Biology 203 1st Edition Lecture 20 Outline of Last Lecture I. Animal Support and TransportII. SpiculesIII. Hydrostatic SkeletonIV. ExoskeletonsV. EndoskeletonsVI. CartilageVII. BoneVIII. Aquatic AnimalsOutline of Current Lecture I. Animals are HeterotrophicII. How do animals find food?III. Handling FoodIV. Digestion and uptake of consumed foodV. Gut MorphologyVI. FrogsCurrent LectureI. Animals are Heterotrophica. Animals depend on already synthesized organic compounds from plants or other animalsb. Food is important for:i. Energy-yielding compounds for immediate and later use (Carbohydrates, lipids, protein)ii. Amino acids for synthesis of into structural and metabolic proteinsiii. Other compounds like vitamins that are used as catalysts or in other biochemical reactionsc. Size matters and good nutrition allows for larger sizei. Selective advantages for increased sizeii. Differential reproductive output – bigger mother = more offspring or larger offspringiii. Differential survival – larger individuals often are more difficult for predators to capture and outcompete smaller individuals for shared resourcesd. Food – for most animals it is limitingThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.II. How do animals find food?a. Host detection b parasitesi. Peremones/chemical detectionii. Components of human sweat stimulate mosquito activityb. Adaptations for capturing food:i. Styletii. Mandiblesiii. Radulaiv. Filtering structuresv. Farmingc. Carnivore adaptions for acquiring foodi. Physically overpower preyii. Venomiii. Overwhelm smaller prey organismsd. Parasites – structures used in food acquisitioni. Tegumentii. “Teeth”iii. HupostomeIII. Handling Fooda. You can be amazing at finding and capturing food but if you can’t keep a hold of it long enough to eat it, why waste the energy?b. Protect your foodIV. Digestion and uptake of consumed fooda. Digestion – the mechanical and chemical breakdown of organic food into small units for absorptionb. Food solids can be carbohydrates, proteins and fatsc. Assimilation – the absorption of digested nutrients for use in the cellsd. Intracellular Digestioni. Among heterotrophic unicellular eukaryotes and sponges digestion is intracellularii. Food particles are taken into vacuoles through phagocytosisiii. Digestive enzymes delivered by lysosomesiv. Waste is released by exocytosisv. Limitations1. Only small particles can be phagocytized2. Each cell must be capable of secreting all necessary enzymese. Absorption and Surface Areai. Sponges – increased pockets and invaginations lined with choanocytes = small particles digested intracellularii. Radiates – coelenteron/gastrovascular cavity with mesenterial filaments =‘ridges’ to enhance uptakef. Benefits of a digestive system with 2 openings that digests extracellularlyi. Can consume more than one prey at a timeii. More areas for processingiii. These specializations could include differential chemical, mechanical and microbial zonesiv. Can absorb more diversity of food, proteins, carbohydrates, fats. v. Problem - now you need a separate respiratory systemV. Gut Morphologya. Regions of a generalized invertebrate guti. In more complex animals, much of the digestion proceeds via enzymes secreted into the lumen of the gut and the products of digestion are then absorbed by the cells of the gut wall. ii. 3 developmental regions:1. Anterior fore-gut (ectodermal origin)2. Posterior hind-gut (ectodermal)3. Absorptive mid-gut (endodermal)b. Length and Specialization (Herbivores)i. Gut modificationsii. Elongated hindgut to increase surface area of absorptioniii. Valves present to slow passage and increase surface areaiv. Extremely complex in mammalsv. Rumen present in mostvi. Enlarged colonc. Ruminantsi. Rumen: ‘An anaerobic, fermentation vat’ii. It can generate 30-50 liters of CH4/hour!iii. Reticulum: receives smaller material for further breakdowniv. Serves as a reservoir for ‘cud’v. Omasum: Not well understood – absorbance of fatty acids and bicarbonatevi. Undulations likely help to breakdown food before moving to the abomasumvii. Abomasum: “true glandular stomach” – acidic, but specialized for processing bacteria (lysozyme breaks down bacterial cell walls)d. Non-Ruminantsi. Ceacum: site of bacterial fermentationii. Most of the nutrient absorption takes place posterior to the small intestine, much of the nutrients are not absorbed and pass in the fecesiii. Coprophagy: Rabbits and many rodents eat their fecal pellets and give their food a second pass to extract additional nutrientse. Gut Florai. Symbiotic bacteria and protists break down cellulose and other indigestible materials1. From snails to mammals2. Passed to juveniles through fecal consumptionii. Diversity in the gut flora1. Snails: 10-12 species2. Termites: 100 species3. Cows: Likely 1000s species4. Only 30 microbes have been studied in detailiii. Omnivores1. 1 x 1014 microbes2. 400-500 species in the intestine alone3. Breakdown items that have not been digested4. Products include vitamins5. Microbial barrier and immune primingf. Length and Specialization – Carnivoresi. Meat is digested more efficiently than plant materialii. Digestive efficiencies are 80% - 95%iii. Dependent on prey type iv. Carnivores – expend energy acquiring animals, but:v. Reward is high quality foodvi. Gut of a carnivore is typically shorter and less complex than those of herbivoresVI. Frogsa. Transition from herbivore to carnivoreb. Head shape changesc. Gut changesi. Extremely long intestines as tadpolesii. Shrinkage of intestine during