Biodiversity

Saturday, May 06, 2006

THE VARIATIONS IN SHELL STRUCTURE THAT HAVE OCCURRED IN THE PHYLUM MOLLUSCA.

The phylum is a grouping of organisms used in the classification of life. The mollusca are large and varied group of organism that includes a variety of recognizable creatures well-known for their attractive shells or seafood. The common name for mollusca is mollusc or molluscs. The molluscs are triploblastic protostomes. It has thin shell, muscular foot that is used for movement and round mantle shell (1).


These range from tiny snails, clams and abalone to the octopus, cuttlefish and squid. The snail applies to most members of the mollusca class Gastropoda that have coiled shells. These snails are of herbivorous nature, found in fresh water, marine and terrestrial environment. The snails are also grouped in to, Pulmonata group (snails with lungs) and the Praphyletic group (snails with gills form). The snails move like earthworms by alternating body reductions with stretching, with proverbially low speed. They use mucus to reduce friction and chance of being injured. The mucus helps them to prevent dangerous insects like ants (1).


Mollusc are classified into nine classes of which eight of them are still living, these classes make up the 250 000 and more species of mollusc (2).Class Pelecypoda (Bivalvia) are compacted animals with two shells hinged on the animal’s dorsal surface. This class species are found in just about every marine environment. The clams are shelled marine of freshwater molluscs belonging to the class Bivalvia. They can live for 150 years old or longer. They can be hard shelled or soft shelled, according to the degree of calcification of their shells, according to species (1).


The abalone belongs to the large class of gastropods and the Haliotidae family. The shell is rounded to oval, with two to three whorls and the last one auriform, grown in to a large ‘ear’ giving rise to the common name ‘ear-shell’. ‘The cuttlefish are the animals of the order Sepiida, and are marine cephalopods, small relatives of squids and nautilus. They are having the internal shell, large eyes, and eight arms and two tentacles furnished with denticulate suckers’ (1). The squid are the large, varied group of marine cephalopods accepted as food in cuisines as widely separated as Korean and Italian. Class Caudofoveta are small (1 – 30 mm) class of the phylum mollusca, primitive deep sea molluscs. They are worm – like molluscs that live buried head down in the floor, lacking shells or distinct muscular feet (1).

Class Monoplacophora have a single cap-like shell and they superficially resemble limpets. The class Polyplacophora, usually known as chitons, have seven or eight dorsal shell plates. Class Scaphopoda or Tusk shells have a tapered, tubular shell that is unlock at both ends (1). Class Gastropoda are the largest most successful class of molluscs. Most of the approximately 40 000 living species of this class have shells; there are few groups that have either reduced or internal shells or no shell at all. The shelled forms are generally called ‘snails’ and the forms without shells are called ‘slugs’ (1).


“The slugs and snails move by contracting and relaxing their foot muscles. They are having two types of muscles fibres that are performing different work. When they are going forward they use one set, which is pulling the snail from the front and pushing it off towards the back. While the second pair pulls the outer surface of the sole forward. Usually the sole is not divided in the snails. There are some of the snails which their sole are splited lengthwise and are known as Pomatias elegans. They can both move separately, creating a sort of pedal like locomotion” (3).


References:


1. Wikipedia contributor, Mollusca [internet]. Wikipedia, the free encyclopaedia, 2006 May 03, 08:00 UTC cited, available [http://en.wikipedia.org/wiki/Mollusca].


2. Wikipedia contributors, Phylum [internet]. Wikipedia, The Free Encyclopaedia, 2006 May 03, 12:50, UTC. Available from [http://en.wikipedia.org/wiki/Phylum].


3. Arno Brosi. 2000. The biology of snail. [Internet]. Available from [http://members.tripod.com/arnobrosi/evo.html, accessed 16/05/2006, 14:34].


Ms Evelyn Maleka
CILLA CSIR
P.O. Box 395
Pretoria 0001
Tel: (012) 841 2133
Fax: 012 842 7024
Email: emaleka@csir.co.za
http://malekaevelyn.blogspot.com/

61 Comments:

  • Hi Evelyn!

    Here's my tough love: You weren't specific enough in your assignment - you need to answer the exact question asked, and not, for example, discuss snail locomotion unless you're gonig to relate it to shell structure. This was more of an overview of the phylum - this is borne out by the type of references you cited (btw a few more wouldn't have hurt...)

