Chapter 8.1: Mendel Discovered Two Laws of Inheritance

Flashcards from Chapter 8.1 of Principles of Life, 3rd Edition.

Genetics

The field of biology concerned with inheritance

• Initially started with the artificial selection of crops and animals

• Later transitioned to studies of “blending inheritance”

• Eventually gave way to Gregor Mendel’s work on particulate traits as a foundation

Gregor Mendel

A monk and teacher who lived in Brno and studied the foundations of genetic inheritance using pea plants in 1853

• While he presented his findings by 1865, his work was unnoticed until 1900 following the discovery of chromosomes

• Pioneered genetic study techniques using the garden pea

Cross-fertilization

The transfer of gametes from one parent organism to another parent organism

Self-fertilization (selfing)

The use of an organism’s own gametes to fertilize itself

Character

An observable physical feature, such as seed shape or flower color, which can vary with multiple traits

• The abundance of these that were easily scored in pea plants was beneficial to Mendel’s studies

Trait

A particular form of a character, such as round versus wrinkled seeds

• Mendel first bred plants that held these constant across parents and offspring before testing crosses

Reciprocal cross

A cross between two true-breeding organisms, serving as the parental (P) generation

First filial generation (F₁)

The offspring of the initial parental generation, created out of the reciprocal cross

• Mendel examined plants in this generation to record the passage of traits

Second filial generation (F₂)

The offspring of the first parental generation

• This was also used to construct new crosses and look for patterns of inheritance

Monohybrid cross

A cross between two parents that differ in a single trait, such as flower color

• Through several of these, Mendel discovered the existence of ratios in genetics