Heredity and Environment: Meaning, Laws, Studies and Educational Importance
This page covers the meaning of heredity and environment, the biological process of heredity, the laws of heredity, key studies, the nature-versus-nurture debate, and the educational significance of how the two relate — all from an exam angle. REET 2024 carried 4 questions on this topic, and it's the foundational topic within CDP's 'child development' section.
- 4 questions in REET 2024
- Teacher-training level
- 8 min read
How REET asks this topic
3 of REET 2024's 4 questions circled the same core idea — development is the result of the interaction between heredity and environment: the mathematical model for their relationship is 'multiplication', interdependence means 'both influence development', and the central takeaway of nature versus nurture is 'intelligence is shaped by both genetic and environmental factors'. The fourth question asked you to identify the definition of Galton's law of Regression. So options with 'only' tend to be wrong, and you need the laws' definitions locked down.
The meaning of heredity and environment
Heredity refers to the physical and mental traits a child receives from their parents through genes at the moment of conception. Heredity is fixed before birth, at the moment of conception, and cannot be changed afterwards — it sets the limits on a child's developmental possibilities.
Environment refers to all the external forces and conditions that influence a person throughout life, from conception onward — the mother's nutrition and health in the womb, family, school, peers, society, culture, and physical facilities. Environment determines how far the possibilities inherited through heredity actually develop.
In simple terms: heredity is the seed, and environment is the soil, water and sunlight. Even a good seed won't grow fully in poor soil, and even good soil can't change the nature of the seed.
The biological process of heredity
- Carrier
- Genes located on chromosomes; genes are made of DNA
- Chromosomes in a human cell
- 46 (23 pairs) — 22 pairs of autosomes + 1 pair of sex chromosomes
- Gametes (sperm / egg)
- 23 chromosomes each; fertilisation produces a zygote with 46 chromosomes
- Sex determination
- Always X from the mother; X or Y from the father — XX = girl, XY = boy. So the father's sperm determines the child's sex
- Identical twins
- Form when a single zygote splits into two; genetically almost identical, always the same sex
- Fraternal twins
- Form from two separate eggs fertilised by two separate sperm; as similar as ordinary siblings
Laws and theories of heredity
| Law / theory | Proposed by | Key point |
|---|---|---|
| Law of similarity | — | Like parents, like offspring; human begets human, and physical traits resemble those of the parents |
| Law of variation | — | Offspring are never an exact copy of their parents; even siblings differ from each other |
| Law of Regression | Francis Galton | The offspring of extremely gifted parents tend to be somewhat less gifted, and the offspring of extremely low-ability parents tend to be somewhat less low — offspring regress toward the average |
| Laws of inheritance (dominance, segregation, independent assortment) | Gregor Johann Mendel | Experiments on pea plants (published 1866); called the 'father of genetics' |
| Transmission of acquired characteristics | Lamarck | Claimed traits acquired in one's lifetime pass to offspring — this idea was not accepted scientifically |
| Continuity of the germ plasm | August Weismann | Only the traits of germ cells pass to the next generation; his mice-tail-cutting experiment disproved Lamarck's idea |
REET 2024 asked for the definition of 'Regression'; the options included similar-sounding terms like 'retrogression' and 'amplification'.
Key studies: evidence for which side
| Study | By / when | Conclusion favours |
|---|---|---|
| 'Hereditary Genius' | Francis Galton, 1869 | Talent runs in families — heredity |
| The Jukes family | Richard Dugdale, 1877 | Crime and poverty across generations — presented in favour of heredity (though environment was equally poor) |
| The Kallikak family | Henry Goddard, 1912 | Compared two family branches — presented in favour of heredity; the methodology was later criticised |
| Twin studies | Multiple researchers | Intelligence is most similar among identical twins raised together; the gap widens when raised apart — showing the effect of both |
| Amala and Kamala ('wolf children') | Reported found near Midnapore (Bengal), 1920 | Raised away from human society, they never developed human language and behaviour — showing the effect of environment (a commonly cited example) |
Nature versus nurture, and how the two relate
The 'nature versus nurture' debate centres on whether intelligence, personality and abilities are innate or shaped by environment. Francis Galton is credited with popularising the phrase 'nature and nurture'. Modern psychology concludes that almost every trait, including intelligence, is shaped by both genetic and environmental factors — 'only heredity' and 'only environment' are both the wrong answer.
The relationship between the two isn't additive, it's multiplicative: Development = Heredity × Environment. In addition, something is left over even if one term is zero; in multiplication, if either factor is zero, the result is zero. In other words, development is impossible without either one — the two are interdependent and complementary.
Heredity's influence shows more strongly on some traits (eye colour, blood group, the upper limit of height), environment's influence shows more on others (language, dialect, food habits, customs, values), and traits like intelligence, temperament and personality show a clear interaction of both.
What this means for a teacher: every child's innate capacities differ (individual differences), so don't expect identical outcomes from everyone; but by improving environment — motivation, nutrition, rich experiences, a caring classroom — every child can be helped toward the upper limit of their capacity. Writing a child off as 'weak by family background' is scientifically wrong.
