Why aren't our evolutionary ancestors extinct?

[synthesizer-patel]

Further, I don't see how a positive mutation can spread through a population, since breeding with non mutated stock will eliminate it.

why would it eliminate it? Genes are passed on to progeny - if a mutated gene increases survival, and therefore increases the number of ofspring produced, a mutated gene would proliferate throughout subsequent generations.

It seems to me that such mutations could only affect a macro species when there are relatively few of them, ie, early on in their evolution.
In fact, thinking about it, I'm not even sure that that it is possible, since in the first generation the mutation would be largely eradicated.

Not sure how you jump to that conclusion - explain.

ps - what's a macro-species?

Shouldn't a scientific example of evolution be free of human action?

Evolution continues regardless of what it is in the environment that is causing the selective pressure - so an example of selection that has been induced by the changes humans have made to the environment has no fundamental difference to selection induced by say the environmental considtions resulting from say an asteroid strike, or an ice age.

However seeing as you ask for one - try this one for size:

http://www.sciforums.com/showthread.php?t=80923

 

[DeepThought]

why would it eliminate it? Genes are passed on to progeny - if a mutated gene increases survival, and therefore increases the number of ofspring produced, a mutated gene would proliferate throughout subsequent generations.

No it wouldn't, unless incest was the norm. Surely I don't have to tell a biology undergraduate that the offspring of a man and a woman is a blending of both their physical attributes, and not a carbon copy of one or the other.

Take the obvious example of skin color, a dark skinned person placed amongst light skinned people will produce offspring lighter than itself, successive breeding with light skinned people will eradicate the heavily melinated skin entirely. Or vice versa.

Unless the mutation occurs simultaneously, in more than one individual, it's a mathematical impossibility for it to proliferate.

However seeing as you ask for one - try this one for size:

http://www.sciforums.com/showthread.php?t=80923

What's the positive mutational adaptation? And where's the original fish in which this occurred?

This adds up to little more than 'we found a bunch of fish that look a lot like these other fish, but with slight differences, and there's a lot more of them than there used to be, lets use it as an example of evolution in action' (and try shut those Christians up?).

 

[synthesizer-patel]

No it wouldn't, unless incest was the norm. Surely I don't have to tell a biology undergraduate that the offspring of a man and a woman is a blending of both their physical attributes, and not a carbon copy of one or the other.

Indeed - but the GENE that gets passed on IS a carbon copy of the gene that comes from one of the parents - not an amalgam of the two genes.

If one parent has red hair and one parent has black hair, the child won't have chestnutty coloured hair - it'll either be red or black

What's the positive mutational adaptation? And where's the original fish in which this occurred?

The adaptation is the featherlike supra-ocular tentacles (the little tencales above the eyes) - the photo's illustrate it reasonably well, and gives an example of the original phenotype.

In terms of what is positive about it, the full version of the paper goes into some detail over possible explanations - I have the full version in PDF if you want it.
Suffice it to say that the increasing frequency of this particular phenotype indicates that there is something advantageous about it - the next thing to do is find out what that is - this is recent research after all.
(and if any funding bodies are reading this I have an excellent hypothesis and access to some very cool accelerometer technology that might prove it)

This adds up to little more than 'we found a bunch of fish that look a lot like these other fish, but with slight differences, and there's a lot more of them than there used to be, lets use it as an example of evolution in action' (and try shut those Christians up?).

Yes - becuase it fits exactly with the definition of evolution - namely "Changes in allele frequencies over time"

 

[synthesizer-patel]

Unless the mutation occurs simultaneously, in more than one individual, it's a mathematical impossibility for it to proliferate.

Fair enough - prove it's impossible mathematically then

 

[Enmos]

OK fair enough, but if we're descendant from apes why haven't apes become extinct? If all life came from the primordial soup, some of which I believe are living beside their evolutionary offspring, why would they need to evolve at all. Am I thinking evolution is a linear process and it's not here?

EmmZ, any intermediate state between species (which is human defined) is a viable life form. It does well within its own habitat.

Under environmental pressure the following things can happen:
- the genepool does not contain any (or too little) genes that will give any individuals a significant advantage in the current (but changing) environment.
The species will likely die out.
- the genepool does contain genes that will give some individuals a significant advantage in the current (but changing) environment. Frequency of these genes will rise in the genepool.
The species may evolve into another species.

Sometimes a group will get separated from the main group because of natural events, such as mountain ranges forming.
The weather on one side of the mountain might stay the same while it changes on the other side. Along with the weather the environment will change.
Eventually the separated group may evolve into a new species.

