The Work of Gregor Mendel Essay Example

large numbers and its reproduction could be manipulated. Like many other flowering plants, pea plants have both male and female reproductive organs, allowing them to undergo self-pollination or cross-pollinate with other plants.

Mendel performed experiments where he selectively cross-pollinated purebred plants to study the outcome across several generations. The resulting offspring of cross-pollinated pea plants only showed purple or white flowers, with no intermediate colors. This observation formed the basis for Mendel's conclusions about genetic inheritance. He identified seven readily identifiable characteristics in pea plants, each having two distinct forms.

1. Flower color: purple or white
2. Flower position: axial or terminal
3. Stem length: long or short
4. Seed shape: round or wrinkled
5. Seen color: yellow or green
6. Pod shape: inflated or constricted
7. Pod color: yellow or green

This observation is crucial because it contradicted the prevailing biological theory that traits blend in offspring plants. Mendel's theory, on the other hand, proved otherwise. Mendel's Law of Segregation comprised four laws, the first of which stated that variations in inherited characters can be attributed to alternative versions of genes.

The idea of alleles refers to different versions of genes that result in the same attribute. For example, each pea plant has two genes that determine pea texture. According to the second law, organisms receive two genes for each trait - one from each parent. Therefore, when somatic cells are formed from gametes, one allele comes from the mother and another from the father. In true-breeding organisms, these alleles may be the same; however, they can differ in hybrids.

The third law states that if two alleles differ,

the dominant allele will fully show in the organism's appearance, while the recessive allele will have no effect on the appearance. The fourth law of segregation states that during gamete production, the two genes for each characteristic separate. This occurs during meiosis when the chromosome count changes from diploid to haploid, and ensures genetic variation through the sorting of genes into different gametes. This sorting process relies on genetic recombination.

The genes undergo a random and specific mixing process during this time. Each trait's genes only exchange with the genes of the same trait on the opposite DNA strand to ensure that all traits are present in the offspring. The Mendel Pea Experiment led to the discovery of the Law of Segregation, which greatly influenced genetic research by demonstrating its applicability to all sexually reproducing organisms. According to Mendel's Law of Independent Assortment, one trait's appearance does not affect another trait's emergence.

The inheritance of certain traits in pea plants, such as purple flowers instead of white ones, does not necessarily mean that other traits, like yellow peas instead of green ones, will be inherited. Mendel's discoveries in this area helped scientists simplify their understanding of how traits emerge by using mathematical probability. Mendel's success can mostly be attributed to his meticulous and unbiased use of the scientific method, as well as his fortunate choice to experiment with peas.

Mendel had complete control over the breeding of peas due to their simple genetic structure. He expressed the data for his experiment numerically and analyzed it statistically, which added credibility to his findings. Additionally, Mendel's use of a large sample size and his

examination of multiple generations of pea plants allowed him to record variations accurately. Had he not been meticulous in his approach, Mendel's work would not have had the profound impact on genetics that it did. This article explores the rivalry between Mendel and Darwin.

Mendel's ideas on heredity and evolution differed greatly from Darwin and his followers. While Darwin believed in the inheritance of acquired characters, which led to his theory of continuous evolution, Mendel rejected both the concept of inheriting acquired characters (known as mutation) and the idea of continuous evolution. Instead, Mendel's laws were seen as laws that applied to constant elements with a significant but limited variation, applicable not only to cultivated varieties but also to wild species.

In his short treatise, Experiments in Plant Hybridization, Mendel consistently discusses concepts such as "constant characters," "constant offspring," "constant combinations," "constant forms," "constant law," and "a constant species." Mendel firmly believed that his laws of heredity supported Gartner's conclusion that species are unchangeable beyond certain limits. However, in the 19th century, the Darwinians prevailed in the scientific community, leaving little room for acceptance of Mendel's true scientific laws of heredity. Despite this, Mendel's work on genetics continued to be pursued mainly by critics of Darwin.