Question on evolution

Discussion Open Forum
1

No, it’s not that question. :unamused:

Its along different lines I think…

So I was having a debate tonight and I was trying to make a point, based on my own drunken logic…I’m still drunk now, and so its at least still making sense to me at this point. And by the way, only drunk people can contribute to this discussion as perhaps by the time I am sober again, it will otherwise seem entirely lonely and embarrassing…I digress…

So…evolution is a continuous process which never ceases, as far as I understand it to be described as. And if evolution never ceases and describes us, as a species as constantly evolving…Then when were we humans? When did we begin to become something else? Or did evolution pause for a moment to allow us to contemplate our position? And if the term humans can be a constant, then when did we become humans exactly and are we ever going to become something else? Aren’t we still fish at this point? I can still find webs, clearly visible between my fingers and toes.

Can someone confirm that I am indeed a human?

My point in tonight’s discussion was that perhaps evolution science, when referring to groupings, is not an exact science in itself as it can’t necessarily take all variables concerning a species into account. If it could, then evolution wouldn’t be happening. If evolution is happening as a constant, then surely group names cannot remain constant. Can they?

Perhaps someone has a reasonable explanation for this I’m hoping…

2

I’m on my second scotch, so I’ll take a stab.

I’ve read that Cro-magnon man were the first humans we would consider as such. If I remember Jared Diamond correctly he believes one could be taught to fly a plane. On the other hand if a Neanderthal walked down the street in a business suit a ruckus would ensue.

I believe his contention was that the Cro-magnon’s new ability of complex speech was what largely caused us to branch off from the other hominids, both instilling the desire in and enabling us to eventually exterminate them and leading us onto the path to corn whiskey, Shakespeare, and the internet.

All animals are constantly evolving.

3

So in this case, it was considered by at least one person to be the case that humans began after one ape descendant began grunting in a different manner to his or her other ape descendant friends, and then this new form of grunting, or sounding became a new fad, due to popularity, and then continued from there I guess. If that’s true, then what level of significant event would it take to now distinguish lets say a human from a thousand years ago to a human now? Is there any significant enough difference to warrant a new specification? Who measures significance exactly?

4

My point of view is that only beings in the future which look at us with retrospect will know what we truly are now, but those beings will not be able to correctly classify themselves as they too will be evolving, like we are. Evolution is only complete when a species becomes extinct, or else it can only be measured at a specific cross section in the past - a cross section of evolution. It is difficult to say where we are heading right now and what we will be in the distant future.

But for the purposes of convenience, humans are humans and life is classified through genealogy and linked through phylogenetic trees. Life is too short to nitpick over technicalities. Literally.

5

I gather biologists argue about this a lot, but in general, animals are the same species if they can produce fertile offspring. Horses and donkeys produce mules (infertile), so horses and donkeys aren’t the same species.

There’s no sharp line when one of our ancestors became a human, and her brother became a chimpanzee. Usually for speciation I think there needs to be some kind of separation, where the two populations can’t interbreed for a long enough time that their genomes become too distinct to produce viable offspring - but through much of that time interbreeding can occur. For example, the thousands of years of separation between native South Americans and Spanish invaders was nowhere near long enough for speciation to occur.

One example of how this gets weird (I think I read this in a Dawkins book somewhere): you’ve got a population of birds surrounding a central mountain, or perhaps a circular island chain - anyway, the distribution is circular. If you think of it as a clock, the birds at 12:00 can breed with the birds at 11:00 and 1:00, and the ones at 2:00, and maybe the ones at 3:00, but not the ones at 6:00; however, the 6:00 birds can breed with their neighbours, as can the 9:00 birds. The definition of species sort of breaks down here, because although the 12:00 and 6:00 can’t interbreed, in most other ways they seem to be the same species.

Another example is orca populations. Off the North American Pacific Coast there are two distinct populations, residents and, um, nonresident (they go up and down the coast). They don’t interbreed, and I gather some are now wondering if they should be considered separate species.

