1500_9_ArthropodBiology

1500_9_ArthropodBiology - BIO1500 W07 Arthopoda: Structure...

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Unformatted text preview: BIO1500 W07 Arthopoda: Structure and function Arthropods key body plan traits Arthropods are triploblastic animals Germ layer Ectoderm Ectoderm Mesoderm Mesoderm Endoderm Endoderm Developmental fate Epidermis, Nervous system Epidermis, Muscle, bone, gonads, circulatory system Muscle, Lining of digestive and respiratory system Lining Arthropods key bodyplan traits 2. Arthropods are Protostomier Protostome development Deuterostome development Arthropods key bodyplan traits 3. True body cavity, coelom. Arthropods key bodyplan traits 5. Chitin exoskeleton - physical protection and water loss - rigid scaffold for for muscle attachment - Postembryonic development requires ecdysis (=molting) Arthropods key bodyplan traits 5. Chitin exoskeleton - physical protection and water loss - region(s) for muscle attachment - Postembryonic development requires ecdysis (=molting) Arthropods key bodyplan traits 5. Chitin exoskeleton - physical protection and water loss - region(s) for muscle attachment - Postembryonic development requires ecdysis (=molting) Arthropods key bodyplan traits 6. Jointed appendages facilitating multiple forms of reproduction, locomotion, food uptage, respiration, olfaction Arthropods key bodyplan traits 6. Jointed appendages facilitating multiple forms of reproduction, locomotion, food uptage, respiration, olfaction Arthropods key bodyplan traits 6. Jointed appendages facilitating multiple forms of reproduction, locomotion, food uptage, respiration, olfaction Arthropods key bodyplan traits Insect mouthparts: modified jointed appendages for predation or other means of food uptage Comparison of arthropod head segment organization Damen et al 1998 Chewing mouthparts of grasshopper Mandible Maxilla Labium Sponging mouthparts of Drosophila Mxp La Mx – Maxilla Mx Mxp – Maxillary palp Mxp La - Labium Mandible completely reduced Piercing mouthparts of mosquito Lb Md Mx La Mx Md Lb La Lb – Labrum Labrum Mx – Maxilla Mx Mxp – Maxillary palp Mxp Md – Mandible La - Labrium Mxp Sucking mouthparts of butterflies La Mx Mx – Maxilla Mx La - Labium Mandible and labrum completely reduced. Arthropod organ systems 1. Muscular system Example: appendage muscles ”Herring bone" arrangement of the muscle blocks in grasshopper femur Arthropod organ systems 1. Muscular system Example: insect flight muscles Visualization of changing Ca2+ concentrations in flight muscle apparatus of transgenic Drosophila. Anatomy of direct and indirect flight muscles in insects. By using the Cameleon-2.1 strain of Drosophila we are attempting to combine transgenic Ca- imaging with electrophysiological recordings to analyze the mechanisms underlying power modulation in flight. Cameleon 2.1 consists of a transgenicaly modified calmodulin sequence and the calmodulin target peptide M13, by the respective fusing of an enhanced cyan fluorescent protein (ECFP) and an enhanced yellow fluorescent protein (EYFP). Calcium influx results in a calcium- Arthropod organ systems 2. Complete digestive system Arthropod organ systems 3. Central nervous system consisting of cephalic brain and ventral nerve cord (double chain of paired ventral ganglia). Arthropod organ systems 3. Central nervous system consisting of cephalic brain and ventral nerve cord (double chain of paired ventral ganglia). Drosophila ventral nerve cord visualized by antibody staining Arthropod organ systems 5. Complex sensory organs: antennae for olfaction Arthropod organ systems 6. Complex sensory organs: compound eyes built from many independent visual units, called ommatidia. Each Each ommatidium is covered with a lens and contains [in most cases] 8 photoreceptor cells. Arthropod organ systems Cellular architecture of the Drosophila ommatidium (Don Ready, Purdue University) Arthropod organ systems 7) Open circulatory system: Hemolymph flows through cavities between the internal organs. Principal unit is a SINGLE longitudinal vessel called dorsal HEART that runs near the dorsal surface of the thorax and abdomen. Arthropod organ systems 7) Open circulatory system: when the dorsal heart contracts, hemolymph is pumped into the head region. When heart releases, hemolymph flows back into the dorsal heart through the series of one-way valves. Arthropod organ systems 8) Respiratory system: !Marine Chelicerata and Crustacea: gills !In marine forms- GILLS on abdominal legs. !In terrestrial forms- TRACHEAL system (insects, myriapods, arachnids) or BOOKLUNGS (arachnids). Arthropod organ systems 8) Respiratory system: Insects, and Myriapods: tracheae In insects, large number of small, branched, cuticle-lined air ducts called TRACHEAE. Tracheae branch into a system of very small tubes (tracheoles) that transmit oxygen throughout the body. Arthropod organ systems 8) Respiratory system: Insects, and Myriapods: tracheae Tracheal system stained for chitin in a wild type Drosophila embryo (Luschnig et al 2006). In insects, large number of small, branched, cuticle-lined air ducts called TRACHEAE. Tracheae branch into a system of very small tubes (tracheoles) that transmit oxygen throughout the body. Arthropod organ systems 8) Respiratory system: Insects, and Myriapods: tracheae Close-up of the tracheal system in a Drosophila embryo stained for chitin (red) and Serp protein (blue) inside the luminal space. The surrounding tracheal cells are labeled in green. Before filling with gas at the end of embryogenesis, the tracheal lumen contains a chitinous matrix. (Luschnig et al 2006). In insects, large number of small, branched, cuticle-lined air ducts called TRACHEAE. Tracheae branch into a system of very small tubes (tracheoles) that transmit oxygen throughout the body. Arthropod organ systems 8) Respiratory system: Insects, and Myriapods: tracheae Mayfly larvae are fully aquatic. They have special gill-like structures connected to the trachea. In this species you can see them along the body as the long strands on the right. Near the base of the gills we can see the trachea as dark tubes. They branch into finer tubes so all the parts of the body can be reached. Tracheae and gills in aquatic mayfly larva (Hexapoda). Arthropod organ systems 8) Respiratory system: !Marine Chelicerata and Crustacea: gills Arthropod organ systems 8) Respiratory system: !Marine Chelicerata and Crustacea: gills Walking appendage epipodites functioning as gills (7) http://www.biology.iastate.edu/Courses/201L/Arthropd%7F/MandibulateArth/%20%20MandibArthpds Arthropod organ systems 8) Respiratory system: Arachnids:booklungs BOOKLUNGS are composed of a series of leaflike plates ! within a chamber. Booklungs may exist alongside tracheae or they may function instead of tracheae. Arthropod organ systems 9) Excretory system In aquatic forms- mostly simple diffusion. In terrestrial forms (insects, myriapods) - unique excretory system composed of Malpighian tubules which are slender projections from the digestive tract attached at the junction of the midgut and hindgut. ...
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