Using this in the classroom
| Classroom situation | The heredity-environment lens | What the teacher should do |
|---|---|---|
| Parents say 'no one in our family is good at maths, so this child won't manage either' | Heredity sets a limit, but achievement is built by environment | Give concrete material, small goals and experiences of success; show parents proof of progress |
| Class 2 children who speak Marwari/Wagdi at home | Language is learned from environment | Respect the home language in class and use it as a bridge toward standard Hindi/English |
| Two siblings from the same family with completely different interests | Law of variation | Don't compare them; give each activities suited to their own interests |
| A child of very gifted parents performs only averagely | Law of Regression | Don't build unrealistic pressure; recognise the child's own capacity |
| A child from a malnourished or neglected environment | The effect of prenatal and early environment | Ensure the mid-day meal, health checks, warmth, and extra academic support |
| Very wide ability levels within the class | Individual differences = Heredity × Environment | Multi-level activities, group work, and questions of varying difficulty |
Memory trick / exam tip
For any question about the relationship, always choose 'multiplication' and 'both' — Development = Heredity × Environment. Remember 'Regression' as 'going back to the average', and pair it with the name Galton. Mendel = peas, Weismann = mice's tails, Lamarck = acquired traits.
Questions asked in REET 2024 (solved)
Question 24
Which mathematical model is used to describe the relationship between heredity and environment ?
- Aजोड़
- Bघटाव
- Cभाग
- Dगुणा
Explanation
आनुवंशिकता और पर्यावरण का संबंध गुणनफल के रूप में समझाया जाता है — विकास = आनुवंशिकता × पर्यावरण (वुडवर्थ, Woodworth)। यदि इनमें से एक भी शून्य हो तो विकास शून्य होगा, इसलिए यह जोड़ नहीं बल्कि गुणा (Multiplication) का संबंध है।
Question 1
Which of the following describe the exact meaning of given statement ? “The tendency for the children of highly talented parents to be less talented than their parents and relative tendency for children of very low-class parents to be less low-class.”
- Aपूर्वावर्तन
- Bप्रत्यागमन
- Cवंशानुक्रम
- Dप्रवर्धन
Explanation
गाल्टन (Galton) के प्रत्यागमन या प्रतिगमन के नियम (Law of Regression) के अनुसार अत्यन्त प्रतिभाशाली माता-पिता की संतानें प्रायः उनसे कुछ कम प्रतिभाशाली होती हैं तथा अत्यन्त निम्न कोटि के माता-पिता की संतानें उनसे कुछ बेहतर होती हैं, अर्थात् संतानें औसत की ओर लौटने की प्रवृत्ति दिखाती हैं। अतः दिया गया कथन प्रत्यागमन (Regression) का वर्णन है। वंशानुक्रम (Inheritance) एक व्यापक शब्द है, इस विशेष प्रवृत्ति का नाम नहीं।
Question 15
What does the interdependence of heredity and environment signify ?
- Aगुण केवल पर्यावरण द्वारा निर्धारित होते है
- Bगुण केवल वंशानुक्रम द्वारा निर्धारित होते है
- Cविकास को वंशानुक्रम और पर्यावरण दोनों प्रभावित करते है
- Dन तो वंशानुक्रम और न ही पर्यावरण विकास को प्रभावित करते है
Explanation
वंशानुक्रम और पर्यावरण की पारस्परिक निर्भरता का अर्थ है कि बच्चे का विकास दोनों के संयुक्त प्रभाव का परिणाम है — वंशानुक्रम क्षमताओं की सीमा तय करता है और पर्यावरण उन्हें विकसित करने का अवसर देता है। केवल एक को निर्धारक मानना इस अवधारणा के विपरीत है।
Question 30
What is the main subject of the nature vs nurture debate ?
- Aबुद्धिमता आनुवंशिक और पर्यावरणीय कारकों से प्रभावित होती है
- Bबुद्धिमता केवल शिक्षा से बढ़ती है
- Cबुद्धिमता केवल माता-पिता से विरासत में मिलती है
- Dबुद्धिमता केवल सामाजिक परिस्थितियों से प्रभावित होती है
Explanation
प्रकृति बनाम पोषण (Nature vs Nurture) वाद-विवाद का मुख्य विषय यह है कि बुद्धि जैसे गुण आनुवंशिकता (प्रकृति) से तय होते हैं या पर्यावरण (पोषण) से; आधुनिक निष्कर्ष यह है कि दोनों का प्रभाव होता है। 'केवल' शब्द वाले विकल्प एकपक्षीय हैं।
Practice questions
Question 1
The number of chromosomes in a normal human body cell is
- A23
- B44
- C46
- D48
Explanation
A human cell has 23 pairs, i.e. 46 chromosomes — 22 pairs of autosomes and 1 pair of sex chromosomes. Gametes carry 23 chromosomes each.
