Ah, but there are. Or at least, there are organisms that fill all the niches from barely-alive to multi-celled. There single-cell orgs that live in colonies, which is a step or two behind becoming one multi-celled org. There are very simple multi-cell orgs, like hydra and sponges.
Since most or all of the evolutionary niches are filled, most evolution occurs “sideways”; i.e., organisms change not to a more advanced stage, but to different characteristics.
Since mankind has invented tools and machines to extend his abilities, I don’t see us evolving physically. For example, why grow our brains even bigger when we have computers that can do our calculating for us? Why develop faster legs muscles when we can drive at 60 mph (100 kg/m)?
I think Smeghead is right on about the change in the environment. There’s basically two sides to the theory of evolution; 1)the mutations, which occur randomly, and 2)the environment, and how those mutations affect survival within it. To wonder why we don’t see things crawling out of the ocean as they did millions/billions of years ago is sort of moot, because things have changed so radically. Heck, these days, the slimy thing would probably get to shore and get run over by the Baywatch crew, or better yet get eaten by a shark before it ever got close to shore. A billion years ago (give or take) those conditions wouldn’t have existed and the thing could have plopped itself down on the beach and caught some rays without having to worry about anything else being alive to kill it.
And Edge, not to debate, but I have to ask for own edification: what physical laws are you talking about? I don’t think I’ve heard this argument before and I’m curious.
Evolution doesn’t make such huge leaps at once. For example, you might go from an animal with NO body temperature regulation (i.e. completely cold blooded), to one with a very simple, weak method to affect body temperature, to an animal with a slightly improved method, etc., and finally, millions (or tens of millions) of years later, an animal with fully regulated body temperature (i.e. warm blooded). In the meantime, many other changes have probably taken place and you’ve got a new species. Of course, there must be some reproductive advantage for the animal to favor a regulated body temperature for it to keep advancing.
Another point to make is that for human-like creatures to show up from the ocean (hey, take dolphins as a starting point, why not?) they would be competing with an established and entreched species already there, namely us.
It’s unlikely that any new species would have a competitive advantange enabling it to thrive against a species already in place, such as humans. Wipe out all the humans, and with our ecological niche open something will likely move in.
Since the OP already has defined the endpoint (human-like) you’d have to clear out the niche first. It’s unlikely that two species could share our place on the ecological tree.
There are some pseudogenes in the human genome, or genes that code for proteins that are not used, but there is NOT code for “scales and gills”. Think more along the lines of alternate genes for hemoglobin. The origin of these pseudogenes is well understood. They typically show up in gene families, where there are also several versions of the gene that are used.
Evolution takes place so slowly that under usual circumstances it is impossible to see it in action. It’s not as if a species suddenly evolves into another species overnight, it takes thousands (or millions) of years worth of small changes.
Even if we could live long enough to see modern apes evolve, we would never see them evolve into humans. The apes we came from are not the same apes that are around today. Humans and modern apes have a common ancestor, but that ancestor species is not around anymore because it evolved. To say that we evolved from the sort of apes that are around today is like confusing your cousin with your grandmother. Modern apes will never become humans just like your cousin (or your cousin’s children) will never become you. Modern apes are still evolving, but whatever they evolve into will be an entirely different and new species.
This mailbag column may be of help, although it is in answer to a slightly different question:
Speciation has been observed. See Observed Instances of Speciation from the Talk.Origins archive for more. Also, pesticide-resistant insects and the annual changes in the flu virus are more cases of evolution at work today.
Okay, my family line has evolved, and your family live has evolved, but what I guess I am really wondering is why don’t I have neighbors who haven’t evolved.
Why aren’t there hairy unerect people walking around.
Alright guys you know what I mean! I am not talking about the in-breed hick types.
How is it possible that all family lines evolved at the same rate?
Oh, and thank you all for so far not turning this into a big debate.
A. Older proto-humans died off, due to either lack of adaptation to changing climate, etc., or by being killed by more advanced humans. By its very nature, if an inheritable trait gives some reproductive advantage, it tends to spread to the entire species, as more individuals with the trait survive, and more without it die, due to finite ecological resources.
I’m sure someone knowledgeable in early human history can fill in the details
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As individuals in a species interbreed among different “family lines”, genes are mixed, thus keeping everyone more or less on the same track. If you had a family that didn’t interbreed for a while (say 50,000 years or more), it would tend to get separated genetically, although it would probably be undergoing its own evolutionary changes by then. If the two resulting species competed in the same niche, see the earlier paragraph
Well mankind has the ability to adapt to change by changing society instead of waiting for biology and chance. It seems to me very likely that (artifical) genetic manipulation will become a dominant force in evolution. As a spieces we have been doing this for thousands of years. we pick characteristics in animals that we breed for… Anyhow it will probably be possible to select genetic characteristics in children in the near future. Sooner or later we will have the ability to radically change a species (including our own.)
