Flatworms Roundworms Segmented worms Worms!. Types of Worms Flatworms (Phylum Platyhelminthes) Class...
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Transcript of Flatworms Roundworms Segmented worms Worms!. Types of Worms Flatworms (Phylum Platyhelminthes) Class...
FlatwormsRoundworms
Segmented worms
Worms!
Types of WormsFlatworms (Phylum Platyhelminthes)
Class Turbellaria (Planeria) Class Trematoda and Monogenea (Flukes)Class Cestoda (Tapeworms)
Roundworms (Phylum Nematoda and Rotifera)AscarisHookwormsTrichinellaPinwormsFilarial worms
Segmented worms (Phylum Annelida)Class Oligochaeta (Earthworms)Class Hirundea (Leeches)
Flatworms: Phylum PlatyhelminthesFlatworms are the simplest creatures with
bilateral symmetery.They develop from three germ layers.They do not have a hollow body cavity.Because they are flat, they can exchange oxygen
and CO2 with the environment through diffusion.They have no circulatory or respiratory
systems. They have an incomplete digestive system
consisting of a gut with a single opening.Nerves and sensory organs are located at one
end. This is known as cephalization. Many flatworms are parasites, living on or in
other creatures. Some are not and are found in freshwaters, marine, and terrestrial environments.
Flatworms: Phylum PlatyhelminthesClass Turbellaria:
Includes the Planarians, such as Dugesia species.Feed by scavenging bits of decaying plant and
animal matter.Food is ingested through a muscular tube which is
extended out from the body.How do they get ride of excess water?
Flame cells draw in excess water; water is transport through tubules and excreted through pores.
What are the cerebral ganglia, and what do they do?Simple brain; respond to stimuli and transmit signals
to musclesDescribe two way Planarians reproduce:
SexuallyFertilize each other and lay eggs on rocks or debris
Asexually Worms splits in two by attaching to solid surface
Flatworms: Phylum PlatyhelminthesPlanaria
Flatworms: Phylum PlatyhelminthesClass Trematoda and Monogenea
Consists of parasitic flukes.They can live in the blood, intestines, lungs, liver, or
other organs and are called endoparasites.Ones that live on the outside of their host are called
ectoparasites.How does a fluke stick to its host and what else does
this structure do?Anterior sucker and ventral sucker
Most flukes are hermaphroditic and have a complex life cycle that involves more than one host.
Once disease caused by flukes includes Schistosomiasis which affects more than 200 million people each year in Asia, Africa, and South America.
Flatworms: Phylum Platyhelminthes
Flatworms: Phylum PlatyhelminthesClass Cestoda
Also known as tapeworms, which can live in the intestines of almost all vertebrates.
At the anterior end is a structure known as the scolex. What is its structure and function?Has hooks and suckers that enable the worm to attach
to its host.Behind the scolex are the body segments called
proglottids.What happens to these during reproduction?
They grow in length; become fertilized from another either from same individual or another individual.
How can a human become infected with a taperworm?When they eat undercooked beef
Flatworms: Phylum PlatyhelminthesTapeworm
Roundworms: Phylum Nematoda and Rotifera Roundworms have bilaterally symmetrical
bodies and a fluid filled space to store eggs and sperm and for support.
They have a complete digestive system, that is, one with two openings, unlike cnidarians, ctenophores, and flatworms.
They have separate sexes. The vast majority are free-living on on land and in the water, and are parasites of plants and animals.
Roundworms: Phylum Nematoda and Rotifera Ascaris
Live in intestines of humans as larvae, then move to bloodstream and are carried to lungs and throat can block air passages and cause bleeding.
HookwormsGo through feet and travel through blood to lungs and
throatIf ingested, they will move to intestines and develop into
adults Trichinella
Live in intestines; larvale travel through blood stream to muscles and form cysts, causing muscle pain and stiffness (trichinosis)
PinwormsLive in intestines; tiny white threads in the lower
intestines; females come out at night and lay eggs on anus which spreads via scratching.
Filarial wormsElephantitis infects lymphatic system and is spread by
mosquito
Roundworms: Phylum Nematoda Ascaris
Roundworms : Phylum Nematoda Hookworms
Roundworms : Phylum Nematoda Trichinella
Roundworms : Phylum NematodaPinworms
Roundworms : Phylum NematodaFilarial worms
Segmented worms: Phylum AnnelidaFeather-duster worms, common earthworms
and leeches, are all members of this phylum. The phylum name means little rings. These organisms are bilaterally symmetrical
and, like mollusks, have a true coelom, a complete internal body tube
What does this structure allow to happen when the organism moves?It allows the body to contract.
Most have external bristles called setae.All organ systems are well-developed.
Segmented worms: Phylum Annelida Class Oligochaeta:
The most familiar members of this class is the earthworm. Describe how it moves (and the structures involved):
Thay have a fluid skeleton, and to move forward, they squeeze circular muscles of each segment, to extend their body.
They use their rough bristles to grip the surface of the ground at the front, then use longitudinal muscles to pull their ends up to meet the front
Complete or incomplete digestive tract? Explain. Complete two openings and one-way
Open or closed circulatory system? Explain. Closedvia two main blood vessels, dorsal and ventral
Oxygen and CO2 diffuse directly through the skin. The nervous system consists of a chain of ganglia connected by a
ventral nerve cord. How do earthworms reproduce? Be sure to mention any special
structures and their functions Two press their ventral surfaces together with anterior ends pointing
in opposite directions They are held be setae and clitellum Exchange sperm with each other, ideally fertilizing each other (they
are hermaphodites!)
Segmented worms: Phylum Annelida- Earthworms
Segmented worms: Phylum AnnelidaClass Hirudinea
Consists of about 500 species of leeches.They have no setae. At each end is a sucker
that can attach to surfaces.What two things do they secrete when they
suck blood?AnaestheticA substance that prevents blood from clotting
Segmented worms: Phylum Annelida- Leeches