Which of the following is not included in Darwin's theory?

Correct option is B

The correct answer is: (b) Evolution through Inheritance

Darwin’s theory of evolution primarily revolves around natural selection, survival of the fittest, and the struggle for existence. However, the concept of "evolution through inheritance" in its original form was not explicitly included in Darwin's theory. Darwin proposed the idea of variation and selection but lacked the modern understanding of genetics (inheritance of traits), which was later developed through Gregor Mendel’s work on heredity.

Key Components of Darwin’s Theory:

1. Natural Selection: The process by which organisms better adapted to their environment survive and reproduce more successfully.
2. Survival of the Fittest: Coined by Herbert Spencer, closely related to Darwin's idea, describing the ability of organisms to compete for resources and reproduce.
3. Struggle for Existence: Competition among organisms for limited resources, such as food, shelter, and mates.

Key Points:

• Darwin was unaware of Mendel’s work on genetic inheritance. His ideas were based on observable traits and variation without understanding the mechanism of inheritance.
• In Darwin’s time, inheritance was explained using "blending inheritance," which was later disproven.

Additional Information:

Mendel's Inheritance Principles:
Gregor Mendel, the "Father of Genetics," conducted experiments on pea plants (Pisum sativum), establishing the foundation of genetics. His principles explain how traits are passed from parents to offspring.

Key Principles:

1. Law of Segregation:

   • Each organism carries two alleles for a trait, one inherited from each parent.
   • During gamete formation, these alleles segregate so each gamete carries only one allele for a trait.
   • Example: A plant with genotype "Tt" (tall) produces gametes with either "T" or "t" alleles.

2. Law of Independent Assortment:

   • Alleles for different traits assort independently during gamete formation, applying to genes located on different chromosomes.
   • Example: Seed color (yellow or green) and seed shape (round or wrinkled) are inherited independently.

3. Law of Dominance:

   • When two different alleles are present, one (dominant) masks the expression of the other (recessive).
   • Example: A tall (T) and short (t) plant cross produces offspring with genotype "Tt," appearing tall because "T" is dominant over "t."

Modern Understanding:
Mendelian genetics provided the missing link, explaining how traits are inherited, enriching Darwin’s theory and forming the modern synthesis of evolutionary biology, integrating natural selection with genetic inheritance.