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Bauplan

Bauplan. Form and Function. How to get BIG. The Problem Unicellular to multicellular SA to Volume ratio Determines maximum size of cell Once the limit is reached, must become multicellular to grow larger Shape SA/Vol ratio also controls size of metazoans Rely on diffusion

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Bauplan

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  1. Bauplan Form and Function

  2. How to get BIG • The Problem • Unicellular to multicellular • SA to Volume ratio • Determines maximum size of cell • Once the limit is reached, must become multicellular to grow larger • Shape • SA/Vol ratio also controls size of metazoans • Rely on diffusion • Cells must be near or in contact with external environment – limit ~ 1.0 mm

  3. How to get BIG • Solutions to problem • Fill body with non-living material ex. Medusae • Body geometry that maximizes SA ex. Flatworms • Sponges have complex branching and folding • Bring environment inside! • Internal transport and exchange systems with large surfaces • Circulatory systems for oxygen, wastes, nutrients • Food absorption – long, folded or branched guts • Led to evolution of organs and organ systems

  4. Bauplan • Body form = Bauplan (structural plan/design): structure and function • Symmetry • Asymmetrical – sponges, amoebas • Radially symmetrical – sea anemones • Biradial (ctenophores) • Pentaradial (most echinoderms) • Quadriradial (jellyfish) • Bilaterally symmetrical –human, crayfish

  5. Asymmetry and Symmetry

  6. Radial symmetry

  7. Biradial Symmetry Ctenophores

  8. Controlled mobility &

  9. Dorsal Dorsal Frontal section Caudal Medial Sagittal section Frontal section Posterior Lateral Anterior Cephalic Cross (or transverse) section Ventral Ventral Front View Lateral View Bilateral symmetry

  10. How to get BIG • Nervous system and sense organs • Sense organs • Tactile • Georeceptors • Proprioceptors • Phonoreceptors • Baroreceptors • Chemoreceptors • Photoreceptors • Thermoreceptors • Hormones and pheromones – chemical communication

  11. How to get BIG • Locomotion and support • Four locomotor patterns • Amoeboid movement • Ciliary and flagellar movement • Hydrostatic propulsion • Locomotor limb movement • Three basic support systems • Structural endoskeletons • Structural exoskeletons • Hydrostatic skeletons

  12. How to get BIG • Animals in water have to do with its viscosity and its flow • If you are large, viscosity is less important in terms of the animal’s energy output, but intertia becomes a problem. Like an oil tanker. • Tough to start up and tough to stop • Takes more energy than start/stop for a small animal • Turbulence decreases swimming efficiency • Inertia keeps you moving for a while

  13. How to get BIG • If you are small, turbulence and inertia are not important, but viscosity is. • Small animals are moving in the equivalent of a human swimming in liquid tar or molasses. • If cilia or flagella stop, the animal stops immediately. No inertia. • No turbulence involved • These small animals spend a huge amount of energy to swim through water.

  14. How to get BIG • Feeding Mechanisms • Intracellular digestion • Phagocytosis • Pinocytosis • Extracellular • Takes place in a digestive tract • Incomplete gut • Only one opening • Complete gut • 2 openings: mouth and anus • Herbivores – long guts • Carnivores – short gut

  15. How to get BIG • Feeding strategies • Suspension feeding • Filter feeding (not too many true filterers) • Deposit-feeding • Swallow sediment • Digest organic material • Unusable material passes out via anus • Herbivory • Scrapers • Chewers

  16. How to get BIG • Feeding strategies • Carnivory and scavenging • Stalkers – Didinium, octopus • Ambush predators (sit and wait) – spiders • Sessile opportunists - barnacles • Grazers – crabs and shrimp • Cannibalism = intraspecific predation • Chemoautotrophy – hydrothermal vent tube worms • Absorption of dissolved organic matter • Across body wall and gills

  17. Body Plans • The sac-like body plan • Has only one opening for both food intake and waste removal. • No tissue specialization • Noorgans • Two Types • Polyp • Medusa

  18. Body Plans • “Tube Within a Tube” • Gut forms one tube with two openings • Mouth and anus • Gut tube lies inside the other tubular space called the coelom. • Contains the other internal organs • Animals with this plan are 10% more efficient at digesting and absorbing their food than animals with the sac-like body plan.

  19. Body Cavity

  20. Ectoderm Ectoderm Developing mesoderm Presumptive mesoderm Blastopore Enterocoelic pouch Endoderm Ectdoderm Two ways to make a coelom Mesoderm Endoderm Gut Ectoderm Ectoderm Developing coelom (Schizocoel) Endoderm Mesoderm Gut Coelom (Enterocoel) Gut Schizocoely- characteristic of protostomes Enterocoely characteristic of deuterostomes

  21. Coelom Gut Mesoderm Endoderm Mesentery Epidermis (ectoderm) Coelom Muscle layer (mesoderm) Peritoneum (mesoderm) Gut Schizocoely Enterocoely

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