaggerated family traits. If it were to have a child with one of its siblings the resultant child would most likely die of complications. Having the same genetic material piled up again and again can be very detrimental. I may actually have underestimated the issues for the original inbred child, but then again I'm not an expert.) A semi-large population is required to keep genetic diversity high enough to avoid this scenario. I believe at least seventeen individuals are required for a stable population, but the requirement may be more or less (some sources consider 50 a minimum to avoid inbreeding, but it also says that 500 may be required, then the numbers rise from there). Additionally, if the breeding can be controlled, the minimum population size may be less. This minimum population problem is the heart of the issue and shows that you need many more than just two original members of any species. The slow nature of evolution is connected by the fact that there must be a certain limit to how small a population can be (and as it should have been learned in science class, the smaller the population the faster the evolution, due to the more rapidly multiplying of mutations), the slowness in turn allows for entire groups of a species to evolve independently eliminating the need for two members of an entirely new species to come from a previous one (which would be an issue with inbreeding anyways).

To wrap this up, we semi-evolved simians could not possibly have come from two individuals, nor could any other organism (except bacteria and protists (asexual reproduction avoids some of the issues of mutation)),or more correctly, complex organism that propagates itself sexually. Sorry Adam and Eve, sorry Noah and your useless Ark. But not really, they're just stories and need no apology.

And if you're keeping score that's
Science: 1 (technically more)
Bible/Other mythologies that require inbreeding for the propagation of life on Earth in their creation stories: 0

Responses

"Just curious..." by Vultren (85)

Are you saying out of the infinite chances of human life starting (science has said this to be true) that more than one of these chances happened? That hundreds of us just evolved the exact same way?

"Not sure what you mean..." by JamesBufkin (25)

First I'd like you to explain your question a little more thoroughly and provide evidence to back up your statement that "science has said this to be true". Honestly I'm not terribly sure what you mean, but from what I presume you are saying, the answer is no.

Evolution is very, very slow. Perhaps I wasn't clear when I said this before. Evolution usually takes thousands of years to be noticeable in complex creatures and millions of years when considering completely different species. When humans evolved from our common ancestor with chimps it wasn't immediate for any one individual. Modern Homo sapiens sapiens, our species, is approximately 80,000-120,000 years old. This statement only means that the changes in the past 100,000 years have been minimal within the species itself. There are dozens if not scores of transitional species between our common ancestor with chimps and ourselves from the past 6 million years. Each one a branch that is related (though not necessarily immediately) to our own direct ancestry.

Now to get back to your question, no we did not "just evolve", because it was a slow process and it happened to POPULATIONS and not INDIVIDUALS. This seems to be a common misconception with those who don't understand evolution, that species evolve based on individuals in a group. But the truth is that it's the population of individuals that make the evolutionary trip together.

I hope this answered your question, if you have any more, feel free to ask.

"Ever so true" by Akulakhan (8)

People seem not to fully understand the process of evolution. Every living being has mutated genes. These genes, if proven useful to survival, will have a greater chance of inheritance (by means of extrapolated reason, of course; not to assert that they become more dominant, for that is a seperate matter). Conclusively, time progresses, and the combination of genetic mutations of the population will have begat a new being.

"evolution creationist diffrent " by Teddyroosevelt (45)

first of all long post based on that i assume your a strong believer in evolution and thats okay i my self belive in evolution and certaintly belive the panet is not 6000 years old [ that is kind of stupid ] but i also cant see why religion and evolution dont get along a some what of a christain and i dont belive it conflicts with my belief mainly contrary to some belief the bible was not written by god but men and so is not an exact truth

most importantly ive always belived the story of adam and eve to slightly go along with evolution and is a way of explaining mans rise. and heres my thesis in genesis man starts like any other creature its only when man pursues gods apple of knowledge to we become something more and what most regard as a punishment a regard as something for are own good when in genesis god throws adam and eve out of his paradise the same way we can assume events pushed early humans out of the jungles of south and central africa where to overcome the suffering off the waste man uses his knowledge to improve the world around and give rise to civilization

its kind of hard to say something like this in print but any way the story of genesis is basically a simplicated version of evolution not to say there is no god