Know the main characteristics of algae and some differences between the groups.
The algae are a heterogeneous group of organisms characterized by the presence of chlorophyll a and do not have a split body root, stem or leaves, due to the lack of actual tissue. They can be single-celled or multicellular organisms. In the latter group, species up to 60 meters long have already been described.
Algae are found in all areas of the planet, being predominantly aquatic, but they can occur in terrestrial environments or in association with other organisms, such as lichens. In aquatic algae, we can observe different forms of life, some fixed in the substrate and others free in suspension in the water, forming the phytoplankton.
All algae are autotrophic , thus producing their food. Like plants, this group is characterized by the process of photosynthesis , in which light energy is used to produce the energy necessary for the algae to survive.
Algae are believed to be one of the oldest organisms on the planet, being responsible for the production and accumulation of oxygen in the atmosphere. This group is also considered the ancestor of modern plants, as it shares some similarities.
The ecological and economic importance of algae is immense, with emphasis on their role in the aquatic food chain (producer) and their participation in the release of oxygen. In addition, algae are widely used in oriental cuisine, mainly for the preparation of sushi, and are also a source of important substances, such as agar, which is widely used in the manufacture of ice cream, sweets and even drinks.
In addition to their importance, algae can also cause economic and ecological damage. The exaggerated increase of some species causes toxic blooms, which can cause a change in the tone of the water and trigger the death of several species of aquatic animals due to the toxins produced by some species. Usually the exaggerated increase in this group of living beings is related to the pollution of aquatic environments, which provides an environment rich in nutrients that facilitate the reproduction of some species.
Some algae are microscopic and form phytoplankton
The vast majority of algae are classified as belonging to the Protoctist kingdom, however, it is worth mentioning that some prokaryotic beings (Reino Monera), called cyanobacteria, are often called blue algae. In this text we will consider only the study of protoctist algae.
Below are the main protoctist algae and some of their characteristics:
|Chlorophyta (green algae)||Uni or multicellular||a, b|
|Phaeophyta (brown algae)||Multicellular||a, c|
|Rhodophyta (red algae)||Uni or multicellular||a, d|
|Bacillariophyta (diatoms)||Unicellular||a, c|
|Chrysophyta (golden algae)||Uni or multicellular||a, c|
|Euglenophyta (euglenoides)||Unicellular||a, b|
|Dinophyta (dinoflagellates)||Unicellular||a, c|
|Charophyta (Carofíceas)||Multicellular||a, b|
Curiosity: The science that studies algae is called Phycology.