Macroevolution

[warri0r45]

I'm making this topic because I am genuinely interested in the issue. ANY STRAYING FROM THE TOPIC AND I WILL HAVE IT LOCKED. Because, well, clearly there is a place for other discussions however supplimentary you think they may be to this one.

 

 

 

Specifically, I have one question that I want everyone to focus on. Generally everyone accepts microeolution as a given as we have seen it happen thousands of times; it's a no brainer, really. But people seem to be resistant to accept macroevolution. Why is that? Do any of you guys think that macroevolution is not possible? Why? What barriers are stopping a whole lot of microevolutionary changes leading to speciation (macroevolutionary) events? Why? What evidence can you guys find for or against macroevolution from a credible source? (preferably something with no religious motivations, for bias reasons.)

 

 

 

As a final note I would really appreciate it if we could center the dicussion around the questions I have posted here. I'm keen to know what, if any, barriers stop macroevolution from occuring. As a final final note, this topic assumes the fact of an old earth, so if you want to debate for a young earth, please, make another topic.

 

 

 

To end this off, I'll have a first dig. DNA and the mutations it undergoes have no limitations. This is clear when we see such things as bad mutations which end up forming severe disabilities or killing the organism. DNA dosen't discriminate nor does it have any barriers to stop any mutational changes occuring. If you think otherwise, explain clearly why. For the purpose of this discussion, the term species, from my perspective (and a widely used definition), will be a specific group of organisms unable to produce offspring with any other organism but those in it's groups. Now I'll present a scenario which leads me to have the view that macroevolution is no where near impossible, given enough time. Consider a population of an organism, sexually reproducing. Consider a split in the population through flood/fire/volcano/storm/predation/lack of food/whatever. Consider the difference of the geographical location of the two subpopulations. Consider the ensuing microevolutionary changes that occur which conform to natural selection for that particular environment. Finally, consider, after many, many generations of mutations that each subpopulation now looks different. It all happens, it's all been seen before and it's all old news. But, consider that the mutations are so extensive, that these two subpopulations can no longer mate with each other to produce fertile offspring. What barriers would stop this from occuring?

 

 

 

Go for it but just remember to keep it on track, please.

 

 

 

(as many of you can tell by now evolution interests me)

[Dalcyte]

having studied this for a while, i'd have to say microevolution is true.

 

 

 

Now, it facinates me still, that this could happen...but what has to be taken into consideration is well, billions of years passed for evolution to happen.

 

 

 

It's a sticky issue, and i think honestly there isn't much of an alternative aside from a divine creator. But things change, and places change, a animal suited for one area, is not suited for the normal one, but finds its special niche, passes on its genes and there we go.

 

 

 

I've forgotten a lot about the subject matter...but when final studying starts, i'll be back :XD:

[Guest XplsvBam]

Regardless if macroevolution is possible a) there is no way to measure it B) there will never be enough time for it to occur c) the world around us has conflicting data against macroevolution.

 

 

 

HOW WIDESPREAD IS DESERTIFICATION?

 

About one third of the world's land surface is arid or semi-arid. It is predicted that global warming will increase the area of desert climates by 17% in the next century. The area at risk to desertification is thus large and likely to increase.

 

 

 

Worldwide, desertification is making approximately 12 million hectares useless for cultivation every year. This is equal to 10% of the total area of South Africa or 87% of the area of cultivated lands in our country.

 

 

 

In the early 1980s it was estimated that, worldwide, 61% of the 3257 million hectares of all productive drylands (lands where stock are grazed and crops grown, without irrigation) were moderately to very severely desertified. The problem is clearly enormous.

 

 

 

http://www.botany.uwc.ac.za/Envfacts/facts/desertification.htm

 

 

 

Macroevolution can't take place because the world hasn't been around long enough for it to occur.

[Barihawk]

I can't even comprehend how we evolved from primordial goo, much less from any other organism.

 

 

 

The same goes for all other life on Earth. Not to mention, it can never be truly tested without taking millions of years.

[Dalcyte]

Regardless if macroevolution is possible a) there is no way to measure it B) there will never be enough time for it to occur c) the world around us has conflicting data against macroevolution.

 

 

 

HOW WIDESPREAD IS DESERTIFICATION?

 

About one third of the world's land surface is arid or semi-arid. It is predicted that global warming will increase the area of desert climates by 17% in the next century. The area at risk to desertification is thus large and likely to increase.

 

 

 

Worldwide, desertification is making approximately 12 million hectares useless for cultivation every year. This is equal to 10% of the total area of South Africa or 87% of the area of cultivated lands in our country.

