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Evolution: Animal Diversity Part 1 Biology 155 Krilowicz Spring 2010 I. Definitions A. Taxonomy: the science of classification of living things; older schemes were constructed without regard for evolutionary relationships among organisms B. Phylogeny: the science that examines the evolutionary relationships among organisms; most taxonomic schemes in use today are based on phylogeny II. What types of information can be used to construct phylogenetic schemes? A. Anatomy: similarities or differences in structure of modern day forms 1. Adult structures – The bones of a human arm are very similar to those in a bird wing, so probably closely related animals (homologous structures) The vertebrate limbs are very different from arthropod limbs, so these two groups are more distantly related Various vertebrate forelimbs Various arthropods Fig. 13.5A II. What types of information can be used to construct phylogenetic schemes? - continued A. Anatomy: similarities or differences in structure of modern day forms – continued 2. Embryonic structure – All vertebrate embryos go through very similar developmental patterns, so probably closely related animals The development of vertebrates (deuterostomes) differs from arthropods (protostomes), so these two groups are more distantly related Fig. 13.5B Two vertebrate embryos at similar stages in development II. What types of information can be used to construct phylogenetic schemes? - continued B. Physiology: function of present day organisms Mammal and reptile lungs function in essentially the same manner, so probably closely related animals Insects use a tracheal system to exchange gases that functions very differently from vertebrate lungs, so these two groups are more distantly related II. What types of information can be used to construct phylogenetic schemes? - continued C. Geologic (Fossil) Record: can be used to determine – 1. Anatomy of extinct organisms 2. First appearance of currently living organisms II. What types of information can be used to construct phylogenetic schemes? - continued D. Biochemical Information: how similar is the structure of enzymes, ribosomes, etc. among groups of organisms?; Reflects similarity in DNA because information in the genes is used to construct proteins, RNA and other biological molecules II. What types of information can be used to construct phylogenetic schemes? - continued E. Gene (DNA) Sequence Data – how similar is the genetic material among living organisms? ultimately what scientists really want is an answer to this question to definitely construct phylogenetic trees Has recently led to a reorganization of living things into three domains versus five kingdoms Five kingdom system of classification Three domain system of classification III.The Taxonomic Hierarchy: Domain (three of these) Kingdom Phylum (Animals) or Division (Plants) Class Order Family Increased relatedness = Genus more traits in Species common Only group with a biological definition Definition of a species • A group of actually or potentially interbreeding organisms that are reproductively isolated* from other organisms * Either cannot mate with another organism or mating produces sterile offspring Species names have two parts Genus species Capitalized italicized lower case italicized Usually Latin Example – Felis domesticus