Evolution: Is it Real? Answers from Biologists

[Nenad]

can you bio pple help me. My brother and I were having a discussion, and we cannot resolve weather the humans and species in the world today actually evolved from other beings. I believe that the other species did, but I do not believe that for humans. Any help would be great.

 

[Monique]

So why is it that other species could have evolved from other beings, but humans couldn't have?
https://www.physicsforums.com/insights/what-is-evolution-a-beginners-guide/

 

[Gokul43201]

There is absolutely no doubt (among the scientific community) that humans evolved from apes.

Monique, you know that's a moot question. Clearly there is a religious opposition to the idea of evolution of man, since "man was made in the image of God", and so, is special. Other creatures are not so special.

 

[GoneRogue]

There is absolutely no doubt (among the scientific community) that humans evolved from apes.

Monique, you know that's a moot question. Clearly there is a religious opposition to the idea of evolution of man, since "man was made in the image of God", and so, is special. Other creatures are not so special.

Let me rephrase that right quick... "There is absolutely no doubt (among the scientific community) that humans and apes evolved from a common ancestor."

 

[Phobos]

Hi Nenad
There is a mountain of scientific evidence supporting the evolution of life on Earth, including humans. If you have a specific question, we could probably discuss that in detail, but otherwise your question so far is very broad and you'll probably need to do some reading.

You could start here which describes several likely ancestral species of modern humans...
http://www.talkorigins.org/faqs/homs/species.html
The link also provides examples of fossils from these species and you can see the shift in anatomy over time.

Also note that we can directly observe small-scale evolution in many species.
Larger degrees of evolution are evident over recorded history (e.g., agriculture).
Even larger scales of evolution (which go beyond our recorded history) are evident from fossil evidence, genetic evidence, etc.

There is a lot of information about it, so be prepared to study. Also watch out for the multitude of websites that argue against evolution. Their arguments may seem to make sense at first (not always) but they don't stand up when you actually check them against the scientific data.

 

[Monique]

Monique, you know that's a moot question.

Moot questions are asked to start discussions, right?

As Phobos said, we need to know what Nenad is thinking in order to debate it.

 

[Phobos]

Moot questions are asked to start discussions, right?

There goes another one!

 

[wasteofo2]

Let me rephrase that right quick... "There is absolutely no doubt (among the scientific community) that humans and apes evolved from a common ancestor."

Show me something that suggests humans didn't come from apes please. As far as I know, there were already apes around when humans evolved, and we came from a sort of tree-dwelling ape, simmilar to a Chimpanzee, which was forced onto the grasslands, needed to stand up to see over the grass etc.

 

[CyrusMcC]

Clearly Evolution is just a THEORY. It has not, and cannot be proven to be FACT. What does it matter where humans and other life forms came from they are here, and so are you. As for me and my beliefs, I'm Christian, and I believe that GOD created everything. But again that's my belief. You are always free to believe that evolution is responsible for the life here on Earth. We may never fully understand and know the origin of life on Earth. I do find it strangely uncanny how apes and humans favor each other, but that isn't credible evidence to support that we derived from the same "common ancestor." Yes, I also know that they say that we share some 98% of DNA contents with chimpanzees, but that too, means nothing. DNA is just molecule made up universal components. Science is a tough thing to swallow down. But it is mainly built on rationalizing ideas in our own human intellectual capacity. Something I believe is quite limited at the moment. As far as what is truth or not, we may never know it. It is up to the individual to accept evolution as truth or THEORY. Yes, evolution is a "real" good THEORY!

 

[iansmith]

CyrusMC how do you define theory?

In science theory is define as a well-substantiated explanation of some aspect of the natural world; an organized system of accepted knowledge that applies in a variety of circumstances to explain a specific set of phenomena; "theories can incorporate facts and laws and tested hypotheses"; "true in fact and theory".

Evolution has been tested and pass. It is true.

Also do not confuse evolution and abiogenesis. Evolution is a theory that explain how life is today, abiogenesis is a hypothesis that tries to explain how life arise.