 

 

 

In the early 1980s it was estimated that, worldwide, 61% of the 3257 million hectares of all productive drylands (lands where stock are grazed and crops grown, without irrigation) were moderately to very severely desertified. The problem is clearly enormous.

 

 

 

http://www.botany.uwc.ac.za/Envfacts/facts/desertification.htm

 

 

 

Macroevolution can't take place because the world hasn't been around long enough for it to occur.

 

 

 

i'm not sure i get how how that quote reflects macroevolution...but ok.

 

 

 

There is no way to measure it, yes and the proof isn't necessarly there, but there still is a little more as oposed to the alternative...just saying.

[Guest XplsvBam]

 

i'm not sure i get how how that quote reflects macroevolution...but ok.

 

 

 

It doesn't reflect macroevolution. It reflects the inability of macroevolution occuring. That means macroevolution isn't capable of happening.

 

 

 

If you need your dough to rise you add the yeast. No matter how much yeast you add if it doesn't have time it will never rise. Time is part of the recipe, if time is not there it is not capable of achieving the steps it needs to be fully developed. Time is a major part of macroevolution and if its not there its not going to happen.

[dracmasta]

well, it seems to me that you are describing something similar to what happened to "apes" and humans. if you believe thats (ie are not a hardcore Christian) then you believe in "macroevolution"

[warri0r45]

 

i'm not sure i get how how that quote reflects macroevolution...but ok.

 

 

 

It doesn't reflect macroevolution. It reflects the inability of macroevolution occuring. That means macroevolution isn't capable of happening.

 

 

 

If you need your dough to rise you add the yeast. No matter how much yeast you add if it doesn't have time it will never rise. Time is part of the recipe, if time is not there it is not capable of achieving the steps it needs to be fully developed. Time is a major part of macroevolution and if its not there its not going to happen.

 

 

 

Why would you say there hasn't been enough time? The earth is estimated at 4.8 billion years old. If you think otherwise, then you missed reading a bit of my post. If you don't like that info, then take it as a hypothetical. What I'm getting from you is that you think if there were time enough for it to happen, which you believe there isn't, then it would and could happen. Am I interpreting your message correctly? And I'm struggling to see what point you're trying to make with your quote on desertification...

 

 

 

And Barihawk, could I reccomend a bit of reading on genetics? I'm assuming that you aren't all that fluent with it, so if my assumption is incorrect, I apologise. It's just that for me, studying genetics made evolution so clear cut, understandable, comprehendable and logical.

 

 

 

As a final note I still haven't heard of any barriers which prevent macroevolution from occuring (apart from time, which I specified wasn't realy a factor here as an old earth is assumed with evolutionary theory, albeit a proven assumtion. Again, if you don't like the piece of information which offends you/you don't believe in/whatever, take it as a hypothetical situation).

[Guest XplsvBam]

If time was given macroevolution could happen, but that doesn't mean that it would happen.

 

 

 

I mentioned desertification because if the world were 5 billion years old it would be all desert.

[warri0r45]

If time was given macroevolution could happen, but that doesn't mean that it would happen.

 

 

 

I mentioned desertification because if the world were 5 billion years old it would be all desert.

 

 

 

I'll look into that. EDIT;

 

 

 

Current desertification is taking place much faster worldwide than historically and usually arises from the demands of increased populations that settle on the land in order to grow crops and graze animals.

 

 

 

WHAT CAUSES DESERTIFICATION?

 

* Overgrazing is the major cause of desertification worldwide. Plants of semi-arid areas are adapted to being eaten by sparsely scattered, large, grazing mammals which move in response to the patchy rainfall common to these regions. Early human pastoralists living in semi-arid areas copied this natural system. They moved their small groups of domestic animals in response to food and water availability. Such regular stock movement prevented overgrazing of the fragile plant cover.

 

 

 

Its essentially due to our over agriculturalising of semi-arid land. Whatever theory you go by, this occurance would have been minimal before we came along. I hardly see how your idea that we would be totally desert holds any water, sorry. I've never even heard this argument before which makes it admirable that you didn't rehash someone elses, at least.

[Barihawk]

I have studies genetics, thank you. My opinion still stands that nature is far too complex (whether it be humans, animals, or a freaking pitcher plant) to have evolved completely from a single cell in the relatively short time span we have been here on Earth.

 

 

 

And mankind itself is so much more complex than anything else. In my opinion (which I am not pushing on you, so don't debate it) is that mankind has only been on this planet for 60,000 years, in almost the same state that we arrived in (barring many microadaptations over that time).

 

 

 

And I believe that even then, plants, animals, dinosaurs...all were given a head start, but still not enough time to develop from ooze.

