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NCERT Solutions Class 12 Biology Chapter 6 Evolution
In Class 12 Biology Chapter 6, Evolution, students learn how life on Earth has changed over millions of years through gradual and continuous processes. This chapter explains the origin of life, evidence supporting evolution, theories of evolution, modern ideas like genetic variation, adaptation, and speciation, etc., to help students understand how new species arise and how organisms become better suited to their environments.
To streamline your preparation, ALLEN offers expertly curated the NCERT Solutions that transforms complex theories and paleontological information into concise, easy-to-understand explanations that prioritize conceptual depth over rote memorization. These solutions are structured to help you develop a logical flow in your answers whcih is important for scoring well in descriptive board exam questions. By choosing ALLEN’s NCERT Solutions for Class 12, you are utilizing a study tool designed for accuracy, ensuring you remain ahead in both your school finals and competitive medical entrance tests.
1.0Key Concepts of Class 12 Biology Chapter 6 Evolution
Evolution explains how living organisms have changed over generations and how new forms of life have developed over time. This chapter covers the major theories, evidence, mechanisms, and stages involved in evolutionary change.
- Origin of Life: Explore early ideas about the origin of life and experiments that proposed how the first forms of life may have developed on Earth.
- Evidence of Evolution: Study fossils, homologous organs, analogous organs, embryological evidence, and molecular similarities that support the process of evolution.
- Lamarck’s Theory of Evolution: Understand the idea of inheritance of acquired characteristics and its historical contribution to the study of evolution.
- Darwin’s Theory of Natural Selection: Learn about variation, the struggle for existence, natural selection, and survival of the fittest as key ideas in Darwin’s explanation of evolution.
- Modern Synthetic Theory: Understand how mutation, genetic recombination, natural selection, and other genetic factors contribute to evolutionary changes in populations.
- Speciation: Learn how new species can arise through factors such as reproductive isolation and the accumulation of differences between populations.
- Human Evolution: Trace the major stages of human evolution and learn about important developments in the evolution of modern humans.
2.0NCERT Class 12 Biology Chapter 6 Evolution : Detailed Solutions
- Explain antibiotic resistance observed in bacteria in light of Darwinian selection theory. Ans. Darwinian selection theory states that individuals with favourable variations are better adapted than individuals with less favourable variation.
- It means that nature selects the individuals with useful variation as these individuals are better evolved to survive in the existing environment. An example of such selection is antibiotic resistance in bacteria. When bacterial population was grown on an agar plate containing antibiotic penicillin, the colonies that were sensitive to penicillin died, whereas one or few bacterial colonies that were resistant to penicillin survived.
- This is because these bacteria had undergone chance mutation, which resulted in the evolution of a gene that made them resistant to penicillin drug. Hence, the resistant bacteria multiplied quickly as compared to nonresistant (sensitive) bacteria, thereby increasing their number. Hence, the advantage of an individual over other helps in the struggle for existence.
- Find out from newspapers and popular science articles any new fossil discoveries or controversies about evolution. Ans. A recent study of fossil revealed a small terrestrial dinosaur with feathers covering the limb and body. This finding established that feathers evolved earlier than wing and may be functioning as thermoregulator to face adverse condition. These newly developed feather earlier helped in gliding and then flying
- Attempt giving a clear definition of the term species. Ans. Species can be defined as a group of organisms which have the capability to interbreed in order to produce fertile offspring.
- Try to trace the various components of human evolution. (Hint : Brain size and function, skeletal structure, dietary Preference etc.)
Ans.
- Find out through internet and popular science articles whether animals other than man has self-consciousness.
Ans. There are many animals other than humans, which have self consciousness. An example of an animal being self conscious is dolphins. They are highly intelligent. They have a sense of self and they also recognize others among themselves and others. They communicate with each other by whistles, tail-slapping, and other body movements. Not only dolphins there are certain other animals such as crow, parrot, chimpanzee, gorilla, orangutan, etc., which exhibit self-consciousness.
- List 10 modern-day animals and using the internet resources link it to a corresponding ancient fossil. Name both.
Ans.
- Describe one example of adaptive radiation.
Ans. Darwin's finches in the galapagos island once had a common ancestor but with evolution they modified into different types according to their food habitat.
- Can we call human evolution as adaptive radiation?
Ans. No, human evolution cannot be called as adaptive radiation because parent species of Homo sapiens have evolved by progressive evolution from Homo habilis to Homo sapiens lineage.
- Using various resources such as your school library or the internet and discussions with your teacher, trace the evolutionary stages of any one animal, say horse. [IMP.]
Ans. The evolution of horse is represented as following:- (A) Eohippus:- This stage is characterized by a short head and neck .It had four functional toes and a splint of 1 to 5 on each hind limb and a splint of 1 to 3 in each forelimb. The molars were short crowned that were adapted for grinding the plant dies. (B) Mesohippus:- It was slightly taller than Eohippus. It had three toes in each foot. (C) Merychippus:- it had the size of approximately 100 cm. Although it still has three toes in each foot, but it could run on one toe. The side toe did not touch the ground. The molars were adapted for chewing the grass. (D) Pliohippus:- It resembled the modern horse and was around 120 cm tall. It had a single functional toe with splint of second and fourth in each limb. (E) Equus :- Pliohippus gave rise to Equus or the modern horse with one toe in each foot. They have incisors for cutting grass and molars for grinding food.
3.0NCERT Solutions for Class 12 Biology | Other Chapter-wise Links
Explore chapter-wise NCERT Solutions for Class 12 Biology with clear and detailed answers to textbook questions using the links below.
4.0Key Features and Benefits of Class 12 Biology Chapter 6 Evolution
- Clear Understanding of Evolutionary Theories: Explore major theories of evolution and understand how different ideas explain the origin and development of life.
- Evidence of Evolution: Learn about important evidence such as fossils, comparative anatomy, embryology, and molecular similarities that support evolutionary relationships.
- Easy Revision of Important Concepts: Revise key terms, theories, examples, and evolutionary events to strengthen understanding and improve recall during examinations.
- Strong Foundation for Competitive Exams: Develop a clear understanding of evolution concepts that can support preparation for NEET and other biology-based entrance examinations.
- Connection with Biodiversity: Understand how adaptation, natural selection, and evolutionary changes contribute to the diversity of organisms around us.