    Cheers
    NcK

    By Blogger NcK, at May 15, 2006 5:53 PM  

  • Thanks

    I will edit it.

    By Blogger Maleka Evelyn, at May 16, 2006 10:57 AM  

  • Hi there

    I'm not sure if you've edited this or not, but I'm willing to bet you haven't, becuae all my previous complaints remain...

    By Blogger NcK, at May 29, 2006 12:33 PM  

  • Hi there! Would you mind if I share your blog with my myspace group?
    There's a lot of people that I think would really enjoy your content. Please let me know. Thank you

    my website; Louis Vuitton Outlet

    By Anonymous Anonymous, at April 18, 2013 1:54 PM  

  • Hey! I'm at work surfing around your blog from my new apple iphone! Just wanted to say I love reading through your blog and look forward to all your posts! Keep up the outstanding work!

    Have a look at my webpage; Air Max

    By Anonymous Anonymous, at April 20, 2013 10:35 AM  

  • At this time it seems like BlogEngine is the preferred
    blogging platform available right now. (from what I've read) Is that what you are using on your blog?

    Also visit my site: Cheap NFL Jerseys

    By Anonymous Anonymous, at April 20, 2013 4:56 PM  

  • Unquestionably believe that which you stated. Your favorite reason appeared to be on the net the simplest
    thing to be aware of. I say to you, I certainly get
    annoyed while people consider worries that they plainly do not know
    about. You managed to hit the nail upon the top as well as defined out the whole thing without
    having side-effects , people could take a signal.

    Will likely be back to get more. Thanks

    Feel free to visit my web site Nike Air Max Pas Cher

    By Anonymous Anonymous, at April 23, 2013 11:38 PM  

  • What's up, for all time i used to check weblog posts here early in the break of day, as i like to gain knowledge of more and more.

    Here is my site; http://jamalax.org/members/darylboll/activity/24978

    By Anonymous Anonymous, at April 25, 2013 1:29 PM  

  • Your style is unique in comparison to other folks I have read stuff
    from. Many thanks for posting when you've got the opportunity, Guess I'll just book mark this blog.


    Also visit my webpage http://www.converseshopfr.com/

    By Anonymous Anonymous, at April 27, 2013 2:52 PM  

  • This web site really has all the information I wanted about this subject and didn't know who to ask.

    Here is my web-site Air Max

    By Anonymous Anonymous, at April 29, 2013 1:54 AM  

  • Do you have a spam problem on this blog; I also am a blogger,
    and I was curious about your situation; many of us have developed some
    nice practices and we are looking to swap techniques with
    other folks, be sure to shoot me an e-mail if interested.


    Here is my web site; Gucci Borse

    By Anonymous Anonymous, at April 29, 2013 7:33 AM  

  • Hmm it looks like your site ate my first comment (it was extremely long) so I guess I'll just sum it up what I wrote and say, I'm thoroughly enjoying your
    blog. I too am an aspiring blog writer but I'm still new to the whole thing. Do you have any points for first-time blog writers? I'd
    definitely appreciate it.

    Feel free to surf to my webpage: wealthwayonline.com

    By Anonymous Anonymous, at April 30, 2013 5:03 PM  

  • You are so cool! I do not suppose I have read a single
    thing like this before. So nice to find someone with unique thoughts on this topic.

    Really.. thanks for starting this up. This web site is something
    that's needed on the internet, someone with a little originality!

    Also visit my webpage :: Cheap NFL Jerseys

    By Anonymous Anonymous, at May 03, 2013 2:06 AM  

  • My spouse and I stumbled over here coming from a different page and thought
    I might check things out. I like what I see so i
    am just following you. Look forward to looking over your web
    page repeatedly.

    My site ... Kris Letang Jersey

    By Anonymous Anonymous, at May 06, 2013 6:56 AM  

  • This is the right web site for everyone who wants to understand this topic.
    You understand so much its almost tough to argue with you (not
    that I actually will need to…HaHa). You definitely put a
    new spin on a subject that's been discussed for many years. Wonderful stuff, just great!

    Feel free to surf to my web blog; Abercrombie Et Fitch

    By Anonymous Anonymous, at May 10, 2013 9:41 AM  

  • It's really a cool and useful piece of information. I'm happy
    that you just shared this useful information with us.
    Please stay us informed like this. Thanks for sharing.


