Evolution (Are They Among Us?)

Evolution

Change in the heritable characteristics of biological populations over successive generations.

Charles Darwin

English natural scientist who formulated a theory of evolution by natural selection (1809-1882)

relative dating

Method of determining the age of a fossil by comparing its placement with that of fossils in other layers of rock

DNA

molecule that stores genetic information in all organisms. All living things share codes of DNA, showing that all living things are related.

Embryology

the branch of biology and medicine concerned with the study of embryos and their development. Can be used to show evidence for common ancestors between species.

common ancestor

the most recent ancestral species from which two or more different species evolved

radiometric dating

the process of measuring the absolute age of geologic material by measuring the concentrations of radioactive isotopes

Tiktaalik

transitional fossil between fish and tetrapods

Natural Selection

A process in which individuals that have certain inherited traits tend to survive and reproduce at higher rates than other individuals because of those traits.

Mutation

A random, naturally occurring change in the nucleotide-base sequence of a gene or DNA molecule (a change in the genetic code). Sometimes gives the organism a new trait.

Palentologist

A scientist who studies fossils to learn about organisms that lived long ago

embryo

An organism in the earliest stage of development

organism

Any living thing

Fossils

Preserved remains of once-living organisms that show how life has changed over time

Homologous Structures

Structures that are similar across species that were inherited from a common ancestor.

Extinction

When every member of a species dies off

genes

a segment of DNA capable of synthesizing a protein and giving organisms their unique traits.