Perhaps one of the most difficult concepts to understand in biology is that of emergent properties in multicellular organisms. As a teacher, I've often been guilty of explaining this idea early on in the IB by saying, "it means an organism is greater than the sum of its parts." And I can further burrow under this blanket statement that magically explains without explaining by segueing into an example that usually engenders some awe and at the least an appreciation for the massively wide scale in which biologists operate: we spend thousands of hours in the world of a neurons microns to understand the very basic mechanism of neural communication.
However, in order to grasp how the network of neurons makes possible the complex cognitive, physical and behavioral characteristics we associate as quintessential "humanness" or "catness" or even "dogness," we must take a step back and place the neuron, the neural tissue, the nervous system, and the organism into the larger context of millions of years of evolution. To use another blanket statement, "we need to look at the trees to understand the forest, but we lose the forest if we only focus on the trees." This is usually enough to leave me swimming for half an hour or so in a kind of existential overwhelm, and I can move on to talking about nucleoli and Golgi apparatuses and endoplasmic reticulums.
I enjoyed this article because it takes the above sensation and punches it up a notch. Look at the organism in the context of evolution but then also place it into the network of other forms of life ---the kind we don't often think about as life unless it makes us sick or is in our yogurt.
I also like this article because it poses a testable question and proposes refutable hypothesis that is both consistent with accepted theories in modern biology but adds a layer of complexity on how they could potentially be conceptualized. You can read the full article by clicking on this link.