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Why aren’t there hairy unerect people walking around.
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Because they would no longer be “people”.
Kricket, have you ever been to the zoo?? There are these things there called gorillas and monkeys… They do not live next door because they are not quite advanced enough to hold a job and drive a car and such. But who knows, give them another 500,000 years and see what happens.
THAT was disappointing… I didn’t expect the same person who suggested “Stick around for another 100,000 years (for large animals) and you’ll see it in action.” to say that. The fact that change is driven intentionally (yet still at random) by an external force does not mean that the adaptations and/or mutations passed on to future generations are not to be considered evolution. Would you say the same if we placed a population of mice in a big fridge and watched as the ones with warmer coats survived to pass on their genes, until we had nothing but fluffy angora mice? There’s no difference between that and evolution driven by an ice age except for scale, and there’s no difference between the fridge & radiation except the form of the human interference.
A guy named Boris obsessed with flying squirrels? Hmmm, where have I heard this joke before?
Actually, you got me thinking. We so often look at existing species and say, “This is what their ancestors looked like.” but look at your squirrels and bats. How do we know that 100,000 years from now, “flying squirrels” might not have become the next “bat” while today’s bats disappear, or turn into something else, or just stay the same? How do we know that todays zoo-bound apes won’t evolve into a speaking, working, tax paying part of society, as long as they don’t put us in cages?
We did see humans evolve. How do you think we got diffrent races. Each one seperated geographicaly. I would think that if humans did not intermingle through out the world and we stayed put for a million more year we would have be become different species. We just did not have enought time to for humans to develop in to bunch of different* home {insert name of racial group here}*s.
You would do well to check out http://www.talkorigins.org …they have lots of good details about evolution.
Based on the past posts, it seems like you understand that evolution takes place over huge amounts of time which is why we don’t see our species evolving during our short lifetimes or our short recorded history. If you check the fossil record, you will see the past evolution of humans.
Another thing to keep in mind is that evolution does not have a goal and humans are not “more evolved” than other plants/animals. Modern day bacteria are just as evolved as we are. We each do well in our own niche. As the environment changes and as other species evolve, our niche will change and we face new competitions (which is a test of our adaptation abilities). Breeding habits, mutations, etc. also keep evolution going. It never ends as long as there is life.
Like Arjuna34 said, it’s the gene pool that evolves. There is interbreeding among the whole population. Portions of the population may become segregated either through geography, breeding preference, etc. in which case evolution can take two different paths (because there would be 2 different gene pools). But if the whole population intermixes, then the species will evolve as a whole.
A gene pool has variations within it but the overall characteristics of the gene pool, taken as a whole, define the species. For example, individual humans have different traits (short/tall, strong/weak, blue/brown eyes, resistence/susceptibility to a particular disease, etc.) but we’re all one species.
Take the ape/human line for example. All primates (which includes humans) had a common ancestor. The population of that ancestor somehow split up (different groups probably spread out geographically in the search for food, escape from competition, etc.). This created different gene pools from that one original gene pool. Each new gene pool was faced with different challenges, circumstances, and random events (like mutations) and so different traits were beneficial to survival and propagated. After millions of years, the differences became so significant that the groups looked different than each other although they had the same underlying theme (ape-like qualities). One group eventually became what we now call gorillas, another became what we now call chimps, another proceeded down a path that led to humans.
No species lasts forever. Either it fails to survive (like when the large dinosaurs all died due to the asteroid impact or whatever) or the population’s gene pool keeps changing until we see it as a new species altogether. I don’t know what happened to the common ancestor for humans/apes/etc…maybe it just transitioned into the species we see now or maybe it died off because it could not compete with its better-adapted descendent species. Remember, this would be a competition on a long-term time line.
Although there are more technical definitions (regarding allele frequencies), but simply put, evolution is a change in the gene pool of a population over time.
A particular species’ DNA may allow for some variations (like short/tall) that can be brought out through behavior (like better nutrition leading to taller/stronger individuals). But the information in DNA does change during evolution (e.g., added or removed). DNA does contain some “junk” sequences that may be remnants from past forms or unused portions, but for example, human DNA does not already contain the information for flight (none of our ancestor species had this ability). That would have to be new information.
Evolution does not break any physical laws. If it did, it would not be accepted by the scientific community. Please specify which laws you mean and we can discuss. (btw, evolution does not break the 2nd law of thermodynamics if that is what you are thinking).
