Presentation on theme: "SZ3: Compare form and function relationships within the Phylum Rotifera ZOOLOGY JAN 6 TH WARM UP: COMPLETE LEARNING STYLES QUIZ (RECORD YOUR RESULTS ON."— Presentation transcript:
SZ3: Compare form and function relationships within the Phylum Rotifera ZOOLOGY JAN 6 TH WARM UP: COMPLETE LEARNING STYLES QUIZ (RECORD YOUR RESULTS ON THE LAST PAGE AND TURN IN) CLASS PROCEDURES REVISITED CLASSWORK: READ ARTICLE TOGETHER AND DISCUSS WATCH VIDEO; WORK ON CHART. CLOSING: LIST 3 THINGS YOU NEED TO IMPROVE ON FOR THIS CLASS; LIST 2 THINGS I CAN IMPROVE ON FOR THIS CLASS; LIST 1 THING THE CLASS COULD IMPROVE ON
Welcome to the Wonderful, Weird World of Rotifers http://www.microscopy- uk.org.uk/mag/indexmag.html?http://www.micr oscopy-uk.org.uk/mag/artnov99/rotih.html http://www.microscopy- uk.org.uk/mag/indexmag.html?http://www.micr oscopy-uk.org.uk/mag/artnov99/rotih.html
The Pseudocoelomate Body Plan: Aschelminthes Chapter 11
SZ3: Compare form and function relationships within the Phylum Rotifera ZOOLOGY JAN 7 TH WARM UP: Get a textbook and open to page 177. On your handout, list the 7 characteristics of the phylum Rotifera: CLASSWORK: Power point notes on Rotifera CLOSING: Vocabulary from powerpoint
Aschelminthes Characteristics – First animal to posses a body cavity – Pseudocoelom Distinct body cavity with no peritoneal lining and mesenteries. Visceral (internal) organs lie free in the cavity
A pseudocoelom – Is a body cavity derived from the blastocoel, rather than from mesoderm Pseudocoelom Muscle layer (from mesoderm) Body covering (from ectoderm) Digestive tract (from ectoderm) Pseudocoelomates such as nematodes have a body cavity only partially lined by tissue derived from mesoderm.
Characteristics Pseudocoelom – acts as an internal hydrostatic skeleton that functions in locomotion
Characteristics Most have a complete tubular digestive tract (mouth-anus) First time mechanical breakdown of food, digestion, absorption, and feces formation
Characteristics Show eutely – same number of cells for each animal and for each given organ in all the animals of the species Ex. Caenorhabditis elegans (a type of nematode) has 959 cells Every worm in the species has 80 cells in their pharnyx
Characteristics – Triploblastic – Most are dioecious – No separate gas exchanges – Some cephalization is present – Cuticle present – may bear spines or scales and is useful for protection and taxonomic identification
Phylum Rotifera Small animals 0.1-3 mm Most abundant in freshwater About 1,000 cells (3 classes) and organs are eutelic
Phylum Rotifera All have a Corona (crown)- ciliated organ for locomotion and food gathering
Phylum Rotifera Posterior toes and adhesive glands called: Pedal glandS- secretions aid in temporary attachment of foot to a substratum.
Feeding and Digestion Feed on small microorganisms and organic material Coronal cilia brings food to mouth Food enters the Pharynx that contains a muscular organ that grinds food called Mastax
Feeding and Digestion Then food passes through a ciliated Esophagus to the ciliated Stomach-complete extracellular digestion and absorption of food occurs.
Feeding and Digestion Some species have ciliated Intestine that becomes Cloacal bladder- receives water from the protonephridia, eggs from ovaries, and digestive waste. Cloacal bladder opens to the outside via an Anus
Reproduction and Development Some reproduce sexually Many reproduce by parthenogenesis- a type of reproduction in which females produce offspring from unfertilized eggs
Reproduction and Development Females Germovitellarium- ovary and vitellarium fuse and produce eggs Males Single testis Eversible penis-injects sperm into the pseudocoelom of female (hypodermic impregnation)
Divided into 3 classes: Reproduction and Development class order
Class Monogononta Females produce two kinds of eggs: – Amictic eggs- diploid eggs that have not undergone reduction division, cannot be fertilized & develop only into females.
Class Monogononta – Mictic eggs- undergone meiosis and are haploid- if: Unfertilized- develop quickly into males Fertilized- they secrete a thick shell and become dormant for several months before developing into amictic females.
Phylum Nematoda External features Noncellular, collagenous cuticle – Can molt 4 times during maturation – Maintains internal hydrostatic pressure – Mechanical protection – Resists digestion by the host
Phylum Nematoda Longitudinal muscles are used for locomotion – Thrashing movements (can’t crawl like worms)
Phylum Nematoda Sensory organs – Amphids – chemoreceptors along the cuticle – Phasmids - chemoreceptors near the anus – Ocelli – eyespots found in aquatic nematodes
Feeding and Digestive System Carnivores, herbivores, omnivores, saprobes(decomposers), or parasitic Complete digestive system mouth->buccal cavity->pharynx ->tubular intestine->rectum->anus Hydrostatic pressure pushes food thru
Other Organ Systems Glandular system – Aquatic nematodes – Renettes – absorb nitrogenous waste Tubular system – Parasitic nematodes – Renettes form a canal
Other Organ Systems Nervous system – Nerve ring from anterior to posterior – Also have neuroendocrine secretions involved in growth, molting, cuticle formation, and metamorphisis
Reproduction Sexual – Dioecious-having separate sexes – Dimorphic-males are smaller than females – internal fertilization
Reproduction – Males » One testis » Bursa- used to insert their sperm into the female » males have ameboid sperm
Reproduction – Females » Pair of convoluted ovaries » Oviducts become uterus » Several hundred to several hundred- thousand eggs per day » Ovovivparity – giving birth to larvae that hatched from an egg
Some Important Nematode Parasites of Humans Ascaris lumbricoides Enterobius vermicularis Necator americanus Trichinella spiralis Wuchereria bancrofti
Ascaris lumbricoides The Giant Intestinal Roundworm- The adult female worm can be over 30 cm long and 2-6 mm wide 800 million infected- most common parasitic worm disease in the world
Ascaris lumbricoides Adults live in small intestines of humans Eggs exit with through feces Once the eggs are ingested, they hatch in intestine and travel to the lungs Larvae molt twice, they travel to the trachea where they are swallowed
Trichinella spiralis Humans become infected by eating improperly cooked pork products Larvae encyst in stomach move to small intestine molt 4 times, turn into Adults
Wuchereria bancrofti The Filarial worms In tropical countries over 250 million human infected
Wuchereria bancrofti Thread-like worms that live in the Lymphatic System, block the vessels This causes enlargement of various appendages: Elephantiasis An Adult female Wuchereria bancrofti is about 80-100 mm long and 0.24-0.30 mm in diameter, whereas a male is about 40 mm long and 0.1 mm in diameter.
Elephantiasis Warning: Pictures not for everyone!
Wuchereria bancrofti Adults copulate produce microfilariae. The microfilariae released into the blood stream A microfilaria is about 240-300 µm (micrometers) long and 7.5-10 µm thick
Wuchereria bancrofti Mosquito ( intermediate host) feeds on human ( definitive host) ingest microfilariae and larvae molts 2 times Mosquito bites another human it injects 3 rd stage larvae into human blood, molts, enters lymphatic system