# of Human Generations

[jotttun]

I am trying to gain a better personal comprehension of evolution (which I generally "understand" fairly well) and one fact that would help me is a ballpark estimation of the number of total primate generations.

 

To clarify

 

A. What is the fastest reproducing primate/ What is the average reproduction for primates----This number by generation as in humans have a new generation ever 20 years ish.

 

OVER

 

B. According to the best knowledge we have when what is the earliest primate known?

 

A

- = total generations

B

 

Am I missing anything in trying to figure this out?

 

Finding this ballpark figure could help me comprehend how many trials there have be since early primates to reach the modern human. Thinking if this number is gigantic evolution seems (seems meaning more comprehensible) more likely etc...

[Quartile]

i think you might be thinking of (length of time that an evolving organism spends in the "primate" section of the evolutionary timeline)/(average length of life of the organism while in the primate section) = number of generations of that organism that occur during that section

 

the wiki article for primates says that they appeared sometime in the mid-late cretaceous, which is a period that lasted from 145 million years ago to 65 million years ago. so primates must have been around from 105 million years ago to 65 million years ago.

 

something that must also be kept in mind when thinking about the speed of evolution in primates is that they underwent a type of accelerated evolution as a result of gaining understanding through tools and fire and whatnot.

 

im just musing. in the event that i am terribly wrong or make no sense whatsoever, please ignore this post =D

[Paralith]

Quartile is right in pointing out that evolution does not occur at a constant rate. Different environmental factors can speed it up or slow it down. Still, even "speedy" in evolutionary terms for animals can be several hundred thousand years, or maybe even millions, especially if we're talking about speciation. But you shouldn't take length of time the process takes as support for the theory, because as I said the rate of change is not always constant. Also, generation time will vary alot across a group as large as primates - humans technically become sexually reproductive around 12-13, chimps around 8-10, baboons around 7-8, capuchin monkeys around 4, etc. It isn't easy to generalize for such a big group. Also, if you're only interested in human evolution, you should focus on hominid species, and not just all primates in general. For example, we split from chimpanzees, our closest relatives, about 3 million years ago.

[jackson33]

As science takes less fragments to simulate more what was, most of these answers to these questions change by the day...however;

 

Primate remains have been found, back to near 55 Million years ago.

 

Home Erectus predecessor to Homo Sapiens, remains have been found dating two million to 600k years ago. (There was a report of a 3 million years old find which I have not seen a follow up on).

 

HE and HS, are thought by many to have existed simultaneous for a long time. The earliest HS was for a long time thought to be about 6 to 700k years ago, but a recent find indicates 1 million years. HS is considered where modern man evolved from. This would give you about 50 thousand generations to get where we are, however its possible many more are involved as these HS lived short lives and sex itself was not regulated.

 

Compared to others primates we have had less chance to mutate, certainly in later years. I like to use Roaches which have been around a while, no doubt mutating to conditions and today are found in most the world, with extremes in there make up. However there are other species of complex life, as the Frog which have changed very little.

[CDarwin]

Yay, a primate question! Unfortunately it's a pretty unanswerable one. The length of a generation has varied ridiculously over the course of primate evolution.

 

The earliest primates were probably like most primitive mammals with short lifespans and high turnover of generations. Think treeshrews, who live about 12 years and breed after the first 3 or so. Mouse lemurs are a living example in this extreme with a similar reproductive regime.

 

On the other end of the scale, you have humans that live 80 years and reproduce after 30. I guess you could try and get a mean and then divide that by 100 million years, but I don't know how terribly useful that would be, and I doubt you could really find data on most of the primates in the fossil record.

 

And just a correction of Quartile: Molecular clock says humans and chimpanzees diverged about 6 million years ago. Sahelanthropus tchadensis (if it does turn out to be a unique human ancestor), is about 8 million years old. So you end up with a more reasonable date of 10-6 million years separating humans from chimpanzees.

[lucaspa]

For example, we split from chimpanzees, our closest relatives, about 3 million years ago.

 

That's 6-7 million years ago. By 3 million years ago, Australopithecus was already in existence.

 

Home Erectus predecessor to Homo Sapiens, remains have been found dating two million to 600k years ago.

