There are six kingdoms or domains:
- protists (crosses over into each)
- archaea: more closely related to animals than to bacteria
- Animal, plant, and fungi are multicellular
- Archaea and bacteria are unicellular
- Protista cross the seam: unicellular and multicellular.
What is the difference between protists and protozoa.
According to this 2012 site, which still uses the term "Monera," the Kingdom Protista is again grouped into three subgroups: protozoa (animal-like); protophyta (plant-like); and, slime moulds. So there you have it. Remember: if you have an organism that is a eukaryocyte (nucleus), you want to try to make it animal, plant, or fungi. If unable to definitely call it plant, animal, or fungi, then call is what is most looks like ( -- animal; -- plant; -- fungi). If the eukaryocyte (nucleus) looks animal list, then the protist is protozoa; if plantlike, then protophyta; if fungi-line, then a slime mold.
Protozoa are mostly aquatic. "Famous protozoa" are the parasitic protozoa: malaria, toxoplasmosis, cryptosporidiosis, leishmaniasis (considered the world's second-deadliest parasite) -- all are apicomplexia (contain spear-like organelle to pierce other eukaryotic cells).
Protozoa are divided into four phyla based on methods of movement and not based on phylogenetic.
- flagellates (or Mastigophora),
- amoeboids (or Sarcodina)
- sporozoans (or Sporozoa, Apicomplexa) -- the deadly parasites (malaria, toxoplasmosis, cryptosporidiosis, leishmaniasis)
- ciliates (or Ciliophora)
Parasites: sporozoans (apicomplexa) can live in almost any animal (including human beings); they can even live inside other apicomplexa.
Most protists cannot move.
So, where do algae fit? Algae = seaweed. Alga is Latin for seaweed
Huge disagreement. No definition universally accepted. Polyphyletic: no common ancestor. Photosynthetic (so they have organelles) and so eukaryocytes. But can be unicellular or multicellular. Having said that, apparently the cyanobacteria (blue-green algae) -- prokaryotes -- photosynthesize, and are considered algae by some (hence the name). My hunch: over time: blue-green algae, being prokaryotes will be placed among the Monera (bacteria or archaea) but due to history will retain the common name, blue-green algae for a long time; only when cyanobacteria becomes standard/common usage (and that may never happen) will blue-green algae be understodd by all to be bacteria (cyanocbacteria).
But this is the problem with trying to classify algae/cyanobacteria with Bacteria: Algae have photosynthetic machinery ultimately derived from cyanobacteria that produce oxygen as a by-product of photosynthesis, unlike other photosynthetic bacteria such as purple and green sulfur bacteria.
The study of marine and freshwater algae is called either phycology or algology. Phycology comes from Greek fukos or phykos which is associated with paint or dye. Ancient Egyptians used cosmetic eye-shadow derived from seaweed (any color: black, red, green).
Algae are further divided into three separate supergoups; another grouping is based on