Protozoan reproduction.
 

[B]Protozoan reproduction.[/B]
[B]Although i have given a link of rep in protozoa its not comprehensive.[/B]
[B]the link i am mentioning now has both detailed description and diagrams of asexual and sexual reproduction.[/B]

[B][URL="http://www.scribd.com/doc/6710273/3-Repd"]Clich here[/URL][/B]

[B]regards[/B]

Zoology Glossary
 

A glossary of Zoology Terms, Click [URL="http://animals.about.com/od/zoologyglossary/Glossary.htm"][B]here[/B][/URL]

Hope it helps ! :)

Diagrams
 

[B]Figures of Invertebrate phylums [/B]
[B]you can also check the glossory.[/B]

[B][URL="http://www-biol.paisley.ac.uk/biomedia/text/txt_pictures.htm#s"]Click here[/URL][/B]

[B]Regards[/B]

Porifera.
 

All about Porifera.Its a 17 page presentation and easily downloaded.
And in the end the classification is also given.
With this most of the phylum porifera is complete now.

[URL="http://cfcc.edu/rogers/courses/msc174/Lectures/Phylum%20Porifera.pdf"]Click Here[/URL]

Regards

@afrms

You mentioned in some of your post about a couple of articles published in Dawn. I tried to find that peculiar post but couldn't succeed. Would you please write again about the title and date on which they were printed?

Regards,

[quote=Lord AvaLon]@afrms

You mentioned in some of your post about a couple of articles published in Dawn. I tried to find that peculiar post but couldn't succeed. Would you please write again about the title and date on which they were printed?

Regards,[/quote]


I think you are talking about post 3 in the thread linked [B][URL="http://www.cssforum.com.pk/css-compulsory-subjects/current-affairs/21803-important-topics-current-affair-2009-a.html"]here [/URL][/B]

[quote=Lord AvaLon]@afrms

You mentioned in some of your post about a couple of articles published in Dawn. I tried to find that peculiar post but couldn't succeed. Would you please write again about the title and date on which they were printed?

Regards,[/quote]

salam
Mohsin has mentioned the link.i was going through the Dawn news articles and found a good article on Irrigation System.
The title is "giving irrigation system a facelift" By bilal hassan.(economic and bsuiness reveiw,feb 16-22 P.III.
do check it might be helpful.
regards

That was helpful afrms,
I request you to keep on pointing out the articles which appears important to you in anyway. Having the clippings would obviously help alot in the high times of exam.

Regards,

[quote=Lord AvaLon]That was helpful afrms,
I request you to keep on pointing out the articles which appears important to you in anyway. Having the clippings would obviously help alot in the high times of exam.

Regards,[/quote]
yes i will keep on doing that.so keep an eye.yes reading newspaper helps a lot i got 50 in current just by reading dawn and shahid books

Phylum Coelenterata
 

[COLOR=black][FONT=Verdana][SIZE=2]Phylum Coelenterata [/SIZE][/FONT][/COLOR]
[COLOR=black][FONT=Verdana][/FONT][/COLOR]
[COLOR=black][FONT=Verdana][B][COLOR=black][FONT=Verdana][SIZE=2][COLOR=sienna]The radiate animals Phylum Coelenterata ( Cnidaria )[/COLOR][/SIZE][/FONT][/COLOR][/B]

[SIZE=2][FONT=Verdana] [/FONT][FONT=Verdana][/FONT][/SIZE]
[B][COLOR=black][FONT=Verdana][SIZE=2]The Phylum Coelenterata includes the polyps, jellyfishes, sea anemones, and corals. All of these animals have a body wall consisting of two layers of cells, between which is a jellylike substance, the mesoglea. Within the body is a single gastrovascular cavity, or coelenteron. Because of the presence of two cellular layers, Coelenterates are side to have a tissue-level organization. They are also acoelomates; that is, they dont possess a second body cavity, the coelom .[/SIZE][/FONT][/COLOR][/B]

[B][COLOR=black][FONT=Verdana][SIZE=2] [/SIZE][/FONT][/COLOR][/B]

[B][COLOR=black][FONT=Verdana][SIZE=2][COLOR=sienna] Position in animal kingdom[/COLOR][/SIZE][/FONT][/COLOR][/B]

