Question

Difficulty: MediumContinuous and Discontinuous Variation

Biological variations in living organisms manifest through distinct phenotypic patterns and underlying genetic mechanisms. Pair each genetic scenario or population trait feature on the left with its correct classification or descriptive feature on the right.

  • Human body mass and adult heightContinuous variation controlled by polygenes and modified by environmental factors
  • Human Rhesus factor status and ABO blood groupDiscontinuous variation controlled by monogenic inheritance independent of environmental influence
  • Frequency curve displaying a smooth, continuous spectrum of intermediate phenotypesGraphical profile typical of quantitative inheritance within a population
  • Histogram featuring separate, distinct bars without intermediate formsGraphical profile typical of qualitative inheritance within a population

Answer

Human body mass and adult height pairs with continuous variation controlled by polygenes and modified by environmental factors; Human Rhesus factor status and ABO blood group pairs with discontinuous variation controlled by monogenic inheritance independent of environmental influence; Frequency curve displaying a smooth, continuous spectrum pairs with graphical profile typical of quantitative inheritance within a population; Histogram featuring separate, distinct bars pairs with graphical profile typical of qualitative inheritance within a population.
Continuous variation involves quantitative traits such as height and body mass, governed by multiple genes (polygenes) and environmental conditions, producing a smooth distribution curve. Discontinuous variation involves qualitative traits such as blood groups, controlled by major single genes (monogenes), producing discrete, non-overlapping categories represented by separate bars on a histogram.

Step-by-Step Solution

1
Analyze polygenic traits and environmental influence.
Human body mass and height vary continuously across a spectrum and respond to environmental factors like diet.
Multiple additive genes working together with environmental conditions produce a continuous range of phenotypes.
2
Identify traits governed by single genes producing distinct categories.
Blood groups (ABO and Rhesus factor) are strictly categorical without intermediate types.
Monogenic inheritance causes discontinuous phenotypic classes that are immune to environmental modifications.
3
Correlate graph types with quantitative and qualitative variation.
A smooth curve depicts quantitative variation, while isolated bars depict qualitative variation.
Quantitative traits span a continuous spectrum forming a bell curve, whereas qualitative traits yield clear-cut distinct categories.

Key Concept

Distinction between continuous (polygenic, quantitative) and discontinuous (monogenic, qualitative) variation
Estimated Time:1m 30s
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