Introduction
Acquired traits are characteristics that an organism develops during its lifetime due to environmental influences, habits, learning, practice, or experiences. These traits are not inherited from parents and are generally not passed on to offspring.
According to NCERT Class 10 Science (Heredity and Evolution), acquired traits result from changes in the body cells and do not affect the genetic material (DNA) present in reproductive cells.
Definition of Acquired Traits
Acquired traits are features or characteristics that an individual develops during its lifetime because of environmental factors, lifestyle, learning, exercise, injuries, or experiences.
Examples
- Strong muscles developed through exercise
- Knowledge gained through education
- Calluses formed on hands due to hard work
- Increased body weight due to diet
- Scars caused by injuries
- Skill in playing a musical instrument
Characteristics of Acquired Traits
| Characteristic | Description |
|---|---|
| Developed During Life | Form after birth during an individual’s lifetime |
| Environmental Influence | Affected by surroundings and lifestyle |
| Non-Genetic | Do not involve changes in genes |
| Not Inherited | Usually cannot be passed to offspring |
| Temporary or Permanent | May remain for life or disappear later |
How Acquired Traits Develop
Acquired traits develop due to:
1. Environmental Factors
- Climate
- Nutrition
- Pollution
- Living conditions
2. Physical Activities
- Exercise
- Sports training
- Manual labor
3. Learning and Practice
- Language skills
- Musical abilities
- Academic knowledge
4. Injuries and Accidents
- Scars
- Loss of body parts
- Physical damage
Why Acquired Traits Are Not Inherited
NCERT explains that only changes in reproductive cells (gametes) can be passed to the next generation.
Acquired traits affect body cells (somatic cells) and do not change the DNA in reproductive cells.
Example
A bodybuilder develops large muscles through exercise.
- Muscle size increases during life.
- DNA in reproductive cells remains unchanged.
- Children do not automatically inherit strong muscles.
Therefore, developed muscles are an acquired trait.
Acquired Traits and Evolution
Jean-Baptiste Lamarck’s Idea
Lamarck suggested that acquired traits could be inherited.
Example
- Giraffes stretched their necks.
- Longer necks were supposedly passed to offspring.
Modern Scientific View
Modern genetics has shown that acquired traits are generally not inherited because they do not alter the genetic material in reproductive cells.
Therefore, Lamarck’s explanation is not accepted as the primary mechanism of evolution.
Examples of Acquired Traits in Daily Life
| Acquired Trait | Cause |
|---|---|
| Strong muscles | Exercise |
| Scar on skin | Injury |
| Calluses on hands | Repeated friction |
| Knowledge | Education |
| Language skills | Learning |
| Swimming ability | Practice |
| Tanned skin | Sun exposure |
| Increased stamina | Training |
Difference Between Acquired Traits and Inherited Traits
| Acquired Traits | Inherited Traits |
|---|---|
| Develop during lifetime | Present from birth |
| Caused by environment or experience | Controlled by genes |
| Not usually inherited | Passed from parents to offspring |
| Affect body cells | Associated with reproductive cells and DNA |
| Example: Muscular body | Example: Eye color |
Importance of Understanding Acquired Traits
- Helps explain heredity correctly.
- Distinguishes genetic traits from learned characteristics.
- Supports the modern theory of evolution.
- Explains why learned skills are not inherited.
- Helps understand the role of genes and environment.
NCERT Key Points
✔ Acquired traits develop during an individual’s lifetime.
✔ They result from environmental influences, habits, and experiences.
✔ They do not involve changes in reproductive-cell DNA.
✔ Acquired traits are generally not inherited.
✔ Evolution mainly occurs through heritable genetic variations.
Practice Questions
Short Answer Questions
1. What are acquired traits?
Answer:
Acquired traits are characteristics developed during an individual’s lifetime due to environmental influences, learning, habits, or experiences.
2. Are acquired traits inherited?
Answer:
No, acquired traits are generally not inherited because they do not affect the DNA of reproductive cells.
3. Give two examples of acquired traits.
Answer:
- Strong muscles due to exercise
- Scar caused by injury
4. Why are acquired traits not passed to offspring?
Answer:
Because they affect body cells only and do not change the genetic material in reproductive cells.
5. Which scientist proposed inheritance of acquired traits?
Answer:
Jean-Baptiste Lamarck.
Fill in the Blanks
- Acquired traits develop during an individual’s __________.
Answer: lifetime - Acquired traits are influenced by the __________.
Answer: environment - Strong muscles developed through exercise are an __________ trait.
Answer: acquired - Acquired traits do not affect the DNA of __________ cells.
Answer: reproductive - Lamarck proposed the theory of inheritance of __________ traits.
Answer: acquired
Multiple Choice Questions (MCQs)
1. What are acquired traits?
A. Traits inherited from parents
B. Traits developed during life
C. Traits found only in plants
D. Traits controlled only by genes
✅ Answer: B
2. Which of the following is an acquired trait?
A. Eye color
B. Blood group
C. Scar on skin
D. Hair color
✅ Answer: C
3. Acquired traits are mainly influenced by:
A. Genes only
B. Environment and experiences
C. Chromosomes only
D. DNA only
✅ Answer: B
4. Which scientist proposed inheritance of acquired traits?
A. Mendel
B. Darwin
C. Lamarck
D. Morgan
✅ Answer: C
5. Which trait is inherited?
A. Scar
B. Language learned
C. Eye color
D. Muscles from exercise
✅ Answer: C
6. Acquired traits affect:
A. Reproductive cells only
B. DNA only
C. Body cells mainly
D. Chromosomes only
✅ Answer: C
7. Which is NOT an acquired trait?
A. Calluses
B. Knowledge
C. Blood group
D. Muscular body
✅ Answer: C
8. Why are acquired traits not inherited?
A. They affect body cells only
B. They increase DNA mutations
C. They create new chromosomes
D. They change species immediately
✅ Answer: A
9. Swimming skill is an example of:
A. Inherited trait
B. Acquired trait
C. Genetic mutation
D. Evolution
✅ Answer: B
10. NCERT states that evolution depends mainly on:
A. Acquired traits
B. Learned skills
C. Heritable genetic variations
D. Injuries
✅ Answer: C
Quick Revision
- Acquired traits develop during life.
- Caused by environment, learning, habits, and experiences.
- Do not alter reproductive-cell DNA.
- Usually cannot be inherited.
- Examples: muscles, scars, calluses, knowledge, and skills.
- Evolution depends primarily on inherited genetic variations.
