P H Y L U M P L A T Y H E L M I N T H E S ( F L A T W O R M S ! ) Diana Luo Hong Joo Kim Carrie Yang...
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Transcript of P H Y L U M P L A T Y H E L M I N T H E S ( F L A T W O R M S ! ) Diana Luo Hong Joo Kim Carrie Yang...
PHYL
UM P
LATYH
ELM
INTH
ES
(“FL
AT W
ORM
S!”)
Diana Luo
Hong Joo Kim
Carrie Yang
Period 5
http://clean-water.uwex.edu/pubs/clipart/critters.plan.htm
Hello!
CLASSES OF FLATWORMS (TURBELLARIA)
Most are marine organisms, some are freshwater
All are free-living organisms Feeds on smaller animals, dead animals Dugesia “planarians” (about 4,500 species)
http://www.thaigoodview.com/library/contest2551/science04/119/kingdon_animalia/Class%20Turbellaria.htm
Diana Luo, Hong Joo Kim, Carrie Yang
CLASSES OF FLATWORMS (MONOGENEA)
Marine and freshwater parasites
Most are external parasites of fish
Relatively simple life cycle
Monogeneans (about 1,100 species)
http://simple.wikipedia.org/wiki/Monogenea
Diana Luo, Hong Joo Kim, Carrie Yang
CLASSES OF FLATWORMS (TREMATODA)
Suckers for attaching to internal organs or outer surfaces of the host
Many require an intermediate host in which larvae develop
Trematodes, flukes (about 11,000 species)
http://biodidac.bio.uottawa.ca/thumbnails/filedet.htm?File_name=Trem054p&File_type=gif Diana Luo, Hong Joo Kim, Carrie Yang
CLASSES OF FLATWORMS (CESTODA)
Live mostly inside vertebrates & are parasites
Flat, slender, long bodies
Scolex – suckers + hooks
Tapeworms (3,400 species)
http://faculty.clintoncc.suny.edu/faculty/Michael.Gregory/files/Bio%20102/Bio%20102%20Laboratory/Animal%20Diversity/Lophotrochozoans/Lophotrochozoans.htm
Diana Luo, Hong Joo Kim, Carrie Yang
BODY SYMMETRY…& BODY CAVITY?
BILATERAL symmetry (identical shape on either side)
Unlike other bilaterians, flatworms do NOT have body cavity between the digestive cavity and outer body wall.
http://www.cartage.org.lb/en/themes/sciences/zoology/biologicaldiverstity/AnimalsI/AnimalsI.htm
Diana Luo, Hong Joo Kim, Carrie Yang
NERVOUS SYSTEM
Flatworms have a Central Nervous System (CNS) – the brain and the ventral nerve cords
A pair of ganglia is located at the anterior end
http://www.cartage.org.lb/en/themes/sciences/zoology/biologicaldiverstity/AnimalsI/AnimalsI.htm
Diana Luo, Hong Joo Kim, Carrie Yang
SENSORY STRUCTURES/FEATURES Ganglia, or clusters of neurons, present at the anterior
end demonstrates cephalization, trend in which nervous tissue becomes concentrated at one end
A planarian’s head is equipped with a pair of light-sensitive eyespots and lateral flaps that function mainly to detect specific chemicals.
http://kentsimmons.uwinnipeg.ca/16cm05/16labman05/lb5pg5.htm Diana Luo, Hong Joo Kim, Carrie Yang
CIRCULATORY SYSTEM
They have no organs specialized for circulation A muscular pharynx that leads to the digestive
system is present instead
http://kentsimmons.uwinnipeg.ca/16cm05/16labman05/lb5pg5.htm Diana Luo, Hong Joo Kim, Carrie Yang
DIGESTIVE SYSTEM
They have a gastrovascular cavity with only one opening. The many branches of this distribute food throughout the animal
http://kentsimmons.uwinnipeg.ca/16cm05/16labman05/lb5pg5.htm Diana Luo, Hong Joo Kim, Carrie Yang
EXCRETORY SYSTEM
They have a excretory system that eliminates nitrogenous waste (ammonia) by diffusion across the body surface.
