- See below:
- 1. Seaweeds
- 2. Classification of higher Marine Animals
- 3. Marine Studies Courses
-
-
WHAT ARE SEAWEEDS?
-
- Seaweeds are marine algae; most are multicellular and some are single-celled organisms. Some biologists prefer to call these organisms “macrophytes”. Though multicellular seaweeds are more complex than unicellular ones, they are nevertheless much simpler organisms than higher plants: They do not have complex structures or involved reproduction like most terrestrial plants, and they do not have true stems, leaves or roots. However, seaweed has apparently been crucial the evolution of land plants, for it generally supposed that the plant groups evolved from freshwater green algae.
-
- Most seaweeds consist of a “thallus”, sometimes called a frond. The term thallus refers to the body of a plant that does not have leaves, roots or stems, and is also use in relation to fungi, though they are no longer classified as plants. The thallus of algae can range in form from a tar-like crust, to a thin sheet, to a simple filamentous branching structure to a more elaborate plant with leaf-like blades.
-
- Flattened parts of the thallus, called blades, function to increase the surface area for photosynthesis and do not possess veins; both upper and lower surfaces are identical. Blades can sometimes have structures known as pneumatocysts which act as gas-filled bladders, maximising exposure to sunlight near the surface. Bladders can also assist flotation. Some algae possess a stipe. Stipe are stem-like in appearance and provide support, but do not hold the algae to a surface. Instead, a feature called a holdfast anchors the thallus to the sea floor. However, holdfasts do not function as roots; instead, nutrients are taken in via the thallus.
-
- Seaweed reproduce by means of spores, which can be produced sexually or asexually. The main difference between a spore and a seed is that a spore contains very little food resource, unlike seed, and rely on favourable conditions for germination. They can also survive long periods until those conditions occur.
Classification of Higher Animals
The sub phylum Vertebrata is placed within the phylum Craniata. The more complex marine animals fall within this group.
Craniata includes animals with a distinct brain.
Vertebrata includes animals with a distinct back bone.
Classes within Vertebrata include:
*Cyclostomata (Lampreys and Hagfish)
*Chondrichthyes (Sharks, Skates & Rays)
*Osteichthyes (Bony fish)
*Choanichthyes (Lungfish)
*Amphibia (Amphibians-frogs etc)
*Reptilia (Crocodiles, Marine Iguanas, Turtles etc)
*Aves (Birds)
*Mammalia (Mammals)
Distance Education Courses available through ACS Distance Education include the following. Click on anything of interest.
Marine Studies Ihttp://www.acsedu.co.uk/courses/product.aspx?id=489
Marine Studies II