Key is that beneficial genes for the new environment must already exist within the genepool before it is selected upon by environmental pressures.

New species can also arise because of accidents.
For example:
A flood kills the larger part of a group of rabbits.
By pure chance a rare gene in the original genepool becomes now common, because precisely those rabbit with the rare gene survive by chance.

Any specific questions ?

 

[EmmZ]

Reading back on that question I asked, I see how I was confused about our common ancestors. It's often said we're descendant from apes, but in fact we're not genetic brothers, more genetic cousins. My original question has now been succinctly answered into a concise, "They are, or will be soon, evolution takes time". I think I was looking at species like Crocodiles who are commonly said to have been around since the dinosaurs, and thought if they'd genetically evolved into another sub species, or even a different species all together, why wouldn't the original croc species have died out (given that its environment forced an evolutionary change).

 

[Enmos]

Cool

 

[iceaura]

Surely I don't have to tell a biology undergraduate that the offspring of a man and a woman is a blending of both their physical attributes, and not a carbon copy of one or the other.

It could hardly be a "blending" - it's probably one sex or the other, just for starters.

 

[Enmos]

It could hardly be a "blending" - it's probably one sex or the other, just for starters.

And not only physical attributes.

The offspring of a man and a woman has a genotype that is a combination of half the mans genotype and half the womans genotype.
This results in a phenotype that shows characteristics shared with either parent and completely new characteristics.

 

[andbna]

DeepThought:

A beneficial mutation will usualy propogate: by breeding with non-mutated members, there is a 50/50 chance (in species which pass on half their chromosomes) that each offspring will have the improved gene. As most animals have several offspring at once, and have several 'batches', it is statisticaly probable that the gene is passed on to more individuals of the second generation.
Furthermore, every large species that I am aware of is attracted to the most fit individual, and hence, the individual with a beneficial mutation will have more opportunities to pass on its gene (sexual selection.)
Now, of the second generation of the gene, the children wit hthe beneficial gene have a better chance of surviving (you don't have to run faster than the predator, you only have to run faster than your buddy.) and hence, there will be less competiton when it comes to breeding for memebers carrying the beneficial gene, untill the point when (after many generations) the gene is common.

Shouldn't a scientific example of evolution be free of human action?

What human action? If it adapts to the environement it adapts to the environement; they aren't psychich to what caused the change.

In the case of bacteria and viruses, mutation would seem to be a necessary characteristic of the organisms survival, rather like our ability to run from predators using our legs, but no evolution seems to occur from this.

The fact that old phynotypes and genotypes are removed rapidly in this environement is irrelevant. If the new mutations are highly necesary for survival, then all the more obviouse the effect (and an obviouse proof is still a proof.) Evolution is this process (by definition), even if the exact speciation is hard to quantify in this instance.

Surely a positive adaptation in micro cellular organisms would see them conglomerating into larger organisms, rather than just changing their structure around, which is just as likely to change back?

Why? If it survives, it survives. You don't see many people recovering from AIDS now do you...
Remember your child proverbs? Bigger isnt always better?
And sure, ther may be just as likely to devolve, but, this is true for all species, however any that do usualy get picked off by natural selection pretty fast, and if they aren't, than they are loosing a now useless trait: like being born without an appendix or wisdom teeth.

Take the obvious example of skin color, a dark skinned person placed amongst light skinned people will produce offspring lighter than itself, successive breeding with light skinned people will eradicate the heavily melinated skin entirely. Or vice versa.

Remember that skin colour is controlled (in humans) by something like 6 genes, who's expression is incompletely dominant: this means that while the offspring will be lighter, it still has at least some of the genes to produce a dark offspring. It would then be up to natural (and possibly sexual) selection to favour darker offspring (if it did not, then the gene would not be called beneficial.) Hence, the lightest individuals with none of the mutated genes would be least likely to breed, and those with more, would be more likely.
That is: the allele would appear to be erradicated, but it would re-emerge after a few generations when those sporting it could interbreed (without it being incest.)

-Andrew

 

[one_raven]

It sounds like you are saying that we evolved so we can use tools but what you are doing is deviating from the natural world to the man made. Nature makes no concessions for or has no link to man made devices.

Concessions for manmade devices?
That makes no sense.
Nature has no specific goals or intentions for any species.
Nature is not some cognizant God.
Nature is simply the environment in which we live and those who are better at surviving in that environment will thrive.
Those who are not as good at surviving will not thrive.
It really is as simpl as that.

The point is that there was absolutely no reason for a physical change and the change was not even an advancement. If it was then show me where.

