A new U.S. study finds that the average size of marine animals has increased 150-fold over the past 500 million years, and the trend toward “big size” is not a random event.
Named after 19th century American paleontologist Edward Kopp, the Copp’s Law holds that animals will grow larger and larger as they evolve, such as dinosaurs and horses. However, some people take birds and insects as examples and think that the “Copper’s Law” is wrong.
To study whether marine animals obey the Copper’s Law, researchers at Stanford University have developed a database of marine animals, which includes body size data of more than 17,000 marine adult animals belonging to more than 17,000 genera, spanning 542 million years from the Cambrian to the present. They found that the smallest size of marine animals “shrank” by 90% during this period, while the largest size surged by more than 100,000 times. Overall, the average size of marine animals increased 150 times.
Research using computer models shows that this trend towards “big” evolution cannot be explained by random processes, but is a positive choice that has evolutionary benefits for animals, such as swimming faster or catching larger prey.
Researchers say the results will help to study other issues related to body size, such as who lives near the equator is larger on average than those living in high latitudes. In addition, scientists will be encouraged to study whether other characteristics of animals also have certain trends in the evolution process.