[SIZE=2][COLOR=sienna][FONT=Verdana] [/FONT][FONT=Verdana][/FONT][/COLOR][/SIZE]
[B][COLOR=black][FONT=Verdana][SIZE=2]Phylum Cnidaria are characterized by primary radial or biradial symmetry . Radial symmetry , in which the body parts are arranged concentrically around the oral-aboral axis , is particularly suitable for sessile or sedentary animals .[/SIZE][/FONT][/COLOR][/B]

[B][COLOR=black][FONT=Verdana][SIZE=2]The phylum has not advanced generally beyond the tissue level of organization, although a few organs occur . [/SIZE][/FONT][/COLOR][/B]

[SIZE=2][FONT=Verdana] [/FONT][FONT=Verdana][/FONT][/SIZE]
[B][COLOR=black][FONT=Verdana][SIZE=2][COLOR=sienna] Biologic contributions[/COLOR][/SIZE][/FONT][/COLOR][/B]

[B][COLOR=black][FONT=Verdana][SIZE=2] [/SIZE][/FONT][/COLOR][/B]

[B][SIZE=2][COLOR=black][FONT=Verdana]a. [/FONT][/COLOR][COLOR=black][FONT=Verdana]The phylum has developed two well-defined germ layers , ectoderm and endoderm ; a third , or mesodermal ,layer , which is derived embryologically from the ectoderm , is present in some . The body plan is saclike , and the body wall is composed of two distinct layers , epidermis and gastrodermis , derived from the ectoderm and endoderm , respectively . The gelatinous matrix , mesoglea , between these layers may be structureless , may contain a few cells and fibers , or may be composed largely of mesodermal connective tissue and muscle fibers .[/FONT][/COLOR][/SIZE][/B]

[FONT=Times New Roman] [/FONT]
[B][SIZE=2][COLOR=black][FONT=Verdana]b. [/FONT][/COLOR][COLOR=black][FONT=Verdana]An internal body cavity, the gastrovascular cavity , is lined by the gastrodermis and has a single opening , the mouth , which also serves as the anus .[/FONT][/COLOR][/SIZE][/B]

[FONT=Times New Roman] [/FONT]
[FONT=Times New Roman] [/FONT]
[B][COLOR=black][FONT=Verdana][SIZE=2]c. Extracellular digestion occurs in the gastrovascular cavity , as does intracellular digestion in the gastrodermal cells . [/SIZE][/FONT][/COLOR][/B]

[B][COLOR=black][FONT=Verdana][SIZE=2] [/SIZE][/FONT][/COLOR][/B]

[B][COLOR=black][FONT=Verdana][SIZE=2]d. Most radiates have tentacles , or extensible projections around the oral end , that aid in food capture .[/SIZE][/FONT][/COLOR][/B]

[B][COLOR=black][FONT=Verdana][SIZE=2]e. The first true nerve cells ( protoneurons ) occur in the radiates , but the nerves are arranged as a nerve net , with no central nervous system .[/SIZE][/FONT][/COLOR][/B]

[B][COLOR=black][FONT=Verdana][SIZE=2]f. Sense organs appear first in the radiates and include well-developed statocysts (organs of equilibrium ) and ocelli.[/SIZE][/FONT][/COLOR][/B]

[SIZE=2][FONT=Verdana] [/FONT][/SIZE][COLOR=black][FONT=Verdana][SIZE=2]g. Locomotion in the free-moving forms is achieved either by muscular contractions . However the groups are still better adapted to floating or being carried by currents than to strong swimming . [/SIZE][/FONT][/COLOR]
[B][COLOR=black][FONT=Verdana][SIZE=2]h. Polymorphism (polyp stage and medusa stage ) in the cnidarians has widened their ecologic possibilities .[/SIZE][/FONT][/COLOR][/B]

[B][COLOR=black][FONT=Verdana][SIZE=2]i. Some unique features are found in this phylum , such as nematocysts ( stinging organoids ) in Cnidarians .[/SIZE][/FONT][/COLOR][/B]

[B][COLOR=black][FONT=Verdana][SIZE=2] [/SIZE][/FONT][/COLOR][/B]

[B][COLOR=black][FONT=Verdana][SIZE=2][COLOR=sienna] characteristics[/COLOR][/SIZE][/FONT][/COLOR][/B]

[B][COLOR=black][FONT=Verdana][SIZE=2] [/SIZE][/FONT][/COLOR][/B]

