When was evolution proposed

Here, "fitness" refers not to an organism's strength or athleticism but rather its ability to survive and reproduce. It is one of the best-substantiated theories in the history of science, supported by evidence from a wide variety of scientific disciplines, including not just genetics which shows that different species have similarities in their DNA but also paleontology and geology through the fossil record, which shows how that species that existed in the past are different from those present today , and developmental biology species that seem very different as adults pass through similar stages of embryological development, suggesting a shared evolutionary past.

See the open-access textbook Concepts of Biology for more information about these lines of evidence. In the first edition of "On the Origin of Species," published in , Darwin speculated about how natural selection could cause a land mammal to turn into a whale. As a hypothetical example, Darwin used North American black bears Ursus americanus , which were known to catch insects by swimming in the water with their mouths open.

The idea didn't go over very well with the public or with other scientists. Darwin was so embarrassed by the ridicule he received that the swimming-bear passage was removed from later editions of the book. Scientists now know that Darwin had the right idea but the wrong animal. Instead of looking at bears, he should have been looking at cows and hippopotamuses. The story of the origin of whales is one of evolution's most fascinating tales and one of the best examples scientists have of natural selection.

To understand the origin of whales, you need a basic understanding of how natural selection works. Natural selection can alter a species in small ways, causing a population to change color or size over the course of several generations. When this process happens over a relatively short period of time and in a species or small group of organisms, scientists call it "microevolution.

But when given enough time and accumulated changes, natural selection can create entirely new species, a process known as "macroevolution. Take the example of whales: By using evolution as a guide and understanding how natural selection works, biologists knew that the transition of early whales from land to water occurred in a series of predictable steps. The evolution of the blowhole, for example, might have started with random genetic changes that resulted in at least one whale having its nostrils farther back on its head.

The whales with this adaptation would have been better suited to a marine lifestyle, since they would not have had to completely surface to breathe. Such individuals were more successful and had more offspring. In later generations, more genetic changes occurred, moving the nose farther back on the head. Other body parts of early whales also changed. Front legs became flippers. Back legs disappeared.

Their bodies became more streamlined, and they developed tail flukes to better propel themselves through water. Darwin also described a form of natural selection that depends on an organism's success at attracting a mate — a process known as sexual selection. The colorful plumage of peacocks and the antlers of male deer are both examples of traits that evolved under this type of selection.

But Darwin wasn't the first or only scientist to develop a theory of evolution. Around the same time as Darwin, British biologist Alfred Russel Wallace independently came up with the theory of evolution by natural selection, while French biologist Jean-Baptiste Lamarck proposed that an organism could pass on traits to its offspring, though he was wrong about some of the details.

Like Darwin, Lamarck believed that organisms adapted to their environments and passed on those adaptations. He thought organisms did this by changing their behavior and, therefore, their bodies — like an athlete working out and getting buff — and that those changes were passed on to offspring. For example, Lamarck thought that giraffes originally had shorter necks but that, as trees around them grew taller, they stretched their necks to reach the tasty leaves and their offspring gradually evolved longer and longer necks.

Lamarck also believed that life was somehow driven to evolve through the generations from simple to more complex forms, according to Understanding Evolution , an educational resource from the University of California Museum of Paleontology.

Though Darwin wasn't sure of the mechanism by which traits were passed on, he did not believe that evolution necessarily moved toward greater complexity, according to Understanding Evolution; rather, he believed that complexity arose through natural selection.

A Darwinian view of giraffe evolution, according to Quanta , would be that giraffes had natural variation in their neck lengths, and that those with longer necks were better able to survive and reproduce in environments full of tall trees, so that subsequent generations had more and more long-necked giraffes.

The wealthy French mathematician and naturalist, George Louis Leclerc, Comte de Buffon , actually said that living things do change through time. He speculated that this was somehow a result of influences from the environment or even chance. He believed that the earth must be much older than years. In , in fact, he speculated that the earth must be at least 75, years old. He also suggested that humans and apes are related. Buffon was careful to hide his radical views in a limited edition 44 volume natural history book series called Histoire Naturelle By doing this, he avoided broad public criticism.

