Heredity Science Before Mendel
The causes of heredity remained a mystery for centuries—until Gregor Mendel.
The timeline below shows key developments in how people thought about heredity before Mendel.
|
 |
8000 BC – Neolithic farmers select plants and animals with desirable traits—the highest-yielding vegetable, the sweetest fruit, or the fattest cow—to crossbreed.
|
|
400 BC – Greek philosopher Hippocrates proposes that tiny particles from every part of the body of each parent became blended, producing an individual with the characteristics of both.
|
|
350 BC – Aristotle dismisses Hippocrates’ theory, noting that children do not always resemble parents. But Aristotle’s thinking about heredity still centers on a mixing of “fluids” from each parent.
|
|
1700s – Scientific thinking about reproduction is dominated by “preformation”: the idea that an organism contains all of its future descendants, encased in increasingly miniature forms, like Russian nesting dolls.
|
|
1760s – Joseph Kölreuter pioneers the scientific study of plant hybrids (a “cross” between parents of different varieties).
|
|
1780s – English livestock breeder Robert Bakewell pioneers the systematic breeding of sheep and cattle to obtain higher quality wool and fatter beef.
|
|
1800s - The idea of heredity as a “blending” process continues to dominate scientific thought until the late 1800s.
|
|
 1856 - An inquisitive friar named Gregor Mendel began conducting experiments that held the answer to the riddle.
|
