I have an evolutionary biology question. Anyone can answer. I bet Viking will know and tell me I'm stupid at the same time, so it's a twofer. Why do some groups of organisms seem to speciate more then others? Take for example and ants and hominids. In the Cretaceous period the ancestors of modern ants looked like... ants. We can't tell how these animals behaved, but physically they seemed a lot like modern ants. Our ancestors at the time looked like squirrels. The changes between us and our squirrely ancestors is quite dramatic. The changes between dinosaur age ant and modern ant aren't. Why? Did they just find an optimal body plan, or are ant genetics just lazy?
God was satisfied with the design of ants. :pope:
You're still kinda squirrelly. :P
Ants do seem to be a very efficient design for a creature if you think about it. There is also the one queen per thousands thing, which may mean less genetic exchange happening. But I don't know that much about ant cross-colony genetic migration.
There is also something to the fact that you are comparing large organisms (hominids) and much smaller ones (ants). Large organisms tend to go extinct during mass extinction events or other more local disruptions. That leaves the niches they filled unoccupied, and an opportunity for a new type of large organism to evolve into that niche.
Number of contemporary ant species: 14,000+
Number of contemporary hominid species. 7
Ants are only one example. Another would be a Coelacanth, which the modern species so resembled the ancient one that it is called a "Living fossil". There are plenty of other examples like crocodiles. On the other hand mammals have changed quite a bit. Humans are but one example, but think of vast differences between the ancestors of whales who evolved from small carnivorous animals that looked like something like a wolverine.
Once something works there is no need to change it.
Quote from: Razgovory on July 29, 2014, 07:36:19 PM
Ants are only one example. Another would be a Coelacanth, which the modern species so resembled the ancient one that it is called a "Living fossil". There are plenty of other examples like crocodiles. On the other hand mammals have changed quite a bit. Humans are but one example, but think of vast differences between the ancestors of whales who evolved from small carnivorous animals that looked like something like a wolverine.
I think you are changing the nature of the question, or at least how I would have interpreted it from the comparison between humans (a large land based animal) and ants (a small land based animal).
The coelacanth is a fish, and fish species tend to be more resistant to extinction. I could point out that it is only considered a living fossil because it was once a quite common body form and is now exceedingly rare, but there are other aquatic animals that you could use as an example too.
Crocodilians are an interesting example. They have a body form that appears to have evolved multiple times -- I believe including in mammals. The larger crocodilians went extinct in the same event as the dinosaurs, so maybe this is a situation that the crocodilians that are similar to the large ones today actually died out, and were re-evolved from their cousins that survived? I don't know.
I had only used humans and ants as examples as they both infest my house. I was noting that humans are radically different in morphology then dino-age ancestors while ants really aren't. Hell, humans are radically different then their ancestors 5 million years ago. Further examples could be crocodiles which look like crocodiles from 100 million years ago and whales that don't look anything like their ancestors from that time period.
I suspect some of it is do to mass extinctions. For instance when the Permian era ended Dinosaurs took on all sorts of forms. When the Cretaceous period came to a close mammals speciated into a whole bunch of forms ranging from flying animals like bats to aquatic animals like whales. Still it doesn't explain why some animals seem to be "In a rut". I use that figuratively. Ants are of course some of the most successful animals on the planet. They just seem so unchanging compared to other animals.
Ok, I think I get your idea.
First, I think it might be a mistake (I honestly don't know) whether ants 60mya were basically identical to ants today. I suspect they are very different from their descendants. But if they aren't--and in terms of morphology, maybe they aren't--it's because they occupied a niche and that niche was never destabilized.
This is why I think they probably aren't identical, but it's feasible.
If humans were incapable of industrialization (for whatever reason, either by being slightly dumber or the Earth itself being poorer) there's a slim possibility that we'd have remained more or less unchanged for the next 60my too due to our easy domination of our ecological niche. As it stands, we'll almost certainly have radically changed ourselves by that point, of course. But superorganisms are pretty good at surviving, and we have a lot in common with ants.
Second, I think you may be overstating the difference in morphologies between a human and a lemur or utahraptor or whatever due to your natural anthropic bias. Ant morphology is that of a six-legged animal with an exoskeleton, and appears relatively constant... well, to an intelligent ant, I imagine so would the evolution of the fleshbound quadrupedal giants. :P
Without calling you stupid, because this is actually a good question. Ants are radically different from other ants. They just all look the same to us. Remember rats (the third species probably living in your house) and humans both have all the same bones and organs in all the same places, they are just slight variations of each other. The same applies to ants. You are underestimating the variation among ants. To match ants in variation we'd have to group ourselves, not as humans, apes, primatesor even mammals but tretrapods (animals with four limbs, yes that means all birds, reptiles, amphibians and mammals).
