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Early in the 19th century, scientists had already recognized that Earth has been inhabited by living creatures for a very long time. On the other hand, they did not understand what mechanisms actually drove [[Biodiversity|biological diversity]]. They also did not understand how [[Trait (biology)|physical traits]] are inherited from one generation to the next. [[Blending inheritance]] was the common ideal at the time, but was later discredited by the experiments of Gregor Mendel. Mendel proposed the theory of '''particulate inheritance''' by using [[pea]] plants (''Pisum sativum'') to explain how variation can be inherited and maintained over time.
=== Blending
* '''Blending
** Offspring are a blend of both parents (i.e. in modern terms, alleles would blend together to form a completely new allele)
** The characteristics of the blended offspring are passed on to the next generation
** Variation is washed out over time<ref name=bioed>{{cite web |author=Lisa M. Meffert |title=Blending Model of Inheritance vs. Particulate Model of Inheritance |work=Introduction to Mendelian Genetics |url=http://www.bioedonline.org/slides/content-slides/heredity/introduction-to-mendelian-genetics/?pageaction=displaySlideDetails&tk=30&dpg=2 |publisher=BioEd Online |accessdate=March 12, 2014}}</ref>
* '''Particulate
** Offspring are a combinations of both parents
** The characteristics of both parents are passed on to the next generation as separate entities
** Variation is maintained over time<ref name=bioed/>
== Mendel's
=== Mendel's
Since Mendel used experimental methods to devise his particulate inheritance theory, he developed three basic laws of inheritance: the [[Law of Segregation]], the [[Law of Independent Assortment]], and the [[Law of Dominance]]:<ref name=bioed/>
==== Law of
Mendel's experiment with tall and short pea plants demonstrates how each individual plant has two particles called [[alleles]]. When a pea plant produces [[gametes]] (reproductive cells), it segregates one allele to each one.
==== Law of
The law states that when the parents differ from each other in two or more pairs of contrasting characters, the inheritance of one pair of characters is independent to that of the other pair of characters.<br/>
==== Law of
In the pea plants, Mendel observed that the "T" allele ([[dominance (genetics)|dominant]]) masked the effects of the "t" allele ([[recessive]]). The terms "dominant" and "recessive" are used for the masking and the covered allele, respectively. All offspring from this cross are [[heterozygotes]] in terms of their [[genotypes]]. They also are tall (because the allele for tall masks the allele for short) in terms of their "[[phenotype]]".<ref>{{cite web |author=Lisa M. Meffert |title=Crossing the Parental Lines: Female Contribution |work=Introduction to Mendelian Genetics |url=http://www.bioedonline.org/slides/content-slides/heredity/introduction-to-mendelian-genetics/?pageaction=displaySlideDetails&tk=30&dpg=6 |publisher=BioEd Online |accessdate=March 12, 2014}}</ref>
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