Difference between protozoa and algae?

Question

Explain the difference between each

Answer 1

Protozoa are animal-like, heterotrophic, usually motile.
Algae are plant-like, autotrophic, many not motile, have cell walls made of cellulose

Answer 2

Algae is food producer and protozoa is a consumer.

Answer 3

Traditionally the animal kingdom has been divided into two subkingdoms; and Metazoa .


Protozoa are the most abundant animals in the world in terms of numbers and biomass. Their principal importance is as consumers of bacteria (PROKARYOTES). Bacteria play a vital role in maintaining the earth as a suitable place for inhabitation by other forms of life and protozoa play a vital role in controlling their numbers and biomass. Protozoa are also important as parasites and symbionts of multicellular animals.


Protozoa are defined as single-celled eukaryotic organisms, that feed heterotrophically and exhibit diverse motility mechanisms. However, it is impossible to draw a line between unicellular animals (consumers), plants (producers) and fungi (decomposers) and it is customary to speak of the Protista as a separate kingdom of unicellular eukaryotes that embraces both heterotrophic protozoa and autotrophic algae
Algae (singular alga) encompass several groups of relatively simple living aquatic organisms that capture light energy through photosynthesis, using it to convert inorganic substances into organic matter.

Although algae have been traditionally regarded as simple plants, they actually span more than one domain, including both Eukaryota and Bacteria (see Blue-green algae), as well as more than one kingdom, including plants and protists, the latter being traditionally considered more animal-like (see protozoa). Thus algae do not represent a single evolutionary direction or line, but a level of organization that may have developed several times in the early history of life on earth.

Algae range from single-cell organisms to multicellular organisms, some with fairly complex differentiated form and (if marine) called seaweeds. All lack leaves, roots, flowers, and other organ structures that characterize higher plants. They are distinguished from other protozoa in that they are photoautotrophic although this is not a hard and fast distinction as some groups contain members that are mixotrophic, deriving energy both from photosynthesis and uptake of organic carbon either by osmotrophy, myzotrophy, or phagotrophy. Some unicellular species rely entirely on external energy sources and have reduced or lost their photosynthetic apparatus.

All algae have photosynthetic machinery ultimately derived from the cyanobacteria, and so produce oxygen as a byproduct of photosynthesis, unlike non-cyanobacterial photosynthetic bacteria. It is estimated that algae produce about 73 to 87 percent of the net global production of oxygen[1]--which is available to humans and other terrestrial animals for respiration.

Algae are usually found in damp places or bodies of water and thus are common in terrestrial as well as aquatic environments. However, terrestrial algae are usually rather inconspicuous and far more common in moist, tropical regions than dry ones, because algae lack vascular tissues and other adaptations to live on land. Algae can endure dryness and other conditions in symbiosis with a fungus as lichen.

The various sorts of algae play significant roles in aquatic ecology. Microscopic forms that live suspended in the water column — called phytoplankton — provide the food base for most marine food chains. In very high densities (so-called algal blooms) these algae may discolor the water and outcompete or poison other life forms. Seaweeds grow mostly in shallow marine waters. Some are used as human food or harvested for useful substances such as agar or fertilizer. The study of marine algae is called phycology or algology.

Protozoa (in Greek proto = first and zoa = animals) are single-celled eukaryotes (organisms whose cells have nuclei) that commonly show characteristics usually associated with animals, most notably mobility and heterotrophy. They are often grouped in the kingdom Protista together with the plant-like algae and fungus-like water molds and slime molds. In some newer schemes, however, most algae are classified in the kingdoms Plantae and Chromista, and in such cases the remaining forms may be classified as a kingdom Protozoa. The name is misleading, since they are not animals (with the possible exception of the Myxozoa).

Protozoan have traditionally been divided on the basis of their means of locomotion, although this is no longer believed to represent genuine relationships:

Flagellates
Amoeboids
Sporozoans
Apicomplexa
Myxozoa
Microsporidia
Ciliates
Most protozoans are too small to be seen with the naked eye — most are around 0.01–0.05 mm, although forms up to 0.5 mm are still fairly common — but can easily be found under a microscope. Protozoa are ubiquitous throughout aqueous environments and the soil, and play an important role in their ecology. Protozoa occupy a range of trophic levels. As predators upon unicellular or filamentous algae, bacteria, and microfungi, protozoa play a role both as herbivores and as consumers in the decomposer link of the food chain. Protozoa also play a vital role in controlling bacteria population and biomass. As components of the micro- and meiofauna, protozoa are an important food source for microinvertebrates. Thus, the ecological role of protozoa in the transfer of bacterial and algal production to successive trophic levels is important. Protozoa such as the malaria parasites, trypanosomes and leishmania are also important as parasites and symbionts of multicellular animals.

Encystment - Under certain adverse conditions, some protozoa produce a protective capsule called a cyst. A cyst permits the organism to survive when food, moisture, or oxygen is lacking, when temperatures are not suitable, or when toxic chemicals are present. A cyst also enables a parasitic species to survive outside its host in order to get a new host. This is important because parasitic protozoa sometimes have to go through the excretory system of one host in order to get a new host. The cysts form in members of the phylum Apicomplexa is called an oocyst. It is a reproductive structure in which new cells are produced sexually