 

http://www.amnh.org/exhibitions/permanent/humanorigins/

H. erectus is not that old and it lasted much longer. H erectus fossils dating to 30,000 years ago have been found in Indonesia.

 

HE and HS, are thought by many to have existed simultaneous for a long time. The earliest HS was for a long time thought to be about 6 to 700k years ago, but a recent find indicates 1 million years. HS is considered where modern man evolved from.

 

1. "Modern man" is Homo sapiens (HS). YOU are Homo sapiens.

2. There are several transitional fossils linking H. erectus to H. sapiens from about 800,000 years ago to about 160,000 years ago, when the oldest completely H. sapiens skull dates from (and even these Bouri skulls have some residual erectus features).

 

This would give you about 50 thousand generations to get where we are, however its possible many more are involved as these HS lived short lives and sex itself was not regulated.

 

1. You don't know the sexual rules of Sapiens society. Chimps regulate sex.

2. Generation time is limited to when individuals reach sexual maturity. In humans, girls cannot conceive until puberty, which is about 12-14 years (as CDarwin noted). So, human generation times cannot be shorter than about 14 years. Since the average lifespan was about 30 years, an average generation time of 20 years for H. sapiens is reasonable. Divide 160,000 years by 20 years gives you 8,000 generations since H. sapiens completely evolved from H. erectus.

3. The transitional time between H. erectus and H. sapiens was at least (800,000-160,000)/20 = 32,000 generations.

 

Compared to others primates we have had less chance to mutate, certainly in later years.

 

The data indicates that the population went thru a bottleneck about 100,000 years ago when there were less than 50 breeding pairs of H. sapiens. Thus, we have a lot less genetic diversity than any other primate.

 

However there are other species of complex life, as the Frog which have changed very little.

 

Frogs are NOT a species. Frogs are an Order in the Class Amphibia. Thus "frog" is a group of hundreds of living and extinct species. And frogs have changed quite a bit since the Order first evolved.

[Paralith]

whoops - that must be what I was thinking of. Early human ancestors. My mistake!

[jackson33]

lucaspa; In my loosely stated post to give an opinion on possible generations of human ancestry, I reviewed a google search on *Homo Erectus to Sapien* which most statistics were taken. Tried to infer there are many different views and tried to indicate the uncertainty of any opinion...which I will put much of yours into that category. I will hold to my potential limit of 50K, assuming HS have been around that million years.

 

88% of Amphibian Species are Frogs (some 5000 different), which known today some date back 250 million years and very much resemble todays Frogs. They are often referenced to show evolutions slow process in some cases. This according to Wikipedia...

 

I am a little curious, since every time I post with regards to this issue, there are so many dead set on a particular pattern. For instance "100K years ago there were 50 pairs of HS". Disregard any possibility for evidence, why not

110K years ago, 57 pairs. For the record however, I am aware of the Mini Ice Age about that time, but doubt your figures. Think you get my point. As for mating habits; they differ in Humans today, only the puberty issue of importance in the past could be argued.

 

So you don't respond with credentials, which have been hard earned I'm sure, your profile indicates a profession which required much Biology. I have only an interest in the field, no background and what there was, long since changed.

[CDarwin]

H. erectus is not that old and it lasted much longer. H erectus fossils dating to 30,000 years ago have been found in Indonesia.

 

I think jackson was lumping Homo ergaster in with H. erectus, and the oldest H. ergaster are about 1.8 mya.

http://www.talkorigins.org/faqs/homs/specimen.html

 

lucaspa; In my loosely stated post to give an opinion on possible generations of human ancestry, I reviewed a google search on *Homo Erectus to Sapien* which most statistics were taken. Tried to infer there are many different views and tried to indicate the uncertainty of any opinion...which I will put much of yours into that category. I will hold to my potential limit of 50K, assuming HS have been around that million years.[/Quote]

 

Erm... I don't think you can really justify putting Homo sapiens as that old. The oldest (fuzzy) specimin is probably the Dali cranium, and it's only 200,000 years old. A lot of it's more a matter of semantics than of palaeontology. Homo heidelbergensis or archaic Homo sapiens?

