Elementary School (3-5)
Some kinds of plants and animals that once lived on Earth are no longer found anywhere.
Fossils provide evidence about the types of organisms that lived long ago and also about the nature of their environments.
Middle School (6-8)
The collection of fossils and their placement in chronological order (e.g., through the location of the sedimentary layers in which they are found or through radioactive dating) is known as the fossil record. It documents the existence, diversity, extinction, and change of many life forms throughout the history of life on Earth.
Anatomical similarities and differences between various organisms living today and between them and organisms in the fossil record, enable the reconstruction of evolutionary history and the inference of lines of evolutionary descent.
Comparison of the embryological development of different species also reveals similarities that show relationships not evident in the fully-formed anatomy.
High School (9-12)
Genetic information provides evidence of evolution. DNA sequences vary among species, but there are many overlaps; in fact, the ongoing branching that produces multiple lines of descent can be inferred by comparing the DNA sequences of different organisms. Such information is also derivable from the similarities and differences in amino acid sequences and from anatomical and embryological evidence.