NCERT Solutions for Class 12 Biology Chapter 6: Evolution

The NCERT Solutions Class 12 Biology Chapter 6: Evolution carries out a thorough discussion of the fundamental concepts from the field of evolutionary biology. This chapter deals with the origin and evolution of life on Earth and explains in detail the main theories concerned with evolution by Darwin. Chapter 6 NCERT Solutions for class 12 biology, Evolution, helps students grasp the processes because of which there has been an origin to the diversity in the forms of life, including genetic variation, and adaptations evolved over time.

Download PDF For NCERT Solutions for Biology Evolution

The NCERT Solutions for Class 12 Biology Chapter 6: Evolution are tailored to help the students master the concepts that are key to success in their classrooms. The solutions given in the PDF are developed by experts and correlate with the CBSE syllabus of 2023-2024. These solutions provide thorough explanations with a step-by-step approach to solving problems. Students can easily get a hold of the subject and learn the basics with a deeper understanding. Additionally, they can practice better, be confident, and perform well in their examinations with the support of this PDF.

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Access Answers to NCERT Solutions for Class 12 Biology Chapter 6: Evolution

Students can access the NCERT Solutions for Class 12 Biology Chapter 6: Evolution. Curated by experts according to the CBSE syllabus for 2023–2024, these step-by-step solutions make Biology much easier to understand and learn for the students. These solutions can be used in practice by students to attain skills in solving problems, reinforce important learning objectives, and be well-prepared for tests.

Evolution

Question 1 :

Can we call human evolution as adaptive radiation?

 

Answer :

Human evolution can be referred to as adaptive radiation because adaptive radiation is an evolutionary process which gives rise to new species from a single common ancestor but in the case of human evolution, although we share a common ancestor, we humans have undergone an eventual but progressive alteration in the eating preferences, structure of body, etc. The evolution of humans does not include diversification and radiating into different species, which in fact, is a distinguishing feature of adaptive radiation.

 


Question 2 :

Explain antibiotic resistance observed in bacteria in light of Darwinian selection theory.

 

Answer :

As per Darwin’s observation, the environment selects entities with favourable variations, and these entities are capable of surviving. When a population of bacteria is attacked by a specific antibiotic, sensitive bacteria tend to perish, while other bacteria possessing favourable mutations turn resistant even in the presence of antibiotics, and these survive, thriving, and rapidly multiplying as the other competing bacteria have died out. Thus, the number of bacteria is on the rise. In addition to this, they mass transfer these genes, which give them resistance to bacteria, to other bacteria. Consequently, bacteria resistant to antibiotics widely spread across, making the entire population become antibiotic-resistant.

 


Question 3 :

 Find out from newspapers and popular science articles any new fossil discoveries or controversies about evolution.

 

Answer :

Fossil discovery of dinosaurs had some interesting revelations. It sheds light on the evolution of reptiles in the Jurrasic era. This revelation gave rise to the discovery of the evolution of other animals, such as mammals and birds. Two unfamiliar fossils recently unearthed in China led to a controversy over the evolution of birds. One such genus of primitive birds were Confuciusornis. These were crow-sized and thrived during the Cretaceous era in China.

 


Question 4 :

Attempt giving a clear definition of the term species.

 

Answer :

Species is a group or population of individuals having the potential to interbreed and produce sustainable and fertile offspring.


Question 5 :

Find out through the internet and popular science articles whether animals other than man have self-consciousness.

 

Answer :

Apart from humans, there are many other animals that possess self-consciousness. One such example is the Dolphin. They are believed to have a high level of intelligence. Also, they have a sense of self and can identify themselves amongst others. They whistle, tail-slap and exhibit body movements to communicate with each other. Some other animals that exhibit self-consciousness are parrots, crows, gorillas, orangutans, chimpanzees, etc.

 


Question 6 :

Practise drawing various animals and plants.

 

Answer :

Take cues from seniors and teachers for names of different plants and animals. Go through different science books, magazines, and encyclopedias to get an idea of different plant and animal species. To get further details, the internet serves as the ultimate option. There is a huge range of plants and animals from which you can pick the easiest one to begin with and practice them. Try tracing the outline first and then fill in the details.

 


Question 7 :

Try to trace the various components of human evolution (hint: brain size and function, skeletal structure, dietary preference, etc.)

 

Answer :

Human evolution can be based on different components, namely:

  • Size of the brain

  • Body posture

  • Food habits/dietary preferences

  • Characteristics/features

The following table depicts the same:

Human evolution stages

Size of the brain

Body posture

Food preferences

Features

Dryopithecus africans

Knuckle-walking, ape-like walk

Leaves and tender fruits

Equal-sized arms and legs, large canines

Ramapethicus

Semi-erect posture

Nuts and seeds

Large molars, small canines

Australopithecus africanus

450 cm3

Completely erect posture, around 1.05m tall

Fruits (herbivorous)

Inhabited trees, stone weapons for hunting, incisors & canines are smaller

Homo habilis

735cm3

Completely erect posture, around 1.5m tall

Carnivorous

Small canines, first to make tools

Homo erectus

800 cm3 to 1100 cm3

Completely erect posture, around 1.5m – 1.8m tall

Omnivorous

For hunting, used bone and stone tools

Homo neanderthalnsis

1300 cm3 to 1600 cm3

Completely erect posture, around 1.5m – 1.66m tall

Omnivorous

Inhabited caves, buried their deads, hid their bodies for protection

Homo sapiens fossils

1650 cm3

Completely erect posture, 1.8m

Omnivorous

Possessed strong jaw with teeth closely placed, inhabited caves, and made carvings and paintings in caves. Developed a culture and were referred to as the first modern men

Homo sapiens sapiens

1200 cm3to 1600 cm3

Completely erect posture, around 1.5m – 1.8m tall

Omnivorous

Possess a high intelligence quotient, referred to as the living modern man. Developed language, speech, culture, art, and language. Cultivation of crops and domestication of animals observed.

 


Question 8 :

List 10 modern-day animals and using the internet resources link it to a corresponding ancient fossil. Name both.

 

Answer :

The list is as follows:

Name of the animal

Name of the fossil

Horse

Eohippus

Man

Ramapithecus

Elephant

Moerithers

Whale

Protocetus

Fish

Arandaspis

Giraffe

Palaeotragus

Dog

Leptocyon

Camel

Protylopus

Tetrapods

Icthyospega

Bat

Archaeonycteris

 


Question 9 :

Describe one example of adaptive radiation.

Answer :

When members of a single assemblage or lineage deviate evolutionarily into a range of different forms, it is adaptive radiation. These are the forms that are governed by natural selection and the usage of resources or habitats. The Darwin’s finches of the Galapagos islands had shared or common ancestors, whereas now, we have different sorts of modified beaks based on their food preferences. In order to suit their feeding habits, these finches have adopted different eating preferences and varied beak types. From a single seed-eating finch ancestor, different finch species with varied dietary habits have evolved, such as blood-sucking, insectivorous entities, etc.

 


Question 10 :

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.

 

Answer :

During the Eocene era, the evolution of the horse began with Eohippus and involved the following evolutionary phases:

Eohippus → Mesohippus →Merychippus → Pliohippus → Equus

Evolutionary traits observed were as follows:

  • Increase in the size of the body

  • Elongated neck

  • Expansion of the third digit

  • Enhanced structural composition of the teeth to feed on grass

  • Broadening of the limbs

  • Eventual decrease in the lateral digits

  • Strengthened back

  • Sense organs and brain development

 


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