 

I think the topic poster just wants an idea as to how many chances for mutation would have passed along the road to humanity, which is a really problematic question because it's impossible to demark the start of that 'road' in any way not completely arbitrary.

 

I am a little curious, since every time I post with regards to this issue, there are so many dead set on a particular pattern. For instance "100K years ago there were 50 pairs of HS". Disregard any possibility for evidence, why not

110K years ago, 57 pairs. For the record however, I am aware of the Mini Ice Age about that time, but doubt your figures.

 

I don't suppose it's a major point, but I don't believe there was a mini anything 100,000 years ago. That was just the last Ice Age, full force. It ended 12,000 years ago and there was the Younger Dryas after that, sort of a mini Ice Age. That's not the same thing, though.

[jotttun]

Thank you all.

 

CDarwin was correct in his observation:

"I think the topic poster just wants an idea as to how many chances for mutation would have passed along the road to humanity, which is a really problematic question because it's impossible to demark the start of that 'road' in any way not completely arbitrary."

 

I understand that it my question was asking for a "completely arbitrary" figure, but nevertheless this discourse has helped my understanding.

 

Furthermore, I want to applaud all of you on this forum. It is one of the only places on the internet that are accesible, inteligent, argumentative, non-adhominen, and polite. Thank you for that.

[jackson33]

CDarwin; As said, an exact figure is not possible and it depends on what are classified Modern Mans descendants. I concede Modern Man is about 100k years old, at best, but erectus to ergaster to habilis could take you back that 3 million years. Frankly, IMO, they were direct ancestors to MM. I used one million as an arbitrary figure to the disputed 3myo Habilis. My answer to jotten, probably should have been much higher and could have gone back to the 6 millions year figure where many feel vertebrates/primates first walked upright, or on hind legs.

 

Of interest, according to Wikipidia, estimated human population 10k years ago was 5 million.

 

On Ice ages, of the four majors 110k years ago was not one. Certainly the 12k year ago was much less and probably a cycle with in a cycle. Think -3 and -5 given compared to the big mama, 700m years ago and -10 to todays mean. Here again, much is disputed and I could find many stats giving completely different limits.

[lucaspa]

lucaspa; In my loosely stated post to give an opinion on possible generations of human ancestry, I reviewed a google search on *Homo Erectus to Sapien* which most statistics were taken. Tried to infer there are many different views and tried to indicate the uncertainty of any opinion...which I will put much of yours into that category. I will hold to my potential limit of 50K, assuming HS have been around that million years.

 

Google searches are not that reliable if you take ALL the sites that come up. Because you get many, many sites where people have no idea what they are talking about. I used the American Museum of Natural History because they have the data. H. sapiens only goes back 160,000 years, not a million.

 

88% of Amphibian Species are Frogs (some 5000 different), which known today some date back 250 million years and very much resemble todays Frogs. They are often referenced to show evolutions slow process in some cases. This according to Wikipedia...

 

Again, Wikipedia is not always a reliable source. Anyone can get on and add stuff; what is there doesn't have to be correct. Wiki is a place to start, not finish.

 

As you note, "frogs" doesn't denote a species, but several thousand. However, the species that are alive today are NOT the same species that were alive 250 million years ago. Frogs have changed, both skeletally (that we can see) and probably physiology (which is harder to see via fossils).

 

I am a little curious, since every time I post with regards to this issue, there are so many dead set on a particular pattern. For instance "100K years ago there were 50 pairs of HS". Disregard any possibility for evidence, why not 110K years ago, 57 pairs.

 

The evidence is in our genomes. We don't have enough genetic variation in our species. That lack of genetic variation can only be due to a bottleneck in population.

 

And yes, I stated it more definitively than I should have. To be precise: the data indicate that approximately 200,000 years ago the human population went thru a genetic bottleneck where the effective breeding size dropped to a maximum of 50 breeding individuals.

