Evolution

[Noah]

I believe that the evolutionary theory is the most "logical" theory for how life formed, but I was thinking about something a minute ago. The answer to this may be common knowledge, but I just haven't study into the specifics a whole lot.

 

Ok, if humans evolved from apes, why is it that nowadays there are still apes, there are humans, but not any creatures in a stage between "ape and man"?

 

[Tormod]

In my eyes we are past the time where evolution is merely a "theory", by which I mean that there is so much evidence for both spontaneous and long-term evolution that evolution can safely be regarded as something that actually happens.

 

Now that does not mean that all the differing theories _about_ evolution are correct. For example, the debate is still on whether birds actually descended from dinosaurs or not. There is also much debate about how the cambrian explosion came about and many other things.

 

As for whether human beings descended from apes - for a long time there was talk (well, I guess there still is) about a so-called "missing link" which would finally prove that humans descended from apes. One way to go about this is to draw a "family tree" (more like a bush, though) and try to trace the lines back to commmon ancestors for both apes and man. It all boils down to a genetics debate and also how "lucky" we are when it comes to digging up old bones...

 

Here is one article about this:

Genetics may help solve mysteries of human evolution

 

The web is full of good sources on evolution, here is one place to start:

Evolution links at U of Toronto

 

Tormod

[deamonstar]

man did not evolve FROM apes, so there is no "missing link". primates and humans are evovled from a common ancestor.

[Tormod]

good point, deamonstar...I think that was my point as well.

[Daisy]

I have several questions about evolution:

 

1. Why don't we see it happening now - whether it be spontaneous or longterm evolution, it appears to no longer take place (at least we cannot observe it happening now). There have been no significant physical changes in humans or animals in thousands of years. Why does the evolutionary process just seem to stop?

 

2. Have there been any experiments conducted to see if scientists can force an evolutionary change in a plant or animal - what I mean by evolutionary change is not simply changing a solid colored cow into a spotted one but change one species into another. I realize that some evolutionary changes take many many years but some are spontaneous and could realistically be done in an experiment.

 

3. Why is it that no other species has human intelligence (but humans).

 

 

 

4.

[Tormod]

1) On what basis can you say that we do not observe evolution taking place in humans any more? I assume from your question that you think it has happened before?

 

2) Ever heard of banana flies?

 

3) Why do humans have tail bones if we don't have tails?

 

I would even add some questions to your list: why do only human beings pose a threat to the environment of the Earth if we're bestowed with this incredible intelligence? Why didn't we pose this threat 2,000 years ago (a blink of an eye in cosmic history)? Or did we? Could the explosive expansion of human culture be seen as evolutionary? Is a human being of 2,000 AD for all practical purposes the same creature as a human being of 10,000 BC?

 

Tormod

[Daisy]

[

1) On what basis can you say that we do not observe evolution taking place in humans any more? I assume from your question that you think it has happened before?

 

-It does not appear that evolutionary changes have taken place in humans for some time - Yes humans have undergone some physical changes over the last 5000 years but I would not consider those changes to be evolutionary. For example humans are taller today than in the past but that can be explained by diet.

 

How do you define evolution? My understanding is that evolution invovles the addition of new genes to someone's genetic makeup.

 

I would even add some questions to your list: why do only human beings pose a threat to the environment of the Earth if we're bestowed with this incredible intelligence? Why didn't we pose this threat 2,000 years ago (a blink of an eye in cosmic history)? Or did we? Could the explosive expansion of human culture be seen as evolutionary? Is a human being of 2,000 AD for all practical purposes the same creature as a human being of 10,000 BC?

 

-Our "incredible intelligence" is the reason we have the power to pose such a threat to the environment. No animal has that power, only humans do. And no animal is even close to having that power (intelligence) even after thousands of years of evolving. Why not?

 

-We did not have the technology 2000 years ago to pose a threat to the environment (toxic waste, pollution etc). Through human desire to make life easier, more comfortable we used our intelligence to create things like cars that pollute the air.

 

-I think the expansion of human culture is a product of our intelligence. And our intelligence is something that we can develop but it does not evlove.

 

By my questions above, I do not mean to imply that some for of evolution did not take place. There is a lot of evidence to suggest that it did. But I don't think it is the only answer. Evolution falls short in explaining human intelligence and, more importantly, human behavior. As your comment about man's threat to the environment suggests, human behavior is far from exemplary. Humans can do awful things to each other (and sometimes very good things). Evolution does not seem to explain this.

[administrator]

The reason why we still have apes and not half bred or all humans and no apes is due to one big reason. Apes came from the western part of central Africa and naturally, they migrated. There were many groups that had migrated and due to the challenges they faced upon, some evolutionised into humans, human-like species, and other variety of species of apes. For more information, or read more upon evolution, please visit site: - http://www.ecotao.com/holism/

[Tormod]

How do you define evolution? My understanding is that evolution invovles the addition of new genes to someone's genetic makeup.

 

Evolution: "theory in biology postulating that the various types of animals and plants have their origin in other preexisting types and that the distinguishable differences are due to modifications in successive generations. The theory of evolution is one of the fundamental keystones of modern biological theory." (Encyclopaedia Britannica).

 

Evolution is not addition of genes. It is adaptiation to the environment due to mutation, specialisation and development of skills.

 

Yes humans have undergone some physical changes over the last 5000 years but I would not consider those changes to be evolutionary. For example humans are taller today than in the past but that can be explained by diet.

 

And a change in diet is not something which is a cause for evolution? And vice versa? People discovered ways to increase food production, which made it possible to sustain larger populations, which eventually lead to the birth of advanced civilisation. This is adaptation.

