NCERT Solutions Class 10 Science Chapter 9

Introduction to NCERT Solutions Class 10 Science Chapter 9

NCERT Solutions Class 10 Science Chapter 9 covers various topics of the chapter Heredity and Evolution. Heredity is the transmission of characteristics from parents to their children through genes, resulting in offspring resembling their mother or father. Heredity also brings variation in genes resulting in a gradual change in the characteristics of the offspring over successive generations; this is called Evolution. On the other hand, genetics is the study of heredity and other variations, and clones are organisms that are identical copies of one another.

To know in detail about Heredity and Evolution, please refer to NCERT Solutions Class 10 Science Chapter 9 on the Extramarks website.

Key Topics Covered in NCERT Solutions Class 10 Science Chapter 9

The key topics covered under NCERT Solutions Class 10 Science Chapter 9 – Heredity and Evolution include the following.

Definition

Heredity and evolution are one of the most important branches of biology. Heredity is the passing down or inheritance of traits or characteristics through genes from parent to offspring during reproduction. Evolution is the variation in the heritable characteristics of a species.

Mendel’s Experiment

Gregor Mendel is the father of genetics. His experiments showed that both parents contribute an equal amount of genetic material to their offspring or children during reproduction. He carried out his experiment on pea plants and discovered the fundamental laws of inheritance of traits. Genes appear in pairs and are inherited as distinct units, one from each parent. Mendel further tracked the segregation of parental genes and their appearance in the offspring as dominant traits and observed mathematical patterns of inheritance from one generation to the next. 

Genes: Genes are considered to be the functional units of heredity. They are short stretches of DNA that transfer characteristics from parents to the offspring.

Alleles: It is the alternate form of a gene that is occupying the same position on a chromosome and impacting the same characters but in two alternative ways. For example, the free and attached earlobes are the alleles of ear lobe characteristic.

We can understand Mendel’s Laws of Heredity by studying the following laws covered under NCERT Solutions for Class 10 Science Chapter 9.

• The Law of Segregation: Gene pairs determine each inherited characteristic. Parental genes are indiscriminately separated from the sex cells or gametes and should receive only one gene copy. Children, therefore, inherit one genetic allele from each parent when sex cells unite in fertilization.

•  The Law of Independent Assortment: Genes for different characteristics are classified separately so that the inheritance of one element is not dependent on the other.

•  The Law of Dominance: An organism with different forms of a gene will indicate the dominant state. 

Evolution by stages: 

Evolution shows that gradual changes take place, right from simple to the more complex forms. Humans have developed from simpler forms. Evolution is thought  to have begun in the oceans billions of years ago. Darwin gave the theory of evolution. In his book – The Origin of Species, Darwin states that evolution has come through a series of natural selection. The theory emphasized the following points:

• Natural Selection
• Variation
• Struggle To Exist
• Survival of the Fittest

Evolution is the outcome of the interaction amongst the following five processes:

• Mutation
• Genetic Recombination
• Chromosomal Abnormalities
• Reproductive isolation
• Natural Selection

Evolution and Classification 

This section has been clearly covered under NCERT Solutions for Class 10 Science Chapter 9. Evolution and its classification are the important keystone of a modern biological theory that helps prove all the proposed theories of evolution. Evidence of evolution can be found through

• Fossils
• Evolution by Stages
• Tracing Evolutionary Relationship 

• Fossils: Paleontological evidence is the remains of non-degraded parts of living beings found within rocks. The fossils found in the deeper layers are older than those found in the upper layers.

• Comparative Anatomy: This type of evidence describes that organisms have the same ancestor, and many different organisms evolved due to natural selection. There are two types of comparative anatomy, namely homologous organs and analogous organs. Examples of homologous organs are human limbs, whales, wings of a bat, which are similar in structures but perform different functions. This kind of evolution is called divergent evolution. In comparison, Analogous organs, for example, wings of other birds and bats, have different anatomy but perform similar functions. This type of evolution is stated as convergent evolution.

• Embryonic Development: Until a certain gestation period, we cannot distinguish the embryos of many species. For example, embryos of humans, birds, and reptiles show the same embryonic development. They develop into individual species as they grow.

• Monohybrid Cross: A Monohybrid cross is a hybrid of two individuals with homozygous genotypes of a single trait resulting in the opposite phenotype.
• Dihybrid Cross: A Dihybrid cross is a hybrid between two individuals With heterozygous for two different traits.
• Sex Determination: It is a biological process that determines the development of sexual characteristics in an organism. In humans, sex is determined by the XX/XY chromosomes.Most females have XX chromosomes, whereas males have XY chromosomes.
• Accumulation of Variation during Reproduction: This is a complex process of determining the similarities and dissimilarities of the offspring. It varies with two types of reproduction, namely Variation in Asexual Reproduction (ex: fruits, vegetables) and Variation in Sexual Reproduction(ex: human offspring).

NCERT Solutions for Class 10 Science Chapter 9 provided by Extramarks gives a detailed and easy to understand explanation.

NCERT Solutions for Class 10 Science Chapter 9 – Exercises & Answer Solutions

NCERT Solutions for Class 10 Science Chapter 9 – Heredity and Evolution, provided by Extramarks, covers all the essential topics from the examination point of view. Students may study using NCERT solutions, including various questions such as MCQs, short answer questions, and more. Students may refer to the different types of questions compiled in NCERT Solutions for Class 10 Science Chapter 9 – Heredity and Evolution by clicking below.

NCERT Solutions – Short-answer Questions

NCERT Solutions – MCQ’s

NCERT Solutions – Long-answer Questions

Furthermore, in addition to NCERT Solutions for Class 10 Science Chapter 9, students may access NCERT solutions for all other chapters. Students may click on the  given links below to refer to NCERT solutions for other classes.

NCERT solutions class 12

NCERT solutions class 11

NCERT solutions class 10

NCERT solutions class 9

NCERT solutions class 8

NCERT solutions class 7

NCERT solutions class 6

NCERT solutions class 5

NCERT solutions class 4

NCERT solutions class 3

NCERT solutions class 2

NCERT solutions class 1

Key Features of NCERT Solutions Class 10 Science Chapter 9

The key features of NCERT Solutions Class 10 Science Chapter 9 – Heredity and Evolution include:

• Heredity and Evolution is an essential and scorable chapter. NCERT Solutions Class 10 Science Chapter 9 – Heredity and Evolution provides answers to all the questions so that students get in-depth knowledge of this chapter.
• The notes are prepared by highly qualified and experienced faculty.
• By referring to NCERT Solutions Class 10 Science Chapter 9, students can be confident about  the concepts and prepare well  ahead of the examination.
• The content on NCERT Solutions provided by Extramarks is regularly updated as per the CBSE board syllabus.

Students may refer to NCERT Solutions for Class 10 Science Chapter 9 on Extramarks.