7. A Gibbons, Studying humans -- and their cousins and parasites. Science 292:627-629, April 27, 2001.

"The findings confirm what some previous studies had suggested: We are all descended from a small founding population whose offspring multiplied rapidly in the past 200,000 years. The lack of diversity in humans is now so striking that it strongly supports the theory that our ancestors survived a "bottleneck" that quickly winnowed a larger, genetically diverse population into a smaller, homogeneous one. ... Studies have shown for a decade that chimpanzees have three to four times as much genetic diversity in their maternally inheri-ted mitochondrial DNA (mtDNA) as humans do. But are chimpanzees exceptionally diverse, or humans exceptionally alike? No one had sequenced enough DNA from other apes to find out, until a study reported in February in Nature Genetics. Geneticists Svante Pääbo and Henrik Kaessmann of the Max Planck Institute for Evolutionary Anthropology compared a 10,000-base-pair stretch of noncoding DNA on the X chromosome in humans, chimpanzees, gorillas, and orangutans. They found that humans had not only much less genetic variation than all other great apes, but also had relatively few of the mutations that accumulate in noncoding regions of the genome at a relatively steady rate. That's a signal that humans underwent a major expansion starting 190,000 to 160,000 years ago, says Pääbo. ...

 

So you don't respond with credentials, which have been hard earned I'm sure, your profile indicates a profession which required much Biology.

 

No, I don't respond with "credentials". What matters is the data -- which is why I sent you to the AMNH site. I only respond when it is suggested I'm not a scientist.

 

I think jackson was lumping Homo ergaster in with H. erectus, and the oldest H. ergaster are about 1.8 mya.

http://www.talkorigins.org/faqs/homs/specimen.html

 

I'm sure he was. I was giving the AMNH data and Tattersall is a "splitter". He uses H. ergastor for the species in Africa and the differences seen later in Asia are H. erectus.

 

Erm... I don't think you can really justify putting Homo sapiens as that old. The oldest (fuzzy) specimin is probably the Dali cranium, and it's only 200,000 years old. A lot of it's more a matter of semantics than of palaeontology. Homo heidelbergensis or archaic Homo sapiens?

 

The Dali cranium is one of the many transitional individuals linking H. ergastor/erectus to H. sapiens.

 

There is also the Tauteval skull that is 200 kya. And the Vertesszollos skull is ~ 400 kya. It has teeth like H. erectus but occipital skull like H. sapiens.

 

The Bouri fossils are ~ 160 kya and are considered the oldest fully H. sapiens. http://news.nationalgeographic.com/news/2003/06/0611_030611_earliesthuman.html

 

Even here, the skulls still bear some erectus features:

"They found that the fossils from Herto are similar to, but do not duplicate, the anatomy of modern humans. Their faces are longer, the skulls more robust, and the brow ridges are larger than those of modern humans, for example. "

 

BTW, there are transitional individuals linking H. sapiens to H. ergastor/erectus to H. habilis to A. afarensis.

 

I think the topic poster just wants an idea as to how many chances for mutation would have passed along the road to humanity, which is a really problematic question because it's impossible to demark the start of that 'road' in any way not completely arbitrary.

 

You can't get a precise number of generations, but the calculation going from 800 kya (where you have the first transitional from erectus to sapiens) to 160kya gives a reasonable estimate.

 

Of course, the situation is even more complicated in that many anthropologists are calling every species in Homo "human". Thus, you see an article that discusses finding H. erectus fossils in Dmansi, Georgia ~ 1.7 mya entitled "Global positioning: new fossils revise the time when humans colonized the earth." Scientific American 283: 23, Aug 2000.

 

CDarwin; As said, an exact figure is not possible and it depends on what are classified Modern Mans descendants. I concede Modern Man is about 100k years old, at best, but erectus to ergaster to habilis could take you back that 3 million years.

 

More like 2.5 mya. Of course, go back to A. afarensis and you are at ~ 3 mya and then some.

 

Of interest, according to Wikipidia, estimated human population 10k years ago was 5 million.

 

Again, Wiki is the place to start, but not the definitive word. Did this calculation reference a scholarly work?

 

As to Ice Age, again use a scholarly work instead of Google. You use Google to try to find .edu or other reliable sites, not treat every site as equally reliable. http://pubs.usgs.gov/gip/ice_age/ This is from the US Geological Survey, a reliable source that is going to give you accurate data and conclusions.