 

 

 

It's also worth noting that if I move to the coast, and my children stay there: My descendants would grow webbed feet. But if they move inland, those features will go away.

 

 

 

Adaptation (aka Microevolution) is not a permanent trait. There's no way even in billions of years that a single cell could adapt into what we have today.

[Dalcyte]

I can't even comprehend how we evolved from primordial goo, much less from any other organism.

 

 

 

The same goes for all other life on Earth. Not to mention, it can never be truly tested without taking millions of years.

 

 

 

it's hard to imagine, but it happened imo...

 

 

 

And its not priomordial goo really to say, what happened is that by chance [again, billions of years to do this], molecules of proteins formed, and RNA that's sole purpose to make proteins that made RNA faster formed, lipid bilayers formed and eventually they grouped. Mutations in the RNA made other things occur besides making those oh so "helpful" protiens, and thus, the first prokaryones (no membrane bound organelles). Eukaryotes eventually developed through one of two known theories, that i really don't wanna explain right now lol, and colonies of them formed, some didn' divide properly and stuck together, and some became more specialized and some millions upon billions of years past and we had our first multicellular critter. So macroevolution says, things became more and more specialized and things like wings and legs formed...with algae for instance, it learned to longer without water, and thus our first plants.

 

 

 

Oh and to bari's other gommcent, i don't find it toooo hard to imgine..3 billion years is quite an inconcievable number. But this is really a sticky issue, and there's no breakthrough point (yet) for either side.

 

 

 

Anyway, that sums up the basic theory in a nuthsell...again, over billions of billions of years.

 

 

 

Xpl, that's...not true at all actually lol. the world is 4.3B years i believe, and at first, there were oceans and volcanoes. Deep under the sea were hyrdothermal vents, hotspots for the beginnings of life, i.e. archaebacteria.

 

 

 

I notice also you use the word "if"...do you not belive its billions of years old? (sorry if that sounds snide, i don't mean it to be, i'm just asking your beliefs is all : )

[warri0r45]

I have studies genetics, thank you. My opinion still stands that nature is far too complex (whether it be humans, animals, or a freaking pitcher plant) to have evolved completely from a single cell in the relatively short time span we have been here on Earth.

 

 

 

And mankind itself is so much more complex than anything else. In my opinion (which I am not pushing on you, so don't debate it) is that mankind has only been on this planet for 60,000 years, in almost the same state that we arrived in (barring many microadaptations over that time).

 

 

 

And I believe that even then, plants, animals, dinosaurs...all were given a head start, but still not enough time to develop from ooze.

 

 

 

It's also worth noting that if I move to the coast, and my children stay there: My descendants would grow webbed feet. But if they move inland, those features will go away.

 

 

 

Adaptation (aka Microevolution) is not a permanent trait. There's no way even in billions of years that a single cell could adapt into what we have today.

 

 

 

You're intitled to your opinion and all, but yes, there is a way that a single cell could adapt into what we have today. That's why we have the theory. Sorry about the asumption that you weren't up to speed with genetics, nothing untoward intended. The example you gave of microevolution being a non-permanent occurance is interesting. Well, considering it is permanent, it's just the tendancy to have the organisms with the new mutations reproducing more itsn't always permanent. It can be though. What if a population of an organism moved to a geographically different area and stayed there. Period. It's not like they would migrate somewhere, become adapted to that environment and move away again. They'd have to adapt to thier new environment and sometimes may not even survive! The organisms with traits best suited to thier environment will thrive and thier genes will be passed on from generation to generation to an extent where we humans may come along and label them as permanent changes which have formed a new (again, just another label) species.

 

 

 

Would you say, for a population that has split and whose subpopulations stay in thier respective geographical areas for a long time, that there is any barrier in thier DNA preventing the subpopulation that moved from the original population to no longer be able to mate with them to form fertile offspring? What is stopping it? That's the specific line of questioning I'm presenting here.

[Guest XplsvBam]

 

 

 

WHAT CAUSES DESERTIFICATION?

 

* Overgrazing is the major cause of desertification worldwide. Plants of semi-arid areas are adapted to being eaten by sparsely scattered, large, grazing mammals which move in response to the patchy rainfall common to these regions. Early human pastoralists living in semi-arid areas copied this natural system. They moved their small groups of domestic animals in response to food and water availability. Such regular stock movement prevented overgrazing of the fragile plant cover.

 

 

 

Its essentially due to our over agriculturalising of semi-arid land. Whatever theory you go by, this occurance would have been minimal before we came along. I hardly see how your idea that we would be totally desert holds any water, sorry. I've never even heard this argument before which makes it admirable that you didn't rehash someone elses, at least.

