Skip to main content

Currently Skimming:

Evidence Supporting Biological Evolution
Pages 9-22

The Chapter Skim interface presents what we've algorithmically identified as the most significant single chunk of text within every page in the chapter.
Select key terms on the right to highlight them within pages of the chapter.


From page 9...
... Contrary to popular opinion, neither the term nor the idea of biological evolution began with Charles Darwin and his foremost work, On the Origin of Species by Means of Natural Selection (1859~. Many scholars from the ancient Greek philosophers on had inferred that similar species were descended from a common ancestor.
From page 10...
... Darwin's original hypothesis has undergone extensive modification and expan sion, but the central concepts stand firm. Studies in genetics and molecular biolo gy fields unknown in Darwin's time have explained the occurrence of the heredi tary variations that are essential to natural selection.
From page 11...
... The Fossil Record Although it was Darwin, above all others, who first marshaled convincing evidence for biological evolution, earlier scholars had recognized that organisms on Earth had changed systematically over long periods of time. For example, in 1799 an engineer named William Smith reported that, in undisrupted layers of rock, fossils occurred in a definite sequential order, with more modern-appearing ones closer to the top.
From page 12...
... River W ~ ~ Wahweap Formation l Straight Cliffs Formation l Tropic Shale Dakota Formation JURASSIC . Entrada Sandstone | Carmel Formation Page Sandstone Navajo Sandstone T R I A S S
From page 13...
... Amphibians Reptiles Mammals Nonhuman primates Earliest apes Australopithecine ancestors of humans Modern humans Boulder screech AND CREATIONISM (6,685 feet) 13 Millions of Years Since First Known Appearance (Approximate)
From page 14...
... The fossil record thus provides consistent evidence of systematic change through time of descent with modification. From this huge body of evidence, it can be predicted that no reversals will be found in future paleontological studies.
From page 15...
... with a double jaw joint one composed of the bones that persist in mammalian jaws, the other consisting of bones that eventually became the hammer and anvil of the mammalian ear. The Distribution of Species Biogeography also has contributed evidence for descent from common ancestors.
From page 16...
... These movements are documented in the fossil record.
From page 17...
... New Evidence from Molecular Biology The unifying principle of common descent that emerges from all the foregoing lines of evidence is being reinforced by the discoveries of modern biochemistry and molecular biology. The code used to translate nucleotide sequences into amino acid sequences is essentially the same in all organisms.
From page 18...
... 153 amino acids wrapped Similar family histories have been obtained from the three-dimensional struc around an oxygen-binding mole- tures and amino acid sequences of other proteins, such as cytochrome c (a protein cure. The sequence of amino engaged in energy transfer)
From page 19...
... The average rate at which a particular kind of gene or protein evolves gives rise to the concept of a "molecular clock." Molecular clocks run rapidly for less constrained proteins and slowly for more constrained proteins, though they all time the same evolutionary events. The figure on this page compares three molecular clocks: for cytochrome c proteins, which interact intimately with other macromolecules and are quite constrained in their amino acid sequences; for the less rigidly constrained hemoglobins, which interact mainly with oxygen and other small molecules; and for fibrinopeptides, which are protein fragments that are cut from larger proteins (fibrinogens)
From page 20...
... In this case, molecular biology has augmented the fossil record. Creationism and the Evidence for Evolution Modern whales trace their Some creationists cite what they say is an incomplete fossil record as evidence ancestry to land mammals for the failure of evolutionary theory.
From page 21...
... Molecular evolutionary data counter a recent proposition called "intelligent design theory." Proponents of this idea argue that structural complexity is proof of the direct hand of God in specially creating organisms as they are today. These arguments echo those of the 18th century cleric William Paley who held that the vertebrate eye, because of its intricate organization, had been specially designed in its present form by an omnipotent Creator.
From page 22...
... simple "eye" of flatworm Irls corneanetopus amplified through natural selection. The complex biochemical cascade resulting in blood clotting has been explained in this fashion.


This material may be derived from roughly machine-read images, and so is provided only to facilitate research.
More information on Chapter Skim is available.