1 / 18

Invertebrate Zoology

Invertebrate Zoology. Lecture 2: Bauplans (cont.). Lecture outline. Animal Bauplans Key features of body plans (cont.) Locomotion and support Feeding. Bauplans: key features. Locomotion and support Type of locomotion limited by type of support system

russellk
Download Presentation

Invertebrate Zoology

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Invertebrate Zoology Lecture 2: Bauplans (cont.)

  2. Lecture outline • Animal Bauplans • Key features of body plans (cont.) • Locomotion and support • Feeding

  3. Bauplans: key features • Locomotion and support • Type of locomotion limited by type of support system • Example: Peristaltic movement requires a hydrostatic skeleton • Locomotion depends upon medium through which an animal moves as well as its size • Reynold’s number Re = • Large animals: high Re(>1.5): Inertial forces rule • Small animals: low Re(<1.5): Viscous forces rule

  4. Bauplans: key features • Locomotion and support • Four key locomotory methods • Amoeboid • Cilia/flagella • Hydrostatic propulsion • Use of limbs

  5. Locomotion and support: amoeboid movement Many cell types move this way Amoebocytes of sponges Extension of pseudopodia Fluid “endoplasm” pushes the more viscous “ectoplasm” in a particular direction. Endoplasm and ectoplasm are the same… ∆ viscosity Movement involves actin and myosin Bauplans: key features

  6. Bauplans: key features • Locomotion and support: cilia/flagella • Operate effectively at low Re • Sometimes associated with secreted mucus • Several Functions • Propulsion of larvae and small adults • Create fluid currents for feeding and gas exchange • Propel food particles and/or waste particles • Role in sensory structures

  7. Locomotion and support: cilia/flagella Structure 9 + 2 microtubule arrangement Dynein arms ATP-powered Microtubules slide past each other slightly Protein cross-links limit sliding  bending Bauplans: key features

  8. Bauplans: key features • Locomotion and support: cilia/flagella • Patterns of movement • Flagella: may beat back and forth, or may move in a helical (or “rotary”) motion • Push or pull along axis of flagellum

  9. Bauplans: key features • Locomotion and support: cilia/flagella • Patterns of movement • Cilia: oar-like movement • Power stroke vs. recovery stroke • Metachronal waves • Coordination of metachronal waves is usually mechanical • Cilia and flagella are very specific terms (not “hairs!”)

  10. Bauplans: key features • Locomotion and support: hydrostatic • Key principle: body fluids are not compressible: • can be pushed into structures  expansion. • can provide support/structure • Complementary action of circular and longitudinal muscles • Circular: decrease diameter with contraction • Longitudinal: shorten with contraction • Fluids move in response to muscle contraction • Helical muscles prevent twisting and kinking • Anchor points important

  11. Bauplans: key features • Locomotion and support: hydrostatic • Peristalsis of earthworm

  12. Phylum Echiura • Fat innkeeper worm: also moves by peristalsis within tube

  13. Bauplans: key features • Locomotion and support: limbs • Involves rigid skeleton • Exoskeleton: usually epidermally-derived • Endoskeleton: usually mesodermally-derived • Some are articulated: with joints • Did skeletons arise “by chance” from accumulation of metabolic wastes? (nitrogenous waste  chitin)

  14. Bauplans: key features • Locomotion and support: limbs • Muscles attach to and push against skeletal elements in order to move • Origin vs. insertion points • Often in pairs of antagonistic muscles (i.e. flexor/extensor pairs) • Note interior attachment points for exoskeleton

  15. Bauplans: key features • Feeding • Digestion • Extracorporeal digestion: occurs outside body • Example: some sea stars open up mussel shell and secrete enzymes to liquefy tissue • Use cilia and mucus to draw fluids into mouth

  16. Bauplans: key features • Feeding • Digestion • Intracellular digestion: occurs within cells • Phagocytosis (particles) • Pinocytosis (fluids) • Role of lysosomes • Absorption of DOM

  17. Bauplans: key features • Feeding • Digestion • Extracellular digestion: within gut chamber • Incomplete • single opening • Complete • two openings • Advantages of complete digestive system?

  18. Bauplans: key features • Feeding • Modes of feeding (briefly) • Suspension feeding: remove food particles from the water column • Deposit feeding: obtain nutrients from the sediments • Herbivory • Carnivory • Scavenging • Direct intake of dissolved organic materials

More Related