Sometimes known as acquired characters or Lamarckism after one of its leading proponents, the French natural philosopher Jean Baptiste de Lamarck (1744-1829), acquired characteristics is a fallacy that should not be confused with mutation. Acquired characteristics theory maintains that changes that occur in an organism's overall anatomy (as opposed to changes in its DNA) can be passed on to offspring.
Any effort directed toward finding the age of a particular item or phenomenon. Methods of dating are either relative (that is, comparative and usually based on rock strata, or layers) or absolute. The latter, based on methods such as the study of radioactive isotopes, typically is rendered in terms of actual years or millions of years.
Deoxyribonucleic acid, a molecule in all cells and in many viruses that contains genetic codes for inheritance.
The mineralized remains of any prehistoric life-form, especially those preserved in rock before the end of the lastice age.
The process by which a once living organism becomes a fossil. Generally, fossilization involves mineralization of the organism's hard portions, such as bones, teeth, and shells.
A unit of information about a particular heritable (capable of being inherited) trait that is passed from parent to offspring, stored in DNA molecules called chromosomes.
The vast stretch of time over which Earth's geologic development has occurred. This span (about 4.6 billion years) dwarfs the history of human existence, which is only about 2.5 million years. Much smaller still is the span of human civilization, only about 5,500 years.
An unproven statement regarding an observed phenomenon.
The high level of occurrence of dark, or melanic, individuals from a particular species (usually insects) within a geographic region noted for its high levels of dark-colored industrial pollution.
An animal without an internal skeleton.
A scientific principle that is shown always to be the case and for which no exceptions are deemed possible.
A series of changes experienced by a once living organism during fossilization. In mineralization, minerals in the organism are replaced or augmented by different minerals or the hard portions of the organism dissolve completely.
Alteration in the physical structure of an organism's DNA, resulting in a genetic change that can be inherited.
The process whereby some organisms thrive and others perish, depending on their degree of adaptation to a particular environment.
The study of life-forms from the distant past, primarily as revealed through the fossilized remains of plants and animals.
A set of principles and procedures for systematic study that includes observation; the formation of hypotheses, theories, and laws; and continual testing and reexamination.
A general statement derived from a hypothesis that has withstood sufficient testing.
An animal with an internal skeleton.
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