Draw a histogram for the given birth weight data and explain polygenic inheritance in comparison to monogenic inheritance.

Here are the solutions to your questions:

27.1
To draw a histogram using the provided data:

• Title: A suitable title would be "Histogram showing the relationship between birth weight and the number of surviving babies."
• X-axis: Label the horizontal axis "Birth weight (kg)". Mark the class intervals: 1.0-1.5, 1.6-2.0, 2.1-2.5, 2.6-3.0, 3.1-3.5, 3.6-4.0, 4.1-4.5, 4.6-5.0. Ensure the bars touch as birth weight is continuous data.
• Y-axis: Label the vertical axis "Number of babies surviving". Scale this axis appropriately to accommodate the highest frequency (2300).
• Bars: Draw rectangular bars for each class interval, with the height of each bar corresponding to the number of babies surviving in that weight range:
  • 1.0-1.5 kg: 100
  • 1.6-2.0 kg: 200
  • 2.1-2.5 kg: 300
  • 2.6-3.0 kg: 1300
  • 3.1-3.5 kg: 2300
  • 3.6-4.0 kg: 1200
  • 4.1-4.5 kg: 250
  • 4.6-5.0 kg: 150 The histogram would show a bell-shaped curve, with the highest frequency (peak) occurring in the 3.1-3.5 kg birth weight range.

27.2
The type of inheritance controlled by many genes, such as in birth weight, is:

• Polygenic inheritance

27.3
Polygenic inheritance (mentioned in 27.2) differs from inheritance due to one gene (monogenic inheritance) in the following ways:

• Number of genes: Polygenic inheritance involves multiple genes contributing to a single trait, while monogenic inheritance involves a single gene determining a trait.
• Phenotypic variation: Polygenic traits show continuous variation, meaning there is a wide range of phenotypes that often form a normal distribution (e.g., height, skin color, birth weight). Monogenic traits typically show discrete variation, resulting in distinct categories or phenotypes (e.g., presence or absence of a specific genetic disorder, blood types).
• Environmental influence: Polygenic traits are often significantly influenced by environmental factors, whereas monogenic traits are generally less affected by the environment.