protostomes and deuterostomes

Describe protostomes and deuterostomes? with diagram.
Why sexual reproduction is unusual in protozoan?

2. Describe protostomes and
deuterostomes? with diagram.
Why sexual reproduction is
unusual in protozoan?
CONTENTS

4. Question no: 01
Definition:
Animals in which the blastopore becomes the mouth
are called protostomes;
The term Protostomia (from the Greek "proto," meaning first, and
"stoma," meaning mouth)Protostome is a clade of animals containing
phyla including the arthropods, annelids, and molluscs. Together with
the deuterostomes and xenacoelomorpha, its members make up the
Bilateria, mostly comprising animals with bilateral symmetry and three
germ layers.

7. 1.Cleavage pattern: spiral cleavage
2.Fate of blastopore: becomes the
mouth
3.Origin of mesoderm arises from
mesentoblast (4d cells)
4.Coelom formation: schizocoely
5.Larval type: trochophore larva

8. Exmple of Protostomes

9. Animals in which the mouth develops after the
anus are called deuterostomes (from the Greek
"deutero," meaning second, and "stoma," meaning mouth). It is a
sister clade of Protostomia, with which it forms the Nephrozoa clade.
Deuterostomia is a subtaxon of the Bilateria branch of the subkingdom
Eumetazoa, within Animalia, and are distinguished from protostomes by
deuterostomic embryonic development; in deuterostomes, the first opening
(the blastopore) becomes the anus, whereas in protostomes, it becomes the
mouth; although deuterostomy has also been observed among
protostomes.Deuterostomes are also known as enterocoelomates because
their coelom develops through enterocoely.

11. 1.Cleavage pattern: radial cleavage
2.Fate of blastopore: becomes the anus
3.Origin of mesoderm: pouches off gut
(endoderm)
4.Coelom formation: enterocoely
5.Larval type: dipleurula

12. Example of deuterosome

13. sexual reproduction required fussion of
gametes and then genetic recombinations
are occures. when we talk about sexual
reproduction in protozoans then we have
to know that its a uniqe character
becauce it can reproduce itself by both
asexually and also sexually.
in sexually reproduction there are two
types in protozoans that are given below.

14. Syngamy is a fusion of two haploid gametes to
form a zygot.
Amphimixis is a union of pronuclei of gametes
to form zygot the resulting nucleus is called
synkaryon
syngamy is futher divided in three types that are
given below
: fussionof two similar
gametes(monocystis)
fussion of two disimilar
gametes(plasmodium)
mature gametes are behaving
as a gamete(trichonympha)

15. •Conjugation is observed in ciliated protozoans
e.g. paramecium and vorticilia
•According to witcherman conjugation is a
temorarily union of two senile ciliates
protozoans
•It caused by reapeted amitotic devisions and
this occuers during the unfavourable
conditions

17. UTE