Evolution By Natural Selection Charles Darwin In 1831 Charles Darwin sailed to the Galapagos islands While exploring he made many observations about the plants and animals there He collected samples and notes and then studied them for 20 years at home in England Through his studies he developed the 4 conditions for Natural Selections NATURAL SELECTION: the process whereby organisms better adapted to their environment tend to survive and produce more offspring. The theory of its action was first fully expounded by Charles Darwin and is now believed to be the main process that brings about evolution. Darwin’s Four conditions for natural selection 1.Traits in a population of organisms exhibit variation ~ parents reproduce offspring that are not exactly the same ~ offspring are “similar” but have differences ~ individuals can vary in traits that range from size and shape to how they act or function chemically 2.Not all individuals survive to reproduce ~ for some species like salmon, they lay thousands of eggs while only one or two will reach adulthood ~ even if an animal makes it to adulthood they may not reproduce, especially if they can’t find a suitable mate 3.Survival is not Random ~ survivors must have an advantage over those that don’t survive ~ this advantage is the result of a particular “variation” in a trait 4. Surviving individuals “good traits” must be heritable (ability to be passed to new generations) ~ Evolution can happen only if “good traits” or advantages can be passed from one generation to the next ~ some individuals contribute more offspring to the next generation and their traits will slowly grow more and more common in the population, when this happens the population is evolving Along with developing the principals of Natural Selection Darwin also developed the description of how animals became so diverse with the explanation of “Adaptive Radiation” which can also be called divergent evolution or speciation. Adaptive Radiation adaptive radiation is a process in which organisms diversify rapidly into a multitude of new forms, particularly when a change in the environment makes new resources available, creates new challenges, or opens new environmental niches.