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Is it possible for a complex organism to evolve into a less complex organism? Like if an organism randomly devoloped some sort of feature that was less complex that aided in the organsims chance of survival. Suppose that somehow almost everyone on earth died of a horrible disease or nuclear war, and the only remaining humans lived in isolated regions of africa where the dominant environments consisted of thick forests. In this scenario, would it be possible for humans to evolve into an organism that closely resembles the modern chimpanzee or gorilla?

2007-05-03 13:10:56 · 8 answers · asked by Diagoras 4 in Science & Mathematics Biology

8 answers

Loss of a function does not simplify a creature. That unused remnant or vestigial appendage is still present or the genetic coding is still present if unexpressed. That appendix or wing means an additional cost is added on survival. Energy to develop the tissue. Energy to maintain it from disease. This is like putting stuff in the attic but still paying for its use. This is not simple it is just the inability to reverse an adaptation. Once a structure is developed for a specific use it is unlikely to be readily adaptable for another specific use. It is more likely another less developed portion of anatomy will be co-opted. Look at Gould's essay on the Panda's thumb.
Look at snails and slugs. All animal evolution uses the basic torus form; mouth at one end anus at the other. Snails still need to excrete, but this is not good inside a shell. So snails contort or twist in their growth with the left half dominating the right half. They put in a 180 so the anus and mouth both face out of the shell. They are stuck with the same basic body tube we have with a slight reorganization just so they can wear a shell.
Now the the slug. They quit the shell but are stuck with a vestigial shell and contorting of body form. They still contort but now they de-tort as they grow. A result of this contorting/de-contorting is that the right-hand-side organs are reduced. They have to grow then shed the shell as the mature. Their vestigial process is very costly and not simple.


Now, your idea of some sort of convergence of form towards a gorilla's. They walk on all four in a specialized mode called knuckle walking. For us to re-adapt to quadrupedal locomotion we would end up looking like a stegosaurus. It had hind legs much bigger than its front legs, despite walking on all fours. This is probably a byproduct of being descended from a two-legged ancestor that went back to walking on all fours. We wouldn't just get long arms and short legs. We would have to use what we have to become quadrupedal.
Then gorillas are vegetarian. We would need to become herbivores and adapt to digesting cellulose. This is not simple. It is another layer of complexity added to the basic we started with.

Arthropods (centipedes, millipedes, arachnids, crustaceans, etc.), have several different configurations of limb specialization and disappearance, including the case of all segments having lookalike limbs. That particular one is found in trilobites, which go back to the base of the Cambrian, which is when hard-shelled marine animals first emerged. Several arthropods of that time, as found in the Burgess Shale fossils, had that sort of limb configuration; each segment was identical to the previous. In fact, it is very likely that the ancestral arthropod was like that. Now many of its descendants have their limbs specialized in different fashions to become antennae or mouth-parts or whatever -- or suppressed as a segment with no appendages at all but the ability to produce a leg is still encoded in their genes if the control slips.
There is a mutation that causes a fruit fly to start to
grow legs on its abdominal segments; but that mutation kills the fly while it is still a maggot. All the abdominal segments can potentially still grow legs, but are not. This is not simpler just because of not growing the legs. It is another layer of control added on top.

2007-05-03 17:57:18 · answer #1 · answered by gardengallivant 7 · 0 1

Absolutely.

While the trend in the evolutionary process is towards increasing complexity, evolution has no direction. Vestigial structures, such as the appendix in carnivores (including humans), wings of an ostrich and eye sockets in blind cavefish are all examples of natural selection favoring "simplified" structures.

Humans becoming more ape-like is highly questionable, though. Natural selection works due to differential reproductive success...meaning some individuals are more successful than others at producing offspring, and therefore passing on their genes. While chimps and gorillas are well-adapted for their environments, our intelligence (ability to use tools, problem solve, change our environment, etc.) gives all humans the ability to survive (to reproduce), thus limits the "pressures" that can drive change within a population.

2007-05-03 13:41:59 · answer #2 · answered by ocedman 1 · 1 0

The thing you have to understand is that a chimpanzee and gorilla are not less complex than humans, biologically speaking.

Socially speaking, it's an entirely different matter. If we don't use our brains then we could lose them, especially since they are so costly to make and maintain. We could get more stupid.

The word deevolution is stupid. Evolution isn't change into more complex things, it is simply change. Even if we did "revert to a primitive form" it is still change so it is still called evolution. Evolution isn't a unidirectional force, it isn't even a force. So any genetic change, good bad or neutral, is evolution.

2007-05-03 22:52:18 · answer #3 · answered by Anonymous · 1 0

Evolution is constantly going on. Each one of us are technically "mutants". Random mutations occur to every individual that is born, though they are slight mutations on their genes. The larger mutations are the ones where there is a defect on the individuals.