Another thing, just because you might look similar that doesn't mean that you are genetically similar. Often the big differences are caused by small genentic mutations.
Wiki says: "More than 12,500 of an estimated total of 22,000 species have been classified."
Which is a lot more than I would have expected, TBH.
Quote from: Viking on July 30, 2014, 03:33:11 AM
Without calling you stupid, because this is actually a good question. Ants are radically different from other ants. They just all look the same to us. Remember rats (the third species probably living in your house) and humans both have all the same bones and organs in all the same places, they are just slight variations of each other. The same applies to ants. You are underestimating the variation among ants. To match ants in variation we'd have to group ourselves, not as humans, apes, primatesor even mammals but tretrapods (animals with four limbs, yes that means all birds, reptiles, amphibians and mammals).
Another thing, just because you might look similar that doesn't mean that you are genetically similar. Often the big differences are caused by small genentic mutations.
I don't think ants and tetrapods are good for comparison. Arthropods and tetrapods may be. I understand that there many types of ants some quite different from each other, however these variants are not nearly as great as those between man and squirrel. Or wolverine and whale. There are radical differences between man and other apes and between different whales but if you were to look at their ancestors prior to the KT boundry you wouldn't immediately be able to say, this squirrel is a hominid or this racoons looking animal is a whale. When we look at ants caught in amber we can immediately identify them as ants. There are no ants that have evolved flippers and moved into the oceans or have started to walk upright and use fire and cell phones.
But perhaps using ants was a poor choice. There are plenty of other animals that are "living fossils", creatures whose morphology has remained static for millions of years. I can't speak for the genetics of the animals. I don't know how to read that sort of thing.
Quote from: Razgovory on July 29, 2014, 11:12:05 PM
I had only used humans and ants as examples as they both infest my house. I was noting that humans are radically different in morphology then dino-age ancestors while ants really aren't. Hell, humans are radically different then their ancestors 5 million years ago. Further examples could be crocodiles which look like crocodiles from 100 million years ago and whales that don't look anything like their ancestors from that time period.
I suspect some of it is do to mass extinctions. For instance when the Permian era ended Dinosaurs took on all sorts of forms. When the Cretaceous period came to a close mammals speciated into a whole bunch of forms ranging from flying animals like bats to aquatic animals like whales. Still it doesn't explain why some animals seem to be "In a rut". I use that figuratively. Ants are of course some of the most successful animals on the planet. They just seem so unchanging compared to other animals.
Raz, I'd point out a few things...first I'd emphasize that you are discounting too quickly the difference between large and small land animals. There are a long list of small animals (like ants) that have similar looking animal ancestors that haven't seemed to change much through the ages.
But try naming the large ones. You did come up with crocodilians. But I'd question that. First, the order evolved just 83m years ago per wiki (http://en.wikipedia.org/wiki/Crocodilia), so their 100m year date you mentioned is probably inaccurate. Second, the larger ones died off with the dinosaurs, so it is possible that the similarities between modern and ancient crocodilians is due to convergent evolution rather than direct ancestory. It is interesting that you brought up whales--I was indirectly alluding to it earlier. The common ancestor of whales was a mammal that had the appearance of a crocodile (http://en.wikipedia.org/wiki/Ambulocetus_natans). I believe there earlier version of the crocodile body type before the crocodilians--it seems to simply be a stable body type that has evolved multiple times.
In any event, crocodilians may be the exception rather than the rule.
Ants may be on the cusp of a major new evolutionary pressure - with one species (the Argentine Ant) apparently taking over vast swaths of territory and eliminating all competition.
Actually, it is even more bizzare than that - as these Argentine ants appear to be, not simply one species, but in some senses a single individual hive - genetically identical, even when on different continents.
This change is caused by humans moving ant colonies around accidentally.
We get a lot of talk about the effect climate change will have on the species diversity, and the effect habitat loss will have on the species diversity, and the effect over exploitation will have on species diversity.
But something that is talked about much more rarely is that humans are moving plants and animals around to new environments. Australia for instance has a very unique set of species because it evolved in isolation: but it is isolated no longer.
