He chose peas because they had been used for similar studies, are easy to grow and can be sown each year. Pea flowers contain both male and female parts, called stamen and stigma , and usually self-pollinate. Self-pollination happens before the flowers open, so progeny are produced from a single plant.
Peas can also be cross-pollinated by hand, simply by opening the flower buds to remove their pollen-producing stamen and prevent self-pollination and dusting pollen from one plant onto the stigma of another.
Mendel followed the inheritance of 7 traits in pea plants, and each trait had 2 forms. He identified pure-breeding pea plants that consistently showed 1 form of a trait after generations of self-pollination. Mendel then crossed these pure-breeding lines of plants and recorded the traits of the hybrid progeny. He found that all of the first-generation F1 hybrids looked like 1 of the parent plants. For example, all the progeny of a purple and white flower cross were purple not pink, as blending would have predicted.
This variation can be due to genes that are inherited, the environment, or some combination of genes and environment. In this section, we will deal only with traits that have a strong genetic component i. Here we will discuss the basic rules of genetic inheritance that cause progeny to resemble their parents in some respects, but not others. Gregor Mendel, who was a monk and teacher in what is now the Czech republic, first described these rules of inheritance in However, his work was not widely recognized until the early s.
Mendel experimented with garden peas, using varieties that differed for traits such as seed shape, seed color, and flower color. Each time, the results were the same as those shown in the figure above. The results of Mendel's second set of experiments led to his second law. This is the law of independent assortment. It states that factors controlling different characteristics are inherited independently of each other. You might think that Mendel's discoveries would have made a big impact on science as soon as he made them, but you would be wrong.
Because Mendel's work was largely ignored. Mendel was far ahead of his time and working from a remote monastery. He had no reputation among the scientific community and limited previously published work. He also published his research in an obscure scientific journal.
As a result, when Charles Darwin published his landmark book on evolution in , although Mendel's work had been published just a few years earlier, Darwin was unaware of it. This made Darwin's arguments about evolution less convincing to many people. Then, in , three different European scientists — named DeVries, Correns, and Tschermak — independently arrived at Mendel's laws.
All three had done experiments similar to Mendel's and come to the same conclusions that he had drawn several decades earlier. Only then was Mendel's work rediscovered and Mendel himself given the credit he was due.
Although Mendel knew nothing about genes, which were discovered after his death, he is now considered the father of genetics. Every mother and father pass down traits to their children. Explore how Mendel's pea plant experiments helped us better understand the genetics of this process here:. Of Peas and People These purplish-flowered plants are not just pretty to look at. The Austrian monk Gregor Mendel experimented with pea plants.
He did all of his research in the garden of the monastery where he lived. Blending Theory of Inheritance During Mendel's time, the blending theory of inheritance was popular. Why Study Pea Plants? Seeds can be round or wrinkled Seeds can have yellow or green cotyledons. Cotyledons refer to the tiny leaves inside the seeds. Flowers can be white or violet The seed pod can be full or constricted The seed pod can be yellow or green The flowers can occur along the stem in axial pods or at the end of a stem in terminal pods Stems can be long feet or short less than 1 foot.
Each pea plant flower has both male and female parts. The anther is part of the stamen, the male structure that produces male gametes pollen. The stigma is part of the pistil, the female structure that produces female gametes and guides the pollen grains to them.
The stigma receives the pollen grains and passes them to the ovary, which contains female gametes. Mendel's First Set of Experiments At first, Mendel experimented with just one characteristic at a time. Each section is described below. Mendel is the guide for students throughout the web lab. My name is Gregor Mendel. I lived in Austria in the s long before anyone knew about genes and genetics.
I experimented with plants to study how traits are passed from parents to offspring ad discovered the basic rules of inheritance that are still used in your textbooks today. Come and try some of my experiments to see what you can discover about inheritance.
Click Next to continue. This section of the web lab allows students to explore the traits on which Mendel experimented, then cross pea plants to see what offspring they produce. Each of the pea plants quickly sprouts. By rolling over the plants with the cursor, the student can see the color of the pea pod, the shape of the pod, and the color and form of the ripe seed. All of the different variations of pea plant can be seen in these growing peas, although the plants are randomly chosen each time the application is run.
After they have planted and grown five plants, Mendel asks students how many distinguishing traits they see in the plants. On the next screen, he reveals that there are seven different traits:. Students are then asked to experiment with plant crosses.
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