Among the oldest living organisms that exist on the planet we find algae. They are organisms that have been and continue to be of vital importance for the biological balance of the planet. Many people don't understand why algae are not plants or just the so-called marine plants. Keep in mind that they are not the same and belongs to different kingdoms. Plants and algae have some aspects in common but they also have big differences.
Therefore, we are going to dedicate this article to tell you everything you need to know about why algae are not plants and what are the characteristics of each one.
Why are algae not plants
First of all is to know the real definition of plants. We must bear in mind that some algae are classified within the Plantae kingdom. Most algae are found in the Protista kingdom which comprises those organisms that are not animals, plants, fungi and bacteria. The usual meaning given to the term plant is somewhat more limited. When we colloquially call plant we are referring almost exclusively to embryophytes. This group of plants are terrestrial plants and they group bryophytes, ferns, club mosses and plants with seeds.
The fact that an alga is not a plant does not mean that they do not have things in common and relationships with each other. The entire group of embryophytes evolved from a certain group of green algae. Once we know this initial reference, we will see what the differences are between algae and plants and why algae are not plants:
- Algae grow almost entirely in an aquatic environment. This means that it needs almost any type of support structure that terrestrial plants have developed to combat the force of gravity. Being inside the water does not need any type of support since the water itself keeps them firm. Therefore, when we remove the algae from the water we see that the canopy can hold itself.
- They do not have roots that absorb water and a vascular system such as xylem and phloem. They do not need to absorb water since they are already in an aquatic environment.
- One of the differences at the biological level is with regard to pigments. Some algae have phycobilins, which are pigments that are only found in this group of organisms and in cyanobacteria.
Key features
Once we know why algae are not plants, we are going to see what the main characteristics of these organisms are. The main characteristic for which this organism stands out is its simple and primitive structure. It is called thallus and constitutes the best known part in terrestrial plants as roots, stems, leaves and vascular decided of plants. As we have mentioned before, since the algae that is in an aquatic place does not need all support structures to absorb and conduct the water.
They are both unicellular and multicellular organisms, although in the latter case each cell performs all the functions instead of grouping together to form specialized tissues. Among the characteristics that algae and plants have in common that both carry out the process of photosynthesis. Both have pigments and chloroplasts, although not all are green pigmented.. Some algae are found at greater depths and have red and brown appearances. It has developed more sensitive pigments to be able to capture light at greater depth. One major limitation of life in the sea is the amount of solar radiation that reaches the water.
Being other synthetic organisms, they are also autotrophic organisms, as is the case with terrestrial plants. They can reproduce both sexually and sexually as with land plants. These organisms can develop both in seas, lakes and rivers, either at the bottom or on the surface of rocks. It must be borne in mind that there are numerous types of algae with normally varied sizes and shapes. Some exceed a few meters in length, while others are microscopic in size.
Why Algae Are Not Plants: Types
If we look at all the characteristics, habitat and type of pigmentation, 7 large types of algae with well differentiated characteristics can be divided. Let's see what these types are:
- Green algae: These are algae that mainly live in fresh water, although not exclusively in these places. There are also thousands of species of green algae in the sea. There are both unicellular and multicellular in their walls are constituted by chloroplasts, cellulose and various flagella.
- Red algae: habitat mainly in the oceans and seas of the tropics. Especially its maximum range is in coral reefs.
- Brown algae: they are the most numerous in the world's oceans. They have developed anchoring fabrics and airbags that allow for flotation. They reproduce by asexual reproduction by spores and sexual reproduction by gametes.
- Greenish yellow algae: they have a smaller number of varieties and are all unicellular with cellulose and silica membranes. They inhabit fresh waters and form small colonies. It has hardly any pigments, although they contain chloroplasts.
- Golden algae: They are a group of algae that are widespread and have only one cell. They inhabit both fresh and salty waters and are an important part of phytoplankton. Diatoms are also found here.
- Fire algae: They are divided into dinoflagellates and cryptocurrencies. The former are responsible for the so-called red tides and are known for their bioluminescence. It makes it seem like the sea is on fire at night. Cryptocurrencies can be very poisonous and cause serious damage to the environment, although their color is more brownish.
- Euglenidas algae: They do not have cell walls but they do have chloroplasts, so they can photosynthesize much like plants. We have some well-known ones like nori seaweed, wakame and agar-agar.
I hope that with this information you can learn more about why algae are not plants.