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.