Evidence of Evolution
The Nobel Prize winning scientist Linus Pauling aptly described science as the search for truth. Science does this by continuously comparing its theories objectively with evidence in the natural world. When theories no longer conform to the evidence, they are modified or rejected in favor of new theories that do conform. In other words, science constantly tries to prove its assumptions to be false and rejects implausible explanations. In this way, scientific knowledge and understanding grow over time. Religious explanations for the order of things are not science because they are based primarily on faith and do not subject themselves to be objectively falsified. Because of this fundamental difference in the approach to understanding our natural world, the U.S. Supreme Court in effect decided in 1987 that the Biblically based "creation science" is not a science and cannot be taught as such in public schools as an alternative or in addition to the mainstream evolutionary theory of the biological sciences. However, religious creation stories and the idea of "intelligent design" can be taught in philosophy, religion, or history courses. Religion and Science provide different approaches to knowledge. It is important to understand both.
What is Evolution?
Biological evolution is genetic change in a population from one generation to another. The speed and direction of change is variable with different species lines and at different times. Continuous evolution over many generations can result in the development of new varieties and species. Likewise, failure to evolve in response to environmental changes can, and often does, lead to extinction.
When scientists speak of evolution as a theory they do not mean that it is a mere speculation. It is a theory in the same sense as the propositions that the earth is round rather than flat or that our bodies are made of atoms are theories. Most people would consider such fundamental theories to be sufficiently tested by empirical evidence to conclude that they are indeed facts. As a result of the massive amount of evidence for evolution accumulated over the last two centuries, we can safely conclude that evolution has occurred and continues to occur. All life forms, including people, evolved from earlier species. Furthermore, all still living species of organisms continue to evolve today. We now understand that there are a number of different natural processes that can cause evolution to occur. These are presented in later tutorials of this series.
For those who have difficulty in accepting evolution because of what they perceive as contradictions with their fundamental religious beliefs, it may be useful to distinguish the ultimate origin of life from its later evolution. Many, if not most, biological scientists accept that primordial life on earth began as a result of chance natural occurrences 3.5-4 billion years ago. However, it is not necessary to believe in that view in order to accept that living creatures evolved by natural means after the origin of the first life. Charles Darwin modified his religious beliefs, as did many others, as a result of the discovery of convincing proof of evolution. Darwin's religious faith was also severely challenged by the death of his 10 year old daughter Annie in 1851. Apparently, he came to believe that his God created the order of the universe including the rules of nature that result in biological evolution. His famous book, On the Origin of Species, was not a denial of his God's existence. However, he did reject a literal interpretation of the Judeo-Christian Bible.
Videos
Isn't Evolution Just a Theory--video clip from PBS 2001 series Evolution
Darwin's Personal Struggles--an interview with Darwin's biographer
Evolution of the Eye--an explanation by zoologist Dan-Erik Nilsson
The Nobel Prize winning scientist Linus Pauling aptly described science as the search for truth. Science does this by continuously comparing its theories objectively with evidence in the natural world. When theories no longer conform to the evidence, they are modified or rejected in favor of new theories that do conform. In other words, science constantly tries to prove its assumptions to be false and rejects implausible explanations. In this way, scientific knowledge and understanding grow over time. Religious explanations for the order of things are not science because they are based primarily on faith and do not subject themselves to be objectively falsified. Because of this fundamental difference in the approach to understanding our natural world, the U.S. Supreme Court in effect decided in 1987 that the Biblically based "creation science" is not a science and cannot be taught as such in public schools as an alternative or in addition to the mainstream evolutionary theory of the biological sciences. However, religious creation stories and the idea of "intelligent design" can be taught in philosophy, religion, or history courses. Religion and Science provide different approaches to knowledge. It is important to understand both.
What is Evolution?
Biological evolution is genetic change in a population from one generation to another. The speed and direction of change is variable with different species lines and at different times. Continuous evolution over many generations can result in the development of new varieties and species. Likewise, failure to evolve in response to environmental changes can, and often does, lead to extinction.
When scientists speak of evolution as a theory they do not mean that it is a mere speculation. It is a theory in the same sense as the propositions that the earth is round rather than flat or that our bodies are made of atoms are theories. Most people would consider such fundamental theories to be sufficiently tested by empirical evidence to conclude that they are indeed facts. As a result of the massive amount of evidence for evolution accumulated over the last two centuries, we can safely conclude that evolution has occurred and continues to occur. All life forms, including people, evolved from earlier species. Furthermore, all still living species of organisms continue to evolve today. We now understand that there are a number of different natural processes that can cause evolution to occur. These are presented in later tutorials of this series.
For those who have difficulty in accepting evolution because of what they perceive as contradictions with their fundamental religious beliefs, it may be useful to distinguish the ultimate origin of life from its later evolution. Many, if not most, biological scientists accept that primordial life on earth began as a result of chance natural occurrences 3.5-4 billion years ago. However, it is not necessary to believe in that view in order to accept that living creatures evolved by natural means after the origin of the first life. Charles Darwin modified his religious beliefs, as did many others, as a result of the discovery of convincing proof of evolution. Darwin's religious faith was also severely challenged by the death of his 10 year old daughter Annie in 1851. Apparently, he came to believe that his God created the order of the universe including the rules of nature that result in biological evolution. His famous book, On the Origin of Species, was not a denial of his God's existence. However, he did reject a literal interpretation of the Judeo-Christian Bible.
Videos
Isn't Evolution Just a Theory--video clip from PBS 2001 series Evolution
Darwin's Personal Struggles--an interview with Darwin's biographer
Evolution of the Eye--an explanation by zoologist Dan-Erik Nilsson
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