 

[0TheSwerve0]

The most common error in all of these debates is thinking that evolution is a theory. It is a fact that evolution occured. We can clearly see, in the fossil record, that the first life found was prokaryotic. Gradually we see the emergence of single-celled eukaryotes, then multicellular eukaryotes. Then we see aquatic plants and animals arise, and eventually terrestrial plants and animals. Soon enough, we see the recognizable large mammals, reptiles, and birds that we are all so familiar with.

The only theory involved is the attempt to explain how evolution occured. Clearly natural selection played a role. Clearly point mutations, mostly due to random replication errors, played a role. Recombination, genetic drift, bottlenecking, and symbiosis (particularly in unicellular life) played a role. Sometimes evolution seems to have occurred at a fairly steady, gradual pace. Sometimes it seems to have occurred in fits and spurts, marked by long periods of stasis. These are the "theories" of evolution, and they are among the most well-tested and verified of all theories in any of the sciences. The only real questions remaining regard tempo, taxonomic relationships, and the evolution of social and sexual behavior. If you want to question the hypotheses that attempt to answer these questions, be my guest. That is the only real debate.

 

[Phobos]

Show me something that suggests humans didn't come from apes please. As far as I know, there were already apes around when humans evolved, and we came from a sort of tree-dwelling ape, simmilar to a Chimpanzee, which was forced onto the grasslands, needed to stand up to see over the grass etc.

I assume GoneRogue meant to say "modern apes".

 

[Mentat]

Show me something that suggests humans didn't come from apes please. As far as I know, there were already apes around when humans evolved, and we came from a sort of tree-dwelling ape, simmilar to a Chimpanzee, which was forced onto the grasslands, needed to stand up to see over the grass etc.

Actually, wasteofo2, it's something of a moot distinction. We didn't evolve from apes, we are apes. If you're asking what suggests that we didn't evolve from other apes, that's fine. But, by every definition of the word "ape", we fit in quite snugly.

 

[Phobos]

Clearly Evolution is just a THEORY.

Just want to re-emphasize the importance of what iansmith and 0TheSwerve0 said. A scientific theory has a different connotation than the layman's use of the term. A scientific theory is an explanatory model that fits the facts. It's a fact that evolution happens (we can directly observe this) and the theory tries to explain how it happens and what the history of it has been.

It seems to be the history part that you are questioning. Which is fine. Consider the evidences and choose your belief. (If you want to pick linguistic nits, scientists don't "believe" in evolution like a religion or a gut instinct, they "accept" it as an explanation to fit the evidence.) But simply dismissing evolution offhand as "just a theory" is a poor argument because, not only is it incorrect, but it ignores the evidences "a priori".

What does it matter where humans and other life forms came from they are here, and so are you.

I'm not going to touch that one right now.

As for me and my beliefs, I'm Christian, and I believe that GOD created everything. But again that's my belief.

And many Christians accept the theory of evolution. (often a "theistic evolution" where God directs it all)

For Christians who believe that nothing ever evolved and that the Earth is "young", then they have a lot of explaining to do because that goes against many independent lines of evidence from many branches of science.

We may never fully understand and know the origin of life on Earth.

We can all probably agree on that!

I do find it strangely uncanny how apes and humans favor each other, but that isn't credible evidence to support that we derived from the same "common ancestor." Yes, I also know that they say that we share some 98% of DNA contents with chimpanzees, but that too, means nothing.

It's one line of evidence. Now overlay that with the physical changes seen in the fossil record (not only anatomically but also in geographic and temporal distribution). And overlay that with genetic similarities over several species and see that the closer the relation (say, in anatomy & time), the closer the genetic similarity. And follow the genetic markers along certain lineages. Etc.

Science is a tough thing to swallow down. But it is mainly built on rationalizing ideas in our own human intellectual capacity.

Which is why scientific ideas are based on evidence (observational, physical, experimental) that is peer reviewed & confirmed by others rather than just opinions or beliefs. The name "theory" is used as a reminder that the work is always in progress. There's always more evidence to gather & details to work out. And yes, theories can be replaced if a better one is found.

