Chapter 23 1 The geological timescale was first developed using the fossil record but this provided only a system of relative dating absolute dates were not established until the discovery of the biological species concept radioactive decay paraphyletic domains molecular biology 2 The evolutionary history of a group of organisms is called a Score 1 of 1 half life phylogeny fossil record synapomorphy homologous event molecular clock phylogeny geologic timescale half life extinction monophyletic paraphyletic polyphyletic Score 1 of 1 3 The amount of time it takes for a radioactive element to decay to its more stable form is called its Score 1 of 1 4 A taxon that includes a single common ancestor and some but not all of its descendants is a group Score 1 of 1 5 How does the fossil record corroborate phylogenetic history The timing of evolutionary events in the fossil record is not consistent with the branching order of a phylogenetic tree Events in the fossil record occur randomly throughout a phylogenetic tree so the two are not related to one another Events that occur early in the fossil record are represented by branching events nearer to the root of a phylogenetic tree Events that occur early in the fossil record are represented by branching events nearer to the tips of a phylogenetic tree Fossil record events are too old to be represented on phylogenetic trees which reconstruct the more recent past Score 1 of 1 6 Why is the fossil record of marine life more complete than living organism in terrestrial ecosystems Marine habitats are places that sedimentation rather than erosion will take place Organisms that live in marine environments don t have bones or other hard body parts Organisms that live in terrestrial habitats are evolutionarily too old to fossilize Fossilization cannot occur without water acting to preserve body part from decomposition Score 1 of 1 7 How do fossils provide evidence of evolutionary history Fossils provide an accurate account of the number of species that exist at any particular time Older fossils are an excellent source of DNA from which we can construct molecular phylogenies Fossils provide a record of extinct species Fossils provide complete information on extinct species Score 1 of 1 8 What is the first event in the fossilization process erosion of soils around the organism burial of the organism by sediments conversion of organic tissue to minerals rock hardening of sediments in to rock Score 1 of 1 9 The largest mass extinction occurred at the end of the Ordovician Devonian Permian Triassic Cretaceous Score 1 of 1 10 What is a trace fossil a small fossil fossil evidence of organisms other than conventional fossils of hard body parts a fossil which is part of a series of fossils that trace the evolution of a group of species a fossil that allows scientists to trace the movement of the fossilized organism Score 1 of 1
View Full Document
Unlocking...