Quote from: alfred russel on July 30, 2014, 09:55:10 AM
We get a lot of talk about the effect climate change will have on the species diversity, and the effect habitat loss will have on the species diversity, and the effect over exploitation will have on species diversity.
But something that is talked about much more rarely is that humans are moving plants and animals around to new environments. Australia for instance has a very unique set of species because it evolved in isolation: but it is isolated no longer.
Agreed - 'invasive species' caused by humans moving stuff around has, so far, had a truly enormous impact. I suspect it is the single most significant thing people have done to affect species diversity.
Quote from: alfred russel on July 30, 2014, 09:16:41 AM
Quote from: Razgovory on July 29, 2014, 11:12:05 PM
I had only used humans and ants as examples as they both infest my house. I was noting that humans are radically different in morphology then dino-age ancestors while ants really aren't. Hell, humans are radically different then their ancestors 5 million years ago. Further examples could be crocodiles which look like crocodiles from 100 million years ago and whales that don't look anything like their ancestors from that time period.
I suspect some of it is do to mass extinctions. For instance when the Permian era ended Dinosaurs took on all sorts of forms. When the Cretaceous period came to a close mammals speciated into a whole bunch of forms ranging from flying animals like bats to aquatic animals like whales. Still it doesn't explain why some animals seem to be "In a rut". I use that figuratively. Ants are of course some of the most successful animals on the planet. They just seem so unchanging compared to other animals.
Raz, I'd point out a few things...first I'd emphasize that you are discounting too quickly the difference between large and small land animals. There are a long list of small animals (like ants) that have similar looking animal ancestors that haven't seemed to change much through the ages.
But try naming the large ones. You did come up with crocodilians. But I'd question that. First, the order evolved just 83m years ago per wiki (http://en.wikipedia.org/wiki/Crocodilia (http://en.wikipedia.org/wiki/Crocodilia)), so their 100m year date you mentioned is probably inaccurate. Second, the larger ones died off with the dinosaurs, so it is possible that the similarities between modern and ancient crocodilians is due to convergent evolution rather than direct ancestory. It is interesting that you brought up whales--I was indirectly alluding to it earlier. The common ancestor of whales was a mammal that had the appearance of a crocodile (http://en.wikipedia.org/wiki/Ambulocetus_natans (http://en.wikipedia.org/wiki/Ambulocetus_natans)). I believe there earlier version of the crocodile body type before the crocodilians--it seems to simply be a stable body type that has evolved multiple times.
In any event, crocodilians may be the exception rather than the rule.
I was thinking of the ancestor of whales even further back, before they even semi-aquatic. It looked like something that might raid your trash can at night. There were some types of crocdilia that looked different, but they are long extinct. The current ones look a lot like their direct ancestors. Other animals that look remarkably similar are some species of frog and fish. A lot of these things are "cold blooded". Perhaps there is some limitation in inherent in their cardiovascular system or nervous system.
Quote from: Razgovory on July 30, 2014, 03:07:35 PM
The current ones look a lot like their direct ancestors.
I'm not sure that they didn't pass through a phase where they looked different though. Virtually all land animals of a certain size went extinct at the end of the Cretaceous. Are you sure they didn't?
QuoteOther animals that look remarkably similar are some species of frog and fish.
Fish--yeah, I excluded them earlier. Larger fish species tend to be more durable. Amphibians--while there are larger specimens, I'm not sure any of the larger specimens have a continuous and consistent history going back so far.
Quote from: Malthus on July 30, 2014, 09:58:03 AM
Quote from: alfred russel on July 30, 2014, 09:55:10 AM
We get a lot of talk about the effect climate change will have on the species diversity, and the effect habitat loss will have on the species diversity, and the effect over exploitation will have on species diversity.
But something that is talked about much more rarely is that humans are moving plants and animals around to new environments. Australia for instance has a very unique set of species because it evolved in isolation: but it is isolated no longer.
Agreed - 'invasive species' caused by humans moving stuff around has, so far, had a truly enormous impact. I suspect it is the single most significant thing people have done to affect species diversity.
Bastard American squirrels and crayfish :ultra:
Quote from: alfred russel on July 30, 2014, 03:28:13 PM
Quote from: Razgovory on July 30, 2014, 03:07:35 PM
The current ones look a lot like their direct ancestors.
