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Animal Diversity The aim of this module is to provide an overview of the diversity of animal life: to look at the evolutionary relationships between animals, to classify the major animal groupings, and to examine links between form, function, ecological niche and biogeography. Students are expected to become familiar with the specimens on display in the Cole Museum of Zoology and in the teaching collection and to be able to identify animals from across taxa. WHO OR WHAT ARE YOU? A) Look at the groups listed below. Which are you in, along with starfish, wasps, cod, pandas and all the animals listed on the right ? Bilateria Myxozoa Cnidaria Ctenophora Placozoa Porifera D) Which of the animals below is not a bilaterian? B) What animal is this? C) What is this odd-looking marine animal? Scientific naming of animals (Linnaean taxonomy). Zoologists need to learn the scientific names and classifications of animals. Every recognized species is given a two-part scientific name, a generic name and a specific name. The generic name groups a number of animals together, e.g. Mus domesticus and Mus dunni are both mice but different species. These names allow zoologists throughout the world to communicate unambiguously about animal species since there are sets of international rules about how to name animals. This system was first developed in the 18th century by Carolus Linnaeaus. It classifies animals into a hierarchy, starting with Kingdoms. These are divided into Phyla (singular: Phylum) which are divided into Classes, and they, in turn, into Orders, Families, Genera (singular: Genus), and Species. Molecular phylogeny Early taxonomic classifications relied on shared morphological (outer form and inner structure), behavioural and physiological characters to group animals together. Today molecular techniques allow us to sequence stretches of an animal’s DNA. By comparing the DNA sequences of different organisms we can discover relationships that cannot otherwise be inferred from morphology. Because genomes evolve by the gradual accumulation of mutations, the amount of nucleotide sequence difference between a pair of genomes from different organisms should indicate how recently those two genomes shared a common ancestor. Animals that diverged in the recent past should have fewer differences than animals whose common ancestor is more ancient. The Cole Museum of Zoology The Cole Museum of Zoology contains some 3500 specimens, 400 of which are arranged in 27 cases in taxonomic sequence. Students use museum specimens as a starting point to study an animal group in more detail. A CD-ROM based on The Cole Museum has been developed to provide in-depth information and aid the learning process. Practical exams are held during the course where students are presented with specimens to identify and comment on. a) Autolytus pachycerus; b) Smilisca phaeota; c) Palomina prasina. Students have the opportunity to design new cases for the Cole Museum and develop temporary exhibitions. Answers: A: Bilateria, bilaterally symmetrical with a body cavity, mouth and anus (includes most animals); B: A springtail, Podura aquatica (Hexapoda, Collembola); C) Holocephali, the “Chimaeras”, related to sharks and rays, D) A trick question, they all are; a),Annelida, b) Deuterostoma, c) Arthropoda. Photos: Steve Hopkin, Greg W. Rouse D. and M. Dimijian. Comparison of morphological and molecular classifications of chalcid wasp species (Heraty, 2003)