[B][COLOR=black][FONT=Verdana][SIZE=2]a. Entirely aquatic , some in fresh water but mostly marine [/SIZE][/FONT][/COLOR][/B]

[B][COLOR=black][FONT=Verdana][SIZE=2]b. Radial symmetry or biradial symmetry around a longitudinal axis with oral and aboral ends ; no definite head[/SIZE][/FONT][/COLOR][/B]

[B][COLOR=black][FONT=Verdana][SIZE=2]c. Two basic types of individuals: polyps and medusae [/SIZE][/FONT][/COLOR][/B]

[B][COLOR=black][FONT=Verdana][SIZE=2]d. Exoskeleton or endoskeleton of chitinous, calcareous , or protein components in some[/SIZE][/FONT][/COLOR][/B]

[B][COLOR=black][FONT=Verdana][SIZE=2]g. Special stinging cell organoids called nematocysts in either or both epidermis and gastrodermis ; nematocysts abundant on tentacles , where they may form batteries or rings[/SIZE][/FONT][/COLOR][/B]

[B][COLOR=black][FONT=Verdana][SIZE=2]h. Nerve net with symmetric and asymmetric synapses; with some sensory organs; diffuse conduction [/SIZE][/FONT][/COLOR][/B]

[B][COLOR=black][FONT=Verdana][SIZE=2] [/SIZE][/FONT][/COLOR][/B]

[B][COLOR=windowtext][FONT=Verdana][SIZE=2] [/SIZE][/FONT][/COLOR][/B]

[B][COLOR=black][FONT=Verdana][SIZE=2]e. Body with two layers, epidermis and gastrodermis, with mesoglea ( diploblastic ) ; mesoglea with cells and connective tissue ( ectomesoderm ) in some ( triploblastic )[/SIZE][/FONT][/COLOR][/B]

[B][COLOR=black][FONT=Verdana][SIZE=2]f. Gastrovascular cavity (often branched or divided with septa ) with a single opening that serves as both mouth and anus; extensible tentacles usually encircling the mouth or oral region[/SIZE][/FONT][/COLOR][/B]

[B][COLOR=black][FONT=Verdana][SIZE=2]i. Reproduction by asexual budding ( in polyps ) or sexual reproduction by gametes ( in all medusae and some polyps ) ; sexual forms monoecious or dioecious ; planula larva ; holoblastic cleavage . [/SIZE][/FONT][/COLOR][/B]

[B][COLOR=black][FONT=Verdana][SIZE=2]j. No excretory or respiratory systems [/SIZE][/FONT][/COLOR][/B]

[B][COLOR=black][FONT=Verdana][SIZE=2]k. No coelomic cavity [/SIZE][/FONT][/COLOR][/B]

[SIZE=2][FONT=Verdana] [/FONT][FONT=Verdana][/FONT][/SIZE]
[B][COLOR=black][FONT=Verdana][SIZE=2][COLOR=sienna]Classification[/COLOR][/SIZE][/FONT][/COLOR][/B]

[B][COLOR=black][FONT=Verdana][SIZE=2] [/SIZE][/FONT][/COLOR][/B]

[B][COLOR=black][FONT=Verdana][SIZE=2][COLOR=sienna]a. Class Hydrozoa[/COLOR][/SIZE][/FONT][/COLOR][/B]

[B][COLOR=black][FONT=Verdana][SIZE=2]This class includes the freshwater polyps , the small jellyfishes , the hydroid zoophytes, and a few stony corals .[/SIZE][/FONT][/COLOR][/B]

[B][COLOR=black][FONT=Verdana][SIZE=2]b. Class Scyphozoa [/SIZE][/FONT][/COLOR][/B]

[B][COLOR=black][FONT=Verdana][SIZE=2]Most of the large jellyfishes are placed in this class .[/SIZE][/FONT][/COLOR][/B]

[B][COLOR=black][FONT=Verdana][SIZE=2][COLOR=sienna]c. Class Anthozoa[/COLOR] [/SIZE][/FONT][/COLOR][/B]

[B][COLOR=black][FONT=Verdana][SIZE=2] In this class are included the sea anemones , and most of the stony and horny corals . [/SIZE][/FONT][/COLOR][/B]