The fact that we are not only here but wildly successful is the only proof necessary.
Size is not everything - if it were, why did the dinosaurs die off and mice thrive?

If you have the ability to survive and prosper in your environment, you will.
If you do not, you can adapt, move or die.
We adapted through our intellect by creating tools, shelters and other "man-made devices" to aid our survival in any environment.
Neanderthal did not.

The irony of it is that we were smart enough to have created this layer above the nevironment in which we live, so we can survive anywhere, which makes us lazy, complacent and stupid, which will be our downfall.

 

[Nasor]

No it wouldn't, unless incest was the norm. Surely I don't have to tell a biology undergraduate that the offspring of a man and a woman is a blending of both their physical attributes, and not a carbon copy of one or the other.

Take the obvious example of skin color, a dark skinned person placed amongst light skinned people will produce offspring lighter than itself, successive breeding with light skinned people will eradicate the heavily melinated skin entirely. Or vice versa.

Unless the mutation occurs simultaneously, in more than one individual, it's a mathematical impossibility for it to proliferate.

Do you really not understand the idea of a dominant genetic trait? If so, your country’s education systen has failed you badly.

 

[John99]

We adapted through our intellect by creating tools, shelters and other "man-made devices" to aid our survival in any environment.
Neanderthal did not.

The irony of it is that we were smart enough to have created this layer above the nevironment in which we live, so we can survive anywhere, which makes us lazy, complacent and stupid, which will be our downfall.

But whatever tools we use to aid our survival or make things easier are not necessary for survival and Neanderthals from what we assume to know about them could have easily survived and thrived just as they were. You are assuming that for some reason evolution wanted to create a species to use shovels, rifles and build elaborate shelters. That is just comical.

Now you give me compelling evidence that humans NEEDED to evolve from whatever they supposedly were before. Do you honestly think a brain can evolve to something more sophisticated because of a natural obstacle or because the organism needs to sit its ass on a couch somewhere? Sounds like BS to me.

We hear about organisms evolving because of need or adaptation, well then you tell me what the need for humans to evolve from whatever you think they were before was. The logical and obvious answer to me is that there was none. Sorry Charlie.

 

[one_raven]

But whatever tools we use to aid our survival or make things easier are not necessary for survival and Neanderthals from what we assume to know about them could have easily survived and thrived just as they were.

They quite obviously could not have or they would have.

You are assuming that for some reason evolution wanted to create a species to use shovels, rifles and build elaborate shelters.

That is just ludicrous and very clearly shows you complete misunderstanding of the very core of what evolution is.
You, as usual, come half cocked with a seriously flawed understanding of that which you argue so vehemently against.
Evoltuion doesn't "want" anything.
Evolution does not have some kind of end goal in sight and forces species to change to fit that mold.
Evolution does not DO anything.

WE adapt to our surroundings or we do not.
It is really as simple as that.
When our surroundings change - such as climate change, for one example, the species that can survive in the new environment will, those who can not will either relocate or die.
Our greatest strengths are our intellect and community, which allow us to build shelters in any environment.
The biggest difference between us an the other animals is that we can dramatically alter our environment on a rapid and wide scale.
This is why we have been as successful as we are now.
Evolution did not intend anything for us, because evolution does not have any intentions.
We learned to adapt to our environment, and perhaps more importantly, we learned to adapt our environement to us.

Neanderthal was quite obviously not as successful.
By the way, another flaw in your understanding seems to be the belief that we evolved from Neanderthal - we did not.
It was a distinct species.

Now you give me compelling evidence that humans NEEDED to evolve from whatever they supposedly were before.

There isn't any, you moron.
We did not NEED to do anything.
Either we would have adapted, or we would have died.

Do you honestly think a brain can evolve to something more sophisticated because of a natural obstacle or because the organism needs to sit its ass on a couch somewhere? Sounds like BS to me.

You seem to have a similar ego-centric view that puts the cart before the horse.
We did not evolve with this being the end-goal.
The world was not created for us.
There was no grand plan or direction.
This is how we happened to evolved, given the restraints, opportunities and nature of the world we lived in and how all the other species happend to evolve as well.

 

[John99]

WE adapt to our surroundings or we do not.
It is really as simple as that.
When our surroundings change - such as climate change, for one example, the species that can survive in the new environment will, those who can not will either relocate or die.
Our greatest strengths are our intellect and community, which allow us to build shelters in any environment.

And you are very wrong about that. What you are displaying is typical narcissist security blanket that nature needs humans, wants humans and that humans are the ideal. Well maybe to other humans they are but nature does not care one way or another.

