Heredity and Adaptations Part 1

Extinct

No longer in existence

Fossil

A trace of an ancient organism that has been preserved in rock.

Fossil Record

Chronological collection of life's remains in sedimentary rock layers

Organism

Any living thing

Paleontologist

A scientist who studies fossils

Principle 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.

Tetrapod

a vertebrate animal having four feet or legs or leglike appendages

Allele

Different forms of a gene

Characteristic

A feature that has different forms in a population

Cladogram

Diagram that shows the evolutionary relationships among a group of organisms

Chromosome

A threadlike, gene-carrying structure found in the nucleus. Each chromosome consists of one very long DNA molecule and associated proteins.

DNA

A complex molecule containing the genetic information that makes up the chromosomes.

Gene

A segment of DNA on a chromosome that codes for a specific trait

Generation

One step in the line of descent of a family

Adaptation

A trait or characteristic that enhances an organism's ability to survive and reproduce in its environment.

Genetics

The study of heredity and the variation of inherited characteristics.