20.) Discuss in detail the evolutionary thought related to the natural selection process.

 20.) Discuss in detail the evolutionary thought related to the natural selection process.

answer:

The theory of evolution by natural selection was published by Charles Darwin in 1859 in a book, “On the Origin of Species by Means of Natural Selection” 

• According to special creation (a) all species are independent; (b) life on Earth is young (6000 years old); and (c) species are immutable, or incapable of change 

• The theory of evolution by natural selection is considered revolutionary, in that it replaces an existing entity with something new and often radically different 

• Darwin claimed that variation among individuals in a population was the key to understanding the nature of species, which is referred to as population thinking 

• Darwin repeatedly described evolution as descent with modification, that species which lived in the past are the ancestors of the species existing today 

• In the early 19th century, researchers began discovering fossil bones, leaves, and shells that were unlike structures from any known animal or plant 

• In 1812, Baron Georges Cuvier published a detailed analysis of extinct species, such as mammoths, mastodons, giant armadillos, giant deer, and giant sloths 

• Darwin reasoned that if species have gone extinct, then the array of species living on Earth has changed through time 

• Recent analyses of the fossil records suggest that species have gone extinct continuously throughout Earth’s history, in more than a few catastrophic events

 • Researchers reported striking resemblances between the fossils found in some geographic areas and the living species succeeding them in the same areas 

• Researchers postulate that most of the critical reactions in • chemical evolution occurred in an aqueous, or water-based, 

• environment Theory Of Evolution By Natural Selection 

• A transitional feature is a trait in a fossil species that is intermediate between those of ancestral (older) and derived (younger) species 

• A vestigial trait is a reduced/incompletely developed structure that has no/reduced function, but is similar to structures in ancestral/related species 

• The timing of bird migrations and the blooming of flowering plants have evolved in response to ongoing climate change 

• During his visit to Galapagos Islands, Darwin gathered extensive collections of plants and animals, including Galapagos finches and mockingbirds

 • Several years after Darwin’s return to England, a colleague pointed out that the mockingbirds collected from some of the different islands were distinct species 

• He proposed that they had descended from a common ancestor, and those that colonized different islands had changed through time forming new species 

• Researchers postulate that most of the critical reactions in chemical evolution occurred in an aqueous, or water-based, environment Theory Of Evolution By Natural Selection Theory Of Evolution By Natural Selection 

• Recent analyses of DNA sequences in these mockingbirds support Darwin’s hypothesis, which placed them on a phylogenetic tree with a common ancestor

 • When biologists first began to study the anatomy of humans and other vertebrates, they were struck by their remarkable similarity (early mammal) 

• The theory of evolution by natural selection predicts that homologies will occur; if species were created independently, homology cannot be explained

 • Some populations have served as particularly well-studied examples of speciation in action, such as populations of fruit flies and sunflowers 

• Biologists draw on data from several sources to challenge the hypothesis that species are immutable and were created independently 

• Perhaps the most powerful evidence for any scientific theory, incl