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Invertebrate Zoology. Invertebrate Classification and Relationships. The Meek Will Inherit the Earth. Many diseases that effect humans and the animals we depend on are caused by invertebrates Invertebrates are the base of most food webs Invertebrates are the base of many medical studies:
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Invertebrate Zoology Invertebrate Classification and Relationships Invertebrate Classification & Relationships
Many diseases that effect humans and the animals we depend on are caused by invertebrates Invertebrates are the base of most food webs Invertebrates are the base of many medical studies: Control of gene expression Aging, cell death, fertilization and chemoreception Transmission of nerve impulses, biochemical basis of learning and memory Genetic basis for the predisposition for major diseases (i.e. type II diabetes) Isolating unique chemicals for biomedical reasons Using invertebrates as indicators in monitoring aquatic systems for pollutants Why Study Invertebrates? Invertebrate Classification & Relationships
Invertebrate Classification and Relationships • Classification by and body symmetry • Classification by developmental pattern • Classification by evolutionary relationship • Classification by habitat and lifestyle Invertebrate Classification & Relationships
Body Symmetry Radial Asymmetrical Bilateral Classification by Body Symmetry Invertebrate Classification & Relationships
Most metazoans are triploblastic Classification by Developmental Pattern • Multicellular animals have been divided into two groups based on the # of germ layers • Germ layer • Diploblastic • Ectoderm • Endoderm • Triploblastic • Mesoderm Invertebrate Classification & Relationships
Tissues Animal body plans also vary according to the organization of the animal’s tissues Tissues are collections of specialized cells isolated from other tissues by membranous layers During development, three germ layers give rise to the tissues and organs of the animal embryo Invertebrate Classification & Relationships
Body Cavities • Most triploblastic animals possess a body cavity • A true body cavity is called a coelomand is derived from mesoderm • Coelomatesare animals that possess a true coelom • A pseudocoelom is a body cavity derived from the mesoderm and endoderm • Triploblastic animals that possess a pseudocoelom are called pseudocoelomates • Triploblastic animals that lack a body cavity are called acoelomates Invertebrate Classification & Relationships
Acoelomate Pseudocoelomate Coelomate Classification by Developmental Pattern • Triploblastic animals can be classified even further Invertebrate Classification & Relationships
Acoelomate Pseudocoelomate Coelomates Protostomes Deutrostomes Different Developmental Types Triploblastic Invertebrate Classification & Relationships
Advantages of the Coelom • The digestive system is independent of the body wall and locomotory activities • Room for the gut, gonads, and embryo’s to bulge • Fluid in coelom can distribute oxygen, nutrients and hormones through the body • Fluid filled coelom leads to more effective locomotory systems Invertebrate Classification & Relationships
Binomial nomenclature Classification by Evolutionary Relationship • By far the most familiar is the frame work created 250 years ago by Linnaeus • Organisms grouped in a taxon show a high degree of similarity Kingdom Family Phylum Genus Class Species Order Invertebrate Classification & Relationships
Deducing Evolutionary Relationships • How do we compile evolutionary relationships? • PCR (polymerase chain reaction) • In what ways are evolutionary relationships depicted? • Cladograms Invertebrate Classification & Relationships
Cladograms Common ancestor
Classification by Habitat and Lifestyle • Terrestrial, marine, or aquatic • Mobile, sessile, or sedentary, planktonic • Herbivores, carnivores • Symbiotic associations • Mutualism, commensalism, parasitism Invertebrate Classification & Relationships