This is why desertification holds water. If the earth is becoming noticeably more desert over time that we can measure then no matter how minimal desertification has been in the past, even to the .1% of what desertification is today, over 5 billion years it would still have shallowed the earth.

[warri0r45]

 

 

 

WHAT CAUSES DESERTIFICATION?

 

* Overgrazing is the major cause of desertification worldwide. Plants of semi-arid areas are adapted to being eaten by sparsely scattered, large, grazing mammals which move in response to the patchy rainfall common to these regions. Early human pastoralists living in semi-arid areas copied this natural system. They moved their small groups of domestic animals in response to food and water availability. Such regular stock movement prevented overgrazing of the fragile plant cover.

 

 

 

Its essentially due to our over agriculturalising of semi-arid land. Whatever theory you go by, this occurance would have been minimal before we came along. I hardly see how your idea that we would be totally desert holds any water, sorry. I've never even heard this argument before which makes it admirable that you didn't rehash someone elses, at least.

This is why desertification holds water. If the earth is becoming noticeably more desert over time that we can measure then no matter how minimal desertification has been in the past, even to the .1% of what desertification is today, over 5 billion years it would still have shallowed the earth.

 

 

 

I'm not really all that interested in desertification, to be honest. Find me some sources and I'll have a look though. If it did really hold sufficient water, I would most likely have heard it. Seeing as I haven't I'm not going to deny it untill I eventually get around to having a look later on.

 

 

 

Edit:

 

Desertification is a historic phenomenon; the world's great deserts were formed by natural processes interacting over long intervals of time. During most of these times, deserts have grown and shrunk independent of human activities. Paleodeserts, large sand seas now inactive because they are stabilized by vegetation, extend well beyond the present margins of core deserts, such as the Sahara. Many deserts have come about around western Asia because of an overpopulation of prehistoric species and subspecies during the late Cretaceous era.

 

 

 

Through dated fossil pollen, it has been found that today's Sahara desert has been changing between desert and fertile savanna. Studies also show that advance and retreat prehistorically varied with on yearly rainfall, whereas a clear trend to increasing amounts of desert began with human driven activities of overgrazing and deforestation.

 

 

 

 

Not the best source, but it counters the argument that it's constant and moving in one direction, which I hardly see it doing before we came along. I'd really rather we talk more on macroevolution, though.

[jin_sakura226]

hmm err no the world wasn't a desert 5 billow years ago...

 

it was said that the world atomsphere change... and as it change organism adapted/ or died off.. And oh yeah meteor or comets also had an effect as well.. especially volcanic activity.. Most of my oldest organisms live in the deep deep sea.. another thing it said that single cell started working together to form colonies..(organelles) to become multicellur.. Anyways hmm too many mysteries in the world

[Viktorkrum77]

Evolution is a tricky subject. However, I don't believe in divine inspiration because, well, have you seen the size of this Universe? However we came about, I doubt any creator, if one existed, put enough consideration into us, because there is so much out there, maybe even thousands, millions, billions of civilizations. So however we came to be, it only appears to be divine until you look at the scale.

 

 

 

Whatever happened to the theory that life on Earth came here from elsewhere? Who's to say it didn't evolve halfway there then finish up here?

[Dalcyte]

Evolution is a tricky subject. However, I don't believe in divine inspiration because, well, have you seen the size of this Universe? However we came about, I doubt any creator, if one existed, put enough consideration into us, because there is so much out there, maybe even thousands, millions, billions of civilizations. So however we came to be, it only appears to be divine until you look at the scale.

 

 

 

Whatever happened to the theory that life on Earth came here from elsewhere? Who's to say it didn't evolve halfway there then finish up here?

 

 

 

perfectly legit theory, and it's a real one...organic compounds from meteors (amino acids, etc) flew in and crashed into earth...there was something debunking it, or maybe not...i forget :P :XD:

[warri0r45]

Evolution is a tricky subject. However, I don't believe in divine inspiration because, well, have you seen the size of this Universe? However we came about, I doubt any creator, if one existed, put enough consideration into us, because there is so much out there, maybe even thousands, millions, billions of civilizations. So however we came to be, it only appears to be divine until you look at the scale.

 

 

 

Whatever happened to the theory that life on Earth came here from elsewhere? Who's to say it didn't evolve halfway there then finish up here?

 

 

 

Perhaps. I generally won't rule anything out that could possibly be explained by nature.