 

[Mentat]

And yes, theories can be replaced if a better one is found.

If you'll forgive my adding one more point to an excellent post, Phobos...even if there were something desparately, scientifically wrong with a current evolutionary theory (which there's not; at least, not to my knowledge), that wouldn't mean that we could just discard it. We could try to refine it, or we could try to find (as Phobos called it) "a better one", but a "better one" would have to be one that explained all the innumerable phenomena that current evolutionary theories explain, and do so just as well (or better than) those theories, without falling into the same mistake into which the replacee fell (or into another, different pit-fall), and it should have equal or less premises/assumptions (Occam's Razor).

So, I don't think we're getting rid of evolution anytime soon.

 

[russ_watters]

Clearly Evolution is just a THEORY. [emphasis added]

Several problems with this (rehash):

-"just a theory" is a classic attempt to show weakness in the theory being discussed, but saying it just makes it readily apparent that you don't understand what a theory is.

-Evolution is more than just a theory. Its data. It is directly observed to occur. Where the theory comes in is figuring out how it hapens and what the implications are of the observed evolution.

As for me and my beliefs, I'm Christian, and I believe that GOD created everything.

Me too. And to me, that's utterly irrelevant to this discussion. If what you mean is you read the bible literally, then that's a different issue. The biblical creation story if read literally is factually inaccurate.

 

[jcsd]

A theory may or may not have data to back it up, a theory may or may not be accepted by scientists. Evolution has mountains of data to back it up and is universally accepted by scientists, so, as well as just being a theory, it is just a theory that we can be certain (as certain as we can be of anything of course) is true.

 

[wasteofo2]

Actually, wasteofo2, it's something of a moot distinction. We didn't evolve from apes, we are apes. If you're asking what suggests that we didn't evolve from other apes, that's fine. But, by every definition of the word "ape", we fit in quite snugly.

Yeah, I meant other apes.

 

[kcballer21]

To add to the "Just a Theory" refutation, I once read a memorable response to that same argument: Yes, evolution is just a theory, but it is also just a theory that the Earth orbits the sun.

If you are going to dismiss evolution as just a theory to be believed or not on a matter of faith, then science in general must become faith based. But of course science offers us a little more than faith.

 

[CyrusMcC]

There is no proof that Humans and Apes "evolved" from a common ancestor. We weren't there to see it! I never said it didn't happen. I said it was “just a Theory,” and that people can choose to believe it, which is the same thing as accepting it, or not. That's all I'm saying. I just want the person to know that. Yes, I can see how it works. There are plenty of good examples of how evolution works. But why do we call it evolution? Why couldn't it have been some other process that controlled life on earth? We call this stuff what we can relate it to. That doesn't mean that's how it goes.


My definition of a theory: is a plausible or scientifically acceptable general principle or body of principles offered to explain phenomena. Now, who says this principle is correct. It may make sense. But it doesn't mean that's what happens. And since when did humans become all knowing, to where everything a group of humans decided was fact became fact. Unless we can go back and actually see that single celled organism, and watch it evolve into millions of different species, until then I say it's just a theory. Just like "the Earth revolving around the sun."

How can you mock me iansmith "Evolution is a theory that explain how life is today” When I said "Evolution is just a THEORY." Um, I think someone is mixed-up here?
As for as I know you cannot disagree with me when I say that evolution is a theory. Also theories can never be proven true or false. Every science professor in my college career has told me that. Since when did that concept change? That’s all my argument is stating. Now, unless you are saying that evolution is more than just a theory let me know. Otherwise, it's just a Theory that attempts to “explain how life is today,” but that does not necessarily mean that's how it is. Even though that's what we see and think is happening here on Earth. That's not enough to validate a theory that cannot be proven true.

 

[selfAdjoint]

Your problem is that you think "Just a theory" is a criticism or that it removes the threat evolution poses to those who want to keep their fundamentalist ideas. But theory is what every statement of science is. That the Earth is round is a theory. It has certain good evidence for it. So does evolution.