[SIZE=2][FONT=Verdana] [/FONT][FONT=Verdana][/FONT][/SIZE]
[B][COLOR=black][FONT=Verdana][SIZE=2][COLOR=sienna] Class Hydrozoa[/COLOR][/SIZE][/FONT][/COLOR][/B]

[B][COLOR=black][FONT=Verdana][SIZE=2] [/SIZE][/FONT][/COLOR][/B]

[B][SIZE=2][COLOR=sienna](1) Characteristics[/COLOR] [/SIZE][/B]

[SIZE=2][FONT=Verdana] [/FONT][FONT=Verdana][/FONT][/SIZE]
[B][COLOR=black][FONT=Verdana][SIZE=2] a. solitary or colonial ;[/SIZE][/FONT][/COLOR][/B]

[B][COLOR=black][FONT=Verdana][SIZE=2] b. asexual polyps and sexual medusae , although one type may be suppressed ; [/SIZE][/FONT][/COLOR][/B]

[B][COLOR=black][FONT=Verdana][SIZE=2] c. hydranths with no mesenteries.[/SIZE][/FONT][/COLOR][/B]

[B][COLOR=black][FONT=Verdana][SIZE=2] d. medusae ( when present ) with a velum;[/SIZE][/FONT][/COLOR][/B]

[B][COLOR=black][FONT=Verdana][SIZE=2] e. both fresh-water and marine .[/SIZE][/FONT][/COLOR][/B]

[B][COLOR=black][FONT=Verdana][SIZE=2] [/SIZE][/FONT][/COLOR][/B]

[B][COLOR=black][FONT=Verdana][SIZE=2][COLOR=sienna] (2) Typical animal[/COLOR] [/SIZE][/FONT][/COLOR][/B]

[SIZE=2][FONT=Verdana] [/FONT][FONT=Verdana][/FONT][/SIZE]
[B][COLOR=black][FONT=Verdana][SIZE=2] Hydra[/SIZE][/FONT][/COLOR][/B]

[B][COLOR=black][FONT=Verdana][SIZE=2] a. The structure of hydra ;[/SIZE][/FONT][/COLOR][/B]

[B][COLOR=black][FONT=Verdana][SIZE=2] b. The physiological function of hydra ;[/SIZE][/FONT][/COLOR][/B]

[B][COLOR=black][FONT=Verdana][SIZE=2] c. The life cycle of hydra .[/SIZE][/FONT][/COLOR][/B]

[B][COLOR=black][FONT=Verdana][SIZE=2] [/SIZE][/FONT][/COLOR][/B]

[B][COLOR=black][FONT=Verdana][SIZE=2] [/SIZE][/FONT][/COLOR][/B]

[B][COLOR=black][FONT=Verdana][SIZE=2][COLOR=sienna] Class Scyphozoa[/COLOR][/SIZE][/FONT][/COLOR][/B]

[B][COLOR=black][FONT=Verdana][SIZE=2] [/SIZE][/FONT][/COLOR][/B]

[B][COLOR=black][FONT=Verdana][SIZE=2][COLOR=sienna](1) Characteristics of Class Scyphozoa[/COLOR][/SIZE][/FONT][/COLOR][/B]

[SIZE=2][FONT=Verdana] [/FONT][FONT=Verdana][/FONT][/SIZE]
[B][COLOR=black][FONT=Verdana][SIZE=2] a. solitary ;[/SIZE][/FONT][/COLOR][/B]

[B][COLOR=black][FONT=Verdana][SIZE=2] b. polyp stage reduced or absent ;[/SIZE][/FONT][/COLOR][/B]

[B][COLOR=black][FONT=Verdana][SIZE=2] c. bell-shaped medusae without velum ;[/SIZE][/FONT][/COLOR][/B]

[B][COLOR=black][FONT=Verdana][SIZE=2]d. gelatinous mesoglea much enlarged ;[/SIZE][/FONT][/COLOR][/B]

[B][COLOR=black][FONT=Verdana][SIZE=2]e. margin of bell or umbrella typically with eight notches that are provided with sense organs ;[/SIZE][/FONT][/COLOR][/B]

[B][COLOR=black][FONT=Verdana][SIZE=2]f. all marine[/SIZE][/FONT][/COLOR][/B]

[B][COLOR=black][FONT=Verdana][SIZE=2] [/SIZE][/FONT][/COLOR][/B]

