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I've got a "fun" assignment. I'm supposed to figure out what animals are being described. I am allowed to ask questions to get more hints. Here is what was given.
1. All members of this group are marine animals, the lineage has existed for at least 600 my and was especially important in the Paleozoic. The group is characterized by a water-vascular system, a skeleton consisting of calcite plates and all adult, living members show a pentameric symmetry. The one we are looking for shows an external bilateral symmetry. They live as burrowers and grazers, living off detritus in sediment. Its common name refers to its habitat and pecuniary shape.
2. The next animal belongs to one of the most success evolutionary lineages ever with millions of species existing today and living almost everywhere except in marine environments. They have an chitin exoskeleton, an open circulatory system, a bilateral symmetry and six legs, breath via tracheae, and eat just about anything using manifold mouth forms. The particular example sought here is the favorite pet of genetists.
3. Animal number 3 lives in marine and freshwater environments, also has a bilateral symmetry, has free-swimming larvae, but most spend their adult lives as more or less sessile animals (burrowed into the seafloor, attached to rocks, drilled into wood). They filter their food out of the water using their gills. Their exoskeleton can be closed by contracting muscles while a ligament keeps it open. Some people like to eat the particular animal we are looking for, but it is too slimy for my taste.
4. This animal lives a lowly life and is often referred to when insulting sniveling people. Nonetheless, it ecological significance cannot be overestimated. It is hermaphroditic, reproduces by exchanging sperm and then laying eggs. It has a bisymmetrical body built of chambers, each containing repeated sets of organs. It also has a brain and ladder like nervous system.
5. Probably none of you have heard of this animal before, but if you saw a microphotograph of it (they are only about 0.5 mm long) it would remind you of a gummibear. It has four pairs of stubby legs, a chitin exoskeleton, a little brain and some have eye spots. Some live in marine and freshwater habitats but most live in moss and can stand drying out for longer periods of time.
I think #3 is an oyster...........any thoughts? Or can anyone think of any questions to ask to narrow it down?
Well the first one is definitely an echinoderm, though I'm not sure it's a starfish. The Bilateral symmetry is what threw me off the track of starfish.
I agree with chi on the second third and fourth
5>... You're looking for some kind of mite I think. the 4 pairs of legs is a good clue.
This question was asked about #5:
This animal reproduce by laying eggs in its shed exoskeleton.
It also eats by using its stylets to pierce moss and leaves to suck and drink the juices.
This animal also gets its own phylum.
The response was: You might just be on the right track, although other animals show the same traits?
Any thoughts on this? Anybody else have an opion on the other ones to? Any of your thoughts would help. THANKS!!
The lists get a little confused.
1 seems to be going for sand dollars (pecuniary), but describes sea cucumbers (bilateral), which are in a different class.
3 has to be a bigger group (since it includes clams and mussels) than 2 (which is just a species), and bivalve shells are not really "exoskeletons."
And what is it with tardigrades? This is the fourth discussion of them I've run into this week!
12 posts • Page 1 of 1
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