I'm not sure that they didn't pass through a phase where they looked different though. Virtually all land animals of a certain size went extinct at the end of the Cretaceous. Are you sure they didn't?
QuoteOther animals that look remarkably similar are some species of frog and fish.
Fish--yeah, I excluded them earlier. Larger fish species tend to be more durable. Amphibians--while there are larger specimens, I'm not sure any of the larger specimens have a continuous and consistent history going back so far.
Of course I can't be sure. When you talk about "large" animals, how large are you thinking. In my mind I was thinking larger then a rat mostly to distinguish it from things like bugs.
Quote from: Sheilbh on July 30, 2014, 05:24:13 PM
Bastard American squirrels and crayfish :ultra:
What have squirrels or crayfish ever done to you? :huh:
Quote from: Admiral Yi on July 30, 2014, 06:19:39 PM
Quote from: Sheilbh on July 30, 2014, 05:24:13 PM
Bastard American squirrels and crayfish :ultra:
What have squirrels or crayfish ever done to you? :huh:
They're both invasive species. American Grey Squirrels kill prettier Red Squirrels.
American signal crayfish are more serious. As well as outcompeting the local crayfish population they fuck up the river banks which causes problems for all sorts of other species. We're encouraged to trap and eat the oversexed bastards :contract:
Quote from: Razgovory on July 30, 2014, 06:02:09 PM
Of course I can't be sure. When you talk about "large" animals, how large are you thinking. In my mind I was thinking larger then a rat mostly to distinguish it from things like bugs.
I didn't have a firm definition in mind, but a bit bigger than yours. More than ~3 ft tall? (or in the case of a crocodile, long)
Evolution isn't a steady progress for any population. There's a variety of reasons for this:
Species that fit their niche well tend to stay in it.
Opportunities to exploit a new niche.
Sexual reproduction rate. Ant's sexual reproduction rate isn't as fast as might be expected, as the majority of it is asexual.
Adaptability of current form.
The ant morphology/hive behavior seems to be one of the sweet spots in evolutionary development. It's been developed independently at least twice (ants and termites) and both times have been very successful.
Quote from: Sheilbh on July 30, 2014, 06:25:54 PM
They're both invasive species. American Grey Squirrels kill prettier Red Squirrels.
Even our squirrels are racists :(
Quote from: frunk on July 31, 2014, 09:47:52 AM
Evolution isn't a steady progress for any population. There's a variety of reasons for this:
Species that fit their niche well tend to stay in it.
Opportunities to exploit a new niche.
Sexual reproduction rate. Ant's sexual reproduction rate isn't as fast as might be expected, as the majority of it is asexual.
Adaptability of current form.
The ant morphology/hive behavior seems to be one of the sweet spots in evolutionary development. It's been developed independently at least twice (ants and termites) and both times have been very successful.
I was not aware that some ants reproduce asexually. :blink: How is evolution even possible in that case?
FWIW I just looked it up on wiki after your comment. It indicates that some species do not mate at all. That may not be 100% accurate of course.
Well, at one point all evolution was driven by asexual reproduction.
Quote from: Maximus on July 31, 2014, 11:29:38 AM
Quote from: frunk on July 31, 2014, 09:47:52 AM
Evolution isn't a steady progress for any population. There's a variety of reasons for this:
Species that fit their niche well tend to stay in it.
Opportunities to exploit a new niche.
Sexual reproduction rate. Ant's sexual reproduction rate isn't as fast as might be expected, as the majority of it is asexual.
Adaptability of current form.
The ant morphology/hive behavior seems to be one of the sweet spots in evolutionary development. It's been developed independently at least twice (ants and termites) and both times have been very successful.
I was not aware that some ants reproduce asexually. :blink: How is evolution even possible in that case?
FWIW I just looked it up on wiki after your comment. It indicates that some species do not mate at all. That may not be 100% accurate of course.
From the wiki:
QuoteThe life of an ant starts from an egg. If the egg is fertilised, the progeny will be female (diploid); if not, it will be male (haploid).
There's always a chance for some random mutation during reproduction even if it is asexual. There isn't nearly as much genetic variety possible, but it is there.
Most of us probably know that bacteria reproduce by fission asexually. But you may not know that some bacteria have methods of gene transfer in their reproductive cycle, creating a sort of sexual mechanism of reproduction.
