What is Evolution?
Evolution is when organisms are constantly adapting to their environment based on what is needed for survival. The organisms change over time in response to their environment. A theory of evolution includes the idea that all organisms on Earth evolved from one common ancestor.
Since fossils show organisms in a sequential order, they provide evidence of the evolutionary changes of specific organisms. Similar anatomy is studying the similarities between different plants and animals reveals how one specie's body parts can resemble another specie's body parts.
Scientists have gathered different types of information to support the theory of evolution, such as the fossil record, homology, and similar development before birth (as shown above).
Similarities that result from sharing a common ancestor are called homologies. There are different types of homologies: -anatomical (structures look the same) -cellular (organelles are the same) -molecular (molecules are the same)
Layers of rock are called rock strata. The further down in the Earth a fossil is, the older it is.
An interesting type of anatomical homology is called a vestigial structure. A vestigial structure is a structure of an organism that has no apparent purpose. estigial structures provide clues about the evolution of the organism. The tailbone is a vestigial structure in humans. We do not have a tail, but we still have the bone to which a tail would be attached.