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Evolution!
People LOVE to "debate" evolution. But that's silly, and doesn't really solve anything. If you are in a debate about whether or not evolution is a valid theory, you are either debating someone who has little to no idea what what evolution is, or ARE the person who has little to no idea what evolution is. That doesn't sound like very much fun, so let's not do that, okay?
Instead, this thread will be about topics in evolution, because it is much more entertaining to talk about specific cases and ideas than one big overarching theory. The topics will be chosen by whoever has the best topic, with all "lesser" topics being ignored and forgotten.
Now, I'll start us off with what actually made me want to start this thread: randomness. I was reading Mage's post at the bottom of this thread, and immediately thought about genetic drift.
Here is a classic example of genetic drift in a fruit fly population:
Basically, genetic drift states that random sampling has a lot to do with the evolution of small populations. Think about it: say you have a population of four individuals, two males and two females. One female homozygous allele for blue fur, the others all have a homozygous allele for red fur. Mating between blue and red fur produces a heterzygous purple fur creature. We would therefore expect the next generation to have some purple and red individuals, and the one after that to have all three colors represented. Basic Mendelian stuff.
Now, it gets interesting. Lightening strikes the blue female. She's dead, and will never reproduce. Now, all individuals in this population will be forevermore purely red. Note that this is regardless of the fitness of these genes. Blue fur might have been much more beneficial (perhaps these creatures lived in blue grass, and it provided camouflage), due entirely to random events (as opposed to evolutionary pressures) it is RED fur that becomes fixed in the population.
Going back to and contradicting Mage's comment from before, due to genetic drift, having the same selective factors won't guarantee a particular evolutionary outcome, due to simple random events.
So.... Discuss?
- 175 Replies
Ah yes, sure. I thought you meant genetics in relation to human groups and evolution. But the process of evolution is intrinsic to life as we know it (life invariably will evolve due to its characteristics) and it has been demonstrated and observed over and over.
The images has no foreseeable connection in the thread, i think. I just can't see the connection
Refuting evoltion...
Refuting evoltion...
Well, as soon as you and your Klingon-in-a-wig get around to writing up a refutation, feel free to post it.
Personally I see this as unveiling one of the problems especially in anthropology: we see ourselves as the ones that made it out alive, and assume we must have been better, which of course sounds very coaxing to us. The true story is likely more complex, though.
I thought it was because we were more generalized than the other species of homo that existed.
The problem is likely that many anthropologists that find a new bone make a new species based on minor morphological differences to other fossils, discounting a certain degree of phenotypical plasticity (variation within a species).
And because of the completeness of our findings it's very difficult for us to pin point exactly where one species ends and another begins.
I thought it was because we were more generalized than the other species of homo that existed.
We did? i thought we are way more specialized than other homo species, as our brain capacity is largest compared to others, losing only to the Neandharthals
I thought it was because we were more generalized than the other species of homo that existed.
Now that you mention it, this must also have been an explanation, yes. The question is, can this be tested sufficiently, or is it just an idea like all others?
Anyway I had a look at the paper (you can read it online) and it seems the interpretations mentioned in there are based on archeological records. Maybe outside the record there are other hypotheses (some genetic issues are mentioned in the discussion). But still they mention the following:
"These include inventiveness and capacity for innovation, complex symbolic and linguistic abilities, more efficient hunting strategies, exploitation of a broader range of resources including plants and aquatic ones, projectile technology, heat treatment of lithic raw materials, hafting technology, planning capacities including larger scale social networks as shown by large transport distances of raw materials, environmental flexibility, memory capacity as well as larger population sizes. Inferiority in one or more of these domains has been at the core of many explanations for the demise of the Neandertals."
Some of these sound like anatomically modern humans were supposed to be more generalised indeed. Though the result of the paper seems to discard most of that.
We did? i thought we are way more specialized than other homo species, as our brain capacity is largest compared to others, losing only to the Neandharthals
Brain sizes has probably been a proxy for cognitive capabilities, but interestingly this might change in the future. There has been a publication recently looking at ant brains:
http://www.uni-wuerzburg.de/en/sonstiges/meldungen/detail/artikel/ameisen-li/
They found out that for the ants they looked at, absolute and relative brain sizes were insufficient to explain the capacities of the brain areas, as the density of the synapses also plays a role.
They say this might prove to be true for other animals as well. Though I do not expect that the different human groups had such different synaptic density, for them brain size likely has some meaning still. How else would we explain the differences?