 

I think the expansion of human culture is a product of our intelligence. And our intelligence is something that we can develop but it does not evlove.

 

I fail to see the difference. And my point was that you labelled the intelligence as "human" in your post - which is why I pointed to another strange feature in humans (the tail bone). Other species do not show human intelligence because they are not human. But I find no basis (and you do not offer one either) to argue that human intelligence is any better (or more important) than, say, the ability of whales to communicate halfway around the world by song.

 

Exactly where does evolution fall short in explaining human intelligence? At what point did humans enter the world, and when did they aquire the intelligence that they then for some reason were able to improve upon? Did every single human being alive at some point in history wake up one day and say, "what is this new thing? It must be intelligence!". Or are you suggesting that evolution has occured with all other beings _except_ humans? This is not clear to me.

 

Tormod

[Tormod]

Originally posted by: Anonymous

The reason why we still have apes and not half bred or all humans and no apes is due to one big reason. Apes came from the western part of central Africa and naturally, they migrated. There were many groups that had migrated and due to the challenges they faced upon, some evolutionised into humans, human-like species, and other variety of species of apes. For more information, or read more upon evolution, please visit site: - http://www.ecotao.com/holism/

 

Hm...a creationist science buying into evolution. Or isn't it?

 

Since you're anonymous I'll just follow up with a few links:

 

Genetics and Evolution Tutorial

 

BBC - Science - Cavemen

 

Tormod

[Daisy]

Other species do not show human intelligence because they are not human. But I find no basis (and you do not offer one either) to argue that human intelligence is any better (or more important) than, say, the ability of whales to communicate halfway around the world by song.

Human intelligence is better - For Us - because it give us power over other living things (which was my point). This power gives us a competitive advantage over other living things for things like food and other resources needed to keep us alive and procreating.

 

If humans wanted to we could destory every lion, every tiger, every whale in the entire world. But those same creatures could not destory us and the reason is that we are smarter. This distinguishes us.

[Tormod]

Originally posted by: daisy7420016

Human intelligence is better - For Us - because it give us power over other living things (which was my point). This power gives us a competitive advantage over other living things for things like food and other resources needed to keep us alive and procreating.

 

Now you are confusing me. You said evolution seemed to have stopped. Of course human intelligence is better for us. That's why we have it. That is evolution.

 

This power gives us a competitive advantage over other living things for things like food and other resources needed to keep us alive and procreating.

 

I couldn't have said it better myself. All your posts actually argue _for_ evolution, not against it.

 

Tormod

[Daisy]

Tormod,

 

1. Does the theory of Evolution postulate that all living things have a common ancestry - that is, do we all trace our genetic ancestry back to one ancestor?

 

2. Has the common ancestor that humans and apes share been identified - do we know who or what this common ancestor is? Is this the missing link?

 

3. According to Evolutionary theory, what triggers evolutionary changes in animals - is it strictly environmental changes?

 

4. Why are some evolutionary changes spontaneous and others take many, many years to happen?

[Tormod]

1. Depends on which theory of evolution you are talking about. If, for example, there are living beings on other planets, then obviously, all living things did not spring from one ancestor. However, the building blocks of life (like carbon and ammino acids) are observed in huge amounts all over the Universe.

 

2. Read deamonstar's answer above. There is no missing link.

 

3. No, evolutionary change is not necessarily "triggered" (in the sense that some innate ability in a creature suddenly kicks into action). It can be a matter of natural selection - say, if the temperature drops over a period of time, then only those creatures who are able to survive the colder weather (or can benefit from it) will survive, and their offspring will have genes more adapted to the colder weather. This is what is known as survival of the fittest. However, it can also be triggered - by mutation, say (hence my note about banana flies, above). If a mutation occurs in a creature and this mutation brings it success (say, it grows a thicker fur by accident), and if it can pass this on to its offspring, then this change could be said to be triggered.

 

4. Because of the reasons in 3).

 

Sincerely,

Tormod

[Daisy]

man did not evolve FROM apes, so there is no "missing link". primates and humans are evovled from a common ancestor.

1. Then who or what is the common ancestor?

 

By isolating a gene and finding out when it evolved, scientists can obtain clues that help them figure out when humans developed certain skills, and possibly what triggered a change in behavior.

Quote from article Genetics may help solve mysteries of human evolution

 

2. How do scientists do this - determine the age of a gene? If the range is great as it appears to be with the Foxp2 gene (gene could be between 1 day to 200,000 years old), how useful is the information. If there is such a range, can scientists really date a gene?

 

3. Could Homo Sapiens have bred with H. Neanderthalensis or H. Erectus? Could this explain some of the differences in humans (example - why Asians, Europeans, Africans, Indians etc all look different and have very different cultures)?

[Tormod]

1. I don't know. It has no relevance to whether evolution happens or not, since evolution is not about human beings but about every living being.

 

2. I don't know. I am not a paleonthologist, nor an anthropologist. Read a book - for example, Ancient DNA Typing http://www.amazon.com/exec/obidos/tg/detail/-/3540430377/qid=1052915847/sr=1-23/ref=sr_1_23/102-8628431-7448922?v=glance&s=books by Susanne Hummel.

 

3. Not likely. I recently posted this news item on our science headlines page: Human DNA Neanderthal-Free

 

This ping-pong discussion offers me no insight. I feel that I have answered quite a few of our questions by now. It would be very interesting to hear your own perspectives.

 

Tormod

[Tormod]

That should of course have read "your" questions, not "our" questions.

 

Tormod