Question

I really need these questions right now please!

2) Please diagram the Mictic/ Amitic lifecycle of the Rotifera. Be sure to include but not be limited to the ploidylevel, the sexual and asexual phases, the type of asexualreproduction, where you have males and where you do not and lastly what causes the population to switch form one phase to the other.

3) In the Mollusca the coelom is greatly reduced. Where is it located, what organ does it surround and what structure does the Mollusca use for their hydrostatic skeleton instead of the coelom ?

4) What is the mantel and what is its function within the class Bivalvia and in the class Cephlopoda ?

Answer 1

Ans. Rotifera:Rotifers were hermaprodite.this was the general failure to find or recognise the male rotifers and led to some amussing attempts to identify male reproductive organs in females.The existence of the amictic females which produce the daughters  by the parthenogenesis and mictic females which produce males by parthenogenesis.the amitic females can produce both amictic and mictic daughters.in the Rotifera alternating the amictic and mictic reproduction is decribed by Maupus is found in the order Mongonata.parasitic marine rotifers strictly dioecious.

mictic and amictic may dffer in reproductive parameters

MITOS MITOSIS 14 GENS பா Poco MIXES STIMULUE MITOSIS fect> OERO AMCTIC 120 FERTILIZATION FIG. 1. Life cycle of the monogonont rotifers. "Mi. tosis" and "mciosis" refer to the oocyte maturation divisions in amictic and mictic females, respective-

3)mollusca:Although molluscs are coelomates their coeloms are rduced to fairly small spaces enclosing heart and gonads.The main body cavity is haemocoel through which blood and coelomic fluid ncirculate and which encloses most of the other internal organs.

Mollusks are schizocoelous eucoelomates,but the coelomic cavity in adult animals has been largely reduced to a cavity around the heart.However a reduced coelom sometimes surround the gonads,part of the kidneys and intestine as well.This overall coelom reduction makes the mantle cavity the major body chamber.Most molluscs are dioecious animals fertilisation occur externally.

4)The mantle cavity functions as a respiratory chamberin the most of molluscs.in bivalves it is usually part of feeding structure.if the animal is undisturbed the valves may be slightly agape ventrally and you can see the posterior end the fringed edges of the mantle,which lines the valves.the posterior edges of the mantle are shaped so as to form openings to the inside of the mantle cavity.

POSTERIOR RETRACTOR MUSCLE MOUTH (BENEATH PALPS) LABIAL PALP POSTERIOR ADDUCTOR ANTERIOR FOOT RETRACTOR ANUS EXCURRENT SIPHON WATER FLOW 7-INCURRENT SIPHON ANTERIOR ADOUCIOR MUSCLE DIRECTION OF FOOU MOVEMENT CTENIDIUM (gills)