@HahiHa
Regarding your last comment, i don't remember saying that brain size= cognitive abilities. so i fail to recognize how this relates to my comment about brain size=specialization, as i was talking about a different matter. Wouldn't this be a strawman fallacy? i just have to point that out
Regarding your last comment, i don't remember saying that brain size= cognitive abilities. so i fail to recognize how this relates to my comment about brain size=specialization, as i was talking about a different matter. Wouldn't this be a strawman fallacy? i just have to point that out
You're right. But then I have a problem, because I don't think brain size is correlated with specialisation. You can be a very specialised organism even as a slug or a flea; being specialised just means you are very well adapted to a specific environment.
If we were more specialised, then this is due to other anatomical differences. And now that I think of it, shouldn't it be the other way around? Neanderthals being just specialised for their own environment, and we were as generalists a very successful lineage world-wide that could out-compete them?
because I don't think brain size is correlated with specialization.
Our brain size is the largest in the animal kingdom, unrivaled in any way. a slug has to compete with a caterpillar, a flea has to compete with a tick, but there is literally nothing in this known world that can match our brain size in comparison to the whole body ( a whale's brain is larger than a human, but it still lose to humans in it's comparison with the whole body ), or it's complexity ( how many animals you know that can create language, civilization, use tools and farming at the same time? ), or even it's rationality ( how many animals you knew that will prefer logic and rationality over pure instinct in most cases ). Surely you can't say that we are more on the generalized group of the animal kingdom?
Even neandhartals are, in my opinion far more generalist than we do, because they have more brain capacity than even us and a larger muscular body, also because they have adapted to living anywhere on the globe minus the Siberian lands ( pretty cold there )and north americas and south ( they have to cross siberia during an ice age without knowledge of fire if they want to reach there). we are just more social than them and had the luck of inventing fire, language and advanced tools first.
Our brain size is the largest in the animal kingdom, unrivaled in any way.
No, it isn't.
[...] but there is literally nothing in this known world that can match our brain size in comparison to the whole body ( a whale's brain is larger than a human, but it still lose to humans in it's comparison with the whole body [...]
Because you've stacked the deck in favour of "relative" brain size. If we rank creatures by actual brain size, we can as easily argue that humans just have abnormally small bodies.
[...] or it's complexity ( how many animals you know that can create language, civilization, use tools and farming at the same time? ), [...]
That's a non sequiter, because none of those things are the direct consequence of brain complexity.
[...] or even it's rationality ( how many animals you knew that will prefer logic and rationality over pure instinct in most cases ).
That would be all of them.
Surely you can't say that we are more on the generalized group of the animal kingdom?
Yes, easily. Our tool-making abilities and complex language have a wide range of applications which allow us to prosper outside of our original environment. Therefore, we are clearly more generalized.
Generalists and specialists
We humans are omnivores and have spread globally. I think that puts us definitely closer to the generalist side.
But that is mostly irrelevant. Your argument was that we are more specialised than Neanderthals. To be honest, I thought it was the contrary, with the Neanderthals having adapted to the colder Northern conditions. That makes us the generalists. But I cannot really confirm anything, I will have to do some more reading as soon as I get the time.
we are just more social than them and had the luck of inventing fire, language and advanced tools first.
But... did we?
No, it isn't.
Yes it is, in comparison to the whole body.
Because you've stacked the deck in favour of "relative" brain size. If we rank creatures by actual brain size, we can as easily argue that humans just have abnormally small bodies.
Humans evolve from primates, which if compared with most other animal species have a disproportionately large brain in comparison with the whole body. In fact in human anatomy, the brain is the second largest internal organ losing only to the liver. So humans don't abnormally have small bodies, because that body size and brain size in comparison with it starts from the of the existence of both Home subspecies and other break-away branches of the tree of primate evolution;"abnormal" literally meant out of place or "not normal".
That's a non sequiter, because none of those things are the direct consequence of brain complexity.
They are a non direct consequence, but are still related to it. What does brain size and capacity do directly is intelligence, in our case it's more often called "sapience". In the long run, that intelligence can accumulate to make those that i had already mentioned.
That would be all of them.
