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RE: “Don’t change… evolve” – is that so? Three misconceptions about evolution that you might have involuntarily assimilated.
Well, I also feel the phenomenon of 'co-evolution' might just be a serendipitous event, that is, it occurred by pure chance. The few evidences available are not just enough to establish it as a theory.
Surely, there are lots of examples of co-evolution? You have predator / prey relations including 'arms races', flowers / insects that have evolved to depend on each other (as opposed to more generalist relationships). Parasite / host relations, along with those of symbiotic species that continually co-evolve as well. There is stacks of evidence for co-evolution. 'Random' (non-directed) genetic mutations happen and natural selection acts on them. Those that natural selection favours spread through populations. If a trait proves favourable and spreads through a particular species, similar processes will take place in other life forms that routinely interact with it (or else the characteristics of the second species' niche will have to change). If something has a specialised diet and can't co-evolve to meet changes in its preferred prey, it has a good chance of going extinct. And species do go extinct, naturally. But many don't - due to co-evolution / evolving to interact with other species instead, successfully enough to sustain sufficient population sizes.
Life's all about co-evolving.
But don't you think the supposed coevolution might actually be as a result of different adaptive radiations that have nothing to do with relationships?
A very quick example off the top of my head and close to my heart...
The apple tree.
Why does it produce flowers? So that it can reproduce but pollen transfer isn't facilitated by the wind. Apples are insect pollinated. Insects get a reward by visiting the flowers in that they eat the nectar. The apple tree gets to reproduce when its pollen is taken to the flowers of other apple trees where it fertilizes an ovule.
Eventually, the ovules develop into seeds which are encased in juicy flesh: the apple. The apple falls off the tree and lands on the ground beneath the tree. As there's a tree already, it doesn't pay the original tree to have its offspring growing directly beneath it. Along comes a horse which likes the taste of apples. It eats it. All of it (seeds included). Then it toddles off and walks a fair distance whilst it digests its meal. Some hours / miles later, it egests its waste. The apple seeds are almost certainly not going to be competing with the parent tree. They land on the ground, covered in rich fertilizer waiting for that moment when they'll be stimulated to germinate. A new apple tree grows. That's life.
You could argue that's all down to 'pure co-incidence' but most people will laugh in your face if you do.
Look at the fossil record. Say, around the time that the flowering plants evolved and the age prior to their evolution. In rock of an age where such fossils can be found, what animal fossils would you expect to find? You're more likely to find flying insects here than in rock from a time before flowering plants. Why? Because they both co-evolved at the same time, to depend on each other.
Older rock would contain fossils of ancestral species that went on to evolve into flowering plants / flying insects that depend on them. But half the flying insects wouldn't have evolved if it weren't for the fact that certain plants went down the path of animal-pollination as opposed to wind pollination.
There are billions of other examples proving coevolution to be true. Evolution isn't your typical 'theory' any more. We're long past that stage. It's effectively law.
Why else would apple trees feed apples to horses? Out of kindness / stupidity? Why else do they produce nectar that is mostly eaten by flying insects and hummingbirds? Kindness? Stupidity?
They all coevolved to rely on each other.
Impressive explanation. But what happens if the apple is not the only thing the horse feeds on? What if the insect pollinates more than just the apple? Assuming the insect actually feeds and pollinates like 10 plants, will the insect evolve along with the 10 plants or just few?
Google 'the red queen hypothesis'.
You might like it.
I will :)
Thanks.
I think it still works, even if horses eat other things (which I think we both know is true, anyway). Because other animals like an apple on occasion, including primates including humans. Of course, many an apple will slowly rot never having attracted something to eat it and will slowly decompose where it fell. That individual is less likely to germinate and if it does is more likely to struggle and die an early death. But the system works on an evolutionary level, doesn't it? There are many an apple tree dotted across the planet. And the fruit they came from didn't all roll randomly to get to where the seeds germinated. They were carried. In bellies.
Finally, we must also remember life isn't about being 100% efficient or 100% perfect, is it? It really isn't about being anything, in fact. It just is. So long as the laws of physics that govern the universe aren't being violated, the thing works.
Regards insects, it's probably a little more complex (they reckon there's over a million named species of beetles, for example). Some plants are 'happy' allowing lots of different types of insect access to their precious pollen / nectar source. Likewise, some insects will not be that fussy about where they're getting their nectar from. Generalists. With a broad diet (in the case of the insects) and broad range of insects that get to carry their pollen (in the case of the plant / flower). Just as there are many, many generalists in both categories, there are lots and lots that are more specialised. Insects that only visit one type of flower (though the flower could theoretically be visited by other species of insect still). Plants that can only have their pollen carried by one species of insect (though the insect could theoretically still visit many other species of plant for its nectar needs). Finally, there'll even be the real close-knit relationship where a plant species exists that provides nectar to a species of insect that feeds 100% on its nectar.
The anatomy of a flower is designed (by nature that is, ie. through evolution) to accept insect visitors. Some flowers will and do allow just about any insect visitor in. Some flowers have a structure that is more restrictive preventing all but a single / few target species from getting to its nectar (and thereby, pollen).
Evolution has been happening for billions of years. We're talking incomprehensively vast numbers of individuals, some of which (in the case of insects, for example) having extremely short life cycles. Let your fruit flies escape in biology class at school and a few weeks later they could be trying to take over the school. Some such animals could see several generations being born in a year. So, in all those billions of years and with all the individuals of the species concerned, some of these interspecies relationships have really got in tune whilst others have gone wrong somewhere along the line. Take for example the orchid that mimics a bee. What possible advantage could the flower get from mimicking a bee? At a guess, I'd expect very few insects will visit them (thinking it's a bee and not a flower) but the ones that do, get to enjoy all the nectar (carrying away some of the plant's pollen, inadvertently, in return). One would have to presume it evolved from an ancestral species that also looked like a bee, an ancestral bee species, even.
Throw a load of shit against a wall and some of it will stick. It seems nature did and some of what stuck is a flower that looks like a bee. Remarkable, eh?
Anyway, it's tea time...