Wikipedy.com                                                                                           Online encyclopedia

   Home     Add article      About

Please, support our  project in social networks:

What is algae? Types of algae

Algae are plants that grow in water or in damp places. The ones that grow on the sea-shore are called seaweeds. A visit to the sea-side tells you how numerous ocean forms are, while fresh-water forms often give rise to the green scum on ponds you see in the summer. Terrestrial forms - those that do not live in water - are not so common, but you may see one form growing as a green crusty coating on tree trunks - particularly on the tree's shaded side.

What is algae plant - types of algae
Algae range in size from microscopic single-celled forms to brown seaweeds 50 yards long. At the pictures above you can see desmid and a diatom, two single-celled microscopic algae.

Algae contain some of the largest as well as the smallest kinds of life. In this enormous group of plants - about 17,000 species are known to man - many kinds consist of just one cell and can be seen only with a microscope. But certain brown seaweeds, called kelps, grow more than 50 yards long. Some single-celled forms are more like animals than plants, since they can move about. They have flagella - long hair-like out-growths of the body - that drive the organism through the water with whip-like lashing movements. Between single-celled forms and large seaweeds are several colonial algae, where groups of cells, each retaining a more or less separate way of life, combine and move about as one.

What is algae plant - types of algae
Pandorina, a microscopic colonial algae which consists of 16 identical cells arranged in a solid ball embedded in jelly. Each cell acts as an individual plant	The leaf-like red seaweed

Algae are a vital link in the chain of life in the water. Single-celled forms, such as desmids and diatoms, make up floating 'soups' of microscopic organisms collectively called plankton. Plankton is a basic source of food for all animal life in the water, both in the sea and in fresh water.

What is algae - types of algae
Bladder wrack seaweed, with a diagram showing the reproductive pits or conceptacles. Male and female cells are released from them and join together in the water to form new plants (click to increase)	Channeled wrack, a common brown seaweed

Seaweeds provide protection for animal life by the sea-shore. Most seaweeds are covered by a slimy substance, called mucilage, which prevents them from losing water and, at the same time, produces a conveniently moist shelter for marine animals when the tide goes out. From a botanical point of view, algae are rather primitive. If you compare them with flowering plants, for example, you find that algae have no proper stems, leaves, or roots, though certain seaweeds have a root-like structure known as a holdfast.

Algae do not have flowers. Instead of the pollen and egg cells of flowering plants, most algae release male and female sex cells of fairly similar size and shape into the water. Nearly all algae can also reproduce without sex cells. The contents of a cell divide into a number of 'units', and the cell then bursts open. Each 'unit' released is capable of developing into a new plant. Most algae possess the green pigment chlorophyll, the substance that traps light energy and puts it to work to make sugars. A lot of algae do not look green, but this is because they contain other pigments besides chlorophyll, which mask the green color.

Wikipedy.com ^@ - Online Encyclopedia