It has been a while since I was in school, so this theory may not be current anymore, but in college I was taught the theory that bacterial lines that can only reproduce by fission--true asexual reproduction--are all less than 10,000 years old. Apparently while asexual reproduction is more efficient in the short term, in the long term it slows evolution to the extent that it is a dead end. So asexual reproduction keeps reevolving, only to die out after some short term success.
Quote from: frunk on July 31, 2014, 11:38:10 AM
There's always a chance for some random mutation during reproduction even if it is asexual. There isn't nearly as much genetic variety possible, but it is there.
Sure, but how does selection work then if it's just random?
BTW, I was referring to these quotes:
QuoteAmong those species that reproduce sexually, the queen may choose to fertilize eggs at will
QuoteAmong ants who do not reproduce sexually, all of the members of the colony are female.
http://en.wikipedia.org/wiki/Queen_ant (http://en.wikipedia.org/wiki/Queen_ant)
Quote from: Valmy on July 31, 2014, 09:55:11 AM
Quote from: Sheilbh on July 30, 2014, 06:25:54 PM
They're both invasive species. American Grey Squirrels kill prettier Red Squirrels.
Even our squirrels are racists :(
Nah, we got black squirrels. Apparently some introduced them to the Stanford area.
Quote from: Maximus on July 31, 2014, 11:44:46 AM
Sure, but how does selection work then if it's just random?
You have mutation x that makes you strong and fast, I have mutation y that makes me slow and weak, you thrive while I die out.
Quote from: alfred russel on July 31, 2014, 11:47:07 AM
Quote from: Maximus on July 31, 2014, 11:44:46 AM
Sure, but how does selection work then if it's just random?
You have mutation x that makes you strong and fast, I have mutation y that makes me slow and weak, you thrive while I die out.
The only mutations that matter from an evolutionary standpoint are the ones that make it into a queen, which is what, one in a million ants? What does it mean for her to be competitive? She's fed and protected. All she has to do is lay eggs.
So I guess the selective pressure isn't for stronger, faster ants; it's for more ants. Which is likely why the individual ants don't change. Their evolution is mostly at a social level.
Well generally speaking, for most female ants mutation is not desirable as they are workers who will not reproduce. Their only job is to care for the queens and drones who will pass on genes.
Quote from: Maximus on July 31, 2014, 11:58:23 AM
Quote from: alfred russel on July 31, 2014, 11:47:07 AM
Quote from: Maximus on July 31, 2014, 11:44:46 AM
Sure, but how does selection work then if it's just random?
You have mutation x that makes you strong and fast, I have mutation y that makes me slow and weak, you thrive while I die out.
The only mutations that matter from an evolutionary standpoint are the ones that make it into a queen, which is what, one in a million ants? What does it mean for her to be competitive? She's fed and protected. All she has to do is lay eggs.
So I guess the selective pressure isn't for stronger, faster ants; it's for more ants. Which is likely why the individual ants don't change. Their evolution is mostly at a social level.
The worker ants share the genetic makeup with queen, so when she reproduces their genes (or copies of them) get passed on as well. It is a bit counter intuitive, but works quite well. Some interesting work has been done on hive species evolutionary biology.
Quote from: Razgovory on July 31, 2014, 12:04:43 PM
The worker ants share the genetic makeup with queen, so when she reproduces their genes (or copies of them) get passed on as well. It is a bit counter intuitive, but works quite well. Some interesting work has been done on hive species evolutionary biology.
There is as far as I know no mechanism where observing random mutation X in one offspring leads to increased likelihood of observing the same mutation in another offspring. So even if a worker gets a beneficial mutation, that mutation is a) not getting passed on and b) completely independent of any natural selection that is going on. The only case where a mutation is going to be selected is when it occurs in a queen AND is beneficial to the queen's reproduction. Being stronger, faster etc, does not seem likely to be a factor. What does seem likely to be a factor is the ability to produce more eggs more quickly. Therefor this seems to be what will be selected for.
Other hive species may be different. Honey bees, which I am more familiar with, reproduce sexually (as well as asexually), and the queens engage in deathmatches with each other so physical traits are more likely to be selected for.
A mutation doesn't have to benefit the queen solely, or at all. A mutation that aids workers (say larger antennae or something) makes the colony more successful and thus she can produce more queens who build their own successful colonies and so on.
Keep in mind, that the genetics for both the workers and the queens are in the queens. A worker who spontaneously has a mutation won't help the hive much, but a mutation in the genetics in the queen may only manifest in the workers. Some people refer to hives of insects as "super-organisms", and that each individual can be compared to a cell. That may go a little to far, but the analogy is good way to understand how they pass on genes.
