Please note: This is a companion version & not the original book. Sample Book Insights:#1 The theory of evolution by natural selection states that organisms are exquisitely tailored for their environments because they have been evolutionarily selected to survive. This process of natural selection causes organisms to change incrementally over time to better adapt to their environments.#2 The process of evolution by natural selection is extremely slow, and it would have taken hundreds of millions of years to create the profusion of life on Earth today. The first evidence of life on our planet dates to about 3. 8 billion years ago.#3 The idea that sex constantly outwits parasites was proposed by the American biologist Leigh Van Valen in 1973. It states that parasites can change rapidly, but a host population can survive their relentless onslaught by changing even more rapidly.#4 The Red Queen Hypothesis is the theory that sex exists because it is a defense against parasites. It received strong observational support in 2011 when biologists genetically engineered two different populations of the roundworm Caenorhabditis elegans to reproduce in two different ways: one asexually, by fertilizing its own eggs, and the other sexually, by female and male worms mating.