Invertebrate Classification and Relationships PDF

Invertebrate Classification and Relationships Invertebrate Classification and Relationships METAZOANS Oldest known multicellular animals 543 to 635 million years old Members of the so-called Ediacaran fauna First discovered in South Africa Invertebrate Classification and Relati...

Invertebrate Classification and Relationships Invertebrate Classification and Relationships METAZOANS Oldest known multicellular animals 543 to 635 million years old Members of the so-called Ediacaran fauna First discovered in South Africa Invertebrate Classification and Relationships METAZOANS Cambrian period Burgess Shale of British Columbia,1909  CAMBRIAN EXPLOSION Rapid diversification of complex animals over several millions of years Cytochrome c Invertebrate Classification and Relationships Increase in the atmospheric oxygen Increased photosynthetic activity Different Classification Systems Different Classification Systems Classification by Cell Number, Embryology, and Body Symmetry  Classification by Cell number Metazoans Multicellular Generally diploid organisms Developed from a blastula Classification by Cell number Other Invertebrates Unicellular Acellular Did not developed from anything resembling a metazoan embryo  Classification by General Body form Body Symmetry Bilateral Has right and left sides that are approximately mirror images of each other Cephalization concentration of nervous and sensory tissues and organs at one end of an animal (posterior and anterior)  Classification by Cell number Body Symmetry Radial An animal can be divided into two approximately equal halves by any cut that passes through its center. Various types of body symmetry  Classification by Developmental Pattern Germ Layers Diploblastic Diplo = Greek: double Only two (2) distinct germ layers form during or following the movement of cells into the embryo’s interior. Ectoderm and endoderm  Classification by Developmental Pattern Germ Layers Triploblastic triplo = Greek: triple Three (3) distinct germ layers form during or following the movement of cells into the embryo’s interior. Ectoderm, mesoderm and endoderm  Classification by Developmental Pattern Coelom internal, fluid-filled body cavity lying between the gut and the outer body wall musculature and lined with tissue derived from embryonic mesoderm  Classification by Developmental Pattern Coelom (1) Acoelomates a=G: without; coelom=G; hollow space The region lying between the outer body wall and the gut of acoelomates is solid  Classification by Developmental Pattern Coelom (2) Pseudocoelomates pseudo=G: false; coelom=G; hollow space Outer wall musculature and the endoderm of the gut is a fluid-filled cavity.  Classification by Developmental Pattern Coelom (3) Coelomates/Eucoelomates eu=G: true; coelom=G; hollow space Internal, fluid-filled body cavity lying between the gut and the outer body wall musculature and lined with tissues derived from the mesoderm.  Classification by Developmental Pattern Coelom formation Protostomes vs. Deuterostomes  Coelom formation Classification by Protostomes Developmental Schizocoely (schizo = G:split) Coelom formation occurs by gradual Pattern enlargement of a split in the mesoderm Classification by Coelom formation Deuterostomes Developmental Enterocoely (entero = G:gut) Pattern Coelom forms from a part of what eventually becomes the gut  Classification by Developmental Pattern Cleavage Animal pole and Vegetal pole Radial cleavage (deuterostomes) and Indeterminate/regulative cleavage (protostomes)  Classification by Evolutionary Relationship Kingdom Phylum Class Order Family Genus Species Classification by Habitat Terrestrial Animals that live on land Marine Animals that live in the ocean Classification by Habitat Marine Intertidal Subtidal Open Oceans Classification by Habitat Marine Mobile Sessile Sedentary Classification by Habitat Marine Mobile Sessile Sedentary planktonic  Classification by Feeding habits Herbivores Carnivores Omnivores Decomposers Detritivores Suspension feeders Deposit feeders  Classification by Symbiosis Intimate association with other species Frequently relate to feeding biology of one or more of the participants Classification by Symbiosis Ectosymbionts Live nearby or on the body of the other participant Endosymbionts Live within the body of the other participant  Mutualism Classification by Mutualism Symbiosis Both symbionts benefit from each other  Commensalism Classification by When the benefit accrues to only one of Symbiosis the symbionts and the other is neither benefited nor harmed  Parasitism Classification by When one of the symbionts benefits Symbiosis from the other and the other may be harmed.