Does evolution explain intelligent life?

Evolution is not a “proven fact.” It is a theory with a lot of supporting evidence. Why are we different from animals? I would like to ask you how come we are so similar to animals? Why are not other animals considered “intelligent” so far? Well, some do consider other animals intelligent. But humans just got there first. Other animals may yet gain enough intelligence to compete with us.

As to finding animals on other planets—all I can say is that I know of no evidence so far to support or gainsay the existence of such creatures. So I remain agnostic on the issue. It is possible. But there’s no evidence I know of to support it.

1. Humans are different from other animals because we have very advanced language, culture, and tools. But, we are not the only animals like this. Chimps make and use multi-part tools. They evolve distinct “cultures” with different groups making tools in different ways. Dolphins also use tools and communicate in ways that approach human language. We aren’t that different, biologically, from other animals—the slight difference between us and chimps has simply allowed us to develop language, and that’s what’s really important.

2. Asking “Why are there still apes?” means, frankly, you don’t understand how evolution works. Evolution is not a ladder, with “lower” organisms evolving into higher organisms. It’s a bush. There are still apes because apes are still very well adapted to their environments. For the same reason, there are still fish, because fish are still adapted to their environments—we evolved from fish, too.

3. Why haven’t other animals developed intelligent societies? They don’t have big brains, and they don’t have language. It’s really as simple as that. But like I said, chimps have developed cultures. The divide isn’t that big.

4. We are animals. Humans are animals. We are not plants, fungi, or single-celled organisms. Asking about planets full of just animals makes it seem like you don’t know that you’re an animal.

@wundayatta, actually, evolution is a fact. In science, the word “theory” doesn’t mean “not a fact.” A scientific theory is a broad idea that is considered proven because it explains such a wide variety of facts. Scientists consider evolution proven and factual.

Finally, “Ancient Aliens”? I just briefly read about this show.

Please, don’t use shows like this to educate yourself about science.

High intelligence is just one of many survival traits that a species can evolve, and we humans are very fortunate to have evolved it. But, like you, I’ve also noticed that we humans are so dissimilar to any other animal on the planet (yes, humans are mammals and are members of the animal kingdom) and sometimes wonder why.

As for other planets, we won’t know the answer until we find a few other life-bearing planets, but I think that high intelligence will prove to be such a rare survival trait that, yes, we’ll find only “animals” on other planets (and the answer to the Fermi paradox).

As for theory vs. fact: yes evolution is a theory, but so is gravity. I’ve yet to see anyone rise up off the earth and float out into space because they believe that gravity is “only” a theory. The evidence for evolution is overwhelming, and so far is the only plausible explanation for all the variation in species, so you wouldn’t be totally off-base for treating it as fact.

And I second what @Qingu said: don’t base your knowledge of science on nonsensical TV shows.

@Qingu A scientific fact is defined as “an observation that has been confirmed repeatedly and is accepted as true (although its truth is never final)” source

The more probabilistic the evidence for a certain theory, the less comfortable I am calling it a fact. And generally, I don’t like to use that word at all, unless I’m being rhetorical. I think that part about truth never being final is a crucial thing to understand. All knowledge is provisional. Calling things facts is misleading in that way.

@wundayatta, that’s pedantic and ultimately much more misleading.

First, I don’t know what you mean by “probabilistic” evidence.

Second, the fact you don’t like to use the word “fact” is more of your own pecadillo; the word has meaning and semantic clarity; it is colloquially used to mean “something which is true.” Evolution is true.

Third, yes, knowledge is ultimately and necessarily provisional. Therefore we can’t say “if you jump off a cliff, it is a fact you will fall to the ground and die?” Because our understanding of the theory of gravity is provisional and we might be wrong? Give me a break.

I expected some of you to point out that humans are just animals, and also expected some to say that animals are intelligent, too. I don’t know how else to explain, but humans are different, very different. So different that sometimes it seems that we don’t belong here, and I think that is why some believe that we may have been transplanted here from another world. Or maybe that intelligent aliens mixed their DNA with local animal life and we were the result. Before you all start calling me a nut and a crackpot, let me say that I don’t really believe all that. I just wonder what theories others may have about how we became so different. Telling me that we’re not different isn’t helping. Even I can see that we are. And thanks, HungryGuy, your answer is very thought-provoking. However, I am not basing my knowledge on a stupid TV show. It just got me thinking about these things.