[B][COLOR=black][FONT=Verdana][SIZE=2][COLOR=sienna]Typical animal[/COLOR][/SIZE][/FONT][/COLOR][/B]

[B][COLOR=black][FONT=Verdana][SIZE=2] [I]Aurelia aurita[/I] [/SIZE][/FONT][/COLOR][/B]

[B][COLOR=black][FONT=Verdana][SIZE=2]a. The structure of [I]Aurelia aurita[/I] [/SIZE][/FONT][/COLOR][/B]

[B][COLOR=black][FONT=Verdana][SIZE=2]b. The life cycle of [I]Aurelia aurita[/I] [/SIZE][/FONT][/COLOR][/B]

[B][COLOR=windowtext][FONT=Verdana][SIZE=2] [/SIZE][/FONT][/COLOR][/B]

[B][COLOR=black][FONT=Verdana][SIZE=2] [/SIZE][/FONT][/COLOR][/B]

[B][COLOR=black][FONT=Verdana][SIZE=2] [COLOR=sienna]Class Anthozoa[/COLOR] [/SIZE][/FONT][/COLOR][/B]

[B][COLOR=black][FONT=Verdana][SIZE=2] [/SIZE][/FONT][/COLOR][/B]

[B][SIZE=2][COLOR=sienna] [B](1) characteristics[/B][/COLOR] [/SIZE][/B]

[SIZE=2][FONT=Verdana] [/FONT][FONT=Verdana][/FONT][/SIZE]
[B][COLOR=black][FONT=Verdana][SIZE=2] a. all polyps, no medusae ;[/SIZE][/FONT][/COLOR][/B]

[B][COLOR=black][FONT=Verdana][SIZE=2] b. solitary or colonial ;[/SIZE][/FONT][/COLOR][/B]

[B][COLOR=black][FONT=Verdana][SIZE=2] c. enteron subdivided by at least 8 mesenteries or septa bearing nematocysts;[/SIZE][/FONT][/COLOR][/B]

[B][COLOR=black][FONT=Verdana][SIZE=2] d. gonads endodermal ;[/SIZE][/FONT][/COLOR][/B]

[B][COLOR=black][FONT=Verdana][SIZE=2] e. all marine .[/SIZE][/FONT][/COLOR][/B]

[B][COLOR=black][FONT=Verdana][SIZE=2] [/SIZE][/FONT][/COLOR][/B]

[B][COLOR=black][FONT=Verdana][SIZE=2][COLOR=sienna](2) Typical animal[/COLOR] [/SIZE][/FONT][/COLOR][/B]

[B][COLOR=black][FONT=Verdana][SIZE=2] sea-anemones[/SIZE][/FONT][/COLOR][/B]

[B][COLOR=black][FONT=Verdana][SIZE=2] [/SIZE][/FONT][/COLOR][/B]

[B][COLOR=black][FONT=Verdana][SIZE=2][COLOR=sienna] Metamorphosis[/COLOR][/SIZE][/FONT][/COLOR][/B]

[SIZE=2][FONT=Verdana] [/FONT][FONT=Verdana][/FONT][/SIZE]
[B][COLOR=black][FONT=Verdana][SIZE=2]Generally, after swimming for a few hours to many days the planula attaches and develops into a polyp or polypoid form , which in colonial species subsequently gives rise to the colony .[/SIZE][/FONT][/COLOR][/B]

[B][COLOR=black][FONT=Verdana][SIZE=2]In some hydroids the planula remains in the gonophore, developing into the tentaculate actinula larva which is liberated and creeps about . After attachment, it develops into a polyp . In many hydrozoans with no polypoid phase the planula develops into an actinula and then a medusa .[/SIZE][/FONT][/COLOR][/B]

[B][COLOR=black][FONT=Verdana][SIZE=2]In most scyphozoans, after attachment, the planula develops into a polypoid scyphistoma, with a stalked trumpet-shaped body . At maturity, the scyphistoma produces a free-swimming medusa stage, the ephyra larva, by transverse fission or strobilization. Ephyrae may be produced singly or several at a time, and develop to adult medusae . [/SIZE][/FONT][/COLOR][/B]

[B][COLOR=black][FONT=Verdana][SIZE=2]In zoantharian anthozoans, the planula does not attach but develops into an anemone-like Edwardsia larva, then the Halcampoides larva. After attachment, tentacles develop and the adult polyp form is attained.[/SIZE][/FONT][/COLOR][/B]

