Transcript WORMS!
WORMS, WORMS, AND MORE WORMS June 2, 2016 Flatworms Classification Kingdom: Animalia Phylum: Platyhelminthes Basic Characteristics 1. 2. 3. 4. Flatworms are the simplest of the worm groups. There are about 20,000 species in this group. They are found many places and can be free living or parasitic. Show cephalization Basic Characteristics (cont.) 5. 6. One of the best-known flatworms is the tapeworm. The tapeworm can get into a person's digestive tract and grow to enormous lengths. Flatworms are found in marine and fresh water. FYI: Longest Tapeworm to be pulled out of a human was 37 feet long Flatworm Systems Body Cavity Acoelomate Combo digestive & excretory Gastrovascular cavity Takes food in and gets rid of wastes through same opening Muscular-Skeletal No skeleton Tiny bristles called cilia that help it move 2 layers of muscles under its skin 3 cell layers (endoderm, mesoderm, and ectoderm) Digestive Nervous Simple nervous system with 2 nerve cords running down either side 2 simple brains called ganglia, which are simple bundles of nerves 2eyespots that help it sense light Flatworm Systems (cont.) Circulation Respiration Fluid in body acts like a primitive circulatory system Takes in oxygen, but has no formal system Reproduction Sexually: simultaneous fertilization Asexually: Reproduces by splitting in two. When it splits up, it immediately forms a new flatworm. Flatworm Systems (cont.) Excretion Gets rid of wastes through the same opening it takes in food Flame cells function like a kidney, removing waste materials Symmetry Bilateral symmetry Appearance Can be microscopic or many feet long and is generally very thin Roundworms Classification Kingdom: Animalia Phylum: Nematoda Basic Characteristics 1. 2. 3. 4. 5. More advanced than flatworms but less advanced than earthworms. They have thin round bodies, without pieces or segments. Roundworms live in salt water, fresh water, & the soil. Many of them are harmful to man as they are parasites. Examples: hookworm, pinworm, & trichinella are part of this group. Roundworm Systems Body Cavity Muscular-Skeletal Pseudocoelomate No skeleton Digestive Definite digestive system that runs the length of their bodies Has mouth, pharynx, intestine, & anus Many are parasites & live off other animals & plants Nervous 2 nerve cords that transmit impulses in the roundworm Roundworm Systems (cont.) Circulation Respiration Has no heart or formal blood vessels Takes in oxygen, but has no formal system Reproduction Sexually Female: has ovary, holds eggs in an oviduct, & then into uterus, where fertilized Male: has sperm cells are made in the testis & stored in vas deferens Roundworm Systems (cont.) Excretion Has an anus at its rear end & a series of excretory tubes that end in an excretory pore Symmetry Bilateral symmetry Appearance Thin, round, smooth and can be up to four feet in length Segmented Worms Classification Kingdom: Animalia Phylum: Annelida Basic Characteristics 1. 2. 3. 4. 5. Earthworms are the most highly developed worms. They are divided into segments or parts. They are found in salt and fresh water as well as in the soil. Earthworms are helpful to man as bait for fishing and more importantly, because they loosen the soil for roots to grow. There are 2700 species of earthworms. Segmented Worm Systems Body Cavity Coelomate Muscular-Skeletal No skeleton Bristles on each segment called setae that help it move 2 sets of muscles; 1 that makes it long & thin and 1 that makes it shorter & fatter Segmented Worm Systems Digestive Eats dirt, digesting the plant and animal matter in the dirt and then eliminates the rest Esophagus for the food to go down Crop to store the food in Gizzard that grinds the food down Intestines for the food to pass through and take out nutrients Anus for the food to come out Segmented Worm Systems (cont.) Nervous Simple brain & ventral nerve cord Circulation Blood & blood vessels with multiple (5) hearts Respiration No formal system Takes in O2 directly through skin & gives off CO2 Skin is always moist Segmented Worm Systems (cont.) Reproduction Has both sperm & eggs within its body Eggs must be fertilized by the sperm of another worm Sexual: Excretion Waste helps to fertilize soil Gets rid of wastes through tubes called nephridia that lead to pores that allow the wastes out Symmetry Bilateral Appearance Earth-tone colors Can be up to 8 ft long