BIO SCI 94 Lecture Notes - Lecture 8: Phylogenetic Tree, Synapomorphy, Natural Selection

• School: UC-Irvine
• Department: Biological Sciences
• Course: BIO SCI 94
• Professor: Brad Hughes

Document Summary

Over large periods of time, nature of life on earth has experienced many changes. Two analytical tools to reconstruct history of life: Ancestral trait-trait that existed in an ancestor. Derived trait- modified ancestral trait, found in descendant. Traits in two or more taxa;present only in most recent ancestors. Allow recognition of monophyletic groups-called clades or lineages. Homology- shared ancestry leads to similar traits. Homoplasy- similar traits due to reasons other than common ancestry. Natural selection favors similar solutions to similar environmental. Some traits may be homologous with traits in another species while others may pressures be convergent. Ichthyosaurs(extinct aquatic reptiles) and dolphins(extant mammals) are simir. Phylogenetic analysis similarities not due to common ancestry. Fossil record data support idea whales evolved from terrestrial mammals. Fossil-physical trace left by organism that lived in past. Fossil record- total collection of fossils found throughout the world. What organisms in the past looked like. Part/all of organism buried in sediment-->fossil formation begins.