Question 2
Who is called the 'father of genetics'?
- Aफ्रांसिस गाल्टन
- Bग्रेगर जॉन मेंडल
- Cलैमार्क
- Dचार्ल्स डार्विन
Explanation
Mendel is called the 'father of genetics' because his experiments on pea plants gave us the laws of heredity.
Question 3
The most appropriate statement about the role of heredity and environment in development is
- Aविकास केवल वंशानुक्रम पर निर्भर है
- Bविकास केवल वातावरण पर निर्भर है
- Cविकास दोनों की अंतःक्रिया का परिणाम है
- Dदोनों का विकास पर कोई प्रभाव नहीं
Explanation
Heredity provides the potential for development and environment realises it; the two are interdependent. 'Only'-type options are one-sided and wrong.
Question 4
A child's sex is determined by
- Aमाँ के अंडाणु के X गुणसूत्र से
- Bपिता के शुक्राणु के X या Y गुणसूत्र से
- Cगर्भकालीन पोषण से
- Dमाँ के Y गुणसूत्र से
Explanation
The mother's egg always carries an X chromosome, while the father's sperm can carry either X or Y. X gives XX (girl), Y gives XY (boy).
Question 5
Who gave the theory of 'continuity of germ plasm' and refuted the transmission of acquired traits?
- Aलैमार्क
- Bऑगस्ट वाइज़मान
- Cहेनरी गोडार्ड
- Dरिचर्ड डगडेल
Explanation
Weismann cut the tails off mice across several generations, yet each new generation was still born with a tail. This disproved Lamarck's idea of the inheritance of acquired characteristics.
Question 6
Who studied the 'Kallikak family'?
- Aहेनरी गोडार्ड
- Bरिचर्ड डगडेल
- Cफ्रांसिस गाल्टन
- Dग्रेगर मेंडल
Explanation
The Kallikak family study was conducted by Henry Goddard (1912). The Jukes family study was done by Richard Dugdale.
Question 7
Which statement about identical twins is correct?
- Aवे दो अलग अंडाणुओं से बनते हैं
- Bवे अलग-अलग लिंग के हो सकते हैं
- Cवे एक ही युग्मनज के विभाजन से बनते हैं
- Dउनमें सामान्य भाई-बहनों जितनी ही समानता होती है
Explanation
Identical twins form from a single zygote splitting into two, which is why they're genetically almost identical and always the same sex. The other traits listed belong to fraternal twins.
Question 8
A teacher believes children from weak family backgrounds can never do well, so attending to them is useless. This belief
- Aसही है, क्योंकि वंशानुक्रम ही सब कुछ तय करता है
- Bगलत है, क्योंकि उपयुक्त वातावरण बच्चे की क्षमताओं को विकसित करता है
- Cसही है, क्योंकि वातावरण बदला नहीं जा सकता
- Dगलत है, क्योंकि वंशानुक्रम का कोई प्रभाव नहीं होता
Explanation
Development is the product of both heredity and environment; a teacher can help every child reach their potential by providing a rich, caring environment. Option D is also wrong because heredity does have an effect.
Question 9
Language, dialect and customs are mainly influenced by
- Aवंशानुक्रम
- Bवातावरण
- Cगुणसूत्रों की संख्या
- Dरक्त समूह
Explanation
A child learns whatever language and dialect is spoken around them, and customs also come from society and culture. Traits like eye colour and blood group are more strongly influenced by heredity.
Question 10
What is the most accurate implication of the formula 'Development = Heredity × Environment'?
- Aदोनों का प्रभाव जोड़कर निकलता है, इसलिए एक की कमी दूसरा पूरी तरह भर देता है
- Bकिसी एक के अभाव में विकास संभव नहीं
- Cवातावरण का महत्व वंशानुक्रम से हमेशा दुगुना है
- Dवंशानुक्रम का महत्व वातावरण से हमेशा अधिक है
Explanation
In multiplication, if either factor is zero, the product is zero. This means both are essential and interdependent — neither is reliably more important than the other.
Frequently asked questions
Which mathematical model represents the relationship between heredity and environment?+
Multiplication — Development = Heredity × Environment. If either factor is zero, development is zero, which is why both are essential.
Who gave the law of Regression?+
Francis Galton. According to it, the offspring of extremely gifted parents tend to be less gifted and the offspring of very low-ability parents tend to be less low — offspring regress toward the average.
What does the nature-versus-nurture debate conclude?+
Traits like intelligence and personality are shaped by both heredity (nature) and environment (nurture); development results from their interaction.
What determines a child's sex?+
The father's sperm — if it carries an X chromosome, the child is a girl (XX); if it carries a Y chromosome, the child is a boy (XY).
How many questions come from heredity and environment in REET?+
REET 2024's question papers carried 4 questions on this topic, 3 on the relationship and interaction of the two, and 1 on the law of Regression.
Read next
Official Sources
Change Log
- 17 September 2026 — English pilot page published — mirrors the fact-checked Hindi page, independently bilingual-accuracy checked