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Review What types of food do herbivores eat, What are nutritional symbionts Relate Cause and Effect How might a corral be affected if all its symbiotic algae died Review what are two types of digestion animals use to break down and absorb food
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Review What types of food do herbivores eat, What are nutritional symbionts • Relate Cause and Effect How might a corral be affected if all its symbiotic algae died • Review what are two types of digestion animals use to break down and absorb food • Compare and Contrast What is a major structural difference between gastrovascular cavities and digestive tracts
Ch 27 Animal Systems I 27.1 Feeding and Digestion
Filter Feeders • Catch algae and small animals by using modified gills or other structures as nets that filter food items out of water • Barnacles to blue whales.
Detritivores • Feed on detritus, often obtaining extra nutrients from the bacteria, algae, and other microorganisms that grow on and around it • Earthworms to cleaner shrimp.
Carnivores • Eat other animals • Wolves or orcas • Use teeth, claws, and speed or stealthy hunting tactics to bring down prey • Carnivorous invertebrates • Cnidarians paralyze prey with poison-tipped darts • Spiders immobilize their victims with venomous fangs.
Herbivores • Eat plants or parts of plants • Locusts to cattle • May specialize in eating seeds or fruits.
Symbionts • Organisms involved in a symbiosis.
Parasitic Symbionts • Parasites live within or on a host organism • Feed on tissues or on blood and other body fluids • Can cause serious diseases.
Mutualistic Symbionts • Reef-building corals depend on symbiotic algae that live within their tissues for most of their energy • Algae gain nutrition from the corals’ wastes and protection from algae eaters.
Digest food inside specialized cells that pass nutrients to other cells by diffusion. Intracellular Digestion
Extracellular Digestion • Process in which food is broken down outside cells in a digestive system and is then absorbed • Most common in more complex animals.
Interior body space whose tissues carry out digestive and circulatory functions Single opening through which they both ingest food and expel wastes. Gastrovascular Cavities
Cells lining the gastrovascular cavity secrete enzymes and absorb digested food Other cells surround food particles and digest them in vacuoles Nutrients then transported throughout body.
Digest food in a tube which has two openings Food moves in one direction Entering the body through the mouth Wastes leave through the anus Many invertebrates and all vertebrates. Digestive Tracts
Specialized structures perform different tasks as food passes through them Mouth secretes digestive enzymes that start the chemical digestion of food Specialized mouthparts or a muscular organ called a gizzard breaks food into small pieces. Digestive Tracts
Chemical digestion begins or continues in a stomach that secretes digestive enzymes Chemical breakdown continues in the intestines, sometimes aided by secretions from other organs Intestines also absorb the nutrients released by digestion. Digestive Tracts
Some indigestible material will always be left Solid wastes, or feces, are expelled through the single digestive opening, or anus. Solid Waste Disposal
Have sharp teeth that grab, tear, and slice food like knives and scissors would Jaw bones and muscles are adapted for up-and-down movements that chop meat into small pieces. Eating Meat
Need to tear plant cell walls and expose their contents Mouthparts that grind and pulverize leaf tissues. Eating Plant Leaves
Carnivors typically have short digestive tracts that produce fast-acting, meat-digesting enzymes.
No animal produces digestive enzymes that can break down the cellulose in plant tissue • Cattle have a pouchlike extension of their stomach called a rumen, in which symbiotic bacteria digest cellulose.
Pieces of boiled egg white are placed in a test tube with hydrochloric acid, water, and pepsin (enzyme that digests protein) 1. Describe the trend in the amount of protein digested over time 2. About how many hours did it take for half the protein to be digested 3. How would you expect the rate of meat digestion to differ in an animal that had less pepsin
Ch 27 Animal Systems I 27.2 Respiration
Gas Diffusion and Membranes • Gases diffuse most efficiently across a thin, moist membrane that is permeable to those gases • Larger the surface area membrane, the more diffusion that can occur.
Requirements for Respiration • Large surface area of moist, selectively permeable membrane • Difference in relative concentrations of oxygen and carbon dioxide on either side of the respiratory membrane.
Respiratory Surfaces of Aquatic Animals • Some aquatic invertebrates and a few chordates rely on diffusion of oxygen and carbon dioxide through their outer body covering.
Respiratory Surfaces of Aquatic Animals • Many aquatic invertebrates and most aquatic chordates exchange gases through gills • Gills • Feathery structures that expose a large surface area of thin, selectively permeable membrane to water • Capillaries • Network of tiny, thin-walled blood vessels.
May actively pump water over their gills as blood flows through inside Gas exchange occurs as water passes over the gills. Respiratory Surfaces of Aquatic Animals
Respiratory Surfaces of Aquatic Animals • Lungs • Organs that exchange oxygen and carbon dioxide between blood and air • Aquatic reptiles and aquatic mammals, must hold their breath underwater.
Respiratory Surfaces in Land Invertebrates • Wide variety of respiratory structures • Respire across their skin • Mantle cavity • Book lungs • Tracheal tubes.
Which are made of parallel, sheetlike layers of thin tissues containing blood vessels. Book Lungs
Air enters and leaves the system through openings in the body surface called spiracles Most invertebrates. Tracheal Tubes
Lung structure in terrestrial vertebrates varies Processes of inhaling and exhaling are similar Lung Structure in Vertebrates
Inhaling brings oxygen-rich air through the trachea (airway) into the lungs • Oxygen diffuses into the blood through lung capillaries • Carbon dioxide diffuses out of capillaries into the lungs • Oxygen-poor air is then exhaled.
Typical amphibian lung is little more than a sac with ridges. Amphibian, Reptilian, and Mammalian Lungs
Reptilian lungs are divided into chambers Increase the surface area for gas exchange. Amphibian, Reptilian, and Mammalian Lungs
Mammalian lungs branch extensively Filled with Alveoli. Amphibian, Reptilian, and Mammalian Lungs
Alveoli • Provide enormous surface area for gas exchange • Enable mammals to take in the large amounts of oxygen required by their high metabolic rates.
Bird Lungs • Air flows mostly in only one direction, so no stale air gets trapped in the system • Gas exchange surfaces are continuously in contact with fresh air • Highly efficient • Enables flight, at high altitude for extended time.
Ch 27 Animal Systems I 27.3 Circulation
Heart • Hollow, muscular organ that pumps blood around the body • May have one or more • May be part of either an open or a closed circulatory system.
Blood is only partially contained within a system of blood vessels Arthropods and most mollusks have open circulatory systems. Open Circulatory Systems
One or more hearts or heartlike organs pump blood through vessels Empty into a system of sinuses (spongy cavities) where blood comes into direct contact with body tissues.
Blood then collects in another set of sinuses and makes its way back to the heart.
Blood circulates entirely within blood vessels that extend throughout the body Many larger, more active invertebrates, including annelids and some mollusks, and all vertebrates have closed circulatory systems. Closed Circulatory Systems
Heart or heartlike organ forces blood through vessels Nutrients and oxygen reach body tissues by diffusing across thin walls of capillaries Pumped at higher pressure and circulates more efficiently. Closed Circulatory Systems
Single pump that forces blood around the body in one direction Most vertebrates with gills. Single-Loop Circulation
Atrium Receives blood from the body Ventricle Pumps blood out of the heart and to the gills Oxygen-rich blood travels from the gills to the rest of the body Oxygen-poor blood then returns to the atrium. Single-Loop Circulation
Two-pump circulatory system Most vertebrates that use lungs First loop is powered by one side of the heart Forces oxygen-poor blood from the heart to the lungs. Double-Loop Circulation