No, a trait does not need to convey a survival advantage to spread through a population, that’s right; it could be neutral, or even slightly disadvantageous. Similarly, slightly advantageous traits can fail to be selected for. (In my defence, I did say that steps ‘up’ in the fitness landscape are only more likely than steps ‘down’, not that the latter can’t occur; however, my wording otherwise was perhaps less than precise.)
My concern was merely that I couldn’t even see these traits (of the sticking stinger and the auto-injector and so on) developing in such a consistent manner even on a flat fitness landscape, where there’s no distinction between advantageous and disadvantageous traits, with any likelihood, and that any sort of actual selection would make this even less likely.
However, I guess if one separates the development, and for instance the detachable venom pump developed to mitigate the disadvantage of the bee’s death, it makes some more sense.
Survival of the fittest is good betting advice, on a micro basis, but for geologic time, nothing survives, the more successful at adapting to change reproduce in greater number.
A species that just happens to be able to digest plant material that evolves after their species has diverged, and spread throughout the ecosystem did not plan on it. The biochemistry that allows it to happen didn’t kill them. When it turned into a benefit, they flourished, while other species became extinct.
Random deaths do affect evolution. It is possible that many useful, and potentially dominant characteristics never became widely enough dispersed in their respective genomes to survive through a time of increased mortality.
The first mammals might have had a 10% incidence of telepathic sensitivity to other animals. Unfortunately the 87% average mortality among the earliest generations of that species included every single one of them. Shame about that.
A particular copy error in one gene set turned elements of a reptilian skeleton inside out during development. Oddly enough some of those who inherited that gene did not die. And for millions of years afterwords that skeletal anomaly evolved into turtles. So successful a genus that all of it’s members have a remarkably similar gene set to this very day.
Did God plan it? That is a philosophical question outside the realm of biology. But the Turtles did not plan it. They just did the two things that an individual life form can do to participate in evolution. Breed first, then die.
“Seems” is the key word here. Your assumption is apparently incorrect. Apparently the sacrifice of one bee in defense of others who share her genetic material, thus passing on her own genes though indirectly, is adaptive behavior.
And I still reject your insistence on metaphors of higher or lower. A better metaphor, I think, is the image of a flood of water seeping onto a plain; as it spreads and separates into various streams, little obstacles or clear paths help to direct its flow. That flow is lateral–even downward. But the process is one of the fluid passively, not actively, finding its path. Evolution tends more toward diversity than toward perfection. As each new iteration of diversity presents itself, some are adaptive and some are not. The illusion of progress toward something “better” is a human concept; in essence a literary metaphor. It has no place in the scientific discussion of natural selection, which is a war of attrition, not perfection.
R. A. Fisher and Sewall Wright would disagree. The notion of fitness landscapes with peaks is a commonly used, if imperfect, metaphor in evolutionary biology.
Evolutionary biologists would speak in terms of “higher (inclusive) fitness”. Nothing wrong with that.
The most straighforward answer to the original question–that the worker’s death is a cost that must be paid for the larger benefits of effective stings–has more or less been given. I don’t think all the discussion about how evolution “really” works adds anything.
I think the point of the question though is what are those critical optimization factors that would make a bee dying a good solution. Sometimes scientists have a decent clue as to what those may be. For example: The answer posted above from wiki in which the stinger is primarily used for bee to bee combat is exactly one of the types of answers I think the op was looking for.
It’s a standard metaphor for assuming the N dimensional optimization solution set can be pictured like a 3D landscape with high areas being better solutions for the specific problem (i.e. niche in this case).
An additional thought regarding the op: Possibly we just happen to be at the point in time where this is a workable solution, but with additional time the stinger or bee will continue to evolve and reduce the number of deaths.
Come now. Nobody could interpret it as a retreat, especially in the context of the post, which contradicted your claims.
You seem to be trying to turn this into an unpleasant argument that is more about who is more clever than what is correct.
I was trying to be relatively gracious. For clarity, here’s a blunter version of what I meant: I don’t see why simple questions such as “why does this seemingly maladaptive trait persist” must be met with often amateurish lectures about how evolution “really” works. Others made similar comments above.
