Three types of natural selectionप्राकृतिक चयन के तीन प्रकार
NCERT Fig 6.8 · Class 12 Biology · Chapter 6 · interactive diagram
Parts and their functions
- Population before selection (चयन से पहले की समष्टि) — Dashed bell curve: most individuals have the mean (average) value; a few are at the two ends.
- Stabilising selection (स्थायीकारी चयन) — More individuals acquire the mean character value; the extremes are removed. Curve becomes taller and narrower.
- Directional selection (दिशात्मक चयन) — More individuals acquire a value other than the mean — the curve shifts to one side.
- Disruptive selection (विदारक चयन) — More individuals acquire peripheral values at both ends; the mean is selected against → two peaks.
Steps
- 1 · Before selection: a normal bell-shaped spread of a trait.
- 2 · After selection: stabilising (mean favoured), directional (one side), disruptive (both ends).
Original diagram drawn by Simple Learning Hub, based on NCERT Fig 6.8. Report a mistake