Word Definition
Adaptation a character or structure that helps an organism live and reproduce successfully in its environment
habitat The area or place where an organism naturally lives in an ecosystem
diversity the variety of life
species the basic unit of classification, the division of a genus, made of very similar organiisms that are able to mate and reproduce offspring of the same type
variation a difference within the species
sexual reproduction Reproduction through the union of a male and a female gamete, each contributing genetic material to the offspring
zygote A cell formed by the union of two sets of genes when a male and a female unite; a fertilizied egg
asexual reproduction Reproduction in which a single individual copies its genetic material
Evolution The concept originated by Charles Darwin, explaining that organisms are the products of historical change and that new species gradually developed from previous ones
natural selection The process by which organisms that are adapted to their environment survive and reproduce, passing there traits on to their offspring
population A group of individuals of the same species living in a particular area
fossil Remains or traces of an organism that lived in the past
extinct Referring to forms of life that have died out
fossil record Record of life on earth provided by fossils
mold A fossil impression left in rock by the hard parts of an organism
cast A fossil formed by minerals in water that build up in a mold