[jackson33]

lucaspa; I have heard Wiki, is not the most reliable. Also I agree a google search could lead to confusion. In some ways I prefer a two sided view of an issue, which in my world leaves room for a diverse understanding. In addition I receive three daily Science news emails and follow Fox News Web site and their Science Department.

 

On diversity in humans, I prefer to look at todays mating habits to explain what you feel is lack of diversity. (Personally I see a great deal, under pigment, size, weight, intelligence and in the immune systems) which by the way is unique to a species. People, mate according to desire or at worst what is acceptable by the opposite. Probably not making sense, but for most of human existence IMO, mating was done and at the will of the fittest, to the ones which pleased the mental desire. Sapiens I suspect existed in minority for some time, until some unknown factor took hold. You lost me on the logic for few sapien couples, but couldn't discuss if understood. If arrogant enough I could say, this could have been a bottleneck and even that unknown factor happened 100K years ago, but 50 still seems a little low...

 

The Wiki estimate 5M population, probably did have a referance and as I recall was from a google search *erectus to sapien* search.

 

On the Ice Age; Downloaded your site and scanned. If this Ice Age was that of 140-120K, falling into the Illinoian glaciation (many ups and down), this was the latest major event, some thinking the 12-14KYA mini, a cycle event on the warming trend from 120K figure. The speculations on previous ages, with far less geological evidence, are suggested to have been extreme by comparison.

 

Some days I feel lucky that I have no set basis for my opinions and often worry that the real minds in this world are too set on what was learned or limit research to particular types of research, Scholarly works.

[lucaspa]

lucaspa; I have heard Wiki, is not the most reliable. Also I agree a google search could lead to confusion. In some ways I prefer a two sided view of an issue, which in my world leaves room for a diverse understanding. In addition I receive three daily Science news emails and follow Fox News Web site and their Science Department.

 

In science, there are often not "two sides" to an issue. Science uses data to falsify ideas, so some "sides" are simply not valid.

 

Getting science from news presents several problems. First is that journalists -- like Fox News -- don't realize that data eliminates some "sides" and follows their rubric of presenting two valid "sides" when there aren't two.

 

What you want to do with science is learn to test ideas to find out accuracy of hypotheses/theories, not "diverse understanding".

 

Instead of subscribing to news services, I suggest you subscribe to Science, Nature, and Scientific American (all of which are online but you do have to pay to subscribe). You can also search the Proceedings of the National Academy of Sciences (http://www.pnas.org) each week.

 

On diversity in humans, I prefer to look at todays mating habits to explain what you feel is lack of diversity. (Personally I see a great deal, under pigment, size, weight, intelligence and in the immune systems) which by the way is unique to a species. People, mate according to desire or at worst what is acceptable by the opposite. Probably not making sense, but for most of human existence IMO, mating was done and at the will of the fittest, to the ones which pleased the mental desire.

 

The lack of "diversity" is in the lack of different alleles (forms of genes). That translates to sequences of bases in the DNA. In particular, it is a lack of neutral mutations -- those that do not affect the phenotype (what you see). What you see as diversity on a visual level is not reflected in the DNA. A single chimpanzee population has more genetic diversity than the entire human species!

 

Yes, sexual selection (mate preference) is active among humans. It has been proposed recently as a hypothesis to explain hairlessness among humans. However, humans have demonstrated that they freely mate across those lines -- pigment, size, weight, intelligence -- that you can "see".

 

Even among ape societies where a single dominant male supposedly controls mating, the females sneak off into the bushes to mate with the beta males and, thus, less than half the offspring are actually those of the alpha male. So you can't use sexual selection to explain the lack of genetic diversity.

 

Sapiens I suspect existed in minority for some time, until some unknown factor took hold. You lost me on the logic for few sapien couples, but couldn't discuss if understood. If arrogant enough I could say, this could have been a bottleneck and even that unknown factor happened 100K years ago, but 50 still seems a little low...

 

The key is this phrase from the article "We are all descended from a small founding population" "Founding population" is a term in evolutionary biology that refers to the decrease in genetic diversity when the population gets very low. The extreme example of "founding population" is a single breeding pair (N=2), such as the founding of Drosophila in Hawaii. In order to lose 50% of genetic diversity, you need to be down to N =10 (Figure 11.6 on page 304 of Futuyma's Evolutionary Biology, 1999). So my figure of N = 50 is probably too high.

