Evolution Chapter 6 : NCERT Solutions for Class 12

Struggling with solving the questions of the Evolution Class 12 Chapter 6 exercises? Looking for the right approach to present your answers? Do not worry. SimplyAcad is here to help with all your issues, the NCERT solutions are provided below for free prepared by the subject-matter experts with years of experience.

The solutions are explained comprehensively to help students grasp the core concepts of the chapter. These are developed using the accurate amount of information required to score well in your examinations. Students must practise and revise them daily to boost their confidence.

Evolution Class 12 Biology Chapter 6 Question 1 to 5

Question 1

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

Solution:

As per Darwin’s observation, the environment selects entities with favorable 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 favorable mutations become 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. Additionally, they transfer these genes, which give them resistance to antibiotics, to other bacteria. Consequently, bacteria resistant to antibiotics widely spread, making the entire population antibiotic-resistant.

---

Question 2

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

Solution:

The fossil discovery of dinosaurs had some interesting revelations. It sheds light on the evolution of reptiles in the Jurassic 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 was Confuciusornis. These were crow-sized and thrived during the Cretaceous era in China.

---

Question 3

Attempt giving a clear definition of the term species.

Solution:

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

---

Question 4

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

Solution:

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
Ramapithecus	–	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	735 cm³	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	Used bone and stone tools for hunting
Homo neanderthalnsis	1300 cm³ to 1600 cm³	Completely erect posture, around 1.5m – 1.66m tall	Omnivorous	Inhabited caves, buried their dead, 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.
Homo sapiens sapiens	1200 cm³ to 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 5

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

Solution:

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.

---

Evolution Class 12 Biology Chapter 6 Question 6 to 10

Question 6

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

Solution:

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	Ichthyostega
Bat	Archaeonycteris

---

Question 7

Practise drawing various animals and plants.

Solution:

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 8

Describe one example of adaptive radiation.

Solution:

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 a common ancestor, whereas now, they 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 9

Can we call human evolution as adaptive radiation?

Solution:

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

---

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.

Solution:

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
• Development of sense organs and brain