Why Can't Evolution Go Backwards?

Originally posted by Heronumber0
Over the course of many millions of years with a Blind Watchmaker (Dawkins) why can't species de-evolve to other forms. For example why didn't the man-like apes de-evolve back into apes, pigs, donkeys or fish?

I can see by this statement that you have a poor grasp of how evolution works. My advice is to study up.

A small addition to my previous post:

The shape of the sacrum (vertebra in the pelvic girdle -- which they do have), shows that the fossil in question actually had a pelvic build like a chimp and didn't have enough curve to it to be a creature that walked upright all the time.

Evolution (in technology or in biology) doesn't go backwards. For example, if for some reason we all went back to riding bicycles, we wouldn't "de-evolve" to the bycicles that we had in the late 1800's (solid tires, solid frame, horrible seats) and they wouldn't be made by blacksmiths. We would be using the materials and manufacturing methods of today... not returning to those of 150 years ago.

Byrd, thanks for the anatomy input here. I was trying to make sense of what Filler was saying but found it too technical to handle. However, he seems quite adamant in saying:

...spine essentially incompetent for routine quadrupedal
locomotion. The lack of any intrinsic mechanism to
resist extension under the force of gravity in a horizontal
pronograde position allowed the lumbar spines of these
apes to function well only in upright or orthograde postures.
The large modern hominiform apes such as gorillas
and orangutans have independently evolved new types of
osseous ridges that lock the lumbar facets against extension.
2 This finding suggests a continuous series of upright
ancestral apes—with body plans more or less like those in
a modern human—from which other apes have descended
to establish diagonograde (between upright and horizontal)
postures during knuckle walking and other straightarm/
flexed-leg gaits.

He seems pretty convinced, if I read this properly, that we had an upright ape which was not capable of bending down like a normal ape. I would see that as a stronger survival feature (from a neo-Darwinian point of view) than a partially upright ape.

I take the point about the fossil record showing loss of features in gradation for example horses getting smaller etc.. but is the fossil record for human/hominids really that complete?

Doesn't the process go through long periods of stasis followed by short periods of rapid change? The punctuated equilibrium theory seems pretty convincing in this regard.

Originally posted by rapturas
I think of it like this, if there was a beginning (big bang) then there should be an end, right? Everything which has a starting point must have a finishing point no?

Why do you think that? Look at a space telescope photo of a supernova. There's something that arguably had a "beginning," the explosion, but where do you suggest will it "end?" When is stops exploding?

WTF is gong on............is someone actually thinking that evolution can go backwards..?

WTF...that is exactly like thinking that people can grow younger......it defies logic.....people grow older over time due to each individuals body processes, that enable everyone to age at different times of progression depending on genetics, the food they eat, and the surroundings they live in eg climate. Every little thing affects ourselves in someway, and each affect causes changes on both our bodies and mind.

To say that evolution should be able to go backwards is a joke.....obviously you know nothing about evolution, i don't blame you, most creationists don't........

Let's see, ever noticed how the more intelligent a person becomes the more common sense he tends lose?

Humans use only a small percentage of their brain and the rest is probably no longer being used. Take Babylon for example, at that time Man had the power to communicate telepathically but he pissed off God and that power was revoked to the point where Man must now communicate verbally.
This can be a form of Devolution. (I can't get me no-satifaction)

Also the more we evolve the more of our natural senses and abilities we lose. Like our sense of smell, compared to animals humans can't smell worth a flip. Now I here this chimp has a much better memory than College kids

Maybe that's why aliens abduct humans, because their sense of smell and other senses are worse than ours.

[edit on 4-12-2007 by Alxandro]

reply to post by Nohup


Can I refer you to a system where mammals evolved less complex organs to become water-living organisms. What I mean is that evolution, any evolution, is subject to environmental and behavioural factors which then filter out a wide variety of genetic mutations to those that suit the environment. By that logic, man should also be able to evolve back into an atavistic form - the ape.

Atavism wiki

[edit on 5/12/2007 by Heronumber0]

reply to post by Heronumber0


Back in high school there was a kid in our class that looked like an ape. He had big jaws and was hairy. We called him Darwin.

Sorry for the late input. I had finals....

Originally posted by Heronumber0
Byrd, thanks for the anatomy input here. I was trying to make sense of what Filler was saying but found it too technical to handle.

Some of that was rather deliberate obfustication on his part -- or bad writing. Poorly mixed metaphors like this one "The next three chapters (4-6) reveal a tectonic change in our understanding of the mechanisms and methods by which important changes take place in evolution certainly don't make it any more readable.

...spine essentially incompetent for routine quadrupedal
locomotion.

That's a rather sweeping statement for him to make with only a sacrum and a vertebra and not the rest of the skeleton. I notice that his redrawn claidagram doesn't actually place Morotopithecus anywhere on the scale.
www.uprightape.net...