Also note that politics can come into this - the Victorian period tried to “rank” different races, with awful political results. I’m sure these days we have our own political biases that aren’t evident to us.

This sort of “one day a daughter was a human, but the mother was a monkey” point does occasionally show up in anti-evolution arguments, but to me that’s a bit like saying “You put dough in the oven, and now you have bread, but you can never point to one instant in time where it’s suddenly no longer dough and now bread, therefore God did it!”

Oh, to go back to confirming that you’re human: make a baby. Wait. Can that baby make a baby? That should do it.

(Yes yes, I’m aware that this leads to all kinds of semantic difficulties: is a eunuch human? Are two men, who for obvious reasons can’t produce offspring with each other, the same species?)

EDIT: Neil Shubin’s got a book called Your Inner Fish. In ways, yeah, we are still fish - a lot of our anatomy comes from our fish ancestors. We are bony vertebrates, just like fish (but not like sharks, right?).

6

[quote=“sulavaca”]
If that’s true, then what level of significant event would it take to now distinguish lets say a human from a thousand years ago to a human now? Is there any significant enough difference to warrant a new specification? Who measures significance exactly?[/quote]

It would just have to be something significantly different from our previous characteristics. For example, complex speech is significantly different from any other form of animal communication (and not grunting of any sort :slight_smile:) If some such change had happened, we would know, certainly much more acutely than any previous hominids. Such changes are happening now no doubt, but too slowly for us to perceive from our narrow time frame. Later generations will note the change once it is significant.

7

I guess, Sula, you might aught to be careful who you ask to confirm your humanity. Men are pigs, and all. I can’t help an inner giggle at a drunken male enlightened enough to need scientific proof of his own humanity!

Now, to play along a bit and stay on topic, there are both men and women who are born infertile. For whatever reason, they can’t make babies. Are they mules (and not just jackasses)? Their parents made a baby, but the baby can’t make another baby, right?

As for asking if humans 1000 years ago were still human, I think that’s much too brief a scale. I mean, that’s gotta be like, half an eye blink as far as this kind of thing goes, right?

8

Humans have been around for a very short time. If the history of the universe were condensed into one year, when did humans arrive on the scene? July 15th?? October 22nd?? Well, my friends the correct answer is that the first humans appeared about December 31st around 10:30 pm.

See the following link for details.

The history of the universe condensed into 1 year
longecity.org/forum/topic/11 … to-1-year/

9

Hang on a mo. We can’t be both pigs and dogs at the same time can we? :laughing:

So from what I can gather, there is never necessarily one singular time, or necessary change that must be so, in order for evolution to have created a new species and this may be open to interpretation. Is this the same as saying that by that reckoning that there can be no absolute specific thing as a ‘species’. My logic tells me this is the case. My logic seems to suggest to me that I may not necessarily be human, and some people suggest here that I may or may not be human, but in another few millennia it might be more apparent whether I was or not.
I guess its like looking at yourself in a mirror. You can only see yourself in the past. You can never visualise yourself in the present, although I understand thats a physics point and not a biology point. Still an interesting twist and similarity however. Is there a point to vanity mirrors and categories? What makes us strive to quantify ourselves, and is it important to do so?

The BBC on human evolution

10

[quote]Humans have been around for a very short time. If the history of the universe were condensed into one year, when did humans arrive on the scene? July 15th?? October 22nd?? Well, my friends the correct answer is that the first humans appeared about December 31st around 10:30 pm.
[/quote]

Aye. It is very surprising for how little time we have been present on this earth. It must getting on for 12:00am now. That’s New Year! Time to don the party hats and make some resolutions!

11

So, in an evolutionary hour and a half, we’ve gone from man 1 to man 7 billion. Impressive procreation!

