1861 Abraham Lincoln becomes sixteenth president of the United States.

Fort Sumter shelled, American Civil War begins.

  Ernst Haeckel (Häckel) outlines the essential elements of modern zoological classification.

Louis Pasteur refutes the doctrine of spontaneous generation.

1864 Sherman captures Atlanta, marches to Savannah. Lincoln's reelection destroys South's hope for a political settlement to the war.
  Mendel presents his work on peas to the Brünn Natural History Society. The results are published the following year.
1865 Lee surrenders, US Civil war ends, Lincoln assassinated.

Andrew Johnson becomes seventeenth president of the United States.

  Gregor Mendel publishes his findings on heredity in peas, in Versuche über Pflanzen Hybriden.

Ernst Heinrich Haeckel (Häckel) hypothesizes that the nucleus of a cell transmits its hereditary information.

Ernst Heinrich Haeckel (Häckel) first used the term ECOLOGY to describe the study of living organisms and their interactions with other organisms and with their environment.

  Darwin publishes Variation in Animals and Plants.
1868 Meiji Restoration in Japan overthrows the feudal shogunate system and initiates Japan's participation in the modern world.
  F. Galton publishes Hereditary Genius. In it he describes a scientific study of human pedigrees from which he concludes that intelligence has a genetic basis.
1869 Ulysses S. Grant becomes eighteenth president of the United States.