BSC 2010L PORIFERA THRU ANNELIDA

Principal Biological Concepts to Emphasize: A. Coloniality vs. multicellularity. B. Specialization of form and function of cells. C. Organization of cells into tissues of specific structure and function. D. Organization of tissues into organs. E. Organization of organs into organ systems. F. Trends in body plan. G. Organ systems and function. H. Detailed anatomy of the earthworm.

Developments in body organization A. Tissue organization - diploblastic vs. triploblastic. 1. Mesoglea is not a tissue. 2. Outer ectoderm or epidermis, inner endoderm or gastrodermis. 3. Triploblastic have mesoderm. B. Radial versus bilateral symmetry C. Cephalization. 1. Concentration of sensory apparati at the anterior end of the body. 2. An adaptive response to bilateral symmetry and linear mobility. D. Coelom development and function. 1. Body cavity isolating internal organs from body wall. 2. Protects organs. 3. Acts as a hydrostatic skeleton.

Structure and Function 1. support 8. excretion 2. movement 9. reproduction 3. circulation a. sexual 4. respiration b. asexual 5. nervous response c. cycles 6. ingestion d. ploidy 7. digestion 10. osmoregulation In small organisms, many functions occur by diffusion.

Functions of structures detailed in the manual will not always be included in the text. You are still required to know the function. If you do not know the function, ask me or look it up.

Kingdom ANIMALIA - KNOW TAXONOMY TO CLASS Kingdom ANIMALIA - KNOW TAXONOMY TO CLASS. Will cover chapters 9 and 10 and handout. Systematics have changed somewhat with new information from molecular studies.

Phylogeny based of body plan grades 1. Parazoa - no true tissues - sponges 2. Eumetazoa - true tissues A. Radiata - radial symmetry, diploblastic - Cnidaria B. Bilateria - bilateral symmetry, triploblastic 1. Acoelomates - Platyhelminthes 2. Pseudocolomates - Nematoda 3. Coelomates - Protostomes - Mollusca, Annelida, Arthropoda - Deuterostomes - Echinodermata, Chordata

A traditional view of animal diversity based on body-plan grades

Phylogeny based on molecular studies 1. Parazoa - no true tissues - Porifera 2. Eumetazoa - true tissues A. Radiata - radial symmetry, diploblastic - Cnidaria B. Bilateria - bilateral symmetry, triploblastic 1. Protostomes - Lophotrochozoa - Platyhelminthes, Mollusca, and Annelida - Ecdysozoa - Nematoda and Arthropoda 2. Deuterostomes

Animal phylogeny based on sequencing of SSU-rRNA

Comparing the molecular based and grade-based trees of animal phylogeny

Phylum PORIFERA - sponges A. Sponges (the Parazoa) are distinct from all other animals (the Eumetazoa). 1. Lack tissues 2. Are either asymmetrical or radially symmetrical

A choanoflagellate colony

Sponges

Anatomy of a sponge

Phylum CNIDARIA A. Radial body symmetry (the Radiata) B. Polyps and medusae in life cycle C. Diploblastic - two tissues layers 1. Ectoderm 2. Gastroderm 3. Also have mesoglea - not a tissue D. Classification: 1. class Hydrozoa- polyps dominant 2. class Scyphozoa - medusae dominant 3. class Anthozoa - medusae absent

Polyp and medusa forms of cnidarians

Medusa

Purple striped jelly, Pelagia panopyra

Sea anemones

Coral polyps

The life cycle of the hydrozoan Obelia

Remainder of animals have bilateral symmetry (the Bilateria) A. Cephalization B. Triploblastic - 3 tissue or germ layers 1. Ectoderm 2. Mesoderm 3. Endoderm

Coelom development a. Acoelomates b. Pseudocoelomates c. Coelomates

Phylum PLATYHELMINTHES - ACOELOMATE A. class Turbellaria - planarians B. class Trematoda - flukes C. class Cestoda - tapeworms - internal parasites

Anatomy of a planarian

Protonephridia: the flame-bulb system of a planarian

Anatomy of a parasitic flatworm

Anatomy of a tapeworm

Phylum NEMATODA - roundworms, hookworms - PSEUDOCOELOMATE A. Ascaris B. Turbatrix C. Trichinella - DEMO

Nematode, C. elegans

Parasite nematode, Trichinella spiralis

Phylum ANNELIDA - segmented worms - COELOMATE A. class Polychaeta - mostly marine worms B. class Oligochaeta - e.g. earthworm C. class Hirudinea - leeches

Annelids, the segmented worms: Polychaete (left), feather-duster worm (middle), leech (right)

Earthworm Dissection A. Study external anatomy first. B. Anesthetize in ETOH. C. Pin to one side of dissecting tray, dorsal side up. D. Study internal anatomy. 1.Small reproductive structures - ovaries, testes, vas deferens, oviduct, sperm funnels - do not need to be found in the worms. Locate these only on the models - know their functions. E. Dispose of in trash.

External anatomy of an earthworm

Anatomy of an earthworm

Metanephridia of an earthworm

Inverts Study Aid