Chapter 24 The Evolution Short Questions Notes RTS

HED RTS Important Exams Short Questions with Answers

alt="Chapter 24 Evolution Class 12 Biology Featured Image - Fossils, Homologous and Analogous Organs, Vestigial Organs, Hardy-Weinberg Principle, Genetic Drift and Extinct Species in Pakistan - Punjab Board Short Questions Notes"

1) Define fossils, where most of the fossils found?

Fossils: Remains or impressions of ancient organisms preserved in rocks. They provide direct evidence of evolution.

Most fossils are found in sedimentary rocks (because these rocks form layer by layer and preserve dead organisms quickly).

2) Difference between homologous and analogous organs

Feature	Homologous Organs	Analogous Organs
Origin	Same embryonic origin (divergent evolution)	Different origin (convergent evolution)
Structure	Similar internal structure	Different internal structure
Function	May differ	Similar
Example	Forelimbs of man, bat, whale, horse	Wings of bird and insect

3) Define vestigial organs with example

Vestigial Organs: Organs that were functional in ancestors but have become reduced or non-functional in present-day organisms due to change in habit.

Examples:

Vermiform appendix in humans
Wisdom teeth
Nictitating membrane (third eyelid)
Coccyx (tail bone)
Body hair and ear muscles

4) State Hardy-Weinberg theory with equation

Hardy-Weinberg Principle (1908): In a large, randomly mating population, allele and genotype frequencies remain constant from generation to generation if no evolutionary forces (mutation, selection, drift, migration) act on it.

Equation: p² + 2pq + q² = 1 (where p = frequency of dominant allele, q = frequency of recessive allele)