Even creationists acknowledge that bacteria evolve, and apparently according to variation and natural selection. This can be demonstrated in the laboratory; by changing the environment the scientists can make the bacteria evolve this way and that way. Speciation in nature has also been observed.

It's ridiculous to deny that natural hereditary variation exists; look around you. And natural selection is a mechanism so simple it doesn't seem to be questionable. Some individuals are better equipped to leave descendents than others. So these things exist, and where they exist, how can evolution be prevented?

 

[iansmith]

How can you mock me iansmith "Evolution is a theory that explain how life is today” When I said "Evolution is just a THEORY." Um, I think someone is mixed-up here? As for as I know you cannot disagree with me when I say that evolution is a theory.

I am not mocking you. What we disagree on is the semantic. To rephrase Phobo, theory in science is more than just "a plausible or scientifically acceptable general principle or body of principles offered to explain phenomena". It this something has been tested and pass virtually everytime the test of the natural world.

From what your saying, you feel that evolution is a hypothesis rather than a theory. In scientific jargon, an hypothesis is a concept that is not yet verified but that if true would explain certain facts or phenomena. Also you seen to have problem with the abiogenesis hypothesis. Do not confuse evolution and abiogenesis, it is two different things. Abiogenesis is a hypothetical organic phenomenon by which living organisms are created from nonliving matter. Evolution is a theory explaning the change of the genes of a population over time, which may or may not resulting in new species.

 

[Nereid]

'gravity': fact "apples fall" (for example)
'theory of gravity': Newton, Einstein etc (BTW, the latter is a very good theory, in the sense that there are no good experimental/observational results which are inconsistent with the theory)

'evolution': fact "antibiotic resistance" (for example)
'theory of evolution': Darwin, Gould, etc (also very good theories).

"Just" a theory: none-too-subtle attempt to equate a highly successful theory with a religious-based idea which is inconsistent with experiments/observations, almost across the board.

 

[shonagon53]

In Europe, "creationism" is taught in cultural anthropology classes, as a case showing how an entire culture (70% of Americans) can both be materialistically prosperous and culturally poor at the same time ("how is it possible that a materially wealthy culture, can hold such bizarre 19th century beliefs?").

America's majority belief in creationism is a very interesting fact for cultural anthropologists, historians and scientists in general.

 

[Gokul43201]

Unless we can go back and actually see that single celled organism, and watch it evolve into millions of different species, until then I say it's just a theory. Just like "the Earth revolving around the sun."

You are right in that the Theory of Evolution has as almost much data backing it as the "earth revolving around the sun" theory. That you doubt that latter statement only suggests to me that you have no understanding of science or the scientific approach.

I'm amazed to come across people who can go about their daily lives in complete disbelief of the accepted results of science.

 

[aychamo]

You are right in that the Theory of Evolution has as almost much data backing it as the "earth revolving around the sun" theory. That you doubt that latter statement only suggests to me that you have no understanding of science or the scientific approach.

I'm amazed to come across people who can go about their daily lives in complete disbelief of the accepted results of science.

Those people amaze you? They downright scare me! I'm a weak atheist (meaning I look at the evidence one puts forth in support of their god claim and I conclude that their evidence is not substantial enough to convince me of their claim, therefore I am without belief in their god claim), and one day I was riding in my vehicle with my girlfriend, and she pointed out someone's emblem on their car. It was a Jesus fish eating a Darwin fish. People who act like that, who think their faith in god is more correct than proven scientific data really scare me.

People who turn a blind eye to fact and believe in 2,000 year old superstitions scare the hell out of me :-)

 

[loseyourname]

All right, Cyrus, clearly you accept that evolution occurs. No one can deny that. As selfAdjoint pointed out, we can observe evolution both in the lab and in nature. What we cannot observe is evolution that occurred in the past. But consider this: there are three ways that I can come up with to explain the fossil record.

