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Saturday, October 16, 2021

Column: Flower love

Flowers are the iconic Valentine’s Day gift. If a person gets nothing else for their significant other, especially since college students are usually on a budget prohibiting expensive dinner reservations or shiny jewelry, the couple will probably still exchange flowers.

I’d like to encourage you to look closer at those flowers. Since this is being published the day after Valentine’s Day, they might still be on your table or desk. If you took a basic biology class, you already know that a flower is the main reproductive part of certain plants; specifically, a group of plants called angiosperms.

In a certain sense, a flower’s purpose is indeed to look “pretty.” However, this isn’t for the good of the people who pick them to give to their lovers; this is for their own good. The more attractive the flower is to its respective pollinator, whether bees, birds or bats, the more likely it is to fertilize and spread its seed.

This is just a basic evolutionary concept. The differences between plants with flowers and people when it comes to reproduction are fairly obvious; since humans can move to their sexual partners, a different species acting as a vector isn’t required.

However, the basic idea is the same: find a way to pass on your genes to the next generation. The only difference is the strategy. Angiosperms split from their non-flowering cousins, gymnosperms, about 200 million years ago. While gymnosperms usually use methods like wind travel to disperse their seeds, flowering plants use other methods.

Even a glance at different types of flowers shows a large diversity of shape. The reason for this is the pollinators. Flowers co-evolved with their pollinators over millions of years, adapting shape and color to be the most attractive to their respective helper.

Not that there are intentions behind these adaptations. Flowers with genes that make them look unappealing to the pollinators in the area don’t reproduce well. They die without descendants to pass on those unappealing genes.

Similarly, a bee doesn’t look at a flower and think, “I’ll help that flower spread its pollen to another flower. I’m just a good bee like that.” All the bee wants is the sweet nectar that the flower makes (another evolutionary attractant for the pollinators). In the process of satisfying its own love for nectar, the fuzzy bee ends up covered in pollen that it then takes to the next flower; fertilization is a happy accident.

Explaining these evolutionary concepts can be difficult without humanizing the players. It feels natural for us to say, “The flower wants to attract the pollinator,” even though plants obviously don’t have a brain to want anything, at least in the same way humans want something.

It seems natural because, on some level, we know that every living thing has the same need — to survive and reproduce. These needs do get complicated when talking about what humans actually want; not everyone wants children, after all.

However, where do we draw the line? At what point between, “The flower needs to reproduce,” and “The flower tries to trick a pollinator to come near,” does it become overly humanizing? This line is actually rather difficult to distinguish.

It seems obvious that the verb “trick,” for example, implies a rationality and purpose that a simple plant does not have. The problem is that it’s hard to think of another word that describes what the Ophrys exaltata, an orchid species, does to bees: it looks like a female bee and even exudes somewhat similar smells, so similar that male bees have been known to attempt to mate with and then ejaculate on the flower.

It goes beyond that, though. The smell they make is actually slightly different than the females in the bee population, making it odd that they are trying to imitate the bees. However, what scientists have found is that the bees are actually much more likely to visit orchids that smell slightly different from their own population than those that smell the same.

The orchid is not trying to be dishonest; it’s just that the orchid flowers that happened to look like the female bee were more likely to survive. There was no intent to deceive. That’s just the way it happened.

I wouldn’t recommend trying to use that as an excuse with your significant other, though.

AMY STEWART can be reached at science@theaggie.org.


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