Amphibians are very different from fish. And yet they evolved from fish.

Oh come on! You know what I mean. No other animal on this planet plants food, raises and domesticates other animals, invents modes of transportation, amasses armies, invents weapons (except maybe throwing sticks or poo.) Surely I don’t have to explain to you what makes humans different than the animals we share this world with.

Actually, ants raise and domesticate aphids and raise armies. Chimpanzees invent weapons (they use spears to hunt) and raise armies too.

And let’s go back to fish and amphibians. Imagine you’re the first true amphibian asking “why am I so different from the other vertebrates?” There are, of course, fish that are a lot like amphibians. The lungfish can breathe out of water, for example. A bunch of little steps and differences separate the lungfish from the first true amphibian.

In both cases, a series of small differences from the ancestors allows the species to take on a hugely different role and survive in a hugely different environment. In the amphibians’ case, a lucky set of adaptations lets them survive mostly out of water, where the lungfish is sort of stuck in both worlds. In humans’ case, a lucky set of adaptations (big brains, developed vocal cords, bipedalism) allows us to use language, transmit culture, and farm—whereas chimps are stuck in between.

@wundayatta – evolution is not really even a theory. It’s an empirically provable phenomenon. The theory explaining it is natural selection, which @Qingu explained pretty well.

So Qingu, I appreciate your input. You are saying that our larger brains and development of language largely allowed us to develop beyond other apes? So, why do you suppose that other apes have not or cannot also develop these adaptations? Why are chimps’ evolution stilted?

@Qingu and @bolwerk just to clarify for my curious mind, when you say natural selection; do you mean individual, kin, group selection or all of the above?

The theory of evolution is one possible explanation.

@Skaggfacemutt, it’s like asking why coalecanths didn’t develop leg-fins and lungfish did. Because, um, they didn’t.

We’re the apes that happened developed huge brains, tool use, and bipedalism; chimpanzees are the ones that relatively large brains, moderate tool use, and stayed half their lives in forest canopy.

Also, the way you phrased that, it sounds like you think chimpanzees or orangs could just up and decide to grow bigger brains and complex larynxes. That’s not how evolution works. Those adaptations takes hundreds of thousands of years of mutations sculpted by natural selection.

@bolwerk, actually, evolution is a theory and a fact. Natural selection is part of the theory of evolution.

The confusion here deals with the word “theory.” In everyday language, a “theory” means something like guesswork. But in scientific language, “theory” has a specific meaning. It’s a complex explanatory idea that is considered proven by the scientific community: for example, “the theory of relativity.”

Scientific theories aren’t necessarily the end-all-be-all. Relativity doesn’t apply to quantum-scale phenomena, only large-scale phenomena. Likewise, biological evolution doesn’t apply to chemicals, or to the formation of galaxies. Theories only fit a certain scale and range of phenomena; but they are considered proven/factual/what-have-you, not guesswork.

My wife is hooked on Ancient Aliens and so I end up being subjected to its “theories” and I can tell you they are nothing but junk science. There is no credible evidence that ancient aliens visited Earth. If that had happened, and if they “messed with” DNA to either create humans or make them vastly more intelligent than other life forms, we would see it in mitochondrial DNA and we do not. We see a smooth progression upward from single-celled organisms through ever more complex organisms to the species that exist today.

Also, we see a slow and steady progression in intelligence of species as evolution proceeds. Certainly homo sapiens and neanderthals were great leaps forward; but we see such specialization in other survival strategies of other species as well. Consider how specialized the nose of the great woolly mammoth and elephant are. The appendage is highly specialized, allowing the huge animals to reach tender leaves far up in trees, pull food up from the ground as if they had hands, breathe, smell, drink water, give themselves a shower, and make a wide range of very loud vocalizations.

Add to that the fact that the Ancient Alien series uses “evidence” such as the pyrimids being impossible to build by ancient humans, etc. This all targets a building spree less than 4000 year aga, and even if Stonehenge is included, no more than 10,000 years ago. How about neanderthal? Neanderthals weren’t stupid either. As far back as 50,000 or 100,000 years ago, they were developing tools, learning to make clothing, etc.