 

The Wiki estimate 5M population, probably did have a referance

So why don't you go back and give us the reference (if it is there)?

 

On the Ice Age; Downloaded your site and scanned. If this Ice Age was that of 140-120K, falling into the Illinoian glaciation (many ups and down), this was the latest major event, some thinking the 12-14KYA mini, a cycle event on the warming trend from 120K figure. The speculations on previous ages, with far less geological evidence, are suggested to have been extreme by comparison.

 

If you had gone over the first paragraph, this talked about the entire Pleistocene Period, going back a million years. It didn't separate the individual glaciations within that time period.

 

Ironically, the Wikipedia article has the Illinoian glaciation as the 2nd to last major glaciation period, from 200-130 kya. The Wurm/Wisconsin glaciation period extended from 100 -12 kya. http://en.wikipedia.org/wiki/Timeline_of_glaciation

 

So I'm puzzled why your claims are contradicted by your quoted source of information.

 

Some days I feel lucky that I have no set basis for my opinions and often worry that the real minds in this world are too set on what was learned or limit research to particular types of research, Scholarly works.

 

This is often the complaint of people who want to challenge the accepted viewpoint. The idea is to cast ad hominem attacks on the accepted viewpoint instead of realizing HOW it got accepted.

 

There are two general steps in scientific/scholarly thinking:

1. Propose an idea. This is imaginative and is not "set".

2. Test the idea against the real world in an attempt to show the idea to be wrong. If you can honestly say you tried your best to show the idea wrong and failed, then and only then can you say the idea has support.

 

And yes, that does end up relying on what has already been learned, since that information becomes the first stop in our attempts to show an idea to be wrong. We test an idea against existing information first. Only if we fail to falsify it there do we go out and deliberately design experiments to test the idea. In graduate school you learn to do "literature searches" and this is the primary purpose of those searches.

 

The reason we concentrate on "scholarly work" is because those are the people who carefully document their attempts to show an idea to be wrong and how they failed. People who just go out and try to find support for their idea are usually ignored because it has been shown that ANY idea, no matter how far-fetched and wrong, can have data that supports it: IF that is what you are looking for.

 

So people looking only to find evidence in favor of their idea can, and usually do, delude themselves. So we, in the interest of time, limit ourselves to people who we know do the work correctly.

[jackson33]

Google *Earths Population 10,000 years ago* and have a ball. In fact The National Academies Press, in a SEM release in 1993, estimates the population was 10 million, 8k year ago 260 million and does give referances....

 

Ice Ages; Of course I picked out the extremes. The warm extremes are higher than todays, which is the basis for the argument.

 

No sir, I often question the excepted opinion/theory but rarely will use as a challenge. If I have a basis or premise to challenge, even then its offered as alternative viewpoint. I might suggest, most every theory today accepted, was at some point disputed theory.

 

Today we have a much different approach to learning, than when I was learning. We used to get an hour or so lecture and the second hour was used for questions, Many times the intend of the person lecturing would take a total shift in outcome. Today its a 30 minute reading from some text (or close to it), with no question allowed, in most cases.

 

Science.Com and some others take most material from the academia you suggest, with an occasional editorial. FOX News on the other hand are press releases in total from a variety of sources. Don't think they have one scientist on board, maybe other than Meteorologist. Seems to be full of attorneys and a few specialized Doctors...The point is, thats my way to keep current....

 

You are welcome to let this thread die. Seems no one much interested and we will not change the others mind. Your attitude on the Dino's, is pretty much along the same lines, but may join in that thread later. Actually its that issue, which gave me interest in this thread, along with a work on Ancient Migrations of humans.

[lucaspa]

Google *Earths Population 10,000 years ago* and have a ball. In fact The National Academies Press, in a SEM release in 1993, estimates the population was 10 million, 8k year ago 260 million and does give referances....

 

You still didn't provide a citation! Why not? If you did it, all you needed to do was copy the web address and paste it in your post, like I did. It was a polite request.

