Charles Darwin and Natural Selection Quiz

Chromosomal Inheritance

• Thomas Morgan established a link between specific genes and specific chromosomes through his research.
• Utilized the fruit fly (Drosophila melanogaster) due to its advantageous breeding characteristics.

Advantages of Using Fruit Flies

• Rapid breeding cycle: They reproduce quickly and can produce offspring in just two weeks.
• Simple genetic makeup: Only possess four pairs of chromosomes (three pairs of autosomes and one pair of sex chromosomes).

Findings on Eye Color

• During a year-long study, Morgan identified a male fruit fly with a white-eyed mutation, diverging from the typical red-eyed wild type.
• Initial cross between a white-eyed male and red-eyed female produced all F1 generation offspring with red eyes.

F1 Generation Analysis

• F1 red-eyed offspring were interbred to produce a second generation (F2).
• The resulting genetic ratio in offspring exhibited a 3:1 ratio of red-eyed to white-eyed flies, aligned with Mendelian expectations.
• All females from the F2 generation were red-eyed, while male offspring showed a 50% red-eyed and 50% white-eyed distribution.

Sex-Linked Genes

• Genes located on sex chromosomes (X and Y) are termed sex-linked genes, occurring in humans, plants, and certain insects.

Linked Genes

• Each chromosome comprises hundreds or thousands of genes.
• Genes positioned closely on the same chromosome are often inherited together during genetic crosses as they are considered a single unit.

Test your knowledge about Charles Darwin's research on the voyage of H.M.S. Beagle, his observations on the Galapagos Islands, and the concept of natural selection as described in 'On the Origin of Species'.