Where do protozoa fit on the three-domain system?

[Genecks]

It it like this?

 

1. Eukaryote

2. Protist

3. Protozoa

 

I cannot figure it out. I haven't ever really been able to figure it out.

I've read the wiki article, but didn't grasp much. Maybe someone can drill this into my head?

[Skye]

Yeah, that's right.

 

The only snag is that protozoa and protista are gradually being phased out as classification terms. They don't fit the requirement to be monophyletic that's required by modern classification schemes. They are still used a lot to describe groups of organisms though.

[Moontanman]

Opps, I misunderstood the question

Edited January 13, 2010 by Moontanman
content

[dttom]

It should be:

1) Eubacteria

2) Arhaea

3) Eukaryotes

Protists disperse into eukaryotes.

[Genecks]

It should be:

1) Eubacteria

2) Arhaea

3) Eukaryotes

Protists disperse into eukaryotes.

 

1) Eubacteria

2) Arhaea

3) Eukaryotes

3.1) Protists

3.1.1) Protozoa

 

Like so?

 

I don't want to draw a tree...

[CharonY]

Actually it is archaea and bacteria (eubacteria has been ditched as a term).

 

The question is actually kind of invalid as the three domains of life classification according to Woese does not include protists (ditched as a taxon) or protozoa.

 

Protists existed in the five kingdom system according to Whittaker consisting of animalia, planta, fungi, protista and monera. Again, it is not really used anymore.

[dttom]

1) Eubacteria

2) Arhaea

3) Eukaryotes

3.1) Protists

3.1.1) Protozoa

 

Like so?

 

I don't want to draw a tree...

 

I should say under the three-domain system, the term 'protist' is no longer a true phylogenetic clade, it intersperses into the group 'eukaryotes', some like choanoflagellates have closer relationship to human than even fungi, while some have more distant relationship.

[Genecks]

Ok... so...

 

Domain: Eukarya

Kingdom: Protista

 

But then again, some people don't want to put various protozoa in Protista, so they are considered excavata? Thus, they then have no kingdom? Why not use a kingdom? What's up with that?

 

Leishmania donovani

 

Scientific classification

Domain: Eukaryota

(unranked): Excavata

Phylum: Euglenozoa

Class: Kinetoplastida

Order: Trypanosomatida

Genus: Leishmania

 

So, is the term "protozoa" out of date?

And the term "protists" is out of date?

 

So, do we still use the kingdom system under the domain system?

[CharonY]

There are different systems and also depending on the context both are still used to loosely describe something. However in the cladistic system both are not used.

[kitkat]

It should be:

 

Archaea

Prokaryotes

Eukaryotes

[CharonY]

Nope. Archaea and bacteria are both prokaryotes.