Living in a Golden Age of Biology

    We are living in a golden age of biology. The largest and best-equipped community of scientists in history is beginning to solve biological puzzles that once seemed unsolvable. We are moving ever closer to understanding how a single cell becomes a plant or animal; how plants trap solar energy and store that energy in food; how organisms form networks in biological communities such as forests and coral reefs; and how the great diversity of life on Earth evolved from the first microbes. Exploring life has never been more exhilarating. Welcome to the big adventure of the twenty-first century! 

    Modern biology is as important as it is inspiring, with exciting breakthroughs changing our very culture. Genetics and cell biology are revolutionizing medicine and agriculture. Molecular biology is providing new tools for investigating ancestry and solving crimes. Ecology is helping us evaluate environmental issues, such as the causes and consequences of global warming. Neuroscience and evolutionary biology are reshaping psychology and sociology. These are just a few examples of how biology is woven into the fabric of society as never before. It is no wonder that biology is part of our daily lives, shown in Figure 1.1.

The Scope of Life

Biology is the scientific study of life. It’s a huge subject that gets bigger every year. We can think of biology’s enormous scope as having two major dimensions. First, life is structured on a size scale ranging from the molecular to the global. The second dimension of biology’s scope stretches across the enormous diversity of life on Earth, now and throughout life’s history. But before we discuss the great number of differences between living creatures, let’s discuss the properties that unify all living things.

The Unity of Life

The phenomenon called life largely defies a simple, one-sentence definition. Yet almost any child perceives that a dog or a bug or a plant is alive, while a rock is not. We recognize life largely by what living things do. All life is unified by a common set of characteristics.

Figure 1.2 highlights some of the properties and processes we associate with life: (a) Order . All living things exhibit complex but ordered organization, as seen in the highly ordered structure of a sunflower. (b) Regulation . The environment outside an organism (a living thing) frequently changes, but mechanisms regulate the organism’s internal environment, keeping it within limits that sustain life. For example, a jackrabbit can adjust its body temperature by regulating the amount of blood flowing through its ears. When the rabbit’s body temperature rises, more blood flows through the vessels in its ears, allowing excess heat to be released to the air. (c) Growth and development . Information carried by genes—the units of inheritance that transmit information from parents to offspring—controls the pattern of growth and development in all organisms, including the Nile crocodile. (d) Energy utilization . Organisms take in energy and transform it in performing all of life’s activities. For example, a hummingbird obtains energy in the form of plant nectar and uses it to power flight and other work. (e) Response to the environment . All organisms respond to environmental stimuli. For example, a Venus flytrap closes its trap rapidly in response to the environmental stimulus of an insect landing on it. (f) Reproduction . Organisms reproduce their own kind. Thus, pandas reproduce only pandas—never crocodiles or hummingbirds. (g) Evolution . Reproduction underlies the capacity of populations to change (evolve) over time. For example, the appearance of the pygmy seahorse has evolved in a way that camouflages the animal in its environment. Evolutionary change has been a central, unifying feature of life since life arose nearly 4 billion years ago.