Charles Darwin's Theory of Evolution: Key Concepts and Timeline, Schemes and Mind Maps of Theory of Evolution

Download Charles Darwin's Theory of Evolution: Key Concepts and Timeline and more Schemes and Mind Maps Theory of Evolution in PDF only on Docsity! Charles Darwin (1809 - 1882) Document Download and print Tree of Life poster (pdf file, 2.6Mb) Open Evolution timeline Darwin's theory of evolution explains how life on Earth has changed over geological time. Scientists believe this is the reason why all living things on Earth exist today. The theory is supported by evidence from fossils, and by the rapid changes that can be seen to occur in microorganisms such as antibiotic-resistant bacteria. Many species have become extinct in the past and the extinction of species continues to happen. The basic idea behind the theory of evolution is that different species have developed over time from simple life forms. These simple life forms first developed more than three billion years ago (as the Earth is believed to be about 4.5 billion years old). This timeline shows key events in the evolution of life forms on Earth, from the first bacteria to the human species. You can see a more detailed history of life timeline on BBC Nature. Charles Darwin is famous for his theory of evolution, but he was not the only person to develop such a theory. Darwin’s theory Charles Darwin was an English naturalist. He studied variation in plants and animals during a five-year voyage around the world in the 19th century. He explained his ideas about evolution in a book called On the Origin of Species, which was published in 1859. Darwin's theory caused controversy among his contemporaries and his ideas were only gradually accepted, although some people still do not believe them today. The reasons for skepticism include: Darwin’s theory conflicted with religious views that God had made all the animals and plants on Earth Darwin did not have enough evidence at the time to convince many scientists it took 50 years after Darwin’s theory was published to discover how inheritance and variation worked. Lamarck’s theory Jean-Baptiste Lamarck was a French scientist who developed an alternative theory of evolution at the beginning of the 19th century. His theory involved two ideas: An evolutionary tree 1. A characteristic which is used more and more by an organism becomes bigger and stronger, and one that is not used eventually disappears 2. Any feature of an organism that is improved through use is passed to its offspring. However, we now know that in most cases this type of inheritance cannot happen. Lamarck's theory cannot account for all the observations made about life on Earth. For instance, his theory implies that all organisms would gradually become complex, and simple organisms disappear. On the other hand, Darwin's theory can account for the continued presence of simple organisms. Different organisms can be classified by studying their similarities and differences. These studies also help us to understand the evolutionary relationships between different organisms. Evolutionary trees Evolutionary trees are used to represent the relationships between organisms. The diagram shows an evolutionary tree. In this evolutionary tree, species A and B share a common ancestor. Species F and G share a common ancestor, which itself shared a common ancestor with species E. All seven species share a common ancestor, probably from the distant past. The theory of evolution states that evolution happens by natural selection. The key points are that: individuals in a species show a wide range of variation this variation is because of differences in their genes individuals with characteristics most suited to the environment are more likely to survive and reproduce the genes that allow these individuals to be successful are passed to their offspring. Individuals that are poorly adapted to their environment are less likely to survive and reproduce. This means that their genes are less likely to be passed on to the next generation. Given enough time, a species will gradually evolve. You need to remember that variation can be caused by both genes and the environment. But it is only variation caused by genes that can be passed on to the next generation. Conditions on Earth Life on Earth today exists because of the conditions that were present when life was evolving. If in the