Unit 2 Earth History and Evolution

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What is the principle of superposition in geology?

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In geology, the principle of superposition states that in any undisturbed sequence of sedimentary rocks, the oldest layers are at the bottom and the youngest layers are at the top.

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What are index fossils?

Back

Index fossils are fossils of organisms that were widespread but only existed for a short period of geological time, used to date and correlate the age of rock layers.

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How do homologous structures provide evidence for evolution?

Back

Homologous structures are anatomical features in different species that share a common ancestry, indicating that these species evolved from a common ancestor.

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What is natural selection?

Back

Natural selection is the process by which organisms better adapted to their environment tend to survive and produce more offspring, leading to evolutionary changes.

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What is the significance of the fossil record?

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The fossil record provides evidence of past life forms, their evolution, and the changes in biodiversity over time, helping scientists understand the history of life on Earth.

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What does the term 'geologic time scale' refer to?

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The geologic time scale is a system of chronological dating that relates geological strata to time, dividing Earth's history into eons, eras, periods, and epochs.

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What is a common ancestor?

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A common ancestor is an ancestral species from which two or more different species have evolved, providing evidence for the theory of evolution.

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What is the difference between relative age and absolute age of rocks?

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Relative age is the age of a rock layer compared to other layers, while absolute age is the actual age of a rock or fossil, often determined by radiometric dating.

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What role do environmental changes play in evolution?

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Environmental changes can create new challenges and opportunities for species, leading to adaptations and evolutionary changes over time.

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What is the concept of adaptive radiation?

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Adaptive radiation is the process by which a single ancestral species rapidly diversifies into a wide variety of forms to adapt to different environments.