The third flaw in The Happening is indicative upon the lack of knowledge about evolution. Shyamalan suggest that plants evolved into neurotoxin creating machines because humans pose a threat to the planet. However, Armstrong stresses that individuals don’t evolve, populations do, a common scientific misdemeanor. Organisms can select for genetic variants that promote the best survival, however, the rate of evolution depends on how fast those plants reproduce. Armstrong says “Something like trees are going to be very slow because their generation time is low,” but “Something like weeds can evolve pretty fast” (McCarthy, 2008).
In order for plants to create such a neurotoxin a few plants would have to have to randomly be selected for and also have the means of creating the genetic variant. Over time those plants would have a better chance for survival because they were more fit than their less toxic relatives and then the rest of the population would also contain the neurotoxin. Even if plants had the means and the evolutionary background to emit the toxin, it is not clearly stated in the movie why killing humans would help these plants evolve.
Further, the ability for all species of plants to evolve simultaneous is virtually impossible. Jenny Cruse-Sanders, director of research and conservation at the Atlanta Botanical Garden, says “it’s unlikely across the entire plant kingdom that all these unrelated species would be producing the same compound.” The likelihood of a single plant producing a compound is slim much less having this same compound being produced by unrelated species. Perhaps, the unrealistic ability of plant communication is how these intelligent plants came to produce the same compound; at least this would be Shyamalan’s understanding.
The forth flaw in The Happening is the idea that plants have the ability to emit a poison. “Botanists agree that plants can emit volatile compounds. There are literally thousands of plants that have neurological impacts on humans when ingested, but researchers have yet to discover any that can emit airborne neurotoxins” (McCarthy, 2008). Producing even simple defense mechanisms has a high energy cost. Big organisms like trees and common, but inefficient, species such as grass typically do not waste their time and energy in creating such toxins, instead they focus most of their efforts on photosynthesis and/or cellular respiration which takes up a large portion of their stored and created energy (Sadava et all, 2011). Armstrong says, “For the most part, trees are big organisms and things eating them are small organisms,” and “Under those circumstances, why expend the energy for chemical defenses” (McCarthy, 2008)?
This problem is faced differently concerning smaller plants that live in less dense populations. Armstrong says “When getting eaten is a problem for smaller plants, that’s a common situation where plants are toxic.” With this in consideration, the North Eastern part of the United States does not house any exotic plant life and therefore, the idea that plants would create a neurotoxin in this area is miniscule. Plants do have the ability to create a toxin, however, this would take many years, it would not happen in all species, and it would only take place among a small group of plants that in essence, probably not have an effect on the human population.
The fifth flaw in The Happening comes from the idea that plants know when humans are around, and possibly the most concerning to a scientist. Most scientists agree that plants can respond to certain stimuli. A plants response to light is called phototropism, its response to gravity is gravitropism and its response to touch is thigmotropism demonstrated by carnivorous plants like the Venus fly trap which have trigger hairs, and if you touch them in the right sequence, the plant will close. (Sadava et al, 2011). Notice that human interaction or speech is not included in this list. Jokingly, Armstrong says that “You can talk to them an awful lot, and raise the CO2 content in their vicinity, but I don’t think plants can sense our presence.”
The ability for plants to sense humans and then target them as potential enemies is too much personification for any biology major. Plants have some response to certain stimuli; however, they lack a central nervous system which means they don’t have thought process and also a peripheral nervous system which means they have a hard time moving as well. This means that plants do not have a mechanism for responding to the presence or lack of presence of people.” Figure 4 shows the fear behind the family’s thought that plants can sense their presence.