GeneticsLesson 1 of 2 in the course Mendel's Experiments and Heredity

Mendelian Inheritance, Pea Crosses, and Probability Rules

5 flashcards · 5 quiz questions · 5 match pairs · 5 fill-in sentences · English

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Summary

This lesson introduces Gregor Mendel and the ideas about inheritance that his experiments challenged. Understanding the difference between continuous and discontinuous variation helps explain why Mendel’s choice of pea-plant traits made patterns of inheritance easier to detect.

Johann Gregor Mendel (1822–1884) was a teacher, scientist, and member of the Augustinian Abbey of St. Thomas in Brno, in what is now the Czech Republic. He taught subjects including physics, botany, and natural science. In 1856, he began a decade-long research project studying inheritance in honeybees and plants. He eventually selected garden pea plants as his primary model system.

All flashcards

Blending theory
The historical proposal that parental traits mix into intermediate offspring forms and are lost or absorbed.
Continuous variation
Variation across a range of values, often influenced by many genes.
Dominant trait
A trait that appears in the F₁ hybrid generation in a dominant–recessive pair.
Reciprocal cross
A pair of crosses in which the parental roles for contrasting traits are switched.
Product rule
For independent events occurring together, multiply their individual probabilities.

Quiz questions

  1. Which reproductive feature made garden peas useful for Mendel’s controlled crosses?Answer: Their flowers naturally self-fertilize.
  2. In Mendel’s pea flower-color experiments, what was the approximate violet-to-white ratio among F₂ plants?Answer: About 3 to 1.
  3. What did Mendel’s reciprocal crosses test?Answer: Whether the outcome depended on which parent supplied each contrasting trait.
  4. When should the product rule be used to calculate a probability?Answer: When independent events must both occur.
  5. A coin is flipped twice. Which rule finds the probability of exactly one head by adding the two possible routes?Answer: The sum rule for mutually exclusive outcomes.

Based on Biology 2e by Mary Ann Clark, Matthew Douglas, Jung Choi (OpenStax), licensed CC BY 4.0. Adapted into a summary, flashcards and quizzes.

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