NCERT Solutions for Class 12 Biology Chapter 6 – Evolution

Chapter 6 – Evolution

6.1

Ans: According to Charles Darwin’s concept, species can thrive in existence by adapting to their particular environment. Once bacteria that have become susceptible to specific antibiotic compounds then it begins to die after coming into contact with it. Nevertheless, when certain bacteria acquire advantageous alterations, they evolve into resistance to the antibiotic. Once the rivalry is removed, bacteria immune to certain kinds of organisms could survive & start to proliferate rapidly. Consequently, there are more of them at different periods. Additionally, a population could pass on traits that offer another immunity to future generations. As a result, microorganisms constantly develop resistance to antibiotics.

6.2

Ans: The Times of India claims that chimpanzees are smarter than us. Scientists discovered in a research study that chimps were more adaptive and flexible than people. There is no denying that humans are one of the most evolved creatures than any other. Human beings have undergone more severe affected through natural selection compared to their primate counterparts, as evidenced by the comparison of 14,000 chromosomes among human beings and chimpanzees.

Our exceptional intellect and huge brains can’t be explained by natural selection. This primate that lived around 5 million generations ago is the common progenitor of the human race and chimpanzees. Their DNA changed over time to provide the subsequent generation with the greatest chance of surviving. However, a US study found that compared to chimps, human beings have a far smaller amount of favorably chosen genetic material.

6.3

Ans: Species are communities or groups of individuals that can interbreed and yield viable, fertile offspring.

6.4

Ans: Here are some crucial elements listed below that are capable of being used to differentiate the theory of human evolution:

1. The human brain’s capacity to process the data
2. The skeletal framework of the human body
3. Structural alignment of your body
4. Personal choices regarding nutritional intake
5. Physical characteristics of humans

The prehistoric ancestral DNA of contemporary humans underwent vital morphological alterations:

• The overall area of the forehead widens & starts rising vertically.
• The nose’s prominence & shape constriction.
• The creation of face chins.
• The cheek ridges are getting thinner.
• The facial structure becomes flattened out.
• There has been a smaller number of hair follicles around the body.
• The spinal column’s inclination to support erect carriage.
• The existence of a hollow cavity assisting the viscera serves as the pelvic girdle base.
• The height increases to a certain extent.
• Walking on 2 feet while maintaining an erect posture.
• Both the expansion and softening around the head.
• A larger and more intelligent brain.

6.5

Ans: One vital trait of self-awareness is the capacity to portray how a living being communicates with other organisms & their desired ecosystem. Human beings possess certain traits, whereas other living species don’t have that luxury. Only humans have showcased this ability among all other animal beings that have been considered. Some well-known instances consist of orangutan species, gorillas, chimps, bottlenose dolphins, elephants, orcas, apes, Rhesus macaques & European magpie birds. Dogs and other members belonging to the Canidae group exhibit minor signs of self-consciousness.

6.6

Ans:

(i) Cockroach, Limulus (king carb), Neopilina, Latimaria (Fish) are fossil that has remain unchanged over years.

(ii) Trilobites – fossil arthropods

(iii) Lung fishes – connecting link between fishes and amphibians

(iv) Peripatus – connecting link between annelids and arthropods

(v) Woody mammoth – ice fossils

(vi) Gastropods – mould and cast fossil

(vii) Giant elk – amber fossil of asphalt

(viii) Dinosaur footprint – imprints

6.7

Ans: Practice drawing a few different plants & animals, which appear to be reasonably simple to come up with, so you can render these representations flawlessly. Teachers & parents may supply recommendations, or you could simply start searching the internet for basic animal or plant representations.

6.8

Ans: The adaptive radiation process causes an ancestral lineage or collection of members to transform into distinct shapes. Resources & ecosystems play a role in the continued development of these kinds of creatures along with the process of natural selection. Despite sharing the same origin, the Galapagos Darwin finches have distinct jaws depending on what they eat. Because of their varied eating patterns, these finch species have a variety of beak forms and feeding preferences. Originating originally as a seed-eating finch, but has developed into insectivorous, blood-sucking & numerous more finch species with diverse appetites.

6.9

Ans: Adaptive radiation does not exist in the gradual development of humans. The adaptive radiation phenomenon can be described as the process by which new species diverge from an ancestral lineage. Despite having a common ancestry, our evolutionary process has resulted in slow but steady modifications within our body parts, diets, and other characteristics. The development of humanity does not include expansion into novel organisms, which is a feature called adaptive radiation.

6.10

Ans: Horses evolved from Eohippus during the Eocene period. The following evolutionary steps were involved.

Eohippus, Mesohippus, Merychhippus, and Pliohippus , that gave rise to Equus.

Evolutionary Development Trends:

1. The weight of the body has increased.
2. Extended neck length.
3. An increase in leg length
4. The third digit is enlarged
5. Gradually decreasing lateral digits
6. Teeth with greater complexity to consume grass
7. Back strengthening.
8. Development of the brain and sensory organs

Related Study Resources of Chapter 6 – Evolution

Students can use the links below to get extra study materials for Class 12 Biology Chapter 6: Evolution.

Sl No.	Related Links
1	Class 12 Biology Chapter 6 Evolution- Important Questions
2	Class 12 Biology Chapter 6 NCERT Textbook

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