Heredity and Evolution

HOTS Questions for Class 10 Science Chapter 9 Heredity and Evolution

Question 1.
Observe the diagram carefully. What does it depict ? Identify the parts shown by lines.

Answer:
Reconstruction of fossil bird Archaeopteryx.

1. Claw
2. Free fingers
3. Beak
4. Teeth
5. Tail
6. Feathers

Question 2.
Name the organism in which feathers appeared for the first time.
Answer:
Members of Dromaesaur family which were small dinosaurs.

Question 3.
Which one is the edible part in Kale, Kohlrabi, Broccoli, Brussel’s Sprout, Cabbage and Cauliflower ?
Answer:
Kale — Leaves,
Kohlrabi — Swollen stem,
Broccoli — Immature green flowers,
Brussel’s Sprout — Axillary buds,
Cabbage — Terminal bud,
Cauliflower — Immature inflorescence of sterile flowers.

Question 4.
Give an example where temperature determines the sex of the new bom.
Answer:

1. Chrysema picta (a turtle). Temperature above 33°C produces females and below 28°C males.
2. Agama agama (a lizard). High temperature produces males.

Question 5.
Name a recessive trait which is quite common in human beings.
Answer:
Blood group O (I°I°).

Question 6.
Why is variation beneficial for the species but not necessarily for the individual ?
Answer:
Preadaptation is a variation which under normal conditions is of no advantage to the individual bearing it. However, it becomes highly useful in survival under changed environment, e.g, heat wave in temperate environment, insecticide or antibiotic resistance.