Transcript Rotifer - I Love Science

Rotifer
Phylum Rotifera
• From the Latin Rota a wheel and Ferre
to bear or carry
• Rotifera is divided into two classes, the
Digononta and the Monogononta
• The members of the class
Monogononta constitutes 90% of the
known species
Characteristics of Rotifers
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1)Bilaterally symmetrical.
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2)Body has more than two cell layers, tissues and organs.
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3)Body cavity is a pseudocoelom[ second body cavity ].
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4)Body possesses a through gut with an anus.
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5)Body covered in an external layer of chitin called a lorica.
6)Has a nervous system with a brain and paired nerves.
7)Has no circulatory or respiratory organs.
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8)Reproduction mostly parthenogenetic [an asexual form of reproduction found in females
where growth and development of embryos or seeds occurs without fertilization by a
male.] , otherwise sexual and gonochoristic[ reproduction with two distinct sexes].
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9)Feed on bacteria, and protists, or are parasitic.
10)All live in aquatic environments either free swimming or attached.
A Lil’ Video !
Physical Characteristics
• The body is generally divided into a head,
a trunk, and a foot region
• The largest organ in the head is the wheel
organ.
• The trunk shape varies from long to
spherical or baglike .
• The foot has one or several sections, and
it often has two toes with sticky glands at
the tips.
Habitat
• Rotifers live in still water and flowing
water environments such as lake
bottoms, rivers, or streams.
• Rotifers are also commonly found on
mosses and lichens growing on rocks
and aquatic insect larvae.
Feeding
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The two wheels on
rotifers are made of
cilia that beat and
create a current that
draws water containing
food into the gut of
the rotifer.
Rotifers eat bacteria
(top left) , protists
(bottom left) , and
other small animals.
Reproduction
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The reproduction of
rotifers can be sexual
and by
parthenogenesis.
The mictic female
produces eggs that
undergo the usual
double meiotic
division and are
haploid.
Sexual reproduction
occurs in the rotifers
of Class Monogononta
Quiz Answers
1.The body is generally divided into a head, a trunk, and
a foot region. The largest organ in the head is the
wheel organ. The trunk shape varies from long to
spherical or baglike .
2. Most Rotifers live in lake bottoms, rivers, or streams.
3. Mitic
4. Phylum Rotifera
5.The corona is the part of a rotifer that is used as a
feeding device and locomotive device.
Diagram
The End
• Tishana
• Shanisa
• Janasia