Q.1. Mention the various evidences for evolution you know.
Ans. (a) Paleontological (b) Comparative anatomy and morphology (c) Biochemical evidence Q.2. Here are given two plants—one with thorn and the other with tendril. What is this type of structure called? What is this type of evolution? Ans.
These structures are called homologous organs. The evolution is called divergent evolu-tion. The organs indicate a common ancestry. These organs are the result of development in different direction due to adaptation to different needs.
Q.3. Describe one example of adaptive radiation? (NCERT) OR Following is the figure of small black birds observed by Darwin in Galapagos Island. What was his observation and conclusion? Ans. The process of evolution of different species in a given geographical area from a point and literally radiating to other areas of habitats is called adaptive radiation. As observed in case of Darwin’s finches, their existed varieties in Galapagos island he observed that small black birds. These birds originally evolved from seed eating to insect-eating birds. The seed eating features in beaks altered to insect eating and vegetarian finches.
Another example is of Australian marsupials that evolved on Australian island from on ancestral stock. Q. 4. (1) What is the basis of Hardy-Weinberg principle? (2) Define the genetic equilibrium and (3) What will be effect of disturbance in genetic equilibrium? Ans. (1) Algebraic expressions.
(2) The total genes and their alleles in a population (gene root) remains constant. This is known as genetic equilibrium. (3) The disturbance in the equilibrium would result in evolution. Q. 5. Try to trace the various components of human evolution, (hint: brain size and function, skeletal structure, dietary preference etc.) Ans. Dryopithecus and Ramapithecus originated 15 mya.
They were hairy and walked like gorillas and chimpanzees. Ramapithecus was more man like Australopithecines came 2 mya and it lived in East African grasslands. They hunted with stone weapons and ate fruits. By same time first human like being the hominid and was called Homo habilis. It had the brain capacity between — 650-800 cc. They were vegetarians.
Homo erectus came 1.5 mya. They had large brain around 900 cc and were probably non-vegetarians. Neanderthal man lived in near last and central Asia around 100,000-40, 000 years ago. They used hide to protect their body and buried their dead.
Homo sapiens arose in Africa and moved across continents. Modern Homo Sapiens came during ice age around 75,000- 10,000 years ago.