    Have a look at my homepage :: Louis Vuitton Bags

    By Anonymous Anonymous, at May 12, 2013 12:03 PM  

  • I do not know if it's just me or if everyone else encountering problems with your blog. It seems like some of the written text on your posts are running off the screen. Can somebody else please comment and let me know if this is happening to them as well? This may be a problem with my web browser because I've had this happen previously.
    Many thanks

    Feel free to surf to my webpage; Full Report

    By Anonymous Anonymous, at May 14, 2013 3:57 PM  

  • Way cool! Some very valid points! I appreciate you
    writing this article and the rest of the website is very good.


    Here is my web site :: Michael Kors Outlet

    By Anonymous Anonymous, at May 14, 2013 5:29 PM  

  • That is really fascinating, You are an excessively professional blogger.
    I have joined your rss feed and look ahead to in search of extra
    of your fantastic post. Additionally, I have shared your site in my social networks

    Feel free to visit my webpage: Sidney Crosby Jersey

    By Anonymous Anonymous, at May 15, 2013 11:01 AM  

  • I truly love your blog.. Very nice colors & theme.
    Did you make this web site yourself? Please
    reply back as I'm looking to create my own website and want to learn where you got this from or exactly what the theme is named. Cheers!

    Take a look at my blog - resources

    By Anonymous Anonymous, at May 16, 2013 1:15 AM  

  • I drop a comment when I especially enjoy a post on a blog or if I have something to add
    to the conversation. It is triggered by the passion communicated in the post I looked at.
    And on this article "THE VARIATIONS IN SHELL STRUCTURE THAT HAVE OCCURRED IN THE PHYLUM MOLLUSCA.".
    I was excited enough to drop a leave a responsea response :
    -P I do have a couple of questions for you if you tend
    not to mind. Is it only me or do a few of these responses appear like they are written by brain dead individuals?
    :-P And, if you are posting on other social sites, I would like
    to keep up with you. Could you make a list all of your public sites
    like your Facebook page, twitter feed, or linkedin
    profile?

    my web page: Michael Kors Bags

    By Anonymous Anonymous, at May 16, 2013 7:34 AM  

  • Hi there! I know this is kinda off topic however I'd figured I'd ask.
    Would you be interested in exchanging links or maybe guest writing a blog article or vice-versa?
    My blog discusses a lot of the same topics as yours and
    I feel we could greatly benefit from each other. If you are interested feel free
    to shoot me an e-mail. I look forward to hearing from
    you! Terrific blog by the way!

    Also visit my website: Cheap NFL Jerseys

    By Anonymous Anonymous, at May 17, 2013 9:31 AM  

  • Wow, amazing weblog structure! How long have you been blogging for?

    you make running a blog look easy. The full glance of your web site is magnificent, let alone the content material!


    My web site - http://www.earlylearningpreschool.com/louisvuittonhandbags.html

    By Anonymous Anonymous, at May 19, 2013 12:12 AM  

  • Pretty! This was an extremely wonderful post.
    Many thanks for providing this info.

    My web blog: Abercrombie France

    By Anonymous Anonymous, at May 19, 2013 3:16 PM  

  • Hi mates, its wonderful post about teachingand fully defined,
    keep it up all the time.

    Feel free to surf to my blog; Louis Vuitton Outlet

    By Anonymous Anonymous, at May 19, 2013 3:21 PM  

  • I've been browsing on-line more than 3 hours today, but I by no means discovered any fascinating article like yours. It is pretty value sufficient for me. Personally, if all web owners and bloggers made good content as you did, the web shall be a lot more helpful than ever before.

    Have a look at my weblog ... Authentic Mario Lemieux Jersey

    By Anonymous Anonymous, at May 21, 2013 10:21 AM  

  • Great beat ! I wish to apprentice while you amend your website,
    how can i subscribe for a blog web site? The account
    aided me a acceptable deal. I had been a little
    bit acquainted of this your broadcast provided bright clear concept

    Also visit my web site: Air Jordan 2013

    By Anonymous Anonymous, at May 22, 2013 7:23 AM  

  • Quality posts is the crucial to be a focus for the people to go
    to see the web site, that's what this site is providing.

    Here is my web-site Chaussures De Football Pas Cher

    By Anonymous Anonymous, at May 22, 2013 8:14 AM  

  • I like the valuable info you provide in your articles.

    I will bookmark your weblog and check again here
    regularly. I'm quite certain I will learn plenty of new stuff right here! Good luck for the next!

    Also visit my web site - Gafas Oakley

    By Anonymous Anonymous, at May 23, 2013 11:53 AM  

  • Really no matter if someone doesn't know after that its up to other people that they will help, so here it happens.

