It's not poachers that cause elephants to evolve not to have tusks.
It's that some elephant got a rare mutation, and those mutated elephants aren't as targeted by poachers, thus are able to survive more easily.
Plenty of popsci journos write as if nature is intelligent and driven by some purpose.
Cause and effect are very complex concepts, probably not even well understood ones, but I would rather avoid descending into the philosophy of cause and effect, so I will just pick a potentially naive idea of cause and effect. Assume a counterfactual world without poachers, would the elephants evolve to be tusk-less? No, so the poachers cause elephants to become tusk-less.
It's that some elephant got a rare mutation, and those mutated elephants aren't as targeted by poachers, thus are able to survive more easily.
That is the mechanism at play under the hood, but it does not mean that the abstraction of poachers causing tusk-less elephants or even more abstractly that evolution causes tusk-less elephants under those circumstances are not also valid descriptions.
Plenty of popsci journos write as if nature is intelligent and driven by some purpose.
Which - to a certain extend - is fine. Countries go to war, wars cause destruction, companies go bankrupt, rivers flow to the ocean, holidays make people happy, programs produce outputs, moving the mouse with the left button down selects text, ... none of this is really true in a certain sense. But that is fine, all our words are abstractions and we understand what they really mean, they do not have to be understood literally and the meaning can be context-dependent.
If a species lacks the preexisting genetic diversity here, it dies.
This sounds like an argument made by creationists to deny evolution. The genes were always there and we are just seeing a change in expression.
When people of science have silly public debates like this, science loses. Stop being pedantic!
Of course they would! I can't see how you can disprove that. In both that world and ours there are or have been tusk-less elephants, elephants with two heads, elephants that live 150 years.
Evolution is pseudo-random. The whole of nature gives context and some variants thrive better within this context. It is illogical to take life out of its natural context and think whether it would have evolved differently.
Your question should be rephrased as "would elephants without tusk thrive and outcompete regular elephants in a poacher-less world?" Maybe yes, maybe no, but my point is that evolution occurs every time a new elephant is conceived, and maybe the resulting animal lives longer.
The word »evolve« in that sentence means exactly what you say, »thrive and outcompete regular elephants«, or at least that is the way I wanted it to be understood. What is your definition of that word in that context that makes the sentence mean something different?
Mutation occurs. Evolution is when the population changes, not individuals.
In this time frame it is unlikely elephants would have evolved without tusks in a world without poachers, because in that scenario tusks are an advantage.
Living longer is secondary to evolution. Producing more offspring, which can produce offspring itself is what matters.
If an animal becomes old and endangers the herd it is harm for selection. If it can't produce offspring anymore, but protects the youngers it can be useful for survival rate.
We only see the result of it. The observation that evolution helps find a better local maximum is literally survivorship bias.
Biological evolution is due to reproductive selection. Evolution is primarily related to reproduction: survival only matters if it affects reproduction (after all, nothing survives in the long term).
Evolution is not really defined as random change: evolution occurs due to selection pressures that amplify the genetic population of the most successful reproducers.
Genetic mutation and recombination is somewhat random, but not purely random (certain mutations are more or less likely, and the pool of successful recombinations is very biased).
It is a frustrating topic, because in biology evolution has a very particular meaning, yet biological evolution is usually misunderstood. The misunderstanding is due to the popular incorrect metaphors and alternative meanings for the word.
https://wikipedia.org/wiki/Evolution
Disclaimer: I am not a biologist. I’m trying to be as clear as I can, while making sweeping simplifications (e.g. ignoring kin selection etcetera!) I welcome any mistakes being corrected by lurking biologists.
You might want to read “The intentional stance” by the famous philosopher Daniel Dennett. This is a pretty useful analytic approach for many problems (e.g. we commonly say things like “the thermostat tries to keep the temperature within three degrees of its set point”).
I agree it is distressing that many people interpret such metaphors literally.
This has become the midwit anthem, as pg put it, whenever we use causal language to describe evolutionary pressure.
You're correct. This happens often, too often.