Not only do we have this straightforward answer, we have another, contradictory one as well - that the bee sting is mainly designed to kill other bees and that its use against mammals is so rare that it hasn’t been fazed out by evolution, even though its use against mammals results in the bee’s death. I’d be interested to know which one is right.
I suspect that the first answer is more likely, but I think this is a much more fruitful area of debate than going over irrelevant details of evolution (and I second the complaint about people who come into threads about evolution and say something like, “Evolution never has to come up with perfect solutions, it just has to come up with something good enough”, then sit back and bask in their intellectual superiority. It’s not helpful).
Not at all. This entire discussion centers specifically on how evolution “works.” To suggest we stay away from that aspect simply because you want to maintain an unworkable metaphor strikes me as vaguely ridiculous.
That’s an astonishing leap. Where were we discussing all scientists and mathematicians? Where were we discussing anything outside of this discussion? (Note: If you have to extrapolate someone’s point into a straw structure that encompasses everyone and everything before you can challenge it, your position is probably not as strong as you think.)
I’m implying nothing further than what I said: such a metaphor, which may or may not be harmful in other contexts, is only serving to muddy the waters in this particular discussion: the metaphor itself, with no other evidence, keeps being offered as a challenge to the factual information that’s been provided. That makes it unhelpful in this context. I was not addressing any other contexts; and it’s only those imaginary contexts that I’m NOT addressing that you’re challenging me on. Fail.
That’s why I like to ask the question like I did, so you have an opportunity to either confirm my understanding or explain your position.
Why do you think the metaphor is muddying the waters?
Is it because you think that the bees current solution is the best they will ever do given the current niche they are in because there is no advantage to changing (with respect to current niche) and the “uphill” better solution thing implies animals evolve even when there is no pressure?
Well then my answer obviously is “no,” to a question that is basically “Are you saying you extend what you specifically say in this discussion to the widest possible range of irrelevant discussions?” Then, yeah, um, “no.”
Because every time someone provides an answer based on fact or science, explaining why the phenomenon under discussion works well enough, which is all that natural selection requires, someone keeps coming back with, “Yeah but wouldn’t it be BETTER if they DIDN’T die?” Which is irrelevant, and is a result, if you ask me, of the insistence on a metaphor which suggests upward or forward progress. Hence muddied waters.
Again, an irrelevant extrapolation that serves more to reveal the faults in your own position than to offer anything substantive to this discussion.
Evolution is outcome, not process. Every reproduction of every critter throughout all history has involved alterations in the genetic code, from the progenitor, to the ancestor. Trillions of such events every year, for billions of years. Each has some interaction with the probability that some genetic code will, or will not be duplicated in subsequent generations.
In the case of the bee, bees that sting mammals are not included in the process of evolution, since they were never going to pass on their genetic heritage. Their near relatives may. The improvement of the probability that those relative will survive is a beneficial genetic characteristic for the hive. The benefit to the individual has no evolutionary importance in this case. Because of that the outcome has favored the continuation of the characteristic in the species.
Note the past tense. Has favored. May favor it in the future, may not. It is not a plan, it is the outcome. The outcome may be different in the future.
Survivability is a probability, and only matters in total populations.
But it is NOT irrelevant. If having the worker bees survive improved the chances of the hive surviving and producing a future queen, then you can bet that barbed stingers would be selected against. (Especially since the gene for smooth stingers already exists - the queens express it!)
On the contrary, the fact of the aforementioned specialization between queens and workers and the fact that most closely related species have smooth stingers both suggest rather strongly that barbed stingers were evolutionarily favorable.
Your idea that evolution stops at “good enough” is quite ass-backwards. “Good” and “better” have clear meaning in evolutionary contexts: they refer to greater reproductive success. What does “good enough” mean? Good enough for what? What process in evolution decides, “Well, I guess that mutation might be an improvement, but this phenotype is good enough”? The answer is none! Even in the absence of selective pressure, mutations occur more or less at random, and unless the mutations result in virtually no differences in reproductive success rates, selection will occur. There is no “good enough” evolutionarily speaking because evolution doesn’t know when to stop.
It also doesn’t know where it’s going or how to get there, but that has nothing to do with the question being asked.