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Heredity and Evolution
Heredity explains how children get traits from their parents through genes. It helps students understand why family resemblance is common, why siblings are not exactly alike, and how traits are passed across generations in a predictable way. Evolution and natural selection explain how useful variations can become more common in a population over time. For CBSE Class 10, the chapter is usually asked through simple crosses, sex determination, differences among individuals, and reasoning-based questions on survival and inheritance.
Difficulty
Medium
Study time
70-90 min
Plan by time
Pick the window that matches what you have right now.
If you have 15 min
Last-pass revision
Skim the Quick Revision table — definitions, formulas, and the traps board examiners reuse.
Open Quick RevisionIf you have 45 min
Targeted practice
Read the high-priority concepts, then take the chapter MCQ quiz to find weak spots.
Start MCQ QuizIf you have 70 min
First full pass
Walk every concept in chapter order, then revise and quiz. Best for the first time you study this chapter.
Open Key ConceptsChapter Learning Map
Start with one of the buckets below, then open the full map when you want the complete concept roadmap.
Key Concepts
Concepts grouped the way the chapter is taught — open the bucket that matches what you want to revise.
Core Concepts
high priorityOpen the chapter concepts in a clean revision order.
Heredity
Heredity is the passing of traits from parents to their children through genes.
Gene
A gene is a small functional part of DNA on a chromosome that carries information for a trait.
Dominant Trait
A dominant trait is the trait that appears even when only one dominant allele is present.
Recessive Trait
A recessive trait is the trait that appears only when both alleles are recessive.
Monohybrid Ratio
The monohybrid ratio is the expected ratio of traits or genotypes when only one character is studied in a cross.
Sex Determination
Sex determination is the process by which the sex of an offspring is decided at fertilisation.
Variation
Variation means differences among individuals of the same species.
Natural Selection
Natural selection is the process in which organisms with useful variations survive and reproduce more successfully in a particular environment.
Exam Intelligence
Use this section to decide what deserves the most revision time.
High Probability Topics
- Heredity
- Gene
- Dominant Trait
- Recessive Trait
- Monohybrid Ratio
- Sex Determination
- Variation
- Natural Selection
Common Traps
- Confusing gene with chromosome.
- Thinking dominant means common or always better.
- Thinking recessive traits appear whenever the allele is present.
- Mixing genotype ratio with phenotype ratio.
- Saying the mother decides sex in humans.
- Treating variation as only environmental or only hereditary.
Likely Question Types
- MCQ: concept checks, applications, and common mistakes
- Very short answer: definitions, formulas, or conditions
- Short answer: worked method, example, or reason-based explanation
- Case-based: chapter scenario with concept-linked subparts
Quick Revision
Concept, formula or equation to remember, and the trap that loses marks — in one scannable view.
- Heredity passes traits from parents to children.
- Genes are the basic units of inheritance.
- Dominant traits show with one dominant allele, while recessive traits need two recessive alleles.
- A monohybrid cross of Tt x Tt gives 3:1 phenotype ratio.
- In humans, the father determines the sex of the child through X or Y sperm.
- Variation helps natural selection act on a population over time.
- Heredity: Heredity is the passing of traits from parents to their children through genes.
- Gene: A gene is a small functional part of DNA on a chromosome that carries information for a trait.
Practice
Use short concept checks first, then move into the full chapter test.
Free Chapter MCQ Quiz
Try a 15-question quiz from this chapter. Get instant score and unlock concept-wise analytics.
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