When our surroundings change - such as climate change, for one example, the species that can survive in the new environment will, those who can not will either relocate or die.

There isn't any, you moron.mad
We did not NEED to do anything.
Either we would have adapted, or we would have die

That is complete BS. I asked you to give me even the simplest guess as to why we needed to adapt or DIE OUT and you cannot give one. Why? Because there is none.

If you take a body of water and introduce a natural toxin to that water then the only things to survive are those that can...for whatever reason those organisms have the ability to survive BUT one species does not morph into another to survive because life DOES NOT WORK THAT WAY. And just as this thread began- we see EXTINCTION all the time- with no replacement and NOTHING to fill in the gap. Gone forEVER.

 

[one_raven]

And you are very wrong about that. What you are displaying is typical narcissist security blanket that nature needs humans, wants humans and that humans are the ideal. Well maybe to other humans they are but nature does not care one way or another.

You couldn't possibly be more wrong.
Humans are certainly not ideal.
We have been successful, but it has been a relatively short time.
All I said is that we have been more successful than Neanderthal has been, and the proof is that we are hee and they are not.

If you think I was saying that nature needs humans somehow, you are even more dense than I had thought.
I was saying precicely the opposite.
How could you possibly get that nature needs humans from anything I said?
We easily could have died, just as countless other species have died.
Idiot.

That is complete BS. I asked you to give me even the simplest guess as to why we needed to adapt or DIE OUT and you cannot give one. Why? Because there is none.

No you didn't.
Go back and read what you said, jackass.
You asked for "compelling evidence that humans NEEDED to evolve from whatever they supposedly were before."
This is quite different from what you just said.
And I answered that question already.
I said there isn't any.

If I stripped you naked and dropped you off at the South Pole you will either A.) Adapt (very quickly find food and find or build shelter)
B.) Find a way out of there.
or
C.) Die.

You have no other options.
Neanderthal died, we adapted.

Tell me, genius, why did Neanderthal die out if it was so wonderfully fit to survive?

If you take a body of water and introduce a natural toxin to that water then the only things to survive are those that can...for whatever reason those organisms have the ability to survive BUT one species does not morph into another to survive because life DOES NOT WORK THAT WAY.

I never said it did, neither did anyone who has even the faintest understanding of evolution.

All you are proving in this argument is that you are ignorant of the precepts of the theory of evolution.

 

[John99]

If I stripped you naked and dropped you off at the South Pole you will either A.) Adapt (very quickly find food and find or build shelter)
B.) Find a way out of there.
or
C.) Die.

Now you are finally beginning to understand...

But you still do not see how foolish you are? Your proving my point. Otherwise you would believe that humans would grow fur or some other means to survive. How about if most of all the good food was high up in trees would humans (if they could not figure out another way) start flying? Would they, over time, grow wings? Fairy tale!

You OneRaven are a fundamentalist. Now go read up on you flying spaghetti monster or offer up some proof.

 

[Myles]

John,

You are very confused. You ask why we needed to adapt. Answer: Environmental pressure. I get the impression that you think every member of a species adapts, which is why you cannot see a reason. Some members adapt, others go extinct. The survivors have an advantage which the others do not. For an easy introduction to what is going on, read up on Mendel's experiments with peas and having done so, imagine that one type is better adapted to a change in its surroundings. That's the one that will survive. Bear in mind that we are talking about many generations before one form becomes firmly established.

Mendel will explain genetics and from that point on you will find it easier to understand evolution which is. of course. a different issue/

 

[one_raven]

Now you are finally beginning to understand...

But you still do not see how foolish you are? Your proving my point. Otherwise you would believe that humans would grow fur or some other means to survive. How about if most of all the good food was high up in trees would humans (if they could not figure out another way) start flying? Would they, over time, grow wings? Fairy tale!

You OneRaven are a fundamentalist. Now go read up on you flying spaghetti monster or offer up some proof.

As I said, learn something about the theory of evolution.
It does not state that food being high in trees will cause a species to evolve so it can reach it.
It states that those animals which have evolved the ability to reach said fruit are more likely to survive.

In other words, you will not grow tall to reach the fruit, the tall ones that can reach the fruit are more fit to survive in that specific environment.

I am not saying that Darwin was 100% correct - in fact I am pretty sure he wasn't.
What I am saying is until you learn something about evolution, arguing about it simply makes you look like an ass.

 

[John99]

You ask why we needed to adapt. Answer: Environmental pressure.

This stems from creatures supposedly leaving the water to go onto land because for some reason living in water no longer suited them. Of course there are still creatures who live quite happily on land and water.

Be that as it may:

Myles, what did humans evolve from?