As you sit there your probably wondering what is evolution. Before you explore As The World Turns, lets explore what you already know about evolution. Make sure to place your answers on WORKSHEET #1.
Now that you thought about evolution, lets learn a little more on how it all began. The theory of evolution is one of the most important topics in Biology. But in many instances it is not taught in the classroom. Some teachers feel that evolution is controversial, but I believe it is important. Evolution is the binding force of all biological research. So that is why I have decided to discuss evolution. I believe that evolution plays a vital role in developing a better understanding of biology. But before you begin your adventure, I want you to know that I do not plan to change anyone's beliefs. My objective is to discuss scientific research and data that supports evolution.
The theory of evolution is strongly supported by geological evidence. Geologists study the earth and it's history. The evidence that supports evolution came from fossils. As paleontologists identified and studied fossils they were puzzled that they did not resemble any living things. The theory of evolution however made it possible to link fossils and living forms and to use fossils as clues to the history of life. So with the discovery of fossils this allowed scientists to develop a geological time scale. The time scale shows the evolution of the history of our earth. It gives evidence that life forms lived along time ago.
Here's an example of a
geological time scale. As you can see the geological time scale is
broken down into 4 eras. Do you remember what is an era? If not
here's the definition. An era is a period of time in which events
occur. For example look below.
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This table gives examples of events that have occurred throughout the history of earth.
As you can see from the examples above the theory of evolution is strongly supported by geological evidence. The discoveries of fossils and the development of the geological time scale has given scientists the opportunity to study our history. For your next question I want you to analyze some fossils. What you will be doing is linking to another web site and previewing a page called The Lucy Test. Once you are done I want you to click on the back button and answer the following question. So to perform the Lucy Test click on the following-> http://www.cen.uiuc.edu/~priestle/aa/
The study of evolution dates back to the philosophers like Plato and Aristotle. They both believed that there were variations in organisms. They both had beliefs that organisms could be arranged on a scale of increasing complexity. Meaning that organisms become more complex as years past. The people responsible for the development of the theory of evolution is based on many scientists but I want to focus on two, Jean-Baptiste Lamarck and Charles Darwin.
Lamarck was a director of the Natural History Museum in Paris and had the opportunity to analyze fossil forms. Through his experience he was able to see a chronological series of older to younger fossils leading to a modern species. Just like Aristotle and Plato, he also saw a complexity of organisms. Through his work, Lamarck was able to develop two important ideas that has impacted the theory of evolution. The first was use and disuse, the idea that those parts of the body used extensively to cope with the environment become larger and stronger, while those that are not used deteriorate. Ex: a blacksmith developing a bigger bicep in the arm that works the hammer and a giraffe stretching its neck to new lengths in pursuit of leaves to eat. The second idea Lamarck borrowed was called the inheritance of acquired characteristics. In this concept of heredity, the modifications an organism acquires during its lifetime can be passed along to its offspring. There is, however, no evidence that acquired characteristics can be inherited.
Even though Lamarck had a significant impact on the theory of evolution, it was not until Darwin published his book called On the Origin of Species by Means of Natural Selection, did evolution obtain attention. Darwin made two points in the Origin of Species. First, he argued from evidence presented that species were not specially created in their present forms but had evolved from ancestral species. Second, he proposed a mechanism of evolution, which he termed natural selection.
Charles Darwin did not set out to discover evolution. It sort of happened accidentally. He had a fond interest in nature. When he was not reading nature books, he was in the fields and forests, fishing, hunting, and collecting insects. The theory of evolution was developed through the experience Darwin had. In December of 1831, Darwin sailed on the survey ship called Beagle. The primary mission of the voyage was to chart poorly known stretches of the South American coastline. As a passenger of the Beagle, Darwin spent a lot of time observing the various adaptations of plants and animals that inhabited the environment. As he traveled through South American he became puzzled when he saw the resemblance of animal species between the South American mainland and the Galapagos islands. What Darwin found confusing was how certain species of animals where able to migrate between two geographical locations. One of the species of animals he was interested in was on finches. What he discovered was that there were diversity between finches. By looking at the picture below you can see many islands linked to Galapagos. What he observed was that though the finches had similar characteristics, they seemed to be quite different. Some were unique to individual islands, while others species were distributed on two or more islands that were close together.
Through his observation and curiosity, Darwin proposed that species would arise from an ancestral form by gradual accumulation of adaptations to a different environment. For example, if one species became fragmented into several localized populations isolated in different environments by geographical barriers, the populations would diverge more and more in appearance as each adapted to local conditions, gradually, over many generations, becoming dissimilar enough to be designated separate species. So through his work Darwin was able to see various characteristics that would show similarities between species, but yet they were different enough to be classified as different types of species.
Before you end this activity I want you to remember evolution is based on theory. This theory was developed along time ago through the observations of many people. But the most notable are Lamarck and Darwin. They are the ones who made a significant impact and showed that evolution may be true. Even though you may not want to agree with the theory of evolution, you must remember that it is based on scientific evidence. It is strongly supported by scientific evidence such as fossils and the geological time scale. It is not based on anyone's belief or thoughts, it is based on science.