Protozoans and some algae species are able to eat food. And lastly, most algae and some protozoans are able to do the process of photosynthesis. Algae come in different colors, shapes, and sizes.
Most algae look green in color and slimy. You can find algae near bodies of water or other humid places. They can thrive in saltwater or freshwater. They may be free-floating on water, or you can see them plastered on rocks. There are four phyla of algae. This includes the phylum Chlorophyta which are the green algae; phylum Phaeophyta, brown algae; phylum Rhodophyta, red algae; and phylum Bacillariphyta, diatomic algae.
All algae have chlorophyll though they do not have leaves, stems, and roots. They are plant-like organisms that can produce their own food. Algae can either be unicellular or multicellular. Seaweeds are examples of multicellular algae. On the other hand, protozoans are unicellular, and they are more animal-like.
People describe protozoa as a blob without a definite shape since they lack a cell wall. And their method of movement can be through the following extensions of their cells: flagella, the whiplike strands; cilia, also known as pseudopods.
Sexual reproduction is common in ciliates, but rare in heliozoans and amoebas, and absent in flagellates. The three basic types of sex are gametogamy, autogamy, and conjugation—all of which are explained on the reproduction strategies page. Ciliates reproduce sexually through conjugation, which involves the exchange of haploid nuclei between two joined protists.
Once the genetic information is exchanged, each of the ex-conjugants clones itself. These resulting daughter cells go through a long period of "sexual immaturity," during which they will only reproduce asexually. Flagellates employ their flagella for both swimming and acquiring food. Sessile or colony-forming members of the collared flagellates use their flagella to create a water current to draw small food particles, such as water-borne bacteria. These food particles are then trapped on mucous- coated microvilli peaks and valleys on the cell membrane that increase the surface area of the cell for the purpose of absorption.
Large amoebas eat algae, other protists and some tiny multi-celled animals, while smaller amoebas feed on bacteria.
Amoebas ingest particles by phagocytosis. They wrap themselves around the food particle and once enclosed it is embedded within a food vacuole for digestion. Amoebas can capture food with pseudopods made of any outer area of the cells, so that their whole body surface is a potential mouth! The same is true for pinocytosis the "drinking" of organic substances and the release of wastes that are contained in contractile vacuoles.
Ciliates have toxicysts that they fire at their prey to subdue it. Sessile forms e. Heliozoans engulf any organism ranging from picoplankton to copepods. Extrusomes at the base of the axopoda secrete cytoplasm over the axopoda.
Food sticks to the cytoplasm, and the flow of the liquid brings the food towards the cell where pseudopods reach out to grab it. Researchers working with the ciliate Paramecium have discovered that protozoans have a very high mortality rate after conjugation. Though the scientific rationale behind each of these classifications implied that protozoans were rudimentary versions of plants and animals, there was no scientific evidence of the evolutionary relationships between these organisms International Microbiology, According to Simpson, nowadays "protozoa" is a term of convenience used in reference to a subset of protists, and is not a taxonomic group.
The term protista, meaning "the first of all or primordial" was introduced in by German scientist Ernst Haeckel. He suggested Protista as a third taxonomic kingdom, in addition to Plantae and Animalia, consisting of all "primitive forms" of organisms, including bacteria International Microbiology, Since then, the kingdom Protista has been refined and redefined many times. Different organisms moved in and out notably, bacteria moved into a taxonomic kingdom of their own. American scientist John Corliss proposed one of the modern iterations of Protista in the s.
His version included the multicellular red and brown algae, which are considered to be protists even today. Scientists, often concurrently, have debated kingdom names and which organisms were eligible for example, versions of yet another kingdom, Protoctista had been proposed over the years. However, it is important to note the lack of correlation between taxonomy and evolutionary relationships in these groupings.
According to Simpson, these groupings were not monophyletic, meaning that they did not represent a single, whole branch of the tree of life; that is, an ancestor and all of its descendants. Today's classification has shifted away from a system built on morphology to one based on genetic similarities and differences.
The result is a family tree of sorts, mapping out evolutionary relationships between various organisms. In this system there are three main branches or "domains" of life: Bacteria, Archaea both prokaryotic and Eukarya the eukaryotes. Within the eukaryotic domain, the protists are no longer a single group. They have been redistributed amongst different branches of the family tree.
According to Simpson, we now know most of the evolutionary relationships amongst protists, and these are often counterintuitive. He cited the example of dinoflagellate algae, which are more closely related to the malaria parasite than they are to diatoms another group of algae or even to land plants. Still, there are pressing questions that remain. This point is called the "root" of the eukaryotic tree of life. Protozoa: Protozoa ingest food particles by phagocytosis.
Algae: Algae produce their own food by photosynthesis. Protozoa: Protozoa do not contain chlorophyll. Protozoa: Protozoa do not have a cell wall. Algae: Algae have a cell wall made up of cellulose. Algae: The resting unit of algae is the spore. Protozoa: Amoeba, Plasmodium, Euglena, Paramecium, Entamoeba histolytica, and Leishmania are the examples of protozoa. Algae: Seaweeds, green algae, red algae, brown algae, and cyanobacteria are examples of algae.
Protozoa: Protozoa like Plasmodium can cause diseases such as malaria in humans. Algae: Algae may produce toxins, which are toxic to humans. Protozoa: Protozoa serve as the foundation of most aquatic food chains. Protozoa and algae are two types of organisms that belong to the kingdom Protista. Protozoa are unicellular, animal-like organisms.
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