7 Most VSAQ’s of Heredity and Evolution Chapter in Class 10th Biology (TS/AP)

2 Marks

VSAQ-1 : Why variations are important? How are variations useful for an organism or a population?

Importance of Variations

  1. Adaptation: Variations enable organisms to adapt to changing environments, enhancing their survival and reproduction.
  2. Evolution: They provide the raw material for natural selection, leading to the emergence of new species.

VSAQ-2 : Write a brief note on Analogous organs.

Definition: Analogous organs are organs in different species that perform similar functions but have different structural designs.

Example and Significance: An example is the wings of birds and bats, which are used for flying but differ structurally. These organs illustrate convergent evolution, where different species independently develop similar features to adapt to comparable environments.

VSAQ-3 : When cross is done between pure yellow and pure green pea seed producing plants the following results were obtained. (y=yellow; y=green) Answer the questions given below based on the above table.
1. Yy – indicates which colour of the seed?

2. What is the phenotypic ratio of the above cross?

  1. Interpretation of ‘Yy’ Genotype
    Yy indicates the yellow color of the seed. In this case, yellow (Y) is dominant over green (y), resulting in a yellow appearance for the Yy genotype.
  2. Phenotypic Ratio of the Cross
    The phenotypic ratio of this cross is 3:1, indicating that for every three plants with yellow seeds, there is one plant with green seeds. This ratio reflects the offspring’s observable characteristics (phenotype) from the cross between pure yellow and pure green pea seed-producing plants.

VSAQ-4 : Why do we call appendix as a vestigial organ?

Definition of Vestigial Organ

A vestigial organ is one that has lost its original function through the course of evolution and is no longer necessary for survival or has diminished functionality.

Appendix in Humans and Ruminants

  1. In ruminants like rabbits, the appendix aids digestion by helping break down cellulose.
  2. However, in humans, the appendix no longer plays a significant role in digestion, as humans do not digest cellulose. Therefore, the appendix is considered vestigial in humans, signifying its loss of original function over time.

VSAQ-5 : What examples will you give to prove that Lamarckism is not correct.

  1. Weismann’s Experiment on Rats:
    The experiment conducted by August Weismann on rats provides evidence against Lamarckism.
  2. Lamarckism and Acquired Traits:
    In Lamarckism, it is believed that acquired traits can be passed on to offspring.
  3. Findings of Weismann’s Experiment:
    Weismann’s experiment showed that cutting off the tails of parental rats for twenty-two generations did not result in tailless offspring. The offspring were born with normal tails, indicating that the acquired characteristic (taillessness) was not inherited by subsequent generations.
  4. Refutation of Lamarckism and Support for Darwin’s Theory:
    This experiment strongly refuted the idea of the inheritance of acquired characteristics proposed by Lamarck and provided support for the concept of genetic inheritance and natural selection proposed by Charles Darwin.

VSAQ-6 : Observe the given flow chart and answer the question. Who decides the sex of the baby-mother or father? How?

  1. Determinant of Baby’s Sex:
    The sex of the baby is determined by the father.
  2. Contribution of Chromosomes by Mother and Father:
    The mother always contributes an X chromosome (XX), while the father can contribute either an X or a Y chromosome (XY).
  3. Formation of a Baby Girl:
    If an X chromosome from the father fuses with the X chromosome from the mother, a baby girl (XX) is born.
  4. Formation of a Baby Boy:
    If a Y chromosome from the father fuses with the X chromosome from the mother, a baby boy (XY) is born.
  5. Role of Father’s Chromosome in Determining Sex:
    Thus, the sex of the baby is determined by the type of chromosome received from the father.

VSAQ-7 : Write two questions ask your teacher to know more information about evolution.

  1. Understanding Evolution Mechanisms:
    What are the mechanisms driving evolution?
  2. Evidence of Common Ancestry in Species:
    How do different species show evidence of common ancestry?