Punctuated evolution

The concept of punctuated evolution suggests that species experience long periods of stability interrupted by rapid changes due to environmental pressures. This theory challenged previously held views on the constant rate of evolutionary change and remains under dispute.
 Stephen Jay Gould, Niles Eldredge United States 1972 Punctuated evolution

The concept of punctuated evolution suggests that species experience long periods of stability interrupted by rapid changes due to environmental pressures. This theory challenged previously held views on the constant rate of evolutionary change and remains under dispute.