I was reading about this plant named Ophrys( an orchid that deceives insects sexually by making structures similar to bees and wasps) I wonder how they make such complex structures and how their ancestors started making such weird structure. Some more question arises in my mind like
How do these plants sense the colour and shape of bees, Aren’t they are technically blind?
What makes these plants make these structures in the first place?
It’s evolution, plants don’t feel colour or that they attract insects, it’s just their shape and scent makes them more attractive => they reproduce better than other specimens, that makes certain aspects of their flower getting in the gene flow of population, becoming a norm. They probably started with a regular orchid flower (which itself is already very complicated).
The above is entirely correct. Plants don’t know anything, and evolution doesn’t follow a plan. The orchid didn’t go “okay, we’re going to start evolving this new shape” and set out along a path to do it. Evolution is one step at a time, random mutations cropping up that happen to pose a slight advantage, until enough stack up to change the species.
What happened with this orchid was likely that the flower happened to bear a very slight resemblance to a female bee, which caused male bees to very occasionally bumble into them. Any flowers that had a tiny bit more resemblance to a female bee had a tiny advantage, and those tiny changes stacked up over hundreds (if not thousands) of generations, until it was a near-perfect lure.
Evolution doesn’t work that way. Many insects — like bees and wasps and butterflies — do the same kind of thing as those plants; they mimic other insects. This doesn’t happen because those insects can see the species they want to mimic. No matter how well they can see another species, nor how hard they concentrated on wanting to look like that, they could never start to mimic the other creature even over millions of generations. There is no feedback from the eyes and the brain into the evolution process. If you wanted a kid with blue eyes, your chances of having a blue eyed kid won’t be improved by looking at people with blue eyes!
In each generation of insect, there are new tiny random genetic mutations. A few of those mutations will result in the creature looking very slightly more like another species. If looking like that other species is a benefit to survival, that mutation will gradually become dominant in the species. Over countless generations, vast numbers of these tiny mutations can build up into sometimes quite remarkable mimicry.
It happens exactly the same way when plants mimic insects. They aren’t aware of what’s happening. There’s no plan on the direction of evolution. It’s just that any chance mutations that happen to be beneficial to survival will have a better chance of making it through into subsequent generations.
The only thing I’d like to add here is that it isn’t all mutations. Evolution can also occur using the natural variation in a population. Some people are taller that others, some have thicker fingers, etc. No mutation needed for some trait to get carried to relative extremes if selection pressures favor some trait.
What really used to confuse me was insects that mimic plants – e.g., this katydid species looks like a leaf, that katydid species looks like a lichen. I wondered, how do they know what they look like? How does the leaf-mimic katydid know that it looks like a leaf, and how does the lichen-mimic katydid know that it looks like a lichen? The explanation I was given is that they don’t – the leaf-mimic katydid doesn’t know that it looks like a leaf; it just has an instinct for staying among leaves, which evolved in the same way and over the same span of time as its leaf-like appearance did.