Pseudocoelomates-ta - Business   Quiz  ...

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Unformatted text preview: Business   Quiz   Presentations   Psuedocoelomate notes   Lab exercise: dissection! 1. Classifica/on   Kingdom ­ Animalia   Phylum ­ Nematoda (ex. roundworms)   Sometimes also known as Phylum Nemata   parasitize almost every type of plant and animal! 2. Organiza/on: organ level 3. Embryonic development   eutely cell consistency   each individual of a species has exactly the same number of cells as any other individual from that species   growth occurs by cells getting bigger not dividing 3. Embryonic Development   triploblastic (3 germ layers)   Pseudocoelomate   Pseudocoelom= false coelom         fluid ­filled body cavity, lined by mesenchyme on the outside and gut on the inside Has incomplete mesodermal lining (eucoelomates have complete) location & support for reproductive and excretory organs gives organs space to enlarge/grow/expand   pseudocoel derived from blastocoel   Fate of blastocoel: PERSISTS! 4. Symmetry: bilateral 5. Skeleton/Support   hydrostatic skeleton   Cuticle = primitive skeleton 6. Locomo/on/Movement   longitudinal muscles only whip like movement   NO muscles around the gut body motion moves food through gut   OBSERVE movement of live Nematoda TODAY! 7. Sensory/Nervous System   cerebral ganglion   dorsal/ventral nerve cords   Papillae (sensory pits) 8. Feeding/Diges/on   Complete gut   Regional specialization!   mouthtri ­lobed esophagus intestine rectum anus   Parasites or free ­living 9. Excretory System Rrenette glands and/or tubular canal system   Lack flame cells 10. Circulatory System   open (pseudocoelom) 11. Respira/on   Diffusion across epidermis 12. Reproduc/on   mostly dioecious   sexual dimorphism   male is smaller and has a curl/hook in tail   NO CILLIA OR FLAGELLA IN NEMATODA   sperm are ameboid crawl to egg   Characteristics of parasites? Nematoda   Live in marine, freshwater, and terrestrial habitats, from polar regions to the tropics, from mountaintops to the depths of the sea   Extremely densely populated – a handful of topsoil may contain thousands of nematodes   Over 50 species found in humans   Female Ascaris may lay 200,000 eggs a day 1. Classifica/on   K: Animalia   P: Rotifera   *only highlighting differences from Nematoda 6. Movement/Locomo/on   Corona   crown of cilia and cirri (*diagnostic characteristic*)   pedal glands/spurs: used for attachment   Circular and longitudinal muscles 7. Sensory   ocelli 8. Feeding/Diges/on   complete; extracellular   feeding currents (corona); suspension feeder   mastax (pharynx) and trophi ( jaws) ­ *diagnostic internal feeding aparatus 9. Excretory System   protonephridia 12. Reproduc/on   BOTH sexual AND asexual   parthenogenesis (amictic cycle; males NOT necessary):   females produce new females from diploid (2n) eggs made via mitosis   Mictic Cycle (environmental stimulus e.g. drought):   females produce haploid (n) eggs via meiosis   unfertilized eggs become haploid males (develop quickly, no gut, short life span)   these haploid males mate with existing females   fertilized eggs become diploid cryptobiotic eggs   cryptobiotic eggs develop into diploid females once environmental conditions are favorable Interes/ng fact about ro/fers   Many species can endure long periods of dessication   Some species found in moss have survived up to 4 years of drought   Some species have been revived after enduring  ­272 C temperatures Phylum Nematoda Preserved Nematodes: (various jars) n/a 1. Vinegar eels: why do they move like that? Slides: 1. Ascaris esophagus c.s. Fig. 5.4 (cuticle, trilobed esophogus, pseudocoel, longitudinal muscle) 2. Ascaris male c.s. BOOK p224 (longitudinal muscles, pseudocoel, intestine, seminal vesicle, testes, vas deferens) 3. Ascaris female c.s. BOOK p224 (ovaries, longitudinal muscles, pseudocoel, uterus, eggs, oviduct, intestine) Other Slides: 1. Trichinella spiralis (encysted larvae) 2. Anclyostoma caninum w.m. Dissections: 1. Male Ascaris Fig. 5.2 (intestine, seminal vesicle, testes, hook, spicule, anterior vs posterior) 2. Female Ascaris (ovaries, oviduct, uterus, intestine, anterior vs. posterior) Phylum Rotifera Wet mount: live Rotifers Slide: Rotifer w.m. Fig. 5.5 (mastax, cirri, corona, head, trunk, foot, spurs) ...
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