I always enjoy looking at all the pictures submitted to the database here but I'm especially enjoying them now that the Fall Color thing is going on. One of the things that strikes me is the amazing diversity of plant types, shapes and colors. I understand why they change with the seasons, respond to the weather and locations the way they do, and I have a very strong feeling that there is a good reason why each flower is shaped the way it is. As someone else said, The Big Gardener knows what s/he is doing! (paraphrased).

Now, I'm not complaining by any means, but me being as ignorant as I am, I don't understand why, as beautiful as it all is, there is such a need for so much diversity in the plant world. So that's my question. Why is such diversity necessary in our ecosystems?

Competition, adaptation, survival... We've gone through multiple changes in climate, species extinction, mutation, and birth of new species. Every plant thrives under a certain set of conditions, and those conditions are always changing. Each plant has to compete for pollinators, rooting space, and sunlight, so each one has its own features and benefits. Pollinators, human & animal populations come and go, and each plant is going to be affected in various ways.

They say beauty is in the eye of the beholder and that's definitely the case with flower types... There are flowers shaped exactly like certain insects, flowers displaying a certain color range.. some flowers that smell like rotten meat. If every plant was exactly the same, they'd all get wiped out if the conditions for that plant are no longer suitable. This diversity at least ensures some plants will survive under the new set of conditions - and there will always be changing conditions.

And of course, that would be adaptation by mutation. It almost goes without saying, but plants also have already inherent adaptations, as well as the possibility of future mutation.

Environments are never exactly the same: temperature, water, sun, insects, disease, weather, elevation, nutrients, etc.
Therefore: competition, adaptation by mutation, and survival will never have the same outcome, either.

-- Thus diversity.

This is exactly what Darwin explained long ago in his Origin of Species. It applies to all life forms, not just plants.

In gardens, a lot of the plant diversity is the result of selective breeding by human beings; namely the result of Artificial Selection.

Darwin supported his case for Natural Selection (selective forces operating within natural environments) by emphasizing the similarity to Artificial Selection.

joanna,
I agree with the feeling I think you're expressing, that the natural world is more beautiful and varied than it "has to be." Maybe the question is not ' why did this flower have to look like this", but "Why not be different and beautiful". Genetic variation is possible, so couldn't things just happen for no particular reason, and persist?

I'm also loving the autumn pictures.

sallyg said:Genetic variation is possible, so couldn't things just happen for no particular reason, and persist?

That makes it sound like mutations only happen when they are needed. This is certainly not the case.
Natural mutations always happen for no particular reason, and it is always random. But it is only the mutations that are advantageous, or at least not disadvantageous, that persist in the natural world.

So yes, mutations constantly happen with little or no consequence, just like they happen with big or lethal conesequences. For instance, a meadow of wild Iris pumila, where white, purple and yellow flowers grow together: no flower color is advantageous enough to preclude another.

From Jurassic Park--
Dr. Ian Malcolm: John, the kind of control you're attempting simply is… it's not possible. If there is one thing the history of evolution has taught us it's that life will not be contained. Life breaks free, it expands to new territories and crashes through barriers, painfully, maybe even dangerously, but, uh… well, there it is.

John Hammond: [sardonically] There it is.

Henry Wu: You're implying that a group composed entirely of female animals will… breed?

Dr. Ian Malcolm: No. I'm, I'm simply saying that life, uh… finds a way.

that's still gotta rank in the top ten memes of all time, no?

The question was not so much why/how does such diversity occur, but rather why does it need to? --yes, as if there must be a need for a thing if a thing is to exist.
When I examine all the evidence around me, I know that many things exist without a need that I can define, so I can totally buy existence without need. Of course, I realize that I am not the knower of all necessities, so it's still possible that everything that is is necessary and I just can't fathom why.
But, as far as all the variation, it's like gambling, recombination and mutation of the coding structures is fantastic blind hypothesis to create something that might work for life to find a way. Maybe it's imperative for life to find a way.

and, else-wise, regarding the need for diversity in our ecosystems here in 'plant world'--diversity begets and supports a much broader diversity of additional life forms (and staves off monotony) whereas uniformity does not.

I was reading this article, and it was interesting how the last sentence fits so well with this discussion.

https://www.nytimes.com/2017/1...