Evolution Mind map for NEET and Class 12 Genetics unit

Evolution Mind map for NEET and Class 12 Genetics unit

NCERT Solutions For Class 12 Biology Chapter 7 Evolution

Question 1. Explain antibiotic resistance observed in bacteria in light of Darwinian selection theory.

Ans. According to Darwin's theory, organisms which develop favourable variations against a given situation, can survive. When we expose a population of bacteria to antibiotics, most of them die. However some bacteria which have  developed resistance against the antibiotics due to mutations will survive and reproduce. This can form all new population of bacteria which is resistant to an antibiotic.

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Question 2. Find out from newspapers and popular science articles any new fossil discoveries or controversies about evolution.

Ans. A fossil of a cat-sized reptile that was closely related to an extinct group of flying reptiles known as pterosaurs has been unearthed in Scotland. Named Scleromochlus taylori, the reptile lived on Earth about 240 to 210 million years ago.

Pääbo, a Swedish geneticist and director of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, was honored for his groundbreaking research on sequencing the genome of the Neanderthals, an extinct relative of humans.

Question 3. Attempt giving a clear definition of the term species.

Ans. Species is the group of individuals that are similar to each other and can interbreed. This definition of species was given by Ernst Mayr.

Question 4. Try to trace the various components of human evolution (hint: brain size and function, skeletal structure, dietary preference, etc.)

Ans. 

Question 5. Find out through internet and popular science articles whether animals other than man has self-consciousness.

Ans. Other than human the following animals are reported to have self consciousness - dogs, birds like Grey Parrot and Corvids, octopus, chimpanzees, gorillas and elephants.

Question 6. List 10 modern-day animals and using the internet resources link it to a corresponding ancient fossil. Name both.

Ans. Some animals and their known fossils -

Elephant -                    Moerithers

Woody mammoth -    Ice fossils

Gorilla -                        Dryopithecus

Frog -                            Triadobatrachus

Horse -                          Eohippus

Bat -                              Archaeonycteris

Fish -                            Arandaspis

Giraffe -                       Palaeotragus

Question 7. Practise drawing various animals and plants.

Ans. Do it yourself.

Question 8. Describe one example of adaptive radiation.

Ans. Darwin's finches that are found in Galapagos Island example of adaptive radiation. On the island Darwin observed that a variety of beaks evolved from the original seed eating finches. Different type of beaks help birds to survive on the island.

Question 9. Can we call human evolution as adaptive radiation?

Ans. The process of evolution of different species  starting from a point and radiating in all directions is called adaptive radiation. Evolution of human cannot be called as adaptive radiation since it did not your any diversification or radiation from a point.

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.

Ans. The evolution of horse began during Eocene era, with species Eohippus and show following evolutionary phases:

Eohippus → Mesohippus →Merychippus → Pliohippus → Equus

Evolutionary traits observed were as follows-

Increase in size of the body

Advancement of the teeth to feed on grass

Broadening of the limbs

Strengthened back

Elongation of neck

Brain capacity development.

The topics that we have to study in this chapter are - 

7.1 Origin of Life

7.2 Evolution of Life Forms – A Theory

7.3 What are the Evidences for Evolution?

7.4 What is Adaptive Radiation?

7.5 Biological Evolution

7.6 Mechanism of Evolution

7.7 Hardy – Weinberg Principle

7.8 A Brief Account of Evolution

7.9 Origin and Evolution of Man

Evolution is the process of change in living organisms over successive generations. It is a process that occurs over long periods of time and is driven by genetic variation due to mutation and environmental pressures. Evolution is responsible for the diversity of life we see today on Earth, and it has been happening since the first living organisms appeared around 3.8 billion years ago.