Resources gathered by animalsAnimals are Heterotrophs Plants are AutotrophsSome Animals obtain their food symbioticallyAnnelida: Vestimentifera – Thermal vent tube wormsHomeostatic mechanisms manage an animal’s fuelAn animal’s diet must supply essential nutrients and carbon skeletons for biosynthesisThe four main stages of food processing are ingestion, digestion, absorption, and eliminationDigestion occurs in specialized compartmentsSome animals use external digestion for the initial stages of digestionAnimals feed on a variety of biological materialsChaetognatha – arrow worm – planktonic marine predatorStar Fish – predator with eversible stomachAnimals use a diverse variety of adaptations for feedingPolychaeta – fan worm – a filter feederPredators use different tactics to obtain preyParasites may be internal, external, or “parasitoids”WaterEnemy Free SpaceMollusca - ShellsGastropoda - spinesFeeding from defensive structuresChemical exudatesChemical ExudatesFeeding at nightWarning colorationCrypsisMimicryMimicryFeeding commensally with a predatorShelterSpaceSpaceAcquiring Thermal Energy by BaskingChemicals for signaling and defensePharmacophagy in Comosoma myodoraSummaryResources gathered by animals• Food for energy and macromolecules• Water • Shelter from enemies (Enemy Free Space) • Space • Thermal energy• Chemicals used for signalingAnimals are Heterotrophs Plants are Autotrophs• Heterotrophs are incapable of producing their own energy as plants do via photosynthesis• Heterotrophs must consume food that contains energy, and both organic and inorganic chemical nutrientsSome Animals obtain their food symbiotically• Corals, and some sponges and jellyfish contain symbiotic algae that photosynthesize and transfer energy to their coral hosts in exchange for certain nutrients• Thermal vent worms (Annelida: Vestimentifera) obtain most of their nutrients from symbiotic bacteria in exchange for H2S and CO2that they absorb from the water • Some beetles (ambrosia) transport, farm, and consume fungi to obtain most of their nutrients and energy • No animals can obtain all their energy without transfer from or consumption of other organismsAnnelida: Vestimentifera –Thermal vent tube worms• For any animal, a nutritionally adequate diet is essential for homeostasis, a steady-state balance in body functions.– A balanced diet provides fuel for cellular work and the materials needed to construct organic molecules.•A nutritionally adequate diet satisfies three needs:–fuel (chemical energy) for all the cellular work of the body; –the organic raw materials animals use in biosynthesis (carbon skeletons to make many of their own molecules);–essential nutrients, substances that the animals cannot make foritself from any raw material and therefore must obtain in food in prefabricated form.Homeostatic mechanisms manage an animal’s fuel• The flow of food energy into and out of an animal can be viewed as a “budget,” with the production of ATP accounting for the largest fraction by far of the energy budget of most animals.– ATP powers basal or resting metabolism, as well as activity, and, in endothermic animals, temperature regulation. However, most invertebrates are ectothermic – their body temperatures conform to the ambient temperature of their environment• Nearly all ATP is derived from oxidation of organic fuel molecules - carbohydrates, proteins, and fats - in cellular respiration.– The monomers of any of these substances can be used as fuel, though priority is usually given to carbohydrates and fats.– Fats are especially rich in energy, containing twice the energy of an equal amount of carbohydrate or protein.•When an animal takes in more calories than it needs to produce ATP, the excess can be used for biosynthesis.–This biosynthesis can be used to grow in size or for reproduction, or can be stored in energy depots.An animal’s diet must supply essential nutrients and carbon skeletons for biosynthesis• In addition to fuel for ATP production, an animal’s diet must supply all the raw materials for biosynthesis.– This requires organic precursors (carbon skeletons) from its food.– Given a source of organic carbon (such as sugar) and a source of organic nitrogen (usually in amino acids from the digestion of proteins), animals can fabricate a great variety of organic molecules - carbohydrates, proteins, and lipids.• Besides fuel and carbon skeletons, an animal’s diet must also supply essential nutrients.– These are materials that must be obtained in preassembled form because the animal’s cells cannot make them from any raw material.– Some materials are essential for all animals, but others are needed only by certain species.• For example, ascorbic acid (vitamin C) is an essential nutrient for humans and other primates, guinea pigs, and some birds and snakes, but not for most other animals.• Animals require 20 amino acids to make proteins.• Most animals can synthesize half of these if their diet includes organic nitrogen.• Essential amino acids must be obtained from food in prefabricated form.– Eight amino acids are essential in the adult human with a ninth, histidine, essential for infants.– The same amino acids are essential for most animals.• While animals can synthesize most of the fatty acids they need, they cannot synthesize essential fatty acids.– These are certain unsaturated fatty acids, including linoleic acids required by humans.– Most diets furnish ample quantities of essential fatty acids, and thus deficiencies are rare.• Minerals are simple inorganic nutrients, usually required in small amounts.– Mineral requirements vary with animal species.– Humans and other vertebrates require relatively large quantities of calcium and phosphorus for the construction and maintenance of bone among other uses.– Iron is a component of the cytochromes that function in cellular respiration and of hemoglobin, the oxygen binding protein of red blood cells.The four main stages of food processing are ingestion, digestion, absorption, and elimination• Ingestion, the act of eating, is only the first stage of food processing.– Food is “packaged” in bulk form and contains very complex arrays of molecules, including large polymers and various substances that may be difficult to process or may even be toxic.• Animals cannot use macromolecules like proteins, fats, and carbohydrates in