↑ "Experiments with sex have been very hard to conduct," Goddard said. "In an experiment, one needs to hold all else constant, apart from the aspect of interest. This means that no higher organisms can be used, since they have to have sex to reproduce and therefore provide no asexual control." Goddard and colleagues instead turned to a single-celled organism, yeast, to test the idea that sex allows populations to adapt to new conditions more rapidly than asexual populations.[1]
↑ Proterospongia is a rare freshwater protist, a colonial member of the Choanoflagellata." "Proterospongia itself is not the ancestor of sponges. However, it serves as a useful model for what the ancestor of sponges and other metazoans may have been like.[3]
↑ "Obviously vertebrates must have had ancestors living in the Cambrian, but they were assumed to be invertebrate forerunners of the true vertebrates — protochordates. Pikaia has been heavily promoted as the oldest fossil protochordate."[4]:289
↑ These first vertebrates lacked jaws, like the living hagfish and lampreys. Jawed vertebrates appeared 100 million years later, in the Silurian.[8]
↑ A fossil coelacanth jaw found in a stratum datable 410 mya that was collected near Buchan in Victoria, Australia's East Gippsland, currently holds the record for oldest coelacanth; it was given the name Eoactinistia foreyi when it was published in September 2006.
↑ Lungfish are believed to be the closest living relatives of the tetrapods, and share a number of important characteristics with them. Among these characters are tooth enamel, separation of pulmonary blood flow from body blood flow, arrangement of the skull bones, and the presence of four similarly sized limbs with the same position and structure as the four tetrapod legs.[11]
↑ "the ancestor that amphibians share with reptiles and ourselves?"..."These possibly transitional fossils have been much studied, among them Acanthostega, which seems to have been wholly aquatic, and Ichthyostega"[4]:250
↑ In many respects, the pelycosaurs are intermediate between the reptiles and mammals[13]
↑ "Thrinaxodon, like any fossil, should be thought of as a cousin of our ancestor, not the ancestor itself. It was a member of a group of mammal-like reptiles called the cynodonts. The cynodonts were so mammal-like, it is tempting to call them mammals. But who cares what we call them? They are almost perfect intermediates."[4]:211
↑ "Fossils that might help us reconstruct what Concestor 8 was like include the large group called plesiadapi-forms. They lived about the right time, and they have many of the qualities you would expect of the grand ancestor of all the primates"[4]
↑ Rubin also said analysis so far suggests human and Neanderthal DNA are some 99.5 percent to nearly 99.9 percent identical.[23]
↑ The conclusion is the old saw that we share 98.5% of our DNA sequence with chimpanzee is probably in error. For this sample, a better estimate would be that 95% of the base pairs are exactly shared between chimpanzee and human DNA.[24]
↑ ...of the three billion letters that make up the human genome, only 15 million--less than 1 percent--have changed in the six million years or so since the human and chimp lineages diverged.[25]