Most of them used instinct most of the time with only limited logic and rational decision making abilities. Most of invertebrates ( Sponges, Cnidarians, Coelenterates, all worms, arthropods, gastropod, you name it)
certainly have extremely limited access to decision making abilities due to their weak neural "brains", with some exceptions like the octopus. Invertebrates make up the most of the animal kingdom about 96%. that left the vertebrates as the candidate for this ability. Excluding the earlier versions of vertebrates like cephalochordates, there are 5 candidates for this ability; fish, amphibian, reptile, birds and mammals. in most bony fishes, their logical making systems ( prefrontal cortex) are small and underdeveloped. their cartilegonous cousins are pretty much the same, with the exception of the whale family. Excluding amphibians ( due to their relatively small body size and brain size in comparison with the whole body) and reptiles ( because all of them lacked further development in the prefrontal cortex ). that left birds and mammals, which mostly have more refined abilities for logical reasoning and rational decision making compared to other types of animals.
So how do birds and other mammals compare to humans? well, they did badly, because so far the most developed prefrontal cortex belongs to humans, which gave us an unbeatable rational and logical reasoning. Only the Chimpanzee and the bonobos can reasonably be compared to us in terms of logical reasoning abilities, and even they still lost to us. Which proved my point
Yes, easily. Our tool-making abilities and complex language have a wide range of applications which allow us to prosper outside of our original environment. Therefore, we are clearly more generalized.
Complex tool making abilities and complex language is a trait only achievable by humans so far, so we are specialist in the light of our abilities. You are arguing that we humans are more generalized in the light of our habitat, which IS correct in a way, but missing my point.
So how do birds and other mammals compare to humans? well, they did badly, because so far the most developed prefrontal cortex belongs to humans, which gave us an unbeatable rational and logical reasoning. Only the Chimpanzee and the bonobos can reasonably be compared to us in terms of logical reasoning abilities, and even they still lost to us. Which proved my point
Raven and crows are very intelligent and highly social:
Problem solving in crows
Ravens keep track of others ranks
And other animals are highly intelligent too:
Other very intelligent animals
Finally, chimpanzees for example have a way better memory than we have:
The Ultimate Animal Experience? Losing A Memory Quiz To A Chimp
Complex tool making abilities and complex language is a trait only achievable by humans so far, so we are specialist in the light of our abilities. You are arguing that we humans are more generalized in the light of our habitat, which IS correct in a way, but missing my point.
Tool making and communication has been documented in many animal groups to varying degrees, sometimes astonishing.
And about your point, a specialist/generalist IS defined by how well he is adapted to a specific habitat; not by his abilities. Our abilities helped us conquer more habitats. That makes us highly adaptable primates.
But I start getting your initial point; you were saying we were more advanced in our abilities than the Neanderthals, and so we prevailed?
about your examples, I have known that some animals have more memory processing power than most humans. elephants and crows have that ability in your example. in the crow case, the subject even showed exceptional problem solving abilities. the chimp can memorize a pattern quickly. it's just that i still felt that in the end, they still lose to us in logic and rational thinking. the crow have problem solving abilities, but it loses to us in a way that it can't create tools, it just use one from the environment. Chimps may have a photographic memory, but it in some degree loses to us in a way that it can't override instinct with logical reasoning. dolphins, they have "languages", powerful memory capability, but they lose to us in the form of creating a new "language". Pigs can use a decent logical reasoning, but lose to us in the form of self-recognition. So, in the end, we still hold the title as the world's smartest animal species, because we don't have those drawbacks.
Tool making and communication has been documented in many animal groups to varying degrees, sometimes astonishing.
Complex tool making from scratch or just combining simple ingredients? Can animals have multiple communication "languages"? i don't think they have those
And about your point, a specialist/generalist IS defined by how well he is adapted to a specific habitat; not by his abilities. Our abilities helped us conquer more habitats. That makes us highly adaptable primates.
Ok then, you are right in this part. Wikipedia said so, so i have to follow through it.
But I start getting your initial point; you were saying we were more advanced in our abilities than the Neanderthals, and so we prevailed?
Yes, that's what i've been trying to imply from this last 5 comments.
At this point I want to go back a few steps and address two points.
1) As I said I think brain size is not related to specialisation. Now we know that by specialisation you actually meant our 'abilities'. This of course I cannot dispute; but then my comment on brain sizes and cognitive abilities was not so misplaced in the end, was it?
2) You say our brain capacity was the largest compared to other Homo species, "losing only to Neanderthals". How then do you explain that our abilities were more advanced than theirs?
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