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Acquired and Inherited traits can be defined as the characteristics possessed by a living being, either passed from parent cells or developed during the lifetime of the living being itself. Human beings are born with different characteristics by which they make up their own unique identity. However, in science, these characteristics are known as traits. Traits are further divided into two parts: Inherited traits and Acquired traits. Inherited traits are the ones that are passed on from generations through DNA however, Acquired traits are the ones that a person develops through age.
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Key Terms: Traits, Inherited Traits, Acquired Traits, Heredity, Genes, Mendel’s Experiment, DNA, RNA, Chromosome, Mutation, Somatic Cells, Genetic Cells, Inheritance, Dominance
What are Traits?
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Traits are the set of characteristics possessed by an individual by which it tends to make its own unique identity. It is a noticeable feature of quality in a person. Everyone has different sets of traits that make them unique. However, there are traits that are passed on from parents like the colour of your hair, such traits are called inherited traits. Some traits are results of your own adaptability in this environment and you’ve learnt them yourself. Those traits are known as acquired traits.
Inherited Traits
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Inherited traits are the traits that are passed on from parents to their offspring. Colour of skin, eyes, type of hair, body, sensitivity to a particular disease, etc are some of the typical examples of inherited traits. Inherited traits of a person can be determined by their genes. A single human cell comprises between 25,000 and 35,000 genes. These genes carry the characteristics that a person inherits from his parents.
In his trials with the pea plant, Gregor Mendel demonstrated the concept of inherited traits. The features that are evident in the phenotype are known as dominant traits, whereas the traits that are not visible are known as recessive traits.
Flow Chart Showing Inheritance of Traits
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Laws of Inheritance
The following rules of inheritance were used by Mendel to explain inherited traits:
- Law of Dominance: One trait in a heterozygote will hide the presence of another trait for the same characteristic, according to Mendel's law of dominance. The dominant allele will be expressed primarily, rather than both alleles contributing to a trait. The law of dominance asserts that dominant traits always dominate or cover recessive features. According to the experiment,
- When round-seeded pea plants (RR) are crossed with wrinkled-seeded pea plants (rr), all seeds in the F1 generation are round (Rr).
- When these round seeds were self-fertilised, both round and wrinkled seeds developed in a 3:1 ratio in the F2 generation.
- As a result, the dominant trait (round seeds) emerged in the F1 generation, while the recessive character (wrinkled seeds) was suppressed, reappearing in F2.
Mendel’s Law of Dominance
- Law of Segregation: According to Mendel's Law of Segregation, a diploid organism distributes a randomly selected allele for a trait to its children, such that each parent has one allele. According to the experiment,
- A true-breeding tall plant (TT) and a true-breeding short plant (SB) were crossed by Mendel (tt).
- This hybrid (F1 generation) only produced tall plants of the genotype Tt. The plants from the F1 generation were then self-crossed, resulting in the F2 generation.
- Tall and dwarf plants were observed in a 3:1 ratio in the F2 generation.
Mendel’s Law of Segregation
- Law of Independent Assortment: Based on the probability of individual gene combinations, independent assortment allows for the determination of genotypic and phenotypic ratios. Segregation of one pair of traits during gamete production is independent of the other pairs of traits when two pairs of features are recombined.
Mendel’s Law of Independent Assortment
Example of Inherited Traits
Mentioned below are some of the examples of inherited traits:
- Eye colour, skin tone and blood group are all traits that a child inherits from their parents.
- Green/Red Colour Blindness can also be passed down the generations. If a person has colour blindness, there's a good possibility that their child will have it as well.
- Hair colour, dimples, freckles and other physical characteristics are frequently seen as inherited traits. These characteristics are passed down via the generations. Furthermore, humans influence these acquired characteristics.
- Attached earlobes, dominant hand, hairline etc are also very important examples of inherited traits.
- Height is a hereditary trait in some circumstances. According to some studies, however, height is not an inherited feature. This is because height is a result of the interaction of over 700 genes in the human body. As a result, assuming that height is inherited solely through one gene is incorrect.
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Acquired Traits
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An acquired trait is a personality attribute that develops in a person as a result of their environment. These characteristics are not encoded in a living organism's DNA and hence cannot be transmitted down to future generations. They're somatics with differing extents of variability.
Darwin and Lamarck on Acquired Traits
Initially, Lamarck believed that acquired traits might be passed on from parents to offspring, making the organism more adaptable to its surroundings. Once he had enough evidence to show that acquired features are not passed down from generation to generation, Darwin withdrew this idea from his publication, Theory of Evolution.
For Example, Horserider’s skill of horse riding can’t be passed from him to his offspring.
Checkout: Difference between Darwinism and Lamarckism
Elongation of Neck in Giraffe According to Lamarck
Examples of Acquired Traits
Mentioned below are a few examples of acquired traits:
- The professional athletic ability of a person is a good example of acquired traits as ability comes with practice
- The scars on a person’s face is an example of an acquired trait too.
- The knowledge of a person in any aspect.
- Calluses on fingers.
- Large muscles of a bodybuilder.
