How to Teach about What Is a Species

SIMPLE SUMMARY: What is a species? According to the biospecies concept, organisms that can mate with each other belong to a species, e.g., Homo sapiens. But does this adequately explain to us what a species is? No! With the help of the biospecies concept, we can only recognize species, but we cannot explain them. To understand what a species is, we must ask ourselves and our students if a species is real—a thing with properties (comparable to an individual)—or just a concept, a natural class of organisms with largely equivalent characteristics. ABSTRACT: To ask students what a species is always has something rhetorical about it. Too quickly comes the rote answer, often learned by heart without ever thinking about it: “A species is a reproductive community of populations (reproductively isolated from others), which occupies a specific niche in nature” (Mayr 1982). However, do two people look alike because they are twins or are they twins because they look alike? “Two organisms do not belong to the same species because they mate and reproduce, but they only are able to do so because they belong to the same species” (Mahner and Bunge 1997). Unfortunately, most biology (pre-university) teachers have no opinion on whether species are real or conceptual, simply because they have never been taught the question themselves, but rather one answer they still pass on to their students today, learned by heart without ever thinking about it. Species are either real or conceptual and, in my opinion, it is this “or” that we should teach about. Only then can we discuss those fundamental questions such as who or what is selected, who or what evolves and, finally, what is biodiversity and phylogenetics all about? Individuals related to each other by the tree of life.