Transcript Round Worms, Flat Worms and Annelids

Round Worms, Flat
Worms and
Annelids
Andrew Sahr
Characteristics
 Roundworms:
 Nemathelminths phylum
 Range from microscopic to as long as 3.3 feet (1
meter).
 Have a hard, sharp spear on their head, and some
have bristles on the head
 Protected by a flexible but strong, grooved body
covering
 A layer beneath this covering releases fluids that
harden to form the covering
 Bilaterally symmetrical
Cont.
 The body has 3 tissue layers and a fluid-filled
false body cavity, meaning the cavity is
between the inner and middle layers rather
than the middle layer and the outer layer, as it
is in complex animals
 Roundworms live in salt water, fresh water and
the soil.
 Many of them are harmful to man as they are
parasites.
Roundworm Life Cycle
 Starts as an egg in a feces of an animal
 Another animal either eats that animal or the
feces of that animal
 Transfers into the animals own intestines
 Molts into the lava
 Larva migrates through the intestinal wall and
into the lungs where its coughed up and
swallowed once more
 Once it returns to the larva it begins to mature
as an adult.
Reproduction
 Sexually
 Most species have a separate male and female but
some are hermaphroditic
 Males are typically smaller
 Females have ovaries for holding the egg
 During the copulation, male protrudes one or
more spicules out of the cloaca and insert them
into genital pore of the female.
Reproduction Cont.
 Amoeboid sperm cells are passed along
the spicules into the female worm
 Eggs can be either embryonated or
unembryonated when passed by the
female, which means that their fertilized
eggs are not yet developed
Roundworms in our Area
 Baylisascaris
 Intestinal Raccoon roundworm
 Effects animals, including humans
 Mature in Raccoon intestine
 Released eggs take 2-3 weeks to become
infective
 When we ingest them from soil or water they
hatch into larvae inside us
 Travel through the body
 Affect our organs and muscles
Characteristics cont.
 Flatworms: also known as flukes
 Bilaterally symmetrical
 Body has 3 layers of tissues with organs and
organelles
 Body contains no internal cavity
 Possesses a blind gut (i.e. it has a mouth but
no anus)
 Has Protonephridial excretory organs instead
of an anus
Cont.
 Reproduction is mostly sexual as
hermaphrodites
 Mostly feed on animals and other smaller
life forms
 Some occur in all major habitats,
including many as parasites of other
animals
 Bilaterally symmetrical
Life Cycle of Flatworms
 Start as an egg
 Passed out in the feces of a bird
 Eaten by Whelks
 Inside the larvae hatches the eggs and multiplies by
budding
 Leave and invade cockles
 Infected cockles are eaten by the birds in
which the flukes mature and lay there eggs
Reproduction
 A flat worm is reproduced when it splits In two
 It will immediately form a new flatworm
 Hermaphroditic
 Each individual produces sperm and egg
 When two flatworms mate, they exchange sperm so
both become fertilized.
 can also reproduce asexually by transverse fission
Reproduction Cont.
 The body constricts at the midsection, and the
posterior end grips a substrate
 body rips apart
 Each half grows replacements of the missing
pieces to form two whole flatworms
 if one of these flatworms is cut in half, each half
will regenerate into two separate fullyfunctioning flatworms
Flatworms in Our Area
 Heterobilharzia americanum
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Waterborne flatworm
Parasite
Affects mostly dogs and raccoons
Sexually reproduces in the intestines
 Eggs are laid in there so they can be carried out
through feces
Characteristics cont.
 Annelids:
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Bilaterally symmetrical
Body has more than two cell layers which are tissues and organs
Body possesses a through gut with mouth and anus
Has true closed circulatory system
Has no true respiratory organs
Lives in most environments
Feed a wide range of material
Reproduction normally sexual and gonochoristic or hermaphoditic
Includes earthworms and leeches
Life Cycle of Annelids, The
Earthworm
 Hermaphrodites.
 When two earthworms mate
 They lie together and cover themselves in sticky mucus
 Pass sperm into each others bodies
 Sperm makes the egg in each body grow
 A thick ring of slime forms around each worm's body
and as the earthworm wriggles forward
 the ring with eggs inside it slips off and is left on the
ground
 The ring closes at both ends and becomes a hard
cocoon that protects the eggs.
Cont.
 The eggs hatch after two weeks if the weather
is warm
 They can take up to three months to hatch
when it is cold
 Usually one or two earthworms hatch out of
each egg
 The young worms are about 12 millimeters
long and light pink in color
 Earthworms are able to mate when they are
twelve months old.
Reproduction
 Asexual
 by dividing into two or more pieces or by
budding off a new individual while the parent
remains a complete organism
 Some reproduce all asexually, while some
reproduce sexually as well
 Leeches have never been seen
reproducing sexually
Annelids in Minnesota
 Earthworms
 All terrestrial earthworms are not native to
Minnesota
 15 species have been identified so far
 Glaciers would have killed any worms
before the European settlements
 First Earthworms probably arrived through
soil and plants from Europe
Sources
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http://animals.jrank.org/pages/1551/Roundworms-Adenophorea-PHYSICAL-CHARACTERISTICS.html
http://www.earthlife.net/inverts/annelida.html
http://www.earthlife.net/inverts/platyhelminthes.html
http://www.getridofthings.com/get-rid-of-roundworm.htm
http://www.teara.govt.nz/en/marine-animals-without-backbones/2/3
http://www.ento.csiro.au/education/allies/annelida.html
http://www.cdc.gov/ncidod/dpd/parasites/baylisascaris/factsht_baylisascaris.htm
http://local.petmd.com/Waterborne_Flatworm_Parasite_in_Dogs_Detroit_Lakes_MN-r1331428Detroit_Lakes_MN.html
http://www.dnr.state.mn.us/invasives/terrestrialanimals/earthworms/index.html
http://www.localriding.com/image-files/roundworm-cycle.gif
http://www.dpd.cdc.gov/dpdx/images/ParasiteImages/A-F/Dioctophymiasis/Dioctophyme_LifeCycle.gif
http://petcaregt.com/blog/wp-content/uploads/2008/11/round-worm.jpg
http://staff.tuhsd.k12.az.us/gfoster/standard/nematod.gif
http://www.cartage.org.lb/en/themes/sciences/zoology/biologicaldiverstity/AnimalsI/flatworm.gif
http://www.starfish.ch/Fotos/worms-Wuermer/plathelminthes-Plattwurm/Pseudobiceros-gloriosus3.jpg
http://www.mcwdn.org/Animals/Roundworms.html
http://www.kidcyber.com.au/topics/worms.htm