Buffon was an early advocate of the Linnaean classification system. He was also a quiet pioneer in asserting that species can change over generations. However, he publicly rejected the idea that species could evolve into other species. One of his most significant contributions to the biological sciences was his insistence that natural phenomena must be explained by natural laws rather than theological doctrine.

Erasmus Darwin Another late 18th century closet-evolutionist was Erasmus Darwin , the grandfather of the well known 19th century naturalist, Charles Darwin. Erasmus was an English country physician, poet, and amateur scientist. He believed that evolution has occurred in living things, including humans, but he only had rather fuzzy ideas about what might be responsible for this change. He wrote of his ideas about evolution in poems and a relatively obscure two volume scientific publication entitled Zoonomia; or, the Laws of Organic Life In this latter work, he also suggested that the earth and life on it must have been evolving for "millions of ages before the commencement of the history of mankind.

He was Jean-Baptiste Chevalier de Lamarck. Unfortunately, his theory about these processes was incorrect. Lamarck believed that microscopic organisms appear spontaneously from inanimate materials and then transmute, or evolve, gradually and progressively into more complex forms through a constant striving for perfection. The ultimate product of this goal-oriented evolution was thought by Lamarck to be humans. He believed that evolution was mostly due to the inheritance of acquired characteristics as creatures adapted to their environments.

That is, he believed that evolution occurs when an organism uses a body part in such a way that it is altered during its lifetime and this change is then inherited by its offspring. For example, Lamarck thought that giraffes evolved their long necks by each generation stretching further to get leaves in trees and that this change in body shape was then inherited.

Likewise, he believed that wading birds, such as herons and egrets, evolved their long legs by stretching them to remain dry. Lamarck also believed that creatures could develop new organs or change the structure and function of old ones as a result of their use or disuse. Lamarck's incorrect idea of the cause of evolution Jean-Baptiste Lamarck Lamarck did not invent the idea of inheritance of acquired characteristics but stated it clearly and publicly in an publication entitled Philosophie Zoologique.

It was relatively easy for the French scientist, George Cuvier , and other critics of Lamarck to discredit his theory.

If it was correct, the children of cowboys who have developed bowed legs as a result of a lifetime of riding horses would be born with bowed legs as well.

That, of course, does not occur. Likewise, the children of professional weight lifters are not born with enlarged muscles. While Lamarck's explanation of evolution was incorrect, it is unfair to label him a bad scientist.

In fact, he was at the cutting edge of biological research for his time. He and George Cuvier were largely responsible for making biology a distinct branch of science. Despite his criticism of Lamarck, Cuvier did not reject the idea that there had been earlier life forms.

National Geographic Society. For information on user permissions, please read our Terms of Service. If you have questions about how to cite anything on our website in your project or classroom presentation, please contact your teacher. They will best know the preferred format. When you reach out to them, you will need the page title, URL, and the date you accessed the resource.

If a media asset is downloadable, a download button appears in the corner of the media viewer. If no button appears, you cannot download or save the media. Text on this page is printable and can be used according to our Terms of Service. Any interactives on this page can only be played while you are visiting our website. You cannot download interactives.

In the mids, Charles Darwin famously described variation in the anatomy of finches from the Galapagos Islands. Alfred Russel Wallace noted the similarities and differences between nearby species and those separated by natural boundaries in the Amazon and Indonesia.

Independently they came to the same conclusion: over generations, natural selection of inherited traits could give rise to new species. Use the resources below to teach the theory of evolution in your classroom. When most of us think about natural selection, we attribute that theory to naturalist Charles Darwin.

However, what most people do not know is that another scientist, Alfred Wallace, a naturalist, a geographer, and a socialist, also deserves some credit for the theory. Evolution is the process by which species adapt over time in response to their changing environment. Use these ideas to teach about the water cycle in your classroom. Evolutionary adaptation, or simply adaptation, is the adjustment of organisms to their environment in order to improve their chances at survival in that environment.

Join our community of educators and receive the latest information on National Geographic's resources for you and your students.