[Barihawk]

 

 

 

You're intitled to your opinion and all, but yes, there is a way that a single cell could adapt into what we have today. That's why we have the theory. Sorry about the asumption that you weren't up to speed with genetics, nothing untoward intended. The example you gave of microevolution being a non-permanent occurance is interesting. Well, considering it is permanent, it's just the tendancy to have the organisms with the new mutations reproducing more itsn't always permanent. It can be though. What if a population of an organism moved to a geographically different area and stayed there. Period. It's not like they would migrate somewhere, become adapted to that environment and move away again. They'd have to adapt to thier new environment and sometimes may not even survive! The organisms with traits best suited to thier environment will thrive and thier genes will be passed on from generation to generation to an extent where we humans may come along and label them as permanent changes which have formed a new (again, just another label) species.

 

 

 

Would you say, for a population that has split and whose subpopulations stay in thier respective geographical areas for a long time, that there is any barrier in thier DNA preventing the subpopulation that moved from the original population to no longer be able to mate with them to form fertile offspring? What is stopping it? That's the specific line of questioning I'm presenting here.

 

 

 

While your examples are also intriguing, I was referring solely to humans in my previous post.

 

 

 

It's extremely rare to find a human who does not mate (even with bad genes) in this world. Like...massively rare. We don't die out if we are not suited to our environment.

[Viktorkrum77]

It's extremely rare to find a human who does not mate (even with bad genes) in this world. Like...massively rare. We don't die out if we are not suited to our environment.

 

 

 

Homosexuals do not mate to procreate. :wink: And they supposedly make up more than 4% of the population.

 

 

 

And mostly due to adaptations, we live in a maladaptative world where we no longer need basic survival instincts.

[Barihawk]

But many homosexual couples do try to procreate using a surrogate mother. Or even those who sell sperm to a donor bank are doing their part to continue the procreation of the human race.

[xvillexvalox]

Assuming by macroevolution, you mean quick physical changes within generations, which if it were a single asexual reproducing cell would happen fairly quickly. But I don't think any large numurous noticable changes could be seen in any organism on earth in 1 lifetime (of a human).

 

 

 

A change to yourself within a lifetime wouldn't be evolution, it would be an adaptation, and not necesarily passed on.

 

 

 

Adaptation (aka Microevolution) is not a permanent trait. There's no way even in billions of years that a single cell could adapt into what we have today.

 

 

 

According to fossil records, everything evolved from the first prokaryotes 4,600 million years ago. [source]Modern Biology[/i]" textbook] And then, it took 4,050 million years for the first marine invertabrates to come into existance.

 

 

 

The only ways this would happen is through evolution of a single cell Prokaryote, or "aliens" dropped new animals off on our globe periodically.

 

 

 

You can think of the first prokaryotes as a sort of "stem organism" in a way, having every living thing stem off from them in evolution.

 

(Apes and humans would have the same "Stem organism", seeing as how closely related they are)

[Barihawk]

You have to remember, though. I believe in microevolution, not macroevolution.

 

 

 

A cell does not adapt into a plant or animal. It would have to evolve. And I still think that's fooey. My evidence is the adaptation patterns of humans. Our changes are not permament unless passed on. Natural selection does not ever apply to us.

[warri0r45]

You have to remember, though. I believe in microevolution, not macroevolution.

 

 

 

A cell does not adapt into a plant or animal. It would have to evolve. And I still think that's fooey. My evidence is the adaptation patterns of humans. Our changes are not permament unless passed on. Natural selection does not ever apply to us.

 

 

 

There's a simple reason why humans appear not to evolve. Very simple, infact. We determine our own nature, therefore natural selection no longer plays a role for us (in the western world, that is) which isn't to say that it didn't. We have evolved to a rediculous point where we actually try to prevent the proliferation of our genes (contraception). Wierd, but it's because we know that overpopulation could be then end of us all.

 

 

 

In the end, you can be of the opinion that macroevolution is fooey, but it's, as far as I can tell, no different from microevolution. They are terms we humans made up to explain the adaptive nature of an organism (micro) and the method of one species (also a human proposed term) separating into multiple populations which, through gene flow and isolation, produces new species. All of these terms are semantically null when it comes to DNA. For some reason (well, entropy, perhaps) DNA does not pair perfectly, and thus forms mutations. When during gamete (sperm + egg) production, these mutations are passed on to the offspring. Any offspring with beneficial mutations (yes, they are rare but they do happen and are multiplied by different factors) will have a greater chance to procreate and spread thier genes. The genes that are in an organism will never change and will always be passed down the line untlill they are themselves mutated. It's a very fluid system, much more than the labels 'species' 'micro/macroevolution' would have you think.

 

 

 

And perhaps you could explain a tad more what you're saying in the bold. I'll listen and want to hear reasons why people don't accept macroevolution, seriously.