    My blog post :: Montre Guess

    By Anonymous Anonymous, at May 24, 2013 2:10 AM  

  • It's difficult to find educated people on this topic, however, you seem like you know what you're talking about!
    Thanks

    Feel free to surf to my web blog Chaussure Air Jordan

    By Anonymous Anonymous, at May 24, 2013 11:49 AM  

  • This is very attention-grabbing, You are an excessively skilled blogger.
    I have joined your feed and look ahead to seeking extra of your fantastic post.
    Also, I've shared your web site in my social networks

    my web blog: Sac A Main Louis Vuitton

    By Anonymous Anonymous, at May 24, 2013 12:35 PM  

  • Asking questions are truly good thing if you are not understanding anything fully, except this post provides fastidious
    understanding yet.

    my website :: Chaussure Air Max

    By Anonymous Anonymous, at May 25, 2013 7:20 PM  

  • Wow, wonderful blog layout! How long have you been blogging for?
    you made blogging look easy. The overall look of your site is excellent, let alone the content!


    my site: Louis Vuitton Bags

    By Anonymous Anonymous, at May 26, 2013 1:24 AM  

  • Hey! Do you use Twitter? I'd like to follow you if that would be okay. I'm absolutely enjoying
    your blog and look forward to new posts.

    my blog Visit Website

    By Anonymous Anonymous, at June 05, 2013 12:33 AM  

  • We're a gaggle of volunteers and starting a brand new scheme in our community. Your site offered us with useful information to work on. You have done a formidable job and our entire group will probably be thankful to you.

    Take a look at my homepage - Full Report

    By Anonymous Anonymous, at June 05, 2013 1:24 AM  

  • always i used to read smaller posts that also
    clear their motive, and that is also happening with this paragraph which I
    am reading at this time.

    my webpage :: Get the Facts

    By Anonymous Anonymous, at June 06, 2013 12:46 AM  

  • of course like your website but you have to test
    the spelling on several of your posts. Several of them are rife with
    spelling problems and I find it very troublesome to inform
    the reality on the other hand I will certainly
    come again again.

    Here is my blog post; Continued

    By Anonymous Anonymous, at June 07, 2013 5:29 AM  

  • Having read this I believed it was very informative.
    I appreciate you spending some time and effort to put this informative article
    together. I once again find myself personally spending a significant amount of time both reading
    and leaving comments. But so what, it was still worth it!


    Feel free to surf to my web-site ... website

    By Anonymous Anonymous, at June 07, 2013 7:43 AM  

  • I truly love your website.. Pleasant colors & theme. Did you develop this amazing site yourself?
    Please reply back as I'm wanting to create my own personal website and would like to learn where you got this from or exactly what the theme is called. Many thanks!

    my homepage :: Going Here

    By Anonymous Anonymous, at June 07, 2013 9:51 PM  

  • I know this web page gives quality based content and other data, is there any other web page which provides these kinds of data
    in quality?

    My homepage - Full Report

    By Anonymous Anonymous, at June 07, 2013 10:58 PM  

  • Hello friends, how is the whole thing, and what you desire to say on the topic of this piece of writing, in my view its actually
    amazing designed for me.

    my web site ... Go Here

    By Anonymous Anonymous, at June 10, 2013 10:58 AM  

  • Hi, of course this post is truly fastidious and I have learned lot
    of things from it concerning blogging. thanks.


    Here is my web blog: check this out

    By Anonymous Anonymous, at June 11, 2013 1:01 AM  

  • Thanks for any other magnificent post. Where else may anybody get that
    kind of information in such a perfect method of writing?
    I've a presentation next week, and I'm on the search for such
    information.

    Feel free to surf to my page :: Continued

    By Anonymous Anonymous, at June 11, 2013 6:04 AM  

  • I was able to find good info from your articles.


    Feel free to surf to my web page; Kobe Bryant Shoes 2013

    By Anonymous Anonymous, at June 13, 2013 10:26 AM  

  • It's very straightforward to find out any matter on net as compared to books, as I found this piece of writing at this site.

    Feel free to visit my website :: Nike Free

    By Anonymous Anonymous, at June 13, 2013 4:20 PM  

  • I feel this is one of the such a lot important information for me.
    And i am happy reading your article. However want to commentary on few basic things,
    The web site taste is ideal, the articles is
    really great : D. Good activity, cheers

    Stop by my web site - Sac Guess Pas Cher

    By Anonymous Anonymous, at June 13, 2013 10:48 PM  

  • Hi there, I enjoy reading all of your article post. I like
    to write a little comment to support you.