12

So, in an evolutionary hour and a half, we’ve gone from man 1 to man 7 billion. Impressive procreation![/quote]

13

— some original contents temporarily not available —

… some recent research has complicated that picture further:

en.wikipedia.org/wiki/Larus#Ring_species

14

Take a pot of cold water, and put a flame under it. Eventually it comes to a boil. At what point does it start being “hot”? Or when climbing a mountain, at what point does the air start being “thin”? You could draw a line somewhere, but there really is no distinct boundary. Same with evolution, when dealing with the issue of at what point Homo sapiens began.

15

Antartic beech, you’ve evolved to somebody else!

Sulvaca, good questions. Species, genus etc are classifications that make broad sense but when we get down to the minutiae things can get pretty messy as has been well described here.

I guess the take home message is…we are all related and we should all cherish our brothers and sisters the animals and plants! Very karmic of me but it is absolutely true.

16

And this is just another example of a fundamental difficulty we humans tend to run into: we often forget that words are not reality but only parts of ta map of reality that we carry in our minds - our concepts are only approximations and convenient shortcuts, and it cannot be otherwise. In reality there is much more gradation and “grey” than we know of. :slight_smile: As someone carefully pointed out, being able to distinguish between two kinds of animals (“species”) by calling one “moneky” and another one “human” is something we can only do now, long after when the species started to diverge - at the beginning there would have been a simgle mutation that perhaps nobody would have noticed - it certainly would not have prevented fertile offspring, otherwise there would be no descendents to compare to anybody else. :wink: Apply that same reasoning to today’s human situation and you realize that we really should assume that among us humans alive today there are some individuals who, if their DNA could be analysed a few hundred thousand or million years later, would be recognized as the ancestors of two different species of post-human animals.

My guess and suggestion is this: If you are intellectually honest you will live without blocking/ banning this unanswered and unanswerable question. If not, you will take shelter in a cosmology that removes the shades of grey from the images of reality: there are enough to choose from that have a certain pedigree, and on top of that many people make up their own. :wink: If you haven’t had this questioning experience before but this is the first time, it might be the right time to say, “welcome to the world of philosophy”, but it’s probably not the first time and you already live in that world to some extent. :thumbsup:

If i may add a personal comment: the world of philosophy is a world full of wonders (i know that only because i’ve lived “there” most of my life :wink: ) - my model of reality consists only of questions (what looks like answers/ assertions are nothing more than convenient snapshots - frozen images pulled off to serve some specific purpose at a given moment), and i have found out that such a model means freedom (a few important aspects of that freedom are: the freedom to change, the freedom to be surprised, the freedom to learn, the freedom to play, the freedom to create/ invent).

17

Bugger! I knew it!
My wife’s gonna flip when she finds out I’m not human! :aiyo:

18

[quote=“sulavaca”]Bugger! I knew it!
My wife’s gonna flip when she finds out I’m not human! :aiyo:[/quote]
I PROMISE you, she already knew this looong ago!

19

In a way we already do. We ignore what we can’t utilize and eat what we can.

20

[quote=“headhonchoII”]
I guess the take home message is…we are all related and we should all cherish our brothers and sisters the animals and plants! Very karmic of me but it is absolutely true.[/quote]

The Endo-symbiotic theory is interesting in this regard (shared connections with all other life and such like). I am not sure if you have heard of it, but if you have not you may find it interesting. Well it was interesting to me anyways, as it was a 20 credit optional course that I chose to take. Others may find it boring, but I found it mind blowing at the time.

en.wikipedia.org/wiki/Endosymbiotic_theory

Very simply it discusses the origin of eukaryotic cells. Humans are comprised of eukaryotic cells whereas bacteria are Prokaryotic. How did eukaryotic cells evolve and why etc. The Endosymbiotic theory is the major theory to address it.

And on another related point

Often organisms survive and pass on their genes through symbiosis. In other words it is often organisms which have a symbiotic rather than predatory relationship with others that survive and pass on their genes.