There are several ‘enigmatic canid’ species in North America. One of them is the red wolf (Canis rufus, Figure 1.1), and another is the Great Lakes Wolf. Red wolves are seriously endangered, with a re-released population in North Carolina and breeding programmes being the last populations. Red wolves weren’t even studied closely until the 1960s, after having been hunted nearly to extinction in the nineteenth and twentieth centuries.

As humans, we have a graspable identity that has been shaped by our individual and collective attempts to seek answers to fundamental questions: Who am I? Where did I come from? Where am I going? Where and to whom do I belong, and how can I help myself and others? The persistence of such questions may signal the insatiability of our human curiosity, but they also offer evidence of our possibly endless search for substantive, finite meaning. We yearn to identify who we are and to be part of something greater than our own limited individuality. This desire leads people to draw strong, even vicious, us-versus-them boundaries in political and social life. But it is also a spiritual wish to connect to all of humanity, indeed to all of life and the cosmos, and to take benevolent action accordingly (Figure 1.1, chapter opener). Even when answers to our questions about identity prove inconclusive, changeable, or otherwise unsatisfying, our search continues apace.

On November 24, 1859, the English naturalist Charles Robert Darwin published On the Origin of Species by Means of Natural Selection, or the Preservation of Favoured Races in the Struggle for Life . In that book (Darwin 1859), he argued that all organisms, living and dead, were produced by a long, slow, natural process, from a very few original organisms. He called the process “natural selection,” later giving it the alternative name of “the survival of the fittest.” This first chapter is devoted to presenting (without critical comment) the argument of the Origin, very much with an eye to the place and role of natural selection. As a preliminary, it should be noted that the Origin, for all it is one of the landmark works in the history of science, was written in a remarkably “user-friendly” manner. It is not technical, the arguments are straightforward, the illustrative examples are relevant and easy to grasp, the mathematics is at a minimum, meaning non-existent. Do not be deceived. The Origin is also a very carefully structured piece of work (Ruse 1979a). Darwin knew exactly what he was doing when he set pen to paper.

For many millennia, humans have gazed up in wonder at the night-time sky. The full panoply of the Milky Way is an awesome sight. The scale of space is immense. Is there life out there somewhere? If so, where, and what form does it take? In the space of a couple of sentences, we’ve already gone from generalized wonder to specific questions. The next step is from questions to hypotheses, or, in other words, proposed answers. Here are two such hypotheses that I’ll flesh out as the book progresses: first, life exists on trillions of planets in the universe; second, it usually follows evolutionary pathways that are broadly similar to – though different in detail from – those taken on Earth.

The quantity of data that is collected, processed, and employed has exploded in this millennium. Many organizations now collect more data in a month than the total stored in the Library of Congress. With the goal of gaining insight and drawing conclusions from this vast sea of information, data science has fueled many of the vast benefits brought by the Internet and provided the business models that pay many of its costs.

Forensic DNA typing was developed to improve our ability to conclusively identify an individual and distinguish that person from all others. Current DNA profiling techniques yield incredibly rare types, but definitive identification of one and only one individual using a DNA profile remains impossible. This fact may surprise you, as there is a popular misconception that a DNA profile is unique to an individual, with the exception of identical twins. You may be the only person in the world with your DNA profile, but we cannot know this short of typing everyone. What we can do is calculate probabilities. The result of a DNA profile translates into the probability that a person selected at random will have that same profile. In most cases, this probability is astonishingly tiny. Unfortunately, this probability is easily misinterpreted, a situation we will see and discuss many times in the coming chapters.

Modern biology has been undergoing a dramatic revolution in recent decades. Enormous amounts of data are produced at an unprecedented rate. These data come in various forms, such as gene and protein expression level data, DNA, RNA, and protein sequencing, high quality biological and medical images. One consequence of this “data explosion” is that computational methods are increasingly being used in life science research. Computational methods in this context are not the mere use of tools, but the integration of computational and algorithmic thinking to lab-experiment design; to data generation, integration, and analyses; and to modeling and simulation. It is becoming widely recognized that such thinking skills should be incorporated into the standard training of life scientists in the 21st century.

The notion that our planet and its inhabitants have not remained exactly as the Creator was supposed to have made them was in the air long before 1859, when the English natural historian Charles Darwin collected and published his evolutionary ideas in his great work On the Origin of Species by Means of Natural Selection. By that time geologists had long known that the 6,000 years allowed by the Bible since the Creation was vastly inadequate for the sculpting of the current landscape by any natural mechanism; and the biologists who were just beginning to study the history of life via the fossil record were not far behind them. Around the turn of the nineteenth century, the French zoologist Jean-Baptiste Lamarck began to argue that fossil molluscan lineages from the Paris Basin had undergone structural change over time, and that the species concerned were consequently not fixed. Importantly, he implicated adaptation to the environment as the cause of change, although the means he suggested – subsequently infamous as “the inheritance of acquired characteristics” – brought later opprobrium.

While it isn’t necessary to do so, it’s often good to start a book by saying something that is clearly true. So, let’s do that. Science has had (and continues to have) a significant impact upon our lives. This fact is undeniable. Science has revealed to us how different species arise, the causes of our world’s changing climate, many of the microphysical particles that constitute all matter, among many other things. Science has made possible technology that has put computing power that was almost unimaginable a few decades ago literally in the palms of our hands. A common smartphone today has more computing power than the computers that NASA used to put astronauts on the Moon in 1969! There are, of course, many additional ways in which science has solved various problems and penetrated previously mysterious phenomena. A natural question to ask at this point is: why discuss this? While we all (or at least the vast majority of us!) appreciate science and what it has accomplished for modern society, there remain – especially among portions of the general public – confusions about science, how it works and what it aims to achieve. The primary goal of this book is to help address some specific confusions about one key aspect of science: how it explains the world.