CBSE Class 10 Science Notes Chapter 9 Heredity and Evolution

Heredity: The passing of traits from parents to offspring. It is governed by genes located on chromosomes. The basic unit of heredity is the gene.

Mendel's Laws of Inheritance: Gregor Mendel's experiments with pea plants led to the formulation of inheritance laws, including the Law of Dominance, the Law of Segregation, and the Law of Independent Assortment.

Evolution: Organisms change over generations through variations, natural selection, and adaptation. Evidence of evolution includes fossils, homologous structures, and genetic similarity.

Most Important Science Class 10 Questions Answers For Board Examination

Here are some of the most asked questions in the last 5 CBSE board exams for Chapter 9: Heredity and Evolution:

What is Mendel’s Law of Dominance?
- The Law of Dominance states that when two different alleles are present in an organism, the dominant allele expresses its trait, while the recessive allele’s trait is masked.
Explain the process of evolution with examples.
- Evolution is the gradual development of species through variations, natural selection, and adaptations. Example: Darwin’s finches evolved beak shapes based on available food sources.
What are homologous structures? Give examples.
- Homologous structures are similar structures found in different species that evolved from a common ancestor. Example: The forelimbs of humans, bats, and whales.
What is the significance of variation in evolution?
- Variation provides the raw material for natural selection, enabling some traits to be favored for survival, thus promoting species adaptation to the environment.
What is a gene? How does it influence heredity?
- A gene is a unit of heredity that carries genetic information from one generation to the next. It influences traits like eye color, height, etc., by determining the expression of specific characteristics.

Most Important MCQs Science Class 10 For Board Examination

Here are some MCQs based on Chapter 9: Heredity and Evolution for Class 10:

Which of the following is an example of a recessive trait in humans?
- A) Brown eyes
- B) Blue eyes
- C) Dark skin
- D) Curly hair
  Answer: B) Blue eyes
The process of evolution is primarily driven by:
- A) Genetic mutation
- B) Environmental changes
- C) Natural selection
- D) Both A and B
  Answer: D) Both A and B
What does the term ‘variation’ refer to in the context of evolution?
- A) Difference in traits among individuals
- B) Traits that are passed from parent to offspring
- C) The survival of only the strongest organisms
- D) Genetic traits that are inherited
  Answer: A) Difference in traits among individuals
Which of the following is a homologous structure?
- A) Wings of a bird and wings of a bat
- B) Flippers of a whale and hands of a human
- C) Eyes of a human and eyes of a fish
- D) Both B and C
  Answer: D) Both B and C
The concept of natural selection was first proposed by:
- A) Lamarck
- B) Darwin
- C) Mendel
- D) Wallace
  Answer: B) Darwin
The gene responsible for colorblindness is located on which chromosome?
- A) X chromosome
- B) Y chromosome
- C) 1st chromosome
- D) 23rd chromosome
  Answer: A) X chromosome
Which of the following is an example of an inherited trait in humans?
- A) Accents
- B) Eye color
- C) Language skills
- D) Height of parents
  Answer: B) Eye color