 

Ice Ages; Of course I picked out the extremes. The warm extremes are higher than todays, which is the basis for the argument.

 

What extremes? The extremes of age? Even so, the chronology of your source doesn't match what you said -- citing your source. I'm puzzled by the discrepancy. Why did you feel you could change your data?

 

No sir, I often question the excepted opinion/theory but rarely will use as a challenge. If I have a basis or premise to challenge, even then its offered as alternative viewpoint. I might suggest, most every theory today accepted, was at some point disputed theory.

 

Yes, every theory accepted today was once disputed. But you need to ask: why did that dispute stop and the theory become accepted? The answer is simple: the data would no longer allow continued dispute! Scientists argue everything that can possibly be argued. Why do you think I come here for relaxation? When scientists stop arguing, it is because they no longer can. So, instead of "challenging", what you need to do is start looking at the scientific publications and find the data that stopped the dispute.

 

Today we have a much different approach to learning, than when I was learning. We used to get an hour or so lecture and the second hour was used for questions, Many times the intend of the person lecturing would take a total shift in outcome. Today its a 30 minute reading from some text (or close to it), with no question allowed, in most cases.

 

When was this and in what context? College? High school? And, if you are not in school anymore, how do you know how it's done today?

 

Science.Com and some others take most material from the academia you suggest, with an occasional editorial. FOX News on the other hand are press releases in total from a variety of sources. Don't think they have one scientist on board, maybe other than Meteorologist. Seems to be full of attorneys and a few specialized Doctors...The point is, thats my way to keep current....

 

And my point is that it is a flawed method to keep current. Instead of doing that, you need to subscribe to the journals I suggested and look at PNAS each week. Don't rely on "attorneys and a few specialized Doctors", but go to the source. The news you get in Science is done by people who know science and how to report it.

 

You are welcome to let this thread die. Seems no one much interested and we will not change the others mind. Your attitude on the Dino's, is pretty much along the same lines, but may join in that thread later. Actually its that issue, which gave me interest in this thread, along with a work on Ancient Migrations of humans.

 

Again, I'm puzzled. Unless you can come up with good data, of course I'm going to stick with the data we have. If you do come up with good data, then I will change my mind. I think it is your mind I'm not going to change, because it doesn't matter what data I post, you ignore it.

[jackson33]

lucaspa; There are three reasons I only give referance when posting. 1- No one can ever accuse me of a virus. 2- I frankly don't know how. 3- I always assume the person replying to my post is as smart or smarter than I am. Since we are arguing a topic, knowing you education, I seriously doubt anything I could say, is or could be new to you.

 

Disputed theory that becomes mainstream is fine and probably 95% of these I would never argue or frankly respond to. Again however, with regards to current accepted theory, my usual reply is to question not necessarily to dispute. On this thread, my response is out of respect and the consistent long replies. My normal reaction would be to ignore and move on...

 

In my world we referance Ice Ages toward there end. 120k and 12k YA, the last two minies. If you feel there were no warm period (above todays average mean) from 200k to 12k YA, then fine, but wrong IMO...

 

No, I do not ignore any data offered. More often than not I have seen it before and in various form. I will admit # of generations, would not normally catch my attention but for some reason it did, thinking the author was inching toward another interest *speed of mutation*, which you know micro-isms can mutate noticeably in a few years, to survive medications.

 

As for educational comparisons from yesterday to today, the level is not material. As for the current methods, your probably correct and I have no idea from the experience angle. I can only go by what others say of todays and recall my own.

[CDarwin]

No, I do not ignore any data offered. More often than not I have seen it before and in various form. I will admit # of generations, would not normally catch my attention but for some reason it did, thinking the author was inching toward another interest *speed of mutation*, which you know micro-isms can mutate noticeably in a few years, to survive medications.

 

I won't say that I'm completely following what this debate is about, but perhaps relevant to the original post, the number of mutations incurred in a period of time (so called "mutation pressure") is fairly over-rated in vis-a-vis the rate of evolutionary change. The majority of variation in a sexually reproducing population (like that of humans) is due to recombination during sexual reproduction, and the majority of evolutionary change is due simply to selection based on the variation introduced by recombination.