Quote from: HVC on July 31, 2014, 03:13:50 PM
A mutation doesn't have to benefit the queen solely, or at all. A mutation that aids works (say larger antennae or something) makes the colony more successful and thus she can produce more queens how build their own successful colonies and so on.
But that's not going to pass the beneficial mutation on any more than if it doesn't exist. And it's only going to affect a single worker among thousands, so it's going to have minimal impact even in the short term.
Bear in mind that many, probably even most, mutations are harmful. More queens doesn't lead to the expectation of more beneficial mutations.
Quote from: Razgovory on July 31, 2014, 03:19:35 PM
a mutation in the genetics in the queen may only manifest in the workers.
This is a good point though.
Still, the low number of mutations getting passed on would go a long way to explain the slow rate of adaptation.
Max, I did my senior paper in college in evolution in eusocial species (though focusing on a rare species of spider that is one of the only eusocial species with "normal" sexual reproduction).
I don't remember all the mechanisms for bees and ants, but what is universal in eusocial species is very close kin relationships (generally through changes in the chromosome number for some members). It is also very common to have many members unable to reproduce.
The result is that the queen's DNA (in species with a single reproductive female) must support the creation of a new community. If the queen's DNA only supports a strong queen and weak workers, her offspring will fail, as the descendant communities will not establish themselves. At the same time, workers who are unable to reproduce are prone to work for the queen's success, because without a chance to reproduce otherwise their only way to spread their genes is through the success of their own kin, such as the queen.
A mutation in the queen that leads to strong workers is beneficial to the queen--her offspring will be better workers, and her fellow queen descendants will also produce better workers.
Sometimes ant communities (similar to some other eusocial species) are referred to as "superorganisms" because despite having many members they are genetically tied to a single cause (and from an evolutionary pov are similar to a single organism).
Quote from: Maximus on July 31, 2014, 03:20:04 PM
Quote from: HVC on July 31, 2014, 03:13:50 PM
A mutation doesn't have to benefit the queen solely, or at all. A mutation that aids works (say larger antennae or something) makes the colony more successful and thus she can produce more queens how build their own successful colonies and so on.
But that's not going to pass the beneficial mutation on any more than if it doesn't exist. And it's only going to affect a single worker among thousands, so it's going to have minimal impact even in the short term.
Bear in mind that many, probably even most, mutations are harmful. More queens doesn't lead to the expectation of more beneficial mutations.
the mutation isnt at the worker level, it's at the queen level. Since one queen produces all the workers all the workers would have that trait. Long antennae or mandibles wouldn't benefit the queen, but they would benefit the colony, and thus would be passed down the generations
Quote from: Valmy on July 31, 2014, 09:55:11 AM
Quote from: Sheilbh on July 30, 2014, 06:25:54 PM
They're both invasive species. American Grey Squirrels kill prettier Red Squirrels.
Even our squirrels are racists :(
Or at least, better armed. :hmm:
Quote from: Maximus on July 31, 2014, 03:20:04 PM
But that's not going to pass the beneficial mutation on any more than if it doesn't exist. And it's only going to affect a single worker among thousands, so it's going to have minimal impact even in the short term.
Bear in mind that many, probably even most, mutations are harmful. More queens doesn't lead to the expectation of more beneficial mutations.
A mutation that goes to a single worker is a dead end.
A mutation that goes to a future reproductive member, such as a future queen, is not.
I don't know that this would slow mutution rates. What could slow mutation rates is that in species with haplodiploidy (common in eusocial species) the haploid members will be unable to mask the effects of a negative mututation.
Quote from: alfred russel on July 31, 2014, 03:24:26 PM
Max, I did my senior paper in college in evolution in eusocial species (though focusing on a rare species of spider that is one of the only eusocial species with "normal" sexual reproduction).
I don't remember all the mechanisms for bees and ants, but what is universal in eusocial species is very close kin relationships (generally through changes in the chromosome number for some members). It is also very common to have many members unable to reproduce.
The result is that the queen's DNA (in species with a single reproductive female) must support the creation of a new community. If the queen's DNA only supports a strong queen and weak workers, her offspring will fail, as the descendant communities will not establish themselves. At the same time, workers who are unable to reproduce are prone to work for the queen's success, because without a chance to reproduce otherwise their only way to spread their genes is through the success of their own kin, such as the queen.