Simple excretory apparatus (which consists of ciliated cells called flame bulbs that waft fluid through branched ducts opening to the outside) functions to maintain osmotic balance with their surroundings
Diana Luo, Hong Joo Kim, Carrie Yang
LOCOMOTION/MUSCULATURE
Glide along surfaces on mucus that they secrete Others use muscles to swim through water with
an undulating motion Planarians move by using cilia on their ventral
epidermis
http://www.deepseaimages.com/dsilibrary/showphoto.php?photo=19535&cat=all&limit=all
Diana Luo, Hong Joo Kim, Carrie Yang
SKELETAL TYPE
The interstitial fluid acts as a hydrostatic skeleton – flatworms change the shapes of the fluid-filled compartments to control their overall form and movement
Diana Luo, Hong Joo Kim, Carrie Yanghttp://kentsimmons.uwinnipeg.ca/16cm05/16labman05/lb5pg5.htm
REPRODUCTION (METHODS, TYPES)
Triploblastic development (ectoderm, mesoderm, endoderm)
Planarians can reproduce asexually (through regeneration) or sexually
Tapeworms have proglottids that produce thousands of eggs
Copulating mates cross-fertilize
http://www.tutorvista.com/content/science/science-ii/reproduction/asexual-reproduction.php
Diana Luo, Hong Joo Kim, Carrie Yang
GAS EXCHANGE (HOW, STRUCTURES)
Flat shape places all the cells close to surrounding water gas exchange by diffusion
No organs are specialized for gas exchange Every cell is able to partake in gas exchange
http://kentsimmons.uwinnipeg.ca/16cm05/16labman05/lb5pg5.htm Diana Luo, Hong Joo Kim, Carrie Yang
QUIZ QUESTIONS 1. While of the following have bilateral symmetry?
a. Porifera (Sponges)b. Cnidaria (Jellyfish and Anemones)c. Platyhelminthes (Flatworms)d. Nematoda (Roundworms)
2. What do Annelida (Segmented Worms) have that Platyhelminthes (Flatworms) do not have?a. Bilateral Symmetryb. Body Cavityc. Respiratory Systemd. Nervous System
Diana Luo, Hong Joo Kim, Carrie Yang
QUIZ QUESTIONS 3. What do all of the following have in common:
Platyhelminthes (Flatworms), Arthropoda (Insects and Arachnids), Mollusca (Snails, Clams, and Squids), and Echinodermata (Sea Stars and Sea Urchins)a. Segmentationb. Open Circulatory Systemc. Asexual Reproductiond. Organ System
4. What is the main difference between Platyhelminthes (Flatworms) and Nematoda (Roundworms)?a. A respiratory systemb. Symmetryc. Digestive Systemd. Segmentation
Diana Luo, Hong Joo Kim, Carrie Yang
QUIZ ANSWERS 1. C and D Explanation: Porifera do not have symmetry and Cnidaria have
radial symmetry. 2. B Explanation: Both have bilateral symmetry and nervous systems
(although their nervous systems slightly differ). Neither has a respiratory system.
3. D Explanation: Only the Arthropoda have segmentation. Only Mollusca
and Arthropoda have open circulatory systems. Mollusca and Arthropoda do not undergo asexual reproduction.
4. C Explanation: Platyhelminthes have gastrovascular cavities while
Nematoda have a separate mouth and anus. Neither have a respiratory system or segmentation. Both have bilateral symmetry.
Diana Luo, Hong Joo Kim, Carrie Yang
Interesting videos for further reference: http://www.youtube.com/watch?v=mh2dTIRR
eXU http://www.youtube.com/watch?v=ET1v9-65J
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