Choice in biological systems

While discussing my research with my committee as a graduate student, I made a reference to plants "seeking out more suitable habitat." A faculty member asked if said plants sprouted legs and walked to a different area before plunking down and setting roots. I was able to resolve this semantic issue because the plants in question are clonal, so they can literally send out a rhizome toward a new area. Her point was well taken, though, and issues related to verbiage in biology continue to intrigue me.

There are common issues in molecular biology wherein enzymes or other portions of biochemical pathways are anthropomorphized in language. These issues arise most often when interactions between molecules are communicated like we would talk about human behavior.

A related but slightly different issue arose in a NESCent seminar today. A discussion about sex allocation included some references to human sex ratios at birth. The ratio of males to females are thought to be altered by a variety of factors, including acute or chronic stress. Someone argued that in certain situations, females may "choose" to alter the sex of their offspring to better suit the demographics of the new environment (i.e., more males to replace those lost in battle).

We're all scientists here. We know that women don't consciously choose to have male or female babies, but someone took issue with the previously mentioned hypothesis because of the failure of that mechanism. In terms of evolutionary time, though, it makes sense. The tendency to produce male offspring when an overabundance of females comprise a population is potentially heritable, and would definitely be positively selected, especially if the male population is low.

I don't know how plausible the latter hypothesis is, or whether selection could mechanistically support it. The point is that "choice" in this instance refers to a trait over which selection occurs throughout evolutionary time. The woman's genetically encoded physiology as shaped by evolutionary time is actually doing the choosing. Such is the plight of evolution research, where misinterpretations of even seemingly innocuous words can yield misunderstandings...even among scientists.