9781422283226

F

our billion years ago, the Earth was not a friendly place. It was excruciatingly hot. The atmosphere was a hydrogen and helium soup that would have been toxic to any life forms. But slowly things began to change. The tem- peratures cooled slightly, allowing molten lava to harden into rocks that became the Earth’s surface. Clouds formed. Rain started. Oxygen began to build up in the atmosphere. By about 3.8 billion years ago, there was enough oxygen to support the first tiny, one-celled organisms.They were sim- ple and yet stunning—the kickoff to a process of evolution that has given rise to millions of species since then. They multiply, adapt, evolve, and die. How does it all work? Why? It is the mission of biol- ogists to study these questions and try to answer them. Above all, they are always asking more questions. Biolo- gists peer into the most microscopic of organisms and gaze into the farthest reaches of the universe to understand the basic processes that form and sustain life. They investigate how life forms adapt to larger, outside forces, from climate change to war. The significance of what they find may not always be obvious, certainly not at first. But just as cells are the building blocks of life, the research findings of biolo- gists are the building blocks of theories and knowledge that affect us in dramatic ways. The study of biology affects every part of human life. Without advances in biology, we would know nothing of evolution. We would have no mechanisms to learn about

8

Black Achievement in Science: Biology