Figure 17-5 Geologic Time Scale Aim: How do we know that evolution Section 17-1 happened ? (millions of (millions of (millions of Era Period Time years ago) Era Period Time years ago) Era Period Time years ago) Permian 290 – 245 Quarternary 1.8–present Vendian 650–544 Carboniferous 363–290 Tertiary 65–1.8 Devonian 410–363 Cretaceous 145–65 Silurian 440–410 Jurassic 208–145 Ordovician 505–440 Triassic 245–208 Cambrian 544–505 Geologic Time Scale Go to Section: • What does Darwin mean when he states that Natural Selection works solely by and for the “good of each being” and that “all corporeal and mental endowments will tend to progress toward perfection” ? Figure 17-2 Formation of a Fossil Section 17-1 The fossil record provides evidence about the history of life on Earth The preserved Water carries small Dead organisms are remains may later rock particles to buried by layers of be discovered and lakes and seas. sediment, which forms studied. new rock. Go to Section: If we could follow the fossils of a particular organism up through the layers of the Earth we would have a clear picture of how organisms changed over time General trend in equid body size over millions of years While such trends as toe reduction and increase in size are real over time, the rate of change varied among different branches of the equid evolutionary bush The cladogram graphically represents a evolutionary process • Phylogenetic tree of the evolutionary relatedness of organisms Anatomical comparisons indicate the similarities in bone structure suggests a common ancestor Comparative Embryology Similarity of embryos during development suggests a common ancestor. Aligned DNA fragment and first chromosome banding patterns for man (Homo sapiens), chimpanzee (Pan troglodytes), gorilla (Gorilla gorilla), and orangutan (Pongo pygmaeus). This cladogram shows that.. ………Humans share a common ancestor with other primates, we did not evolve from them Prepare a refute to this situation • Someone tells you that they are teaching that humans evolved from monkeys. Aim: What paths did evolution follow? • DIVERGENT EVOLUTION "One ancestral stock evolves into two species, which continue to evolve and become less and less alike over time." • PARALLEL EVOLUTION "In PARALLEL EVOLUTION two related species arise from a common ancestor. The two species then evolve in much the same way over time, probably in response to similar environmental selection pressures." • "CONVERGENT EVOLUTION occurs when two or more groups that are not closely related come to resemble each other more and more as time passes. This is usually the result of occupation of similar habitats and the adoption of similar environmental roles.." • Punctuated equilibrium • This type of diagram reflects the theory that evolution has not occurred at a constant rate, rather it has occurred in short bursts with long periods of stability between. This theory explains the absence of the infinite range of intermediate fossils in branches of evolution such as the vertebrates. Evolution of the Whale Started on Land and moved to the Sea What happened to the Dinosaurs?
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