Question and Answer:

Question 1.
Explain antibiotic resistance observed in bacteria in light of Darwinian selection theory.
Answer:
When a bacterial population is exposed to an antibiotic, the sensitive bacteria die, while a few with mutations that provide resistance survive. These resistant bacteria multiply rapidly, passing the resistance genes to their offspring. Over time, the entire population becomes resistant. This process of survival and multiplication of individuals with favorable variations is called natural selection, as proposed by Darwin.

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

1. Archaeopteryx (Feathered Dinosaur):
   Fossil of a small feathered dinosaur showing advanced wing feathers indicating it could perform powered flight — a link between reptiles and birds.
2. Psittacosaurus (Transitional Dinosaur):
   Fossil showing both scaly and feather-covered skin patches — indicates a mix of reptilian and avian features during evolution.
3. Mirasaura grauvogeli (Feather-like Reptile):
   Fossil of a Triassic reptile found with feather-like structures, suggesting such skin appendages evolved earlier than true birds.
4. Oldest Dome-headed Dinosaur:
   Fossil of the oldest dome-headed dinosaur (~110 million years old) discovered in North America — helps trace the early evolution of pachycephalosaurs.

Question 3.
Attempt giving a clear definition of the term species.
Answer:
A species is a group of organisms that are similar in structure and function and can interbreed among themselves to produce fertile offspring, but are reproductively isolated from other groups.

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

Additional Notes:

• Brain size: Increased gradually from 400–600 cc (Australopithecus) to 1400 cc (Homo sapiens).
• Dietary preference: Changed from herbivorous → omnivorous.
• Skeletal structure: Gradual change from ape-like to erect man.

Question 5.
Find out through internet and popular science articles whether animals other than man has self-consciousness.
Answer:
Yes, chimpanzees are the animals most closely related to humans and have self-consciousness. They can recognize themselves in mirrors and show emotions like joy, sorrow, and empathy, indicating a sense of self-awareness similar to that of humans.

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

These fossil links show how modern animals evolved gradually from ancient forms through natural selection and adaptation over millions of years.

Question 7.
Practise drawing various animals and plants.
Answer:
The process of evolution of different species in a given geographical area starting from a common ancestor and spreading to other habitats is called adaptive radiation.
A classic example is the Australian marsupials, where a number of marsupial species, each adapted to a different mode of life, evolved from a common ancestral stock — all within the Australian continent.
For example, kangaroos (herbivorous), marsupial wolves (carnivorous), and marsupial moles (burrowing) show adaptive radiation.

Question 8.
Describe one example of adaptive radiation.
Answer:
Adaptive radiation is the process of evolution of different species from a common ancestor in a given geographical area.
A well-known example is Australian marsupials, where different species such as kangaroo, koala, and marsupial wolf evolved from a common ancestral marsupial, each adapted to different ecological niches within the Australian continent.

Question 9.
Can we call human evolution as adaptive radiation?
Answer:
No, human evolution cannot be called adaptive radiation.
Adaptive radiation refers to the evolution of different species from a common ancestor in different ecological habitats.
In contrast, human evolution is a gradual process that occurred within a single lineage, where different ancestral forms like Australopithecus, Homo habilis, Homo erectus, and Homo sapiens appeared sequentially over time — not as separate radiating species in different habitats.

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:
The evolution of the horse is one of the best examples showing gradual evolution through natural selection. Fossil records show how horses evolved from small, forest-dwelling animals to large, fast-running grassland dwellers.

➡️ Summary:
Horse evolution shows an increase in size, reduction in toes, and adaptation of teeth for grazing, reflecting environmental changes from forest to grassland habitats.