The problem with us is, we have slowed down evolution for our species down to a crawl. We do not let nature takes it course because of "human compassion and empathy". Do you know what diseases are for? To limit the population and to allow the strongest specimen to survive and reproduce. The problem is, we are trying to save everyone.

AIDS, malaria, bubonic plague, all catastrophic diseases that kill many many people. Yet, we have/are trying to find cures for them. Why? There are people that have natural resistance for these diseases. Nature did not intend for us to be this many. We, in a sense, became too smart for our own good. There are tons of other animal diseases out there that limit the population of other animals. Its natural.

The human population did not explode until the late 18th century with the advent of the Industrial Revolution. Before that time, human population mirrored that of other animals. Periods of incline, then decline, up and down. The Industrial Revolution lead to creations of modern technology and led the way for modern medicine, cultivation of high-yielding crops, and other modern "wonders". We have since then, EXPLODED and have not been brought down since (minor temporary decline during wars)

This is the same principle as to why the other animals have not evolved as much, especially ones in which humans have cultivated. We have destroyed the gene pool. Chickens, cows, turkeys, etc, are bred to a specific standard. We all want our chickens to be the same, cows to taste the same - we dont like variation. Because of this, we have purposefully bred these animals to have certain characteristics. How can we expect them to evolve when we are not allowing natural selection to occur.

This goes with people as well. How can we expect evolution to continue if we keep saving those that nature deemed, weak? I'm not saying we shouldn't save or help others. I'm asking you how can you expect us to evolve on a normal course if we interfere with the process itself. We are still evolving, but on a much slower speed than if we have let natural selection to occur. But I do not think we humans will evolve into an organism that closely resembles the modern chimpanzee or gorilla because if we believe in Darwin we technically came from them. I do not think we are going back.

For evolution to take place also takes thousands and thousands of years. But the survivors through evolution will gain certain traits to live in that environment.

Note that:

We're "evolving" right now. Generations are steadily growing just a little taller than the previous one. Our eyes are becoming smaller to help shield our eyes from so much smog and other air pollutants. Our wisdom teeth usually don't fully develop because they are no longer needed. True blond-haired people are becoming less. These are just a few of the examples of the ongoing process of evolution.

2007-05-03 13:35:28 · answer #4 · answered by Bonga 1 · 1 0

Look to tape worms and many other parasites, as they have evolved to be little more that living mouths. The organism they are parasite on is supplying all the digestive work. Your human scenario seems a bit outside of evolutionary forces ability to accomplish what you surmise.

2007-05-03 13:26:15 · answer #5 · answered by Anonymous · 2 0

Intresting question- us as humans probably would even could degress into our counterparts that we evolved from. That would be ironic- humans who pride themselves on being knowledgable would be totally wiped out by their own invention of a nuclear bomb, and the animals that we keep in captivity could be what we degress into

2007-05-03 14:01:27 · answer #6 · answered by fireflyspace23 3 · 0 0

Sure... since we don't have a full and complete history of human evolution, it is possible that we devolved from a more complex type of human that actually used their appendix....

The process of devolution is just as feasible as evolution.

2007-05-03 13:15:58 · answer #7 · answered by v_2tbrow 4 · 2 0

Yes it's happening everyday just watch the news. Seriously, you need to challenge the propaganda you've been fed in regards to evolution. I would suggest beginning by checking out http://www.sciohio.org/.

2007-05-03 14:17:02 · answer #8 · answered by William R 2 · 0 2

I BELIEVE IN THE BIBLE!!! BUT, AS MUCH AS I HAVE FOLLOWED SCIENCE AND DARWINISM; I HAVE ONLY SEEN WALKING CATFISH IT MAY SUPPORT YOUR THEORY OF "DE-EVOLVING" THIS WAY... IN THE GROWTH OF FEET INSTEAD OF FINS BEING THE ONLY WAY FOR THE FISH TO TRAVEL BUT IT USES THIS EVOLUTION TO MOVE FROM WATER SUPPLY TO WATER SUPPLY THUS THIS NEW MUTATION BEING BETTER SO... I SAY NO! ALSO WITH OUT THE MISSING LINK THE EVOLUTION OF MAN- IS STILL A THEORY!!!
WE STILL HAVE GORILLAS AND MONKEYS I BELIEVE THERE WOULD BE NONE IF EVOLUTION HAPPENED!!!
SO THE ALLIGATOR AND MAN (AND WOMAN) ARE THE TWO MAMMALS TO HAVE STOOD THE TEST OF TIME!!!

2007-05-03 13:32:48 · answer #9 · answered by finderoflostsheep 2 · 0 5

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