Darwin’s theory of evolution by natural selection was considered dangerous in 19th-century England because it threatened the prevailing views of the Anglican Church and society at large. Evolution can seem to be in direct conflict with deeply held belief systems of how life came to exist on Earth.

Darwin “didn’t know anything about why organisms resemble their parents, or the basis of heritable variations in populations,” says Niles Eldredge, a paleontologist at the American Museum of Natural History in New York City.

There are five lines of evidence that support evolution: the fossil record, biogeography, comparative anatomy, comparative embryology, and molecular biology.

Darwin’s exploratory survey on the H.M.S. Beagle had brought him into contact with a wide variety of living organisms and fossils. Darwin concluded that species change through natural selection, or – to use Wallace’s phrase – through “the survival of the fittest” in a given environment.

Darwin had been working on his theory since 1837, soon after his epic voyage on the HMS Beagle. Darwin was still working on his magnum opus when in June 1858 he received a letter from an English naturalist working in Malaysia.

Evolutionary ideas came to prominence in the early 19th century with the theory (developed between 1800 and 1822) of the transmutation of species put forward by Jean-Baptiste Lamarck (1744-1829). At first the scientific community – and notably Georges Cuvier (1769 – 1832) – opposed the idea of evolution.

1) No empirical proof exists that macro-evolution (that is, evolution from one distinct kind of organism into another) is occurring at present, or has ever happened in the past. No one, throughout recorded history, has ever seen it.

Evolution can’t explain complex organs Organs that allow detection of light could then have been favoured by natural selection, even if it did not provide full vision. These ideas have been proven correct many years later by researchers studying primitive light-sensing organs in animals.

These successions in the fossil record are the most obvious evidence to macroevolution (Figure 2). In fact, the entire fossil record is a set of millions of intermediate fossils that provide solid evidence of how macroevolution worked in the past billion years.

Darwin argued that human evolution could be explained by natural selection, with sexual selection as a significant supplementary principle. Wallace always had doubts about sexual selection, and ultimately concluded that natural selection alone was insufficient to account for a set of uniquely human characteristics.

Alfred Wallace

Alfred Russel Wallace was a naturalist who independently proposed the theory of evolution by natural selection. This encouraged Darwin to collect his scientific ideas and collaborate with Wallace. They published their scientific ideas jointly in 1858.

Ernst Mayr observed, “The basic theory of evolution has been confirmed so completely that most modern biologists consider evolution simply a fact.

The theory of evolution is a shortened form of the term “theory of evolution by natural selection,” which was proposed by Charles Darwin and Alfred Russel Wallace in the nineteenth century.

Jean Baptiste Lamarck (1744-1829) is one of the best-known early evolutionists. Unlike Darwin, Lamarck believed that living things evolved in a continuously upward direction, from dead matter, through simple to more complex forms, toward human “perfection.” Species didn’t die out in extinctions, Lamarck claimed.

Their theories are different because Lamarck thought that organisms changed out of need and after a change in the environment and Darwin thought organisms changed by chance when they were born and before there was a change in the environment.

Charles Darwin is centrally important in the development of scientific and humanist ideas because he first made people aware of their place in the evolutionary process when the most powerful and intelligent form of life discovered how humanity had evolved.

Evidence for evolution

• Anatomy. Species may share similar physical features because the feature was present in a common ancestor (homologous structures).
• Molecular biology. DNA and the genetic code reflect the shared ancestry of life.
• Biogeography.
• Fossils.
• Direct observation.

Evolution is the process by which populations of organisms change over generations. Genetic variations underlie these changes. If a trait is advantageous and helps the individual survive and reproduce, the genetic variation is more likely to be passed to the next generation (a process known as natural selection).