[SIZE=2][FONT=Verdana] [/FONT][FONT=Verdana][/FONT][/SIZE]
[B][COLOR=black][FONT=Verdana][SIZE=2][COLOR=sienna]Reproduction [/COLOR][/SIZE][/FONT][/COLOR][/B]

[SIZE=2][FONT=Verdana] [/FONT][FONT=Verdana][/FONT][/SIZE]
[B][COLOR=black][FONT=Verdana][SIZE=2]There are both dioecious and hermaphroditic species .[/SIZE][/FONT][/COLOR][/B]

[B][COLOR=black][FONT=Verdana][SIZE=2] [/SIZE][/FONT][/COLOR][/B]

[B][COLOR=black][FONT=Verdana][SIZE=2] Sexual reproduction [/SIZE][/FONT][/COLOR][/B]

[B][COLOR=black][FONT=Verdana][SIZE=2] [/SIZE][/FONT][/COLOR][/B]

[B][COLOR=black][FONT=Verdana][SIZE=2] Asexual reproduction [/SIZE][/FONT][/COLOR][/B]

[SIZE=2][FONT=Verdana] [/FONT][FONT=Verdana][/FONT][/SIZE]
[B][COLOR=black][FONT=Verdana][B][SIZE=2][COLOR=sienna]Asexual reproduction[/COLOR] is common, it may occur by :[/SIZE][/B][/FONT][/COLOR][/B]

[B][COLOR=black][FONT=Verdana][SIZE=2]a. budding ;[/SIZE][/FONT][/COLOR][/B]

[B][COLOR=black][FONT=Verdana][SIZE=2]b. pedal laceration, e.g. in sea anemones ;[/SIZE][/FONT][/COLOR][/B]

[B][COLOR=black][FONT=Verdana][SIZE=2]c. transverse fission, e.g. in the production of ephyrae by scyphistomae [/SIZE][/FONT][/COLOR][/B]

[B][COLOR=black][FONT=Verdana][SIZE=2]d. longitudinal fission , e.g. in many sea anemones .[/SIZE][/FONT][/COLOR][/B]

[B][COLOR=black][FONT=Verdana][SIZE=2] [/SIZE][/FONT][/COLOR][/B]

[B][COLOR=black][FONT=Verdana][SIZE=2] Polymorphism [/SIZE][/FONT][/COLOR][/B]

[SIZE=2][FONT=Verdana] [/FONT][FONT=Verdana][/FONT][/SIZE]
[B][COLOR=black][FONT=Verdana][SIZE=2]In many cnidarians the life-cycle contains two morphologically dissimilar individuals , the pulp and the medusa . In colonial species, each of these types may occur in a number of different morphological forms , specialized to perform a particular function .[/SIZE][/FONT][/COLOR][/B]

[B][COLOR=black][FONT=Verdana][SIZE=2]The main types of modified polyp are :[/SIZE][/FONT][/COLOR][/B]

[B][COLOR=black][FONT=Verdana][SIZE=2] a. the gastrozooid ---- feeding polyp [/SIZE][/FONT][/COLOR][/B]

[B][COLOR=black][FONT=Verdana][SIZE=2] b. the gonozooid ---- reproductive polyp[/SIZE][/FONT][/COLOR][/B]

[B][COLOR=black][FONT=Verdana][SIZE=2] c. the dactylozooid ---- protective polyp , or tentaculozooid [/SIZE][/FONT][/COLOR][/B]

[B][COLOR=black][FONT=Verdana][SIZE=2]a, b and c are found in hydrozoan colonies [/SIZE][/FONT][/COLOR][/B]

[B][SIZE=2] d. the autozooid ---- feeding and reproductive polyp[/SIZE][/B]

[B][COLOR=black][FONT=Verdana][SIZE=2] e. the siphonozooid ---- current producing polyp[/SIZE][/FONT][/COLOR][/B]

[B][COLOR=black][FONT=Verdana][SIZE=2]d, and e are found in some authozoan colonies[/SIZE][/FONT][/COLOR][/B]

[B][COLOR=black][FONT=Verdana][SIZE=2]A colony may also bear medusoid forms in different stages of formation or degeneration, which may or may not be freed . Medusae may become modified as swimming bells, floats , protective bracts or phyllozooids, or gonophores which serve only for reproduction . [/SIZE][/FONT][/COLOR][/B]

