Approximately 13 and a half billion years ago, the Big Bang set in motion events that created our world. Our sun and our earth formed and shortly thereafter（其后） water and organic molecules, the ingredients of life. A biological world was seeded and a powerful force set in motion, evolution. Organic molecules slowly began assembling（集合） into simple cells around four billion years ago and then eventually multicellular（[生物] 多细胞的） organisms evolved, comprising millions, billions, even trillions of individual cells organized into functional（ 实用的） units, tissues, organs and systems with specialized yet complementary（补足的） roles, a citizenship（[法] 公民身份） of cells, working（使工作） together to meet its organisms needs, fine-tuning its organisms structure, organization and operation through natural experiments in evolution, insects, fish, birds, apes and eventually humans. I'm a scientist at the Charbonneau Cancer Institute and for nearly 25 years I've been studying human health and disease. I think a lot about evolution, the simple, powerful principle that underpins all of biology.

  Evolution has so much to teach us and over the next few minutes I'm going to explain to you how biomedical scientists like me learn from evolution to solve health problems and then I'm going to pose a question. Can a similar principle be applied to solving bigger problems in our world? Specifically, can the ways in which advanced multicellular organisms like human beings evolved to function help create solutions to the structural（结构的）, organizational（ 组织的） or operational（操作上的） problems that face our world today? The basic premise（前提） of evolution is that organisms adapt to the stresses they face through a process called natural selection. The result is a more capable organism, one better able to meet its needs, survival of the fittest. Evolution is shockingly simple.

  It requires three basic components. First, stress. Second, adaptability（ 适应性）. Third, time. Apply stress or selective（选择性的） pressure onto an adaptable life form and allow nature to produce an optimization（最佳化） over time. Evolution doesn't just happen to big organisms like plants and animals.

  It happens to all organisms, including cells and microbes. Scientists are students of evolution. We look to evolution to teach us and help us solve big problems in the world. Think about it for a minute. Everything in the biological world is the product of millions of years of tinkering（做焊锅匠） through natural experiments and evolution. The amount of data（资料） generated in these experiments is mind boggling.

  It's actually quite funny that humans pride ourselves in having invented science, the process of doing experiments, generating data, and then generating knowledge and applying that knowledge from those data. The biological world has been doing that naturally for over four billion years. And where are all these data? Much of it's recorded in the genomes（[生]基因组） of living organisms, and the application of knowledge created from those data manifest（载货单） in the way those organisms function. That's why scientists like me were always asking, why did this ecosystem, this organism, this organ, this tissue, this cell, this molecule evolve the way that it did? Because answering that question not only helps us learn about the biological world, but also gives us insight and ideas for tackling our biggest challenges.

  Medical science is full of examples where studies in some form of evolution have seeded an innovation that have transformed human health. The discovery of antibiotics（抗生素）, development of vaccines, and aseptic techniques, to name a few. Here's a specific example. I study cancer, a disease with staggering（蹒跚的） impact on humanity（人性）, and a daunting adversary（敌手） for doctors and scientists for centuries. My area of research, cancer immunotherapy, is the direct product of studies in evolution, cancer evolution. You see, cancer is a highly adaptable life form.

  It originates（引起） from one of your cells, which is adaptable, and it further amplifies its capacity to respond to stress with a special trick by increasing the rate at which it accrues（产生） mutations（变化）, the linchpin of evolution. That's how cancer solves its problems and can thrive（兴旺） in very hostile（敌对的） environments, including when being treated by chemotherapy or radiation. In studying cancer over decades, scientists have learned something really interesting about it, that cancer commonly engages in an evolutionary（进化的） war with the human immune system. Our immune system, of course, is the collection of cells and antibodies that evolved to protect your body from potentially dangerous germs. It does this in two simple steps. First, it learns what you look like, immunologists call this "self," so as not to attack and kill cells of your own body.