Echinoderms

Echinoderms

 

 Echinoderms are characterized by several arms around a central mouth forming radial symmetry, spiny skin, a water vascular system, internal skeleton, and tube feet. A water vascular system is filled with fluid and carries out many essential body functions such as respiration, circulation, and movement. A tube foot is a suction cup like structure that operates from a muscle pulling the center of the center of the sucker upwards which creates suction so the foot can hold onto surfaces very strongly. 

Echinoderms sexually through external fertilization. In reproduction the sperm that is produced in the testes of a male and the eggs produced in the ovaries of a female are shed into the water where the fertilization then takes place. After the bilateral larvae swim around they settle to the bottom of the ocean where they develope into adults with radial symmetry.

Some examples of Echinoderms are

Sea Urchins

Sand Dollars

Brittle Stars

Sea Cucumbers

Sea Stars

 Cite:

Pictures:

http://www.biog1105-1106.org/labs/deuts/echinoderms.html

http://photos.igougo.com/pictures-photos-p308039-Bishop_Cap_Sea_urchin.html

http://www.scuba-equipment-usa.com/marine/NOV04/Black_Sea_Urchin%28Centrostephanus_rodgersii%29.html

http://www.wildabouttheworld.com/gallery/showphoto.php/photo/240

http://myfishtanks.info/fish-profile/saltwater-invertebrate-profiles/brittle-star-tiger-striped-serpent-seastar/

http://www.aquaticcommunity.com/news/lib/164

http://www.seascape-photos.co.uk/norway/norway02.html

Info:

http://www.starfish.ch/reef/echinoderms.html

Pretice Hall Biology book

Arthropods

Arthropods

 Arthropods are characterized by a segmented body, exoskeleton, jointed appendages, open circulatory system, and a dorsal brain with a ventral nerve cord. A segmented body is called metamerization and in many arthropod groups, the segments have evolved into specialized distinct body regions. The exoskeleton of Arthropods are made chitin and usually hardened with scerotin (a protein) or calcium carbonate.When an Arthropod outgrows its exoskeleton, it undergoes a period of molting when it sheds its exoskeleton. Arthropods also have jointed appendages. "Appendages are structures such as legs and antennae that extend from the body wall." These structures include legs, sucking tubes, gills, jaws, antennae, etc. Arthropods also have a open circulatory system which means their blood is not completely contained in blood vessels. They also have a Dorsal brain which is a brain located at the front of the body. Along with the dorsal brain arthropods have a ventral nerve cord. 

Arthropods reproduce sexually through internal fertilization and aquatic arthropods use external fertilization. During internal fertilization the males use reproductive organs to place sperm inside females or the male could deposit a sperm packet that is picked up by females. In the aquatic arthropods, the female releases eggs into the outside environment and males shed sperm around the eggs. 

Some examples of Arthropods are

spiders

crabs

millipedes

butterflies

cite:

Pictures:

http://nashzoology.ning.com/forum/topics/arachnid-research-1?commentId=2223964%3AComment%3A7166&xg_source=activity 

 http://www.bighairyspiders.com/pic_cobalt.shtml

http://tripwow.tripadvisor.com/slideshow-photo/galapagos-dreaming-of-mcfish-with-fries-by-travelpod-member-anywherebuthere-puerto-ayora-ecuador.html?sid=13527792&fid=tp-7

 http://octopunkpix.blogspot.com/2007_04_01_archive.html

http://pal2pal.com/BLOGEE/index.php?/site/glass_wing_butterflies/

Info:

http://userwww.sfsu.edu/~biol240/labs/lab_19arthropod/pages/arthrochars.html

 Pretice Hall Biology book

Mollusks

Phyla Mollusca

Mollusks are a common invertebrate. They are most commonly characterized for having soft bodies and a hard external or internal shell. The body plan of a mollusk consists of 4 main parts: foot, mantle, shell, and visceral mass. The mantle is a cloak-like thin layer of tissue that covers most of the mollusks body. The foot is unlike our feet, but is used for locomotion. It uses a spade shaped structure for digging, a flat structure for crawling, and sometimes tenticles to catch prey.

 

 Mollusks can reproduce sexually by external fertilization or asexually if the mollusk is hermaphroditic (has both male and female sex organs). During external fertilization they release huge numbers of sperm and eggs into the surrounding water. The eggs become fertilized and develop into larvae. In some cases where there is a hermaphroditic mollusk, individuals of this type fertilize eggs from another individual.

Some examples of mollusks are

nudibranchs

sea hares

octopi

Cite:

Pictures:

 http://scienceray.com/biology/marine-biology/mollusks-one-of-the-largest-phyla-in-the-animal-kingdom/

http://www.thefullwiki.org/Gastropod

http://scottpenny.smugmug.com/Underwater/Favorite-Photos/Macro-Photos-1/3710902_a4E68/1/483251229_Sxydq#483251229_Sxydq

http://www.divebums.com/week/2006/Jul03-2006/index.html

http://www.wonderquest.com/octopus-and-energy.htm

Info:

http://www.earthlife.net/inverts/mollusca.html

Pretice Hall Biology book

 

Annelids

Annelids

Annelids have segmented bodies and can be found almost anywhere in the world. Annelids also have well-developed internal organs and bilateral symmetry. Some annelids have bristles for movement called cilia. The body cavity of a annelid is a true coelom, often divided by internal septa. The body possesses 3 seperate sections; a prosomium, a trunk, and a pygidium as well as  a mouth and anus. 