[B][COLOR=black][FONT=Verdana][SIZE=2] [/SIZE][/FONT][/COLOR][/B]

[B][COLOR=black][FONT=Verdana][SIZE=2] [/SIZE][/FONT][/COLOR][/B]

[B][COLOR=black][FONT=Verdana][SIZE=2][COLOR=sienna]Phylum Ctenophora[/COLOR]
[/SIZE][/FONT][/COLOR][/B]

[B][COLOR=black][FONT=Verdana][SIZE=2]About 100 species known . Ovoid forms measure up to about 5 cm , flattened forms may be up to 1 meter or more in length .[/SIZE][/FONT][/COLOR][/B]

[SIZE=2][FONT=Verdana] [/FONT][FONT=Verdana][/FONT][/SIZE]
[B][COLOR=black][FONT=Verdana][SIZE=2][COLOR=sienna](1) Characteristics[/COLOR] [/SIZE][/FONT][/COLOR][/B]

[B][COLOR=windowtext][FONT=Verdana][SIZE=2] [/SIZE][/FONT][/COLOR][/B]

[B][COLOR=black][FONT=Verdana][SIZE=2]a. symmetry biradial ; arrangement of internal canals and the position of the paired tentacles change the radial symmetry into a combination of the two ( radial + bilateral )[/SIZE][/FONT][/COLOR][/B]

[B][COLOR=black][FONT=Verdana][SIZE=2]b. usually ellipsoidal or spherical in shape , with radially arranged rows of comb plates for swimming [/SIZE][/FONT][/COLOR][/B]

[B][COLOR=black][FONT=Verdana][SIZE=2]c. Ectoderm , endoderm , and a mesoglea ( ectomesoderm ) with scattered cells and muscle fibers ; may be considered tripoblastic [/SIZE][/FONT][/COLOR][/B]

[B][COLOR=black][FONT=Verdana][SIZE=2]d. Nematocysts absent ( except in one species ) , but adhesive cells ( colloblasts ) present [/SIZE][/FONT][/COLOR][/B]

[B][COLOR=black][FONT=Verdana][SIZE=2]e. Digestive system consisting of mouth, pharynx , stomach , and a serious of canals [/SIZE][/FONT][/COLOR][/B]

[B][COLOR=black][FONT=Verdana][SIZE=2]f. Nervous system consisting of a subepidermal plexus concentrated around the[/SIZE][/FONT][/COLOR][/B]

[B][COLOR=black][FONT=Verdana][SIZE=2]mouth and beneath the comb plate rows; an aboral sense organ ( statocyst )[/SIZE][/FONT][/COLOR][/B]

[B][COLOR=black][FONT=Verdana][SIZE=2]g. No polymorphism or attached stages [/SIZE][/FONT][/COLOR][/B]

[B][COLOR=black][FONT=Verdana][SIZE=2]h. Reproduction monoecious, gonads ( endodermal origin ) on the walls of the digestive canals , which are under the rows of comb plates ; determinate cleavage ; cydippid larva[/SIZE][/FONT][/COLOR][/B]

[B][COLOR=black][FONT=Verdana][SIZE=2]i. Luminescence common [/SIZE][/FONT][/COLOR][/B]

[SIZE=2][FONT=Verdana] [/FONT][FONT=Verdana][/FONT][/SIZE]
[B][COLOR=black][FONT=Verdana][SIZE=2][COLOR=sienna] Comparison with Cnidaria[/COLOR] [/SIZE][/FONT][/COLOR][/B]

[SIZE=2][FONT=Verdana] [/FONT][FONT=Verdana][/FONT][/SIZE]
[B][COLOR=black][FONT=Verdana][SIZE=2][COLOR=sienna]A. Ctenophores resemble the cnidarians in the following ways:[/COLOR][/SIZE][/FONT][/COLOR][/B]

[SIZE=2][FONT=Verdana] [/FONT][FONT=Verdana][/FONT][/SIZE]
[B][COLOR=black][FONT=Verdana][SIZE=2]a. Form of radial symmetry ; together with the cnidarians , they form the group Radiata [/SIZE][/FONT][/COLOR][/B]

