What are the main characteristics of these?
platyhelminth
nematode
arthropod
chordata

I know first two are worms, third insects and fourth include humans. but what's the main characteristic of each?

Question

What are the main characteristics of these?
platyhelminth
nematode
arthropod
chordata

I know first two are worms, third insects and fourth include humans. but what's the main characteristic of each?

anonymous · Answer

Arthropods aren't all insects, and while Platyhelminthes and Nematodes are indeed "worms", they aren't the kind that you see on the pavement when it rains. Typical Platyhelminthes worms would be e.g. liver flukes or tapeworms, and some typical Nematodes include Ascaris sp., Wuchereria bancrofti, and guinea worms. There are plenty of free-living species as well, but they're not nearly as much fun.

liliakarina · Answer

All right. Thank you for correcting me. Well, is there any main characteristic that can describe each of these phylum?

anonymous · Answer

Are you looking for Apomorphies or something more general and descriptive?

liliakarina · Answer

More general and descriptive. Like, maybe, morphology or sth like that.

anonymous · Answer

Well... with Chordates, it's easy. What feature does the name "Chordate" suggest?

The other names are descriptive too: do you know what they mean?

liliakarina · Answer

Not literally, but like I said before, first two - worms, I think nematodes have no anus and arthropods have exoeskeletons.

anonymous · Answer

Nematodes have anuses: I've seen one! Sort of. I dissected one once.

A literal translation of the names will help:
Plat = flat
Helminth = worm
Nema = thread
Arthro = joint
Pod = foot

(I don't know Greek or Latin. It's possible that I parsed those words incorrectly, but the translations should be more or less correct.)

liliakarina · Answer

I see. Neither do I know Greek not Latin, maybe that's why I coudln't figure it out. Nevertheless, your answer has been helpful. I think that pretty much covers what I needed to know.

anonymous · Answer

I would REALLY recommend looking up the Greek/Latin roots of scientific names/terminology: the same prefixes/suffixes/etc. come up over and over again, and when you know what a name means, it's much easier to remember it for an exam. If, for example, you know that "pod" means "foot", it's much easier to remember/understand "Gastropod" (stomach foot -> snails have this scientific name because it looks like they're crawling on their stomachs) or "pseudopod" (false foot -> Amoebas use pseudopods to get around).

liliakarina · Answer

Thank you!

anonymous · Answer

No problem!