A Dynamic Planet

Unit Review Sheet

Facts and Definitions

Lesson 1: The Dating Game

• Geology is the study of the Earth, including its rocks, minerals, and the processes that shape its surface over time.
• Evolutionary biology is the study of the processes that brought about the diversity of life on Earth.
• Relative dating of rocks can determine which ones are older or younger than others, even if the exact age of those layers is unknown.
• Radiometric dating of rocks can determine the age of the rocks by measuring the decay of radioactive elements in those rocks.
• The geological column is a record of the rock layers of the Earth in the order that they were formed.
• Stratigraphy is the study of layers of rock.
• The principle of superposition states that since sedimentary rocks are laid down on top of one another, the layers at the bottom are older than the layers that are on top.
• The principle of original horizontality states that sediments that form sedimentary rock are laid down flat (horizontally) due to gravity. If a sedimentary rock layer appears to be vertical, it must have been moved from its original position.
• The principle of lateral continuity states that when sediments are laid down, they spread out in all directions until some sort of boundary confines them or the sediment is used up.
• The acronym mya stands for "million years ago."
• The acronym bya stands for "billion years ago."

Lesson 2: Plate Tectonics

• Tectonic plates are massive, irregularly shaped slabs of rock that float upon the Earth's mantle.
• When two tectonic plates move toward each other, the boundary formed between them is called a convergent boundary.
• When two tectonic plates move away from each other, the boundary formed between them is called a divergent boundary.
• When two tectonic plates rub against each other, the boundary formed between them is called a transform boundary.
• Oceanic crusts flow beneath a continental crust at a subduction zone.

Lesson 3: The First Four Billion Years

• The Hadean is the first eon in the geological history of Earth. It begins with the formation of the Earth about 4.5 bya and lasts for 500 million years.
• The Archean is the second eon in the geological history of Earth. It begins 4 bya and lasts for 1.5 billion years.
• The Proterozoic (which means "age of former life") is the third eon in the geological history of Earth. It begins 2.5 bya and is almost 2 billion years in length.
• Precambrian refers to the first 4 billion years of the Earth's history before large visible fossils are found in the rock history.

Lesson 4: The Age of Visible Life

• The Phanerozoic eon has lasted from 545 mya until present day.
• Phanerozoic means "the age of visible life."
• The Paleozoic era is the first era of the Phanerozoic eon, and it lasted from 545-248 mya.
• Paleozoic means "the age of ancient life."
• The Mesozoic era is the second era of the Phanerozoic eon, and it lasted from 248 mya until 65 mya.
• Mesozoic means "the age of middle life."
• The Cenozoic era is the final era of the Phanerozoic eon, and it lasted from 65mya until today.
• Cenozoic means "the age of recent life."
• An index fossil is a fossil that is found only in one or a few rock layers and can therefore be used to identify the rock layer it is found in.
• The geologic column is a timescale that relates layers of the Earth's rock with chronological time — the youngest layers are on top, and the oldest layers are on the bottom.

Lesson 5: Digging for Clues

• Evolution is a process that results in changes capable of being inherited in a population spread over many generations.

Lesson 6: Natural Selection

• A species is a group of living things that can reproduce with one another but not with other lifeforms.
• Natural selection is the process whereby organisms that are better adapted tend to survive and produce more offspring.
• Artificial selection is the process whereby organisms are selectively bred to produce or eliminate certain traits.

Lesson 7: Survival of the Fittest

• A mutation is an accidental, permanent change in the genetic instructions for making a living thing.
• Genetic variation refers to the diversity of mutations that exist within a population.

Lesson 8: Convergent Evolution

• Convergent evolution is the tendency for living things to evolve similar features in response to similar challenges.

Final Project: Fast Forward

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