Transcript Notes
Dissection SPONGE HYDRA Phylum: Porifera Classified as an animal because they are multicellular, hetertrophic, have no cell walls and contain no specialized cells Body Plan assemmitrical Feeding Filter feeding Respiration Diffusion Circulation diffusion Reproduction Asexually/sexually Response No nervous system Sponge osculum - a large opening in a sponge through which water flows out of the sponge. Sponges may have more than one oscula. spicule - spicules are sharp spikes (made of calcium carbonate) located in the mesohyl. Spicules form the "skeleton" of many sponges. porocyte - cells with pores that allow water into the sponge; they are located all over the sponge's body. epidermis (pinacocyte) - the epidermis is the layer of cells that covers the outer surface of the sponge. The thin, flattened cells of the epidermis are called pinacocytes. flagellum - the whip-like structure of a choanocyte; the flagellum moves, pushing water (which contains nourishment) through the sponge. Phylum: Cnidarian Soft bodied, carnivorous animals that have stinging tentacles arranges in circles around their mouths. They are the simplest animals to have body symmetry and specialized tissues Body Plan radial Feeding diffusion Gastrovascular cavity Respiration Diffusion Circulation Reproduction external Response Specialized sensory cells HYDRA hydrozoa have a single distinct mouth which also serves as their anus, where waste is released, internal stomach-like cavity,specialized to digest prey. Stinging cells, nematocysts, are located in the arms". Hydrozoan movement is coordinated by a network of cells, known as a nerve net, that acts to regulate contractile muscle cells. Together the nerve net and muscles cells generate coordinated movements. There is no central brain, which in its simplest form is just a dense mass of nerve cells. Nevertheless, a hydra can displays movement complicated enough to capture and engulf small fish! Phylum: Annelid Worms with segmented bodies. They have a true coelom that is lined with mesoderm Body Plan bilateral Excretory Gills nephridia Feeding Pharynx pumps food Respiration Circulation closed Reproduction Sexually (clitellum) into esophagus, then Response moves into crop, where Nervous system stored and finally into gizzard where gound into smaller pieces External Internal Earthworm muscular pharynx (food ingestion). followed by a tube-like esophagus which terminates in a crop (the wider organ) which serves as a storage stomach. Posterior to the crop you will find the gizzard. While the crop is soft and thin, the gizzard is muscular (soil is ground up and churned within the gizzard). The gizzard is followed by a long intestine in which digestion and absorption occur HYDROSTATIC SKELETON The muscles in the body wall do not have anything firm to attach to. However as the body is fluid-filled and has a limited volume the muscles can deform either the whole body, or segments of the body by contracting the circular and longitudinal muscles alternately. In the earthworm each segment is an independent compartment. That is why it is still able to move off even when cut in half. Reproduction: Although each earthworm is hermaphroditic (having both male and female reproductive systems), it takes two worms to mate and reproduce. The reproductive organs are in the clitellum (the enlarged segments in the middle of an earthworm). The clitellum later forms a cocoon which protects the developing eggs. Phylum: Arthropoda Crustaceans typically have two pairs of branched antennae, two or three body sections, and chewing mouthparts called mandibles Body Plan bilateral Excretation Open system Malpighian tubes Feeding Circulation Reproduction internal Response Gastrovascular cavity Well developed Respiration Spiracles nervous system brain External Internal Crayfish Carapace - The protective shell (exoskeleton) of the cephalothorax Cheliped - One of two big claws used for defense and food handling. Swimmerets - Five pairs of short appendages on the abdomen; they are used for swimming. Uropods - Two pairs of appendages on the tail fan that surround the telson Long antennae - Two long, sensory organs towards the front of the crayfish. Short antennae - Two short antennae, also called antennules. This crustacean has a hard exoskeleton that protects and supports the body 8 jointed walking legs, a segmented body, 2 pairs of sensory antennae, and compound eyes If a crayfish loses a leg, the leg will regenerate (regrow) Using gills, a crayfish breathes oxygen that is dissolved in water Phylum: Chordata An amphibian is a vertebrate that, with some exceptions, lives in water as a larva and on land as an adult, breathes with lungs as an adult, has moist skin that contains mucus glands, and lacks scales and claws. Body Plan Closed, double loop Excretory 3 chambers Feeding Mouth to anus Circulation bilateral rkidneys Reproduction external Response Respiration Well developed nervous Lungs and sensory system External Internal Frog The frog heart is the only organ contained within the coelom which has its own protective covering The frog does not breathe through its skin alone. Adult frogs have paired, simple, saclike lungs. Food passes from the frog's mouth into the stomach by way of the esophagus. From the stomach, the food moves into the small intestine, where most of the digestion occurs. Large digestive glands, the liver and the pancreas, are attached to the digestive system by ducts. A gall bladder is also present (see Digestive System). Liquid wastes from the kidneys travel by way of the ureters to the urinary bladder. Solid wastes from the large intestine pass into the cloaca. Both liquid and solid waste material leave the body by way of the cloaca and the cloacal vent. Frog The frog has a highly developed nervous system. It consists of a brain, a spinal cord, and nerves The cerebrum is very small in the frog. By comparison the human cerebrum is very large. In man the cerebrum is involved in many important life processes. THE END