Annelids reproduce sexually and asexually. When reproducing asexually, annelids split into 2 or more pieces in a process called budding. During sexual reproduction, animals with seperate sexes let sperm and ova into the water from their nephridia and the fertilized eggs then live as plankon. They later sink to the bottom and go through metamorphosis to mature into the full adult form.

Some common examples of annelids are 

earthworms

leaches

 

ragworms

Cite:

Pictures:

 http://www.pbs.org/kcet/shapeoflife/animals/annelids.html

 http://www.kidport.com/reflib/science/animals/annelids.htm

http://kentsimmons.uwinnipeg.ca/16cm05/16labman05/lb6pg1.htm

 http://www.hidrostal.co.uk/news.aspx?p=41

Info:

http://www.earthlife.net/inverts/annelida.html 

http://www.kidport.com/reflib/science/animals/annelids.htm 

http://en.wikipedia.org/wiki/Annelid#Reproduction_and_life_cycle

Nemotodes (roundworms)

Phylum Nematoda (roundworms)

roundworms have bilateral symmetry and their bodies have no more than 2 cell layers. Their body fluids are under high pressure and they have a pseudocoel body cavity and possesses a through gut with an anus. A roundworms body is covered with a complete cuticle. Nematodes apear in almost every habitat except for dry places. 

They reproduce sexually or hermaphroditism may also occur. The basic reproductive structures of a male nematode include: one testis, a seminal vescicle and a vas defrens opening at the cloaca.  Basic female reproductive structures include: one or two ovaries, seminal receptacles, uteri, ovijectore, and a vuvla. The females ovary(ies) that holds the eggs in an oviduct. It then passes them to the uterus. They are fertilized here from the male sperm. The males sperm cells are stored in the vas defrens after being produced by the testis. The sperm passes through the spicule when it is time to reproduce. Over 200,000 eggs can be deposited, once they are fertilized, into the soil.

Some Examples of nematodes are;

Ascaris

 

Wuchereria

Cite:

Pictures:

http://www.ars-grin.gov/ars/SoAtlantic/fp/stpp/burelle/nematode.html 

http://withfriendship.com/user/neeha/ascaris.php

http://www.parasitesinhumans.org/wuchereria-bancrofti-lymphatic-filariasis.html

Info:

http://www.mcwdn.org/Animals/Roundworms.html 

http://www.earthlife.net/inverts/nematoda.html 

http://nematode.unl.edu/reproduc.htm 

Platyhelminthes (Flatworms)

Platyhelminthes (Flatworms)

Flatworms are the simplest of the worm groups and are found in marine and fresh water. They can be free living parasites. One example of a well known parasitic flat worm is a Tapeworm. Flatworms are also the simplest animals to have bilateral symmetry and are triplobastic, which means they are composed of 3 fundamental cell layers. Flatworms are flat because of their lack of a body cavity. They also lack an anus, the same pharyngeal opening expels waste as well as taking in food. Because they only have a gut and no real digestive system they must respire by diffusion. They are also flat because no cell can be too far from the outside.

Most Platyhelminthes have reproductive systems that produce gametes. The majority of flat worms are hermaphroditic, simultaneously male and female. Because of this many reproduce asexually.

Some other examples of flat worms are tapeworms, planarians, and flukes.

tapeworm

 

Planarian

Fluke

 

Cite:

Pictures:

 http://www.starfish.ch/c-invertebrates/flatworms.html

 http://curezone.com/ig/i.asp?i=1358

http://web.mit.edu/neuro/planaria.html 

 http://www.whatsthelatest.net/health/10-human-adversaries/

Info:

http://faculty.fmcc.suny.edu/mcdarby/animals&plantsbook/animals/03-Flatworms.htm

http://www.ucmp.berkeley.edu/platyhelminthes/platyhelminthes.html

http://www.mcwdn.org/Animals/Flatworm.html

Cnidaria

Phyla Cnidaria

Cnidarians have radial or biradial symmetry around a mouth as illustrated in the picture above. They have no head or segmentation of any kind. Cnidarians have an external epidermis and an inner gastrodermis. The mouth of a cnidaria is surrounded by soft tentacles connected to a digestive system that resembles a sac. This cavity may branch out or be divided by a septa. A cnidaria has no circulatory, excretory, or respiratory organs. They have no central nervous system as well, but they do have a diffuse network of unpolarized nerve cells. These nerve cells are located in the body wall. Cnidocyte cells contain nematocysts. This is for stinging and paralyzing prey.There are mainly 2 forms cnidarians can take. 

Polyp and Medusa

Cnidarians are classified into 4 classes;

Hydrozoa

Scyphozoa

Cubozoa

Anthozoa

Cniadrians commonly reproduce sexually. They use budding when in the polyp stage and reproduction gametes in the medusa stage.

Examples of cnidaria are sea anemones, corals, hydras and their relatives, as well as jellyfish.

Cite

pictures:

http://eastchestereagles.wikispaces.com/Animal+Phyla+-+Even+-+Cnidarian

http://storiesfromoceansedge.blogspot.com/2009_08_01_archive.html 

http://www.doc.govt.nz/conservation/native-animals/invertebrates/protected-coral/

http://www.ucmp.berkeley.edu/cnidaria/C_sivickisi.html

http://www.fotopedia.com/items/flickr-129181039

http://bio1151b.nicerweb.com/Locked/media/ch33/cnidaria.html

Info:

http://library.thinkquest.org/26153/marine/cnida.htm

Pretence Hall Biology book