In the eighteenth century the French naturalist Jean Baptiste de Lamarck believed that an animal’s use or disuse of an organ affected that organ’s development in the animal’s offspring.
Topic
The inheritance of acquired characteristics—how some traits gained during life can actually be passed to offspring, possibly supporting Lamarck’s old theory.
Framework
Old / New
Main Point
Recent research has uncovered ways in which acquired characteristics can be inherited—contrary to previous belief—and this may vindicate Lamarck’s idea that traits acquired during an organism’s lifetime can be passed to offspring. The Most Valuable Sentence is at the end of the last paragraph:
P1: Introduction—Lamarck’s Idea and Its Dismissal
We’re introduced to Lamarck’s old theory: that traits acquired during life (like a giraffe’s long neck) are inherited by offspring. For a long time, scientists dismissed this idea, but new evidence suggests it might occur after all.
P2: Example—Environmentally Induced Traits in Bacteria
Scientists discovered that bacteria can inherit the loss of a cell wall due to changes in how genes interact (not changes to the genes themselves), showing a form of inheriting acquired characteristics.
P3: Example—Genes Added or Removed by the Environment
There are other ways acquired traits can be inherited: viruses can introduce genes to fruit flies, or genetic material (plasmids) can pass from one bacterium to another, giving new abilities quickly—suggesting this process may have sped up evolution.