Disagree. Humans are still very dependent upon the natural ecosystem…clean air, clean water, other plants/animals to eat, suitable temperatures, parasites, etc. Wait for another ice age (likely). Or a comet impact that blots out the sun’s rays for a few months (inevitable). Or a disease that wipes out our basic crops. Or a new deadly strain of virus. etc.
Even if we could totally control all of these with our technology, humans would still evolve through other mechanisms (e.g., sexual selection, mutation, genetic drift, etc.). Perhaps we can slow evolution, but I don’t think we can stop it.
There used to be. As little as 30,000 to 40,000 years ago (IIRC), both Neandertals and H. sapiens were walking around. But somehow, H. sapiens survived and the Neandertals didn’t. Now we’re the only species (sapiens) of our genus (Homo).
“Artificial selection” is still a valid form of evolution. Whether changes are caused by human activity or other natural causes, they are still changes. And changes = evolution.
Actually the opposite is true. Technology actually allows for greater genetic diversity. Here’s why: In the old days, humans with genetic traits like nearsightedness would have dificulty tracking and killing their food (they couldn’t see it). Unable to eat, they would eventually starve and die, failing to pass their bad eyesight genes to any offspring. Charles Darwin proved this. Its called natural selection.
Nowadays, Technology allows us to compensate for such physical shortcommings, so those genes continues to pass down to our offspring.
Just because humans don’t live in the jungle anymore does not mean that we do not continue to adapt to our environment. Subtle mutations still occur. Since technology has removed much of the natural selection process, it is MORE likely that the mutant gene will continue to pass through the population. The exception to this is if the gene is a horrible disfigurment like a third eye or something that prevented the human in question from mating (no offense to any triclops out there).
Um, well it was meant to be partly tongue-in-cheek, since I was smiling in that sentence :). I agree that that experiment demonstrates the mechanics of evolution, but it doesn’t necessarily demonstrate that evolution occurs in the natural world.
BTW, I don’t think “modern” life has affected the rate of human evolution much, just changed it’s course somewhat.
I agree. If anything seems to have a serious chance to significantly affect “recent” human evolution, I’d say it was technological advances in communication. As more and more people can share ideas faster that ever, the influence of trends spreads more rapidly, driving changes in “natural selection” from choices based on “survival traits” to choices based on personal biases.
Take for example the current trend to use “thin” women in advertising. While I don’t doubt the existence of a genetic predisposition towards body types, if advertisers emphasized something like eye color, or six fingers on one hand, it could affect future generations, and we could wind up being “bred” for aesthetic traits rather than functional traits.
Hi, Kricket. I wanted to see if I can get back to your original questions, and perhaps give a top level clarification.
Things are still evolving. Humans are still evolving. We are more controlling of certain factors that would kill us off otherwise (like poor eyesight), so people can reproduce that normally wouldn’t. But evolution is still occurring, if there is less pressure from the environment driving us in a direction.
There are lots of different organisms, from animals and plants, to single-celled monera, to fungi. These are at all sorts of complexity levels. It is difficult for a species to transition between complexities because, as was pointed out, those ecological niches are already filled. There is only a certain amount of resources (sunlight, plant matter, whatever serves as food source) in a given niche. If a current species already occupies that niche, it is difficult for a new, non-established species to move into that niche because the established one will out compete it. It has to be highly advantageous to take over a particular niche. Also, major changes of this type don’t show up in a week, a month, a year, a human lifetime. So it would be very difficult to witness.
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Or, if we came from apes, why haven’t we seen once of them evolve?
I think you mean, evolve into human-like primates (i.e. intelligent, upright, large cranium, etc). That’s because we are already here, so the environmental pressures that would drive those species in this direction are hindered by them having to compete with us for those resources.
Also, you seem to think evolution has a goal of producing smarter or more complex beings. It doesn’t. The only goal is making each species survive better. Or eliminating it. More properly, there is no goal, only populations changing by the natural processes. There is no direction to evolution, up = better. Think about this - even after the millions of years to evolve humans, bacteria are still running rampant across the globe. If evolution were only about progress, all the bacteria would have died out when there was something better, i.e. multicelled organisms.
Since nothing “just stopped”, this is a meaningless question.
You may not see it, but it’s happening. It just takes so much longer than human observational ability that the changes aren’t visible at the level they’re occurring.
You seem to have some misconceptions about what evolution is and how it works. These misconceptions are what makes many people find it hard to accept. http://www.talkorigins.org/ is a very good resource for learning about what it is all about.
