9: Evolution
- Page ID
- 33303
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The biosphere is filled with patterns. This is true not only in the ecosystems around us today, but also in our planet’s fossil past. These patterns force scientists to ask questions:
- Why is there so much shared DNA among life forms that seem so different, even across different environments?
- Why do so many life forms that live such different lives have such similar features?
- Why do humans and reptiles share four limbs?
- Why do both butterflies and birds have wings?
- Why do some features of organisms not have clear functions?
- Why do I need to put on a jacket, hat, and gloves to venture out into the winter cold?
- Why are ecosystems arranged in a hierarchy with primary producers on the bottom and omnivorous organisms on top?
Evolutionary theory presents us with answers to these questions. Using it as a framework, we can answer these questions and more. Evolution explains the observable patterns in the living world around us. It also explains the patterns we see in the fossil past.