www wap dating ru - Relative and absolute age dating of rocks

This is an informational tour in which students gain a basic understanding of geologic time, the evidence for events in Earth’s history, relative and absolute dating techniques, and the significance of the Geologic Time Scale.

acquired trait: A phenotypic characteristic, acquired during growth and development, that is not genetically based and therefore cannot be passed on to the next generation (for example, the large muscles of a weightlifter).

adaptation: Any heritable characteristic of an organism that improves its ability to survive and reproduce in its environment.

As more and more layers are deposited, the older rock layers end up at the bottom and the newer ones toward the top. What is the difference between relative and absolute age?

Relative age is the age of a rock layer (or the fossils it contains) compared to other layers.

It can be determined by looking at the position of rock layers.

Absolute age is the numeric age of a layer of rocks or fossils.

The term can also be applied to larger groups of organisms, as in "the adaptive radiation of mammals." adaptive strategies: A mode of coping with competition or environmental conditions on an evolutionary time scale.

Species adapt when succeeding generations emphasize beneficial characteristics.

Then, even if circumstances change such that it no longer provides any survival or reproductive advantage, the behavior will still tend to be exhibited -- unless it becomes positively disadvantageous in the new environment.

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