1. Older species evolved into newer species. How they evolved does not matter. Perhaps it was random, perhaps it was directed by some intelligent force. Either way, they evolved.

2. Each species was individually created from scratch.

3. The entire planet was created in such a way as to make it appear that evolution took place when it fact it did not. In effect, God simply planted the fossils where they are and placed a certain ratio of radioisotope:daughter element in the surrounding rock to fool us.

Let's evaluate these options. Number 2 has a slight problem. We have observed speciation take place, both in the lab and in nature. We have seen one species become two, through nothing more than natural processes. Given that this is the case, we can at least that these species we have observed coming into existence were not created. Given this fact, scientific induction dictates that this is the method by which all species come into existence.

It may be true that inductive reasoning does not produce absolute certainty. We are moving from the specific to the general here, but that is the way science works. We have measured the force of gravity so many times and every time it can be expressed by the equation $F = G \frac{m_1 m_2}{r^2}$, so we induce that this equation will always hold under the circumstances in which it was derived. It's the same way with evolution. We observe it happening on this planet, operating according to a principle of environmental pressures selecting for certain allele frequencies within a given population. We observe new species coming into existence by this process, so we conclude that all species on this planet, which possesses the same variability for the same reasons and which face the same environmental pressures, come into existence naturally through a process of evolution. If you will not believe this, then in order to be consistent, you must reject all scientific theories, all of the conclusions come to on the basis of independent verification by many researchers working in many labs, including all of the equations of physics. You can't even believe that gravity will continue to hold you to this planet. The simple fact that it always has is not proof enough that it always will if you do not accept the principle of scientific induction.

Now let's look at number 3. If you believe this, I have nothing to say to you. This hypothesis is neither falsifiable nor verifiable, even in principle. It is factually meaningless.

Then we have number 1. Countless lines of evidence in countless fields of research all point to this one conclusion. All of the modern principles of the biological sciences are built on the fact that organisms evolve by the mechanism of natural selection.

Which explanation would you accept, Cyrus? Which do you think any reasonable, sane person would accept?

 

[Mentat]

Yeah, I meant other apes.

My point, when I bring that up, is that many people tend to think that humans are "above the animals" and thus immediately dismiss the concept of their having evolved from other animals, because that would make them just another part of nature. The fact that we are apes is meant to direct attention away from our supposed "superiority", so that it's no longer like saying that gods evolved from animals, but that animals evolved from a common ancestor of other, very similar, animals.

 

[O Great One]

Nenad,
Evolution is a fairy tale and everybody posting on this board knows it. It is the one theory that is accepted by scientists that has no support. Notice how everybody says that evolution is a 'fact' supported by mountains of evidence. This is what you say when you have no support.

 

[loseyourname]

So how would you answer this, O Great One? Or do you have another suggestion?

All right, Cyrus, clearly you accept that evolution occurs. No one can deny that. As selfAdjoint pointed out, we can observe evolution both in the lab and in nature. What we cannot observe is evolution that occurred in the past. But consider this: there are three ways that I can come up with to explain the fossil record.

1. Older species evolved into newer species. How they evolved does not matter. Perhaps it was random, perhaps it was directed by some intelligent force. Either way, they evolved.

2. Each species was individually created from scratch.

3. The entire planet was created in such a way as to make it appear that evolution took place when it fact it did not. In effect, God simply planted the fossils where they are and placed a certain ratio of radioisotope:daughter element in the surrounding rock to fool us.

Let's evaluate these options. Number 2 has a slight problem. We have observed speciation take place, both in the lab and in nature. We have seen one species become two, through nothing more than natural processes. Given that this is the case, we can at least that these species we have observed coming into existence were not created. Given this fact, scientific induction dictates that this is the method by which all species come into existence.

