Evolution,is supported by evidence from many fields of science. The fossil record is the history of life recorded by remains from the past. Fossils include skeletons, shells, seeds, insects trapped in amber, dung, DNA and other chemicals, imprints of leaves, and tracks of organisms that lived in the distant past. Most fossils are at least 10,000 years old. [img]http://www.emc.maricopa.edu/faculty/farabee/BIOBK/pro_plfr.gif[/img] The fossil records of some protist and plant groups. The width of the shaded space is an indicator of the number of species. [img]http://www.emc.maricopa.edu/faculty/farabee/BIOBK/animalevol.gif[/img] First appearances and relative diversity (width of shaded area) for major groups of animals. he fossil record traces history of life and allows us to study history of particular organisms. Fossil evidence supports the common descent hypothesis; fossils can be linked over time because they reveal a similarity in form, despite observed changes. Transitional forms reveal links between groups: Archaeopteryx is between reptiles and birds; Eustheopteron is an amphibious fish; Seymouria is a reptile-like amphibian; therapsids were mammal-like reptiles. [img]http://www.emc.maricopa.edu/faculty/farabee/BIOBK/archie.gif[/img] Archaeopteryx, once considered the first bird.The fossil is from the Solenhoefen Limestone (Jurassic) of Germany. The fossil record allows us to trace the history of the modern-day horse Equus. The earliest fossils in this lineage is Hyracotherium , which was the size of a dog, with cusped low-crowned molars, four toes on each front foot, three on each hind foot--all adaptations for forest living. When forests were replaced by grasslands, the intermediates were selected for durable grinding teeth, speed, etc. with an increase in size and decrease in toes. Living organisms resemble most recent fossils in the line of descent; underlying similarities allow us to trace a line of descent over time. [b]Stages in the evolution of the horse.[/b] [img]http://www.emc.maricopa.edu/faculty/farabee/BIOBK/evolhorse.gif[/img] Biogeography: Separation and Divergence Biogeography is the study of the distribution of plants and animals throughout the world. Distribution of organisms is explained by related forms evolving in one locale and spreading to other accessible areas. Darwin observed South America had no rabbits; he concluded rabbits originated elsewhere. Biogeography explains why many finch species are on the Galápagos Islands but not mainland. Physical factors, such as the location of continents, determine where a population can spread. Cacti are restricted to North American deserts and euphorbia grow in African deserts. Marsupials arose when South America, Antarctica, and Australia were all joined; Australia separated before placental mammals arose, so only marsupials diversified in Australia. Comparative Anatomy: Similarities Due to Common Ancestry Organisms have anatomical similarities when they are closely related because of common descent, as substantiated by comparative anatomy. Homologous structures in different organisms are inherited from a common ancestor. Vertebrate forelimbs contain the same sets of bones organized in similar ways, despite their dissimilar functions. Vestigial structures are remains of a structure that was functional in some ancestor but is no longer functional in the organism in question. Most birds have well-developed wings, although some birds have reduced wings and do not fly. Humans have a tail bone (the coccyx) but no tail. The presence of vestigial structures is explained by the common descent hypothesis. Embryological development reveals a unity of plan. During development, all vertebrates have a notochord and paired pharyngeal pouches. In fishes and amphibian larvae, the pouches become gills. In humans, first pair of pouches becomes a cavity of middle ear and auditory tube; second pair becomes tonsils, while third and fourth pairs become thymus and parathyroid glands. This makes sense only if fish are ancestral to other vertebrate groups. [img]http://www.emc.maricopa.edu/faculty/farabee/BIOBK/jawevol_2.gif[/img] [img]http://www.emc.maricopa.edu/faculty/farabee/BIOBK/jawevol_1.gif[/img] [img]http://www.emc.maricopa.edu/faculty/farabee/BIOBK/jawevol_3.gif[/img] Steps in the evolution of jaws by modification of gill arches Biochemistry: Differences and Similarities Almost all living organisms use the same basic biochemical molecules, including DNA, ATP, and many identical or nearly identical enzymes. Organisms utilize the same DNA triplet base code and the same 20 amino acids in their proteins. Many organisms share same introns and types of repeats, which is remarkable since we know of no obvious functional reason why these components need to be so similar. These similarities can be explained by descent from a common ancestor. This is substantiated by analysis of degree of similarity in amino acids for cytochrome c among organisms. [img]http://www.emc.maricopa.edu/faculty/farabee/BIOBK/cytochromec,2.gif[/img] [img]http://www.emc.maricopa.edu/faculty/farabee/BIOBK/cytochromec.gif[/img] Interpretation of results of biochemical study of cytochrome c among the eukaryotes. Also read this: [url=http://www.space.com/scienceastronomy/051220_building_blocks.html]Life's building blocks found in space[/url] It is hypothesized that life came from the sea onto land, at least that is the basic argument of this, and here is the evidence to hold this hypothesis up: [img]http://www.brazilmax.com/fotos/pl_amazon16.jpg[/img] [i]The pirarucu must come up for air. An adult needs to surface every 15 minutes to gulp oxygen through an organ called a cellular swimming bladder. keep in mind taht it is not a mammal like dolphins or whales[/i] Also, check out the lung fish, a fish that can breathe air also: [img]http://www.ucmp.berkeley.edu/vertebrates/sarco/lungfish1.jpg[/img] "The Dipnoi are a group of sarcopterygiian fish, are are commonly known as the lungfish. Their "lung" is a modified swim bladder, which in most fish is used for buoyancy in swimming, but in the lungfish also absorbs oxygen and removes wastes. Modern lungfish in Africa and South America are able to survive when their pools dry up by burrowing into the mud and sealing themselves within a mucous-lined burrow. During this time, they breathe air through their swim bladder instead of through their gills, and reduce their metabolic rate dramatically. These fish will even drown if they are kept underwater and not allowed to breathe air! Fossilized lungfish burrows of Gnathorhiza have been found in rocks as old as the Permian, with the lungfish still inside, and older (empty) burrows are known from the Carboniferous and Devonian. The oldest fossil dipnoan is Diabolichthyes, from the Lower Devonian of Yunnan, China. It is not clear whether this particular fish was marine or lived in freshwater like modern lungfish, but both marine and freshwater fossils of other groups are known. " Where is the evidence for your creator in regards to this fish? What does creationism have to say... god did it? Wheres the evidence? [url=http://www.berkeley.edu/news/media/releases/2004/09/16_uranium.shtm]Uranium dating[/url] [/quote]

Post edited by: vincent, at: 2007/01/23 16:20