...and his comparative anatomy drawings of the sacrum don't include the Morotopithecus sacrum... and they're only drawn one half and from the back. That's sort of a cheat, because when you draw them from the side, the human sacrum has a curve in it that the chimp and gorilla and apes don't have. Scroll down to "figure 4" in this PDF and you'll see what I mean... ape sacrums are quite straight, like that fossil:
cmpd.umd.edu...

And while he calls gibbons bipedal, the truth is that they spend very little time walking on two feet and they sway lots while doing it.

The lack of any intrinsic mechanism to
resist extension under the force of gravity in a horizontal
pronograde position allowed the lumbar spines of these
apes to function well only in upright or orthograde postures.
The large modern hominiform apes such as gorillas
and orangutans have independently evolved new types of
osseous ridges that lock the lumbar facets against extension.

Here, he's talking about how the vertebra sort of 'lock' into place to allow or restrict flexibility. There's a number of ways that nature evolves this (including, in dinosaurs, long ribs that run down along the neck vertebra and thick tendons that run along the tail vertebrae.)

This finding suggests a continuous series of upright
ancestral apes—with body plans more or less like those in
a modern human—from which other apes have descended
to establish diagonograde (between upright and horizontal)
postures during knuckle walking and other straightarm/
flexed-leg gaits.

According to others, it suggests that human-ape ancestors had more flexible spines. This is not surprising, given that they were much smaller animals and a flexible spine gives more 'spring' to the leap.
He seems pretty convinced, if I read this properly, that we had an upright ape which was not capable of bending down like a normal ape. I would see that as a stronger survival feature (from a neo-Darwinian point of view) than a partially upright ape.

I take the point about the fossil record showing loss of features in gradation for example horses getting smaller etc.. but is the fossil record for human/hominids really that complete?

Nowhere near as complete as we'd like... and we'd like to see fossils from all areas of the globe. It's reasonably good for Australopithecus on upwards, but further back there's fewer hominid fossils.

My theory is that hominids were considered tasty, catchable dinners by almost every predator around.

Doesn't the process go through long periods of stasis followed by short periods of rapid change? The punctuated equilibrium theory seems pretty convincing in this regard.

It is if you look at selected material. In other cases, the changes take place over a long period of time (and may show up in the form of 'zillions of different species of this kind of critter.' In the Cretaceous, the ceratopsian dinosaurs evolved to many different species (including torosaurus), and we're still finding new ones (my boss is working on some material that may be a new one, and I worked on a horn frill 2 years ago that seemed to come from an unknown ceratopsian species.

Originally posted by Alxandro
Humans use only a small percentage of their brain and the rest is probably no longer being used.

That's an urban legend, actually. We use all of our brain.
faculty.washington.edu...

Take Babylon for example, at that time Man had the power to communicate telepathically but he pissed off God and that power was revoked to the point where Man must now communicate verbally.
This can be a form of Devolution. (I can't get me no-satifaction)

Not sure where you got that information, but we have a lot of records from Babylon (in cuneiform) and there is no mention of telepathy. Several civilizations at that time had writing... none of them mention the Biblical legend OR mention telepathy.

Originally posted by Heronumber0
reply to post by Nohup

 

Can I refer you to a system where mammals evolved less complex organs to become water-living organisms.

Actually, the structures that evolved were more complex than the primitive forms had.

What I mean is that evolution, any evolution, is subject to environmental and behavioural factors which then filter out a wide variety of genetic mutations to those that suit the environment. By that logic, man should also be able to evolve back into an atavistic form - the ape.

Which won't happen, actually.

As I said, it's similar to the evolution of the bicycle. The first forms were primitive and uncomfortable. We've developed new forms of transportation that supplanted the bicycle... but if for some reason we had to "re-evolve" back to the bicycle, we would be using new technologies (plastics and lighter metals and air inflated tires and springs) rather than the old blacksmith-built ones. While it might look very similar, it would be far more sophisticated than the old one.

Same with evolution.

Originally posted by Beachcoma
reply to post by Heronumber0

 

Back in high school there was a kid in our class that looked like an ape. He had big jaws and was hairy. We called him Darwin.

... and we wonder why disgruntled, dysfunctional teens go on their shooting sprees?
Thanks for contributing pal, you're a class act.

the way we are going it looks like we may regress back into an ape.
i suggest highly watching the movie "idiocracy" and if you can't get a copy, at least watch the trailers/plotline/summary of the film.

[edit on 7/12/07 by cheeser]

what about humans de evolution. sure we stood up and kept walking...and swimming too.
we can do just about anything we want. but we cant eat raw meat.

Originally posted by cheeser
the way we are going it looks like we may regress back into an ape.
i suggest highly watching the movie "idiocracy" and if you can't get a copy, at least watch the trailers/plotline/summary of the film.

[edit on 7/12/07 by cheeser]

I've seen that movie! I would say that the human race is headed in that direction.

More people seem to just want to get on with their "lives", which as always is conforming to society. But it is this modern society & world that we live in that is turning us into nothing but digital existance. The act of going out & talking to real people is being replaced with instant messaging. This worries me.