A mutation in the queen that leads to strong workers is beneficial to the queen--her offspring will be better workers, and her fellow queen descendants will also produce better workers.
Sometimes ant communities (similar to some other eusocial species) are referred to as "superorganisms" because despite having many members they are genetically tied to a single cause (and from an evolutionary pov are similar to a single organism).
That's where sit gets wierd with these Argentine ants - they have many queens who are all very closely related genetically - forming, as it were, a single, globe-spanning mega-colony: in a sense a single organism (in that the individual ants treat each other as if from the same colony, rather than competitors).
Given the Argentine ant's aggressiveness towards other ants, it is possible that this single organism may displace most other ants - that is, until it is killed off by some disease. That's the problem with being TOO genetically similar.
Quote from: alfred russel on July 31, 2014, 03:24:26 PM
A mutation in the queen that leads to strong workers is beneficial to the queen--her offspring will be better workers, and her fellow queen descendants will also produce better workers.
But this was half my point. Only the mutations that hit the queen are going to matter. Only one in a million(or whatever rate) is going to even get a chance to compete. How could that not slow adaptation?
The other half of my point, that "worker" traits would not be selected, has been refuted and I withdraw it.
Quote from: Maximus on July 31, 2014, 03:23:17 PM
Quote from: Razgovory on July 31, 2014, 03:19:35 PM
a mutation in the genetics in the queen may only manifest in the workers.
This is a good point though.
Still, the low number of mutations getting passed on would go a long way to explain the slow rate of adaptation.
I do remember reading an explanation of how genetics work with eusocial insects from one of Dawkins books (I think). I'm on record here as a critic of the man, but his explanation of how natural selection worked impressed me.
Quote from: Maximus on July 31, 2014, 03:35:23 PM
But this was half my point. Only the mutations that hit the queen are going to matter. Only one in a million(or whatever rate) is going to even get a chance to compete. How could that not slow adaptation?
The other half of my point, that "worker" traits would not be selected, has been refuted and I withdraw it.
The male ants that queens mate with also can contribute to evolution. From that perspective it isn't any different than any other normally sexually reproducing animal.
Quote from: Malthus on July 31, 2014, 03:33:37 PM
That's where sit gets wierd with these Argentine ants - they have many queens who are all very closely related genetically - forming, as it were, a single, globe-spanning mega-colony: in a sense a single organism (in that the individual ants treat each other as if from the same colony, rather than competitors).
Given the Argentine ant's aggressiveness towards other ants, it is possible that this single organism may displace most other ants - that is, until it is killed off by some disease. That's the problem with being TOO genetically similar.
That sounds like a similar dynamic of the spiders I did my paper on...sexually reproducing, but considered eusocial. It seems it evolved because of massive inbreeding--even though each member of a community could selfishly go their own direction to the detriment of the others, they were actually so inbred they were more related than most haplo-diploid species that are more common eusocial examples (like ants). The thoughts were that this might be an evolutionary dead end. Inbreeding might be great for promoting teamwork, but over the long term has drawbacks.
Only your ants, rather than forming more normal eusocial communities based on inbreeding, seem to have squared the relationship, but compounding normal eusociality with the inbred version.
Quote from: alfred russel on July 31, 2014, 03:58:31 PM
The male ants that queens mate with also can contribute to evolution. From that perspective it isn't any different than any other normally sexually reproducing animal.
I was referring to the species that only reproduce asexually. None of this applies if there is sexual reproduction in the mix.
Quote from: Maximus on July 31, 2014, 04:33:58 PM
Quote from: alfred russel on July 31, 2014, 03:58:31 PM
The male ants that queens mate with also can contribute to evolution. From that perspective it isn't any different than any other normally sexually reproducing animal.
I was referring to the species that only reproduce asexually. None of this applies if there is sexual reproduction in the mix.
I'm not aware of a species that only reproduces asexually.
Quote from: alfred russel on July 31, 2014, 04:56:00 PM
Quote from: Maximus on July 31, 2014, 04:33:58 PM
Quote from: alfred russel on July 31, 2014, 03:58:31 PM
The male ants that queens mate with also can contribute to evolution. From that perspective it isn't any different than any other normally sexually reproducing animal.
I was referring to the species that only reproduce asexually. None of this applies if there is sexual reproduction in the mix.
I'm not aware of a species that only reproduces asexually.
Fags.