@Skaggfacemutt, upon reading my answers, I think I come across as more flippant than I should. I actually think you’re asking a very good, and fascinating, question. Because you’re absolutely right: something is clearly going on with us humans that is unprecedented in the history of biology. To be clear: what I’m disputing is that this requires supernatural explanation, whether through aliens or whatever.

To give some perspective, we can look back at the history of life on our planet and see a few “watershed” events that completely changed the course of life. I would say humans are obviously doing that right now. But there were other developments that were just as amazing:

• The development of multicellular creatures. It’s hard to believe that only a billion or so years ago, everything on this planet was single-celled. And there are organisms that skirt the line between single-celled and multicellular creatures. For example, you can put a sponge through a fine-mesh strainer. It will break up into individual cells. Then the cells will eventually all migrate together again, forming the multicellular sponge animal. Is the sponge a single animal, or a colony of cells? It’s on the boundary.

• The development of sexual reproduction. Before there were “males” and “females,” all organisms reproduced by cloning. Cloning meant there wasn’t much genetic variation. Bacteria sometimes get around this by “gene-swapping.” But it’s pretty clear that sexual reproduction is hugely responsible for the tremendous diversity of multicellular life. It’s hard to appreciate how amazing this is, because all familiar animals use sexual selection.

• The cell nucleus and organelles. This is another thing that’s easy to take for granted. But most organisms are bacteria, and they don’t have a nucleus. They also don’t have the energy-storage sacs in their cells, mitochondria. Without a nucleus and without mitochondria, cell size and complexity was hugely limited. Again, once these structures develop, life took on a quantum leap in complexity. Scientists think these structures may have come from “engulfed” bacteria eaten by other bacteria but not digested.

And then there’s the development of life itself from complex chemicals. We actually have a pretty good idea how this happened (lipids form bilayers in water spontaneously; RNA could have acted both as a catylyst—like proteins—and info storage like DNA), but of course, it was still amazing.

So, maybe humans are on the verge of another world-changing epoch in the history of life. Richard Dawkins proposed an idea, the “meme,” as a unit of cultural evolution that works sort of like genes in biological evolution. Clearly our cultures and technologies evolve (look at the evolution of cars in the past 100 years, or computers in the past 20). And this evolution also appears to be much, much faster than biological evolution—almost all of it has happened in just 10,000 years, which is a blink of an eye in terms of biological evolution.

What I would say is, we are the lucky apes whose biological evolution allowed us to jump-start an entirely new form of life. Just like sponges were the lucky single-celled creatures with a few lucky mutations that let them form colonial “big bodies.” But in both cases, it was a smooth progression. Evolution is a bush that is always branching out in new directions, and some of those directions end up leading to whole new worlds of complexity.

@bkcunningham, sorry, I missed your question. I am certainly willing to believe that natural selection occurs on multiple “levels” apart from the genetic level (I’m assuming this is what you mean by “individual.”)

Dawkins would argue that all levels of selection (kin, sexual, group, evo-devo) can ultimately be reduced to genetic selection, that genes are the fundamental “units” of evolution. While genetic-level selection is certainly the most robustly understood, I’m not so sure about this; at least, I worry that this might be naively reductionist.

@Qingu Thanks for your most fascinating answer. Your knowledge of science and biology is staggering. @ETpro Sorry that your wife likes Ancient Aliens, but maybe she just uses their theories to start a stimulating conversation, like I do. Thanks to all of you for sharing your knowledge. I don’t know much about the mechanics of evolution and science. I am really not stupid; it just hasn’t been a subject that I have studied much. From what you have told me, I think the likelihood of finding intelligent life on another planet would be significantly more unlikely than I originally thought.

@Qingu: I understand that it’s conflated with natural selection much of the time, but I wouldn’t really call evolution a theory unto itself. There have been plenty of theories of evolution, and the most fitting is usually natural selection. Evolution itself is more a process, one that can be empirically observed. It resembles a law more than a theory.

But yes, I agree with your point about the term theory confusing people in day-to-day language.

Evolution favors complexity as long as a sun keeps shining.