Evidence for Evolution

fossil

a preserved remnant or impression of an organism that lived in the past; must have been biotic

Theory of Continental Drift

theory created by Alfred Wegener to describe the movement of continents away from the supercontinent Pangaea over time

Pangaea

large, ancient landmass that was composed of all the continents joined together

plate tectonics

the theory that pieces of Earth's lithosphere are in constant motion, driven by convection currents in the mantle which cause various landforms

fossil record

chronological collection of life's remains in sedimentary rock layers

Law of Superposition

the geologic principle that states that in horizontal layers of sedimentary rock, each layer is older than the layer above it and younger than the layer below it

relative age

the age of a rock compared to the ages of rock layers

index fossil

a fossil that existed in a particular geologic era (one rock layer) and nowhere else; used to relatively date rock layers above and below

coexist

to exist at the same time or in the same place

molecular homology

similar DNA (amino acid sequences) among different species from a common ancestor