Mendels Experiment

• Gregor Johann Mendel, widely regarded as the ‘Father of Genetics’, conducted experiments on pea plants with the aim of comprehending the principles of heredity.
• The rules of inheritance of traits are based on the fact that genetic material is contributed equally by both mother and father. Thus, for each trait, a child will inherit two versions, or alleles.
• Mendel proposed 3 laws known as Laws of Inheritance.
• Mendel’s experiments demonstrated the principles of inheritance and the concept of dominant and recessive traits.

Dominant and Recessive Traits

A dominant trait is one that is expressed when at least one copy of the dominant allele is present in an organism’s genotype. For example In Mendel’s experiment height is the dominant trait.                                          

A recessive trait, on the other hand, is expressed only when two copies of the recessive allele is present in an organism’s genotype. For example Mendel’s short height of pea plant.      

Monohybrid Cross

A cross between two organisms that involves only one character is referred to as a monohybrid cross.                                                                           

Mendel bred pea plants that differed in one specific trait, such as the height of the pea plant. He first crossed two plants that were true-breeding for different heights, one with tall height and the other with short height. The height of the plant offspring was all tall. He called this generation as F1 generation. Next, he crossed two of the F1 plants with each other and observed that the resulting offspring, the F2 generation, had a 3:1 ratio of tall to short plants. This meant that the trait for tall height was dominant over the trait for short height.

Dihybrid Cross                                           

A cross between two organisms that involves two characters is referred to as a Dihybrid cross.

Mendel chose two pea plant characteristics, seed color, and seed shape, and crossed two true-breeding plants that had different alleles of both traits. One parent had a round, yellow seeds (RRYY), and the other had wrinkled, green seeds (rryy). The offspring, called the F1 generation, all had a round, yellow seeds (RrYy), which showed that one allele of each trait was dominant over the other.

Mendel then crossed two of the F1 plants with each other to create the F2 generation. He observed that the offspring had a 9:3:3:1 ratio of seed types, with 9 plants having round and yellow seeds, 3 plants having round and green seeds, 3 plants having wrinkled and yellow seeds, and 1 plant having wrinkled and green seeds.    

Hereditary and Evolution Class 10 Notes: Hereditary is the transmission of traits or characters from parents to their offspring through genes. Offspring may not inherit the same combination of genes from their parents which can result in variations in physical characteristics. This variation causes rise to the evolution of species.

The CBSE Science Heredity and Evolution Class 10 Notes are provided here for quick revision. We have also provided Heredity and Evolution Class 10 important questions for last-minute preparation.