Difference Between Acquired and Inherited Traits
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Tabulated below are the major differences between acquired and inherited traits:
| Acquired Traits | Inherited Traits |
|---|---|
| These traits can’t be inherited from the previous generations instead they are developed by adaptability to the environment | These traits are inherited from the old generations. |
| No involvement of genes and DNA is there. | They evolve from the changes in DNA. |
| Cannot be passed from one generation to another generation. | Passed from one generation to another generation. |
| These are a result of somatic variations. | These are a result of genetic variation. |
| These traits develop throughout the lifespan of an individual and fade away with the death of the individual. | These traits get passed on from parent to offspring and do not die with the death of the individual. |
| Example: Swimming, Cycling, Singing etc. | Example: Colour of eyes, hair, skin etc. |
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Things to Remember
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- Traits are a person's various characteristics that help them form their own distinct identity.
- Inherited traits are characteristics that are passed down from one generation to the next.
- A personality feature that develops in a person as a result of their environment is known as an acquired trait.
- RNA can pass on numerous compounds acquired to the next generation. In humans and other species, researchers have discovered that acquiring acquired traits is becoming a significant cause of 'evolution'. DNA molecules are not included in this form of inheritance.
- Examples of inherited traits are Eye colour, Hair colour, Sensitivity to a disease, etc.
- Examples of Acquired traits are cycling, swimming, painting, singing and activities that can’t be passed on from generation to generation and has to be learnt within the life cycle to adapt to the environment.
- The structural unit of 'genes' is DNA. Chromosomes are made up of these genes. As a result, DNA is involved in the creation of chromosomes.
- The entire form of RNA is ribonucleic acid, which joins with DNA. These molecules aid in the conversion of genetic information into body proteins during the inheritance process. As a result, the body is formed (developing embryo).
- One of the most fundamental ideas in Mendelian inheritance and classical genetics is dominance.
Sample Questions
Ques. What is an Inherited Trait? Explain with examples. (2 marks)
Ans. An inherited trait is one that an organism inherits from its parents. Individual genes regulate these characteristics, which are passed down from generation to generation. Hair colour, eye colour, height, skin colour, and vulnerability to certain diseases are all examples of hereditary features.
Ques. "An individual cannot transmit his or her life experiences to his or her offspring." With the use of an example, justify the statement and provide a reason for it. (2 marks)
Ans. An individual's gene does not alter as a result of his or her experiences during their lifespan. For example, if a person reads a book about birds, the knowledge he gains from reading the book has no effect on the gene, and hence this knowledge will not be passed down to his descendants. The term "acquired trait" refers to such a feature.
Ques. Explain the Law of Dominance. (2 marks)
Ans. The first law of inheritance is known as the law of dominance. Each character is controlled by a pair of separate components known as factors. The law of dominance states, in basic terms, those recessive qualities are always overshadowed or concealed by dominant traits. When round-seeded pea plants (RR) were crossed with wrinkled-seeded pea plants (rr), all seeds in the F1 generation were found to be round (Rr).
Ques. Pea plants of the F1 generation are produced by crossing pure-bred tall (dominant) pea plants with pure-bred dwarf (recessive) pea plants. If we now self-cross the F2 generation pea plant, we will get F2 generation pea plants. (3 marks)
(a) What do F2 generation plants look like?
(b) In the F2 generation, what is the ratio of tall to dwarf plants?
(c) Describe the types of plants that were not present in the F2 generation but appeared in the F2 generation, as well as the reasons for this.
Ans. (a) The F1 generation's plants will all be tall.
(b) 3 to 1
(c) Dwarf phenotype is a recessive trait that was not expressed in the F1 generation; the recessive trait manifests in the F2 generation following self-pollination.
Ques. What is the Law of Independent Assortment? (2 marks)
Ans. When reproductive cells mature, the Principle of Independent Assortment outlines how various genes separate from one another independently. Independent assortment allows for the estimation of genotypic and phenotypic ratios based on the probability of individual gene combinations.
Ques. Give an example of both inherited and acquired traits in people. Mention the distinction between inherited and acquired traits. (2 marks)
Ans. A person's inherent character is their eye or hair colour, but their acquired character is their body weight. The primary distinction between inherited and acquired character is that hereditary traits are passed down from one generation to the next, whereas acquired traits are acquired by an individual throughout the course of his life, based on his lifestyle.
Ques. What are the various methods for increasing the number of people with a given trait in a population? (2 marks)
Ans. Individuals having a certain trait may be increased in a population in the following ways:
(a) If they can live in unfavourable conditions, i.e., naturally chosen.
(b) It can also be increased by inheritance.
Ques. Why are the modest numbers of surviving tigers a matter of concern from a genetic standpoint? (2 marks)
Ans. The minimal number of tigers is creating concern among geneticists because if they go extinct, this species' DNA will be gone forever. Without their genes, there will be no way to bring this species back to life.
Ques. A man of blood group A marries a lady of blood group O, and their daughter is of blood group O as well. Is this information sufficient to determine if blood group A or O dominates? Why do you think that is? (2 marks)
Ans. The information provided is insufficient to determine whether blood group A or O is predominant. Blood type A is always dominant in blood heredi, while blood type O is usually recessive. In this case, the father's blood group can be 1AIA (homozygous) or IAi heterozygous), whereas the mother is if. The daughter must receive one I type gene from both her father and mother in order to be born with blood group O. For this, the father must be heterozygous for the IAi blood group and the mother must have a homozygous blood group.
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