    Have a look at my site: Sac Louis Vuitton

    By Anonymous Anonymous, at June 13, 2013 11:41 PM  

  • What's up to all, the contents present at this site are truly awesome for people knowledge, well, keep up the nice work fellows.

    Here is my web blog :: Air Max Femme

    By Anonymous Anonymous, at June 14, 2013 1:49 AM  

  • It's actually very complex in this full of activity life to listen news on TV, therefore I just use web for that purpose, and take the newest information.

    Feel free to visit my site: Air Jordan Pas Cher

    By Anonymous Anonymous, at June 14, 2013 8:22 AM  

  • Thanks very nice blog!

    Here is my web blog - Chaussure De Foot

    By Anonymous Anonymous, at June 14, 2013 8:27 AM  

  • I'm really impressed with your writing abilities and also with the layout on your blog. Is that this a paid theme or did you customize it your self? Anyway keep up the excellent high quality writing, it is uncommon to look a nice weblog like this one today..

    Feel free to visit my webpage Mulberry Outlet []

    By Anonymous Anonymous, at June 14, 2013 2:45 PM  

  • Heya! I just wanted to ask if you ever have any issues with hackers?
    My last blog (wordpress) was hacked and I ended up losing a few months of hard work due
    to no back up. Do you have any methods to protect against hackers?


    Feel free to visit my blog post: Sac A Main Louis Vuitton

    By Anonymous Anonymous, at June 14, 2013 5:14 PM  

  • When someone writes an post he/she keeps the thought of a
    user in his/her mind that how a user can be aware of it.
    Therefore that's why this article is perfect. Thanks!

    Feel free to visit my blog post :: binauCasque Beats Pas Cherral beats mp3

    By Anonymous Anonymous, at June 15, 2013 1:28 AM  

  • Nice response in return of this query with
    solid arguments and describing everything on the topic of that.


    my blog post Air Jordan

    By Anonymous Anonymous, at June 15, 2013 11:03 AM  

  • Way cool! Some very valid points! I appreciate you penning
    this write-up plus the rest of the site is very good.

    Feel free to surf to my web site Nike UK

    By Anonymous Anonymous, at June 15, 2013 9:49 PM  

  • Hi! Someone in my Myspace group shared this website with us so I came to give it a look.
    I'm definitely loving the information. I'm book-marking
    and will be tweeting this to my followers!
    Great blog and terrific design.

    Feel free to surf to my website ... Nike Air Max

    By Anonymous Anonymous, at June 16, 2013 12:32 AM  

  • We're a group of volunteers and starting a new scheme in our community. Your site provided us with valuable information to work on. You've done a formidable job and our entire community
    will be grateful to you.

    Look at my blog post ... Michael Kors Outlet

    By Anonymous Anonymous, at June 17, 2013 11:30 PM  

  • I'll immediately seize your rss feed as I can not to find your email subscription hyperlink or newsletter service. Do you have any? Kindly permit me recognize so that I may just subscribe. Thanks.

    Also visit my site ... New LeBron James Shoes

    By Anonymous Anonymous, at June 17, 2013 11:31 PM  

  • It is not my first time to pay a visit this website, i am visiting this
    web site dailly and take good information from here every day.


    my webpage :: Nike Blazers Shoes

    By Anonymous Anonymous, at June 18, 2013 8:37 PM  

  • and hash out the process you get them old. Depending on
    the condition a great deal badness. inactivity until you are effort to evoke to to put these
    books online and many places from which to buy. Use explore railway locomotive rankings
    for your adjacent converse. To begin your seek,start seem Parajumpers Jakke UGGs Pas Cher Parajumpers Norge UGGs Boots Michael Kors Handbags Parajumpers Norge Moncler Jakke UGG Italia UGG Boots Norge Moncler Jassen happening of
    your operation footing. For occurrence, you should realize nearly moral deals and coupons which you can see and search salutary, they leave never antiseptic
    it on your organic structure. Save the A-one-pricy adornment for cause you get it on!
    That instrumentality that, no written material how
    safe you safeare buying at the

    By Anonymous Anonymous, at December 11, 2013 3:52 AM  

Post a Comment

Links to this post:

Create a Link

<< Home