Invertebrates

Invertebrates Jellyfish The Jellyfish are truly a wonder of nature. They have always been objects of deep observation and admiration. Not to mention the fact, that they are also considered in great awe, fear and even repulsion by some folks. The repulsion and fear have originated from the fact that these creatures can be quite beautiful to behold, but extremely painful when stung by them. These marine creatures are classified under the group of Cnidarians. They typically have a soft jelly like consistency to their body, prompting the people to call them as Jellyfish. There are numerous surprises in store, when we deal with Jellyfishes.The first and foremost of the surprise is the vast reservoir of chemical factories, inside the tiny body. Though this creature does not have a vertebral column, a proper demarcation of body and head, and not even a brain, yet this Jellyfish is seen to possess numerous different chemicals, some of which are extremely toxic and poisonous too. Next in stor e for the observer or the scientist is the next surprise, which is the fluorescent quality of these creatures. The Jellyfish possess a chemical protein inside their body fluid, called as aequorin, which was derived from the species of Jellyfish called as Aequorea Victoria.The GFP or the green fluorescent protein was derived from this protein. Both these proteins have a property of photo luminescence, which means lighting up in the dark, and also the property of fluorescence. Then there are the Neon Jellyfish which are also called as rainbow Jellyfish. These do not produce any photo luminescent protein as such. But yet they manage to shine or light up in the dark. They possess a hair like structure called cilia which help in their motility. The light which falls on these cilia is reflected back and this simple property of light reflection makes these rainbow Jellyfish fluorescent.Cycloporus Venetus (Blue Flatworm) FLATWORMS – UMMM. THEY'RE FLAT We have to run out of steam ther e. But that's the one obvious connection between all of the worms in this group. Sure we can tell you that there are over 20,000 known species. Most of the species are parasitic. They are super-primitive organisms that were the first to develop mesoderm. The big thing you should remember is that they are flat. There may be one more fact to remember. They are found in every environment that has water. Many scientists believe there are hundreds of species we will still discover. BASIC TYPESYou'll learn about a few classic examples of flatworms in your classes. Tapeworms are always a nasty example. They live in intestinal tracts of many species. Cats, dogs, and even you could wind up with tapeworms. You'll also hear about flukes. It's another parasitic species that has a close relationship with man and other mammals. They are suckers in the flatworm family. Planaria are harmless flatworms that are often used in your biology labs. They are freshwater flatworms that have a head like an a rrow. They're black with two white spots on their heads. Those spots are not eyes, but they do sense light.Flatworms have very simple nervous systems. WHERE WILL YOU FIND THEM? If you find water, there's a good chance flatworms will be around. Most are very small and not obvious immediately. Flatworms get most of their oxygen through diffusion. Since they have no specialized circulatory system, their flatness gives them a greater surface area to absorb more oxygen. There are species in many freshwater and saltwater environments as well as inside larger organisms. While we made them seem easy to find, it's sometimes very hard to track them down. Since many flatworms are parasites, they have lifecycles in different hosts.Eggs many be deposited in the feces of one species. Another organism might eat those eggs and development begins in the digestive system. The flatworm might then mature in the muscle tissue. Flatworms can get around. SOME STRUCTURE STUFF Although really simple, flatwo rms have some advanced structures compared to some other animals. They were the first species to develop mesoderm. That mesoderm tissue develops into organs and muscles as the organism grows. They also have simple nervous systems and sensory organs. While they don't have a respiratory system or circulatory system to speak of, they do have a neat little digestive system.Most species of flatworms have no anus and a cavity with only one opening. While not all species do, many flatworm species use a mouth to eat. The only problem with no anus is that the stuff you don't digest has to go out the mouth when you're done. Other materials that need to be removed from the system can be excreted through specialized cells called flame cells. Flame cells are the first appearance of excretory ducts in organisms. Flame cells have cilia that beat and filter out materials that the flatworm wants to get rid of.