[B][COLOR=black][FONT=Verdana][SIZE=2]b. Aboral - oral axis around which the parts are arranged [/SIZE][/FONT][/COLOR][/B]

[B][COLOR=black][FONT=Verdana][SIZE=2]c. Well - developed gelatinous ectomesoderm [/SIZE][/FONT][/COLOR][/B]

[B][COLOR=black][FONT=Verdana][SIZE=2]d. No coelomic cavity [/SIZE][/FONT][/COLOR][/B]

[B][COLOR=black][FONT=Verdana][SIZE=2]e. Diffuse nerve plexus [/SIZE][/FONT][/COLOR][/B]

[B][COLOR=black][FONT=Verdana][SIZE=2]f. Lack of organ systems [/SIZE][/FONT][/COLOR][/B]

[B][COLOR=black][FONT=Verdana][SIZE=2] [/SIZE][/FONT][/COLOR][/B]

[B][COLOR=black][FONT=Verdana][SIZE=2][COLOR=sienna]B. They differ from the cnidarians in the following ways:[/COLOR][/SIZE][/FONT][/COLOR][/B]

[SIZE=2][FONT=Verdana] [/FONT][FONT=Verdana][/FONT][/SIZE]
[B][COLOR=black][FONT=Verdana][SIZE=2]a. No nematocysts except in Euchlora [/SIZE][/FONT][/COLOR][/B]

[B][COLOR=black][FONT=Verdana][SIZE=2]b. Development of muscle cells from mesenchyme[/SIZE][/FONT][/COLOR][/B]

[B][COLOR=black][FONT=Verdana][SIZE=2]c. Presence of comb plates and colloblasts [/SIZE][/FONT][/COLOR][/B]

[B][COLOR=black][FONT=Verdana][SIZE=2]d. Mosaic, or determinate type of development [/SIZE][/FONT][/COLOR][/B]

[B][COLOR=black][FONT=Verdana][SIZE=2]e. Presence of pharynx generally [/SIZE][/FONT][/COLOR][/B]

[B][COLOR=black][FONT=Verdana][SIZE=2]f. No polymorphism[/SIZE][/FONT][/COLOR][/B]

[SIZE=2][FONT=Verdana] [/FONT][FONT=Verdana][/FONT][/SIZE]
[B][COLOR=black][FONT=Verdana][SIZE=2][COLOR=sienna] Classification[/COLOR] [/SIZE][/FONT][/COLOR][/B]

[SIZE=2][FONT=Verdana] [/FONT][FONT=Verdana][/FONT][/SIZE]
[B][SIZE=2][FONT=Times New Roman] [COLOR=sienna] [/COLOR][/FONT][COLOR=sienna]Class Tentaculata[/COLOR] [/SIZE][/B]

[B][COLOR=windowtext][FONT=Verdana][SIZE=2] [/SIZE][/FONT][/COLOR][/B]

[B][COLOR=black][FONT=Verdana][SIZE=2]With tentacles. Tentacles may or may not have sheaths into which they retract . Some types flattened for creeping ; other compressed to a bandlike form . In some the comb plates may be confined to the larval form. [/SIZE][/FONT][/COLOR][/B]

[B][SIZE=2][COLOR=sienna][FONT=Times New Roman] [/FONT]Class Nuda[/COLOR][/SIZE][/B]

[B][COLOR=windowtext][FONT=Verdana][SIZE=2] [/SIZE][/FONT][/COLOR][/B]

[B][COLOR=black][FONT=Verdana][SIZE=2]Without tentacles; conical form; wide mouth and pharynx; gastrovascular canals much branched . [/SIZE][/FONT][/COLOR][/B]

[B][COLOR=black][FONT=Verdana][SIZE=2][/SIZE][/FONT][/COLOR] [/B]

[B][COLOR=black][FONT=Verdana][SIZE=2][IMG]http://content.tutorvista.com/biology_11/content/us/class11biology/chapter10/images/img45.jpeg[/IMG][/SIZE][/FONT][/COLOR][/B]

[B][COLOR=black][FONT=Verdana][SIZE=2][/SIZE][/FONT][/COLOR] [/B]

[B][COLOR=black][FONT=Verdana][SIZE=2][IMG]http://gurungeblog.files.wordpress.com/2008/11/obelia.jpg[/IMG][/SIZE][/FONT][/COLOR][/B]

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