Genetic drift operates in :-
- Small isolated population
- Large isolated population
- Fast reproductive population
- Slow reproductive population
The Correct Option is A
Solution and Explanation
The random changes in gene frequencies in a population occurring by chance alone rather than by natural selection are called genetic drift or the Sewall Wright effect. The effects of genetic drift are mostly visible in tiny isolated populations, although it occurs in all people.
Important Notes on Genetic Drift
- By genetic drift often the phenotype of this small population becomes different from the parent population.
- According to the Hardy-Weinberg principle, there are many factors that contribute to the Hardy-Weinberg equilibrium. Any change to this results in evolution.
- Gene flow, genetic drift, mutation, genetic recombination, and natural selection can affect this equilibrium.
- Gene frequency changes in the population during migration as new alleles get lost from the older population.
- Gene flow occurs when gene migration happens multiple times. If it occurs by chance, it is called genetic drift.
- The population from which the new one was formed became founders and this is called the founder effect.
Top Questions on Evolution
- Define Adaptive Radiation and give examples like Darwin's Finches.
- HBSE Class 12 - 2026
- Biology
- Evolution
- On which island group did Darwin observe finches?
ডারউইন কোনটিকে 'প্রকৃতির খেলা' রূপে আখ্যায়িত করেছিলেন?
সমবয়ী অঙ্গের বিবর্তনকে বলা হয়
একটি মৌমাছি কীভাবে শ্রমিক মৌমাছি অন্য শ্রমিক মৌমাছিদের খাদ্য উৎসের বার্তা দেয় ব্যাখ্যা করো। ডারউইনের অভিব্যক্তি সংক্রান্ত তত্ত্বের তিনটি বিষয় ব্যাখ্যা করো — প্রাকৃতিক নির্বাচন, অস্তিত্বের জন্য সংগ্রাম, প্রকরণের উৎপত্তি।
Questions Asked in NEET exam
- Given below are two statements:
Statement I: The DNA fragments extracted from gel electrophoresis can be used in the construction of recombinant DNA.
Statement II: Smaller size DNA fragments are observed near the anode while larger fragments are found near the wells in an agarose gel.- NEET (UG) - 2025
- Molecular Biology
Given below are two statements:
Statement I: Transfer RNAs and ribosomal RNA do not interact with mRNA.
Statement II: RNA interference (RNAi) takes place in all eukaryotic organisms as a method of cellular defence.
In the light of the above statements, choose the most appropriate answer from the options given below:- NEET (UG) - 2025
- RNA interference
- Given below are two statements: Statement I: In the RNA world, RNA is considered the first genetic material evolved to carry out essential life processes. RNA acts as a genetic material and also as a catalyst for some important biochemical reactions in living systems. Being reactive, RNA is unstable.
Statement II: DNA evolved from RNA and is a more stable genetic material. Its double helical strands being complementary, resist changes by evolving repair mechanisms. In the light of the above statements, choose the most appropriate answer from the options given below:- NEET (UG) - 2025
- Structure of DNA and RNA
- A microscope has an objective of focal length \(f_o = 2\) cm and an eyepiece of focal length \(f_e = 4\) cm. The tube length of the microscope is \(L = 40\) cm. If the distance of distinct vision of eye is \(D = 25\) cm, the magnification in the microscope is:
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- Optical Instruments
- Two gases A and B are filled at the same pressure in separate cylinders with movable pistons of radii \(r_A\) and \(r_B\) respectively. On supplying an equal amount of heat to both the cylinders, their pressures remain constant and their pistons are displaced by 16 cm and 9 cm respectively. If the change in their internal energies is the same, then the ratio \(r_A / r_B\) is:
- NEET (UG) - 2025
- Thermodynamics
Concepts Used:
Evolution
Evolution is a process that occurs in changes in the genetic content of a population over time. Evolutionary change is generally classified into two: microevolution and macroevolution. The process of changes in allele frequencies in a population over time is a microevolutionary process. Three main mechanisms that cause allele frequency change are natural selection, genetic drift, and gene flow. On the other hand, macroevolution refers to change at or above the level of the species.