It may be true that inductive reasoning does not produce absolute certainty. We are moving from the specific to the general here, but that is the way science works. We have measured the force of gravity so many times and every time it can be expressed by the equation $F = G \frac{m_1 m_2}{r^2}$, so we induce that this equation will always hold under the circumstances in which it was derived. It's the same way with evolution. We observe it happening on this planet, operating according to a principle of environmental pressures selecting for certain allele frequencies within a given population. We observe new species coming into existence by this process, so we conclude that all species on this planet, which possesses the same variability for the same reasons and which face the same environmental pressures, come into existence naturally through a process of evolution. If you will not believe this, then in order to be consistent, you must reject all scientific theories, all of the conclusions come to on the basis of independent verification by many researchers working in many labs, including all of the equations of physics. You can't even believe that gravity will continue to hold you to this planet. The simple fact that it always has is not proof enough that it always will if you do not accept the principle of scientific induction.

Now let's look at number 3. If you believe this, I have nothing to say to you. This hypothesis is neither falsifiable nor verifiable, even in principle. It is factually meaningless.

Then we have number 1. Countless lines of evidence in countless fields of research all point to this one conclusion. All of the modern principles of the biological sciences are built on the fact that organisms evolve by the mechanism of natural selection.

Which explanation would you accept, Cyrus? Which do you think any reasonable, sane person would accept?

 

[O Great One]

We have observed speciation take place, both in the lab and in nature. We have seen one species become two, through nothing more than natural processes. Given that this is the case, we can at least that these species we have observed coming into existence were not created. Given this fact, scientific induction dictates that this is the method by which all species come into existence.

When we observe speciation, it is the result of duplication of genetic information or the shuffling of information that is already there. Therefore, scientific induction dictates that this isn't the method by which all species come into existence.

 

[loseyourname]

Wait a second. Explain this a little better. Because we have observed new species come into existence through wholly natural processes, scientific induction dictates that the rest were created? There's a middle step or two in this argument that you aren't revealing. What is it?

 

[spuriousmonkey]

'gravity': fact "apples fall" (for example)
'theory of gravity': Newton, Einstein etc (BTW, the latter is a very good theory, in the sense that there are no good experimental/observational results which are inconsistent with the theory)

This is not really a criticism, but merely a remark:
I'm not a physicist, but isn't the current idea that gravity actually doesn't exist, but is just a result of curvature of spacetime? Gravity is therefore not a fact, but a theory, and in this case a wrong theory. That the apple falls is also not a fact, but an observation in my opinion.

See it is not easy to talk about facts. Because facts could well not be facts at all, although they might seem so.

I found this link quite useful on the matter of proof:

http://evolution.berkeley.edu/evosite/footshooting/Iterminology.shtml

 

[spuriousmonkey]

Nenad,
Evolution is a fairy tale and everybody posting on this board knows it. It is the one theory that is accepted by scientists that has no support. Notice how everybody says that evolution is a 'fact' supported by mountains of evidence. This is what you say when you have no support.

Fossil record
homology
genetic relationships between species
observed speciation events
etc
etc

what do you mean by no support?

Did you know that there is not a single creationist paper in a peer reviewed scientific journal? Do you know why? (the answer is not: conspiracy)

 

[Mentat]

This is not really a criticism, but merely a remark:
I'm not a physicist, but isn't the current idea that gravity actually doesn't exist, but is just a result of curvature of spacetime? Gravity is therefore not a fact, but a theory, and in this case a wrong theory. That the apple falls is also not a fact, but an observation in my opinion.

I hope I don't side-track the thread, but I felt it right to clarify some points here:

1) Gravity is the apparent attraction between objects. Spacetime curvature is an explanation for what causes this apparent attraction.

2) That is the role of theories vs. facts. The fact is that there is an apparent attraction between objects. The theory is what explains the cause of this attraction (i.e. how it works). The fact is that there is a variety of life today, and there wasn't always. The theory is what explains why this is the case (again, how it works).

See it is not easy to talk about facts. Because facts could well not be facts at all, although they might seem so.

3) Facts are always facts, but sometimes we might take things for fact that are not actually fact...that's why it's such a good thing that science doesn't deal much in facts ("fact" having the scientific definition of a readily observable phenomenon that is beyond reasonable doubt), but in theories ("theory" having the scientific definition of an explanation of a "fact").