EVOLUTION
2016 MARCH
2. Read the principle and answer the questions:
"Allele frequencies in a population are stable and constant from generation to generation called genetic equilibrium."
a. Name the principle mentioned here.
b. Mention any two factors affecting the equilibrium.
c. What is the significance of disturbances occur in the genetic equilibrium? (Scores : 3)
OR
“Natural selection can lead to stabilisation, directional change and disruptive changes.”
Explain the terms stabilization, directional change and disruptive change mentioned above. (Scores: 3)
2016 SAY
1. Observe the diagram
a. Identify the types of evolution in the concept diagrams A and B. (Score 1)
b. Write example pair each for homologous and analogous organs. (Score 1)
2. Statements below show the features of some human fossils. Read carefully and identify the fossil.
a. Human like beings with brains capacities between 650 – 800 cc.
b. Lived in East and Central Asia with brain capacity of 1400 cc. (Scores 2)
2017 MARCH
1. A population of 208 people of MN blood group was sampled and it was found that 119 were MM group, 76 MN group and 13 NN group. Answer the following questions:
(a) Determine the gene frequencies of M and N alleles in the population.
(b) How does the above frequencies affect evolution? (Scores: 3)
OR
Examine the pictures of Darwin’s Finches given below and answer the following questions:
(a) What phenomenon in evolution is represented in the picture?
(b) Explain the phenomenon with the help of an additional example.
2. Which of the following sets of gases were used in Miller’s experiment? (Score: 1)
(1) CH4, NO2, H2O, CO2 (2) NH3, CH3. H2O, H2
(3) H2, CH4, NH3, H2O (4) H2O, N, CH4, H2
2018 MARCH
1. Complete the boxes with the suitable words given below:
[Analogues, Homologues, Convergent evolution, Divergent evolution]
2. Explain the factors affecting the Hardy-Weinberg equilibrium.