Download bio 211 worksheet 12 answers

Worksheet 12:
Invertebrates answers
Supplemental Instruction
Iowa State University
Leader:
Course:
Instructor:
Date:
Courtney
Bio 211 (4)
Boury
10/1/12
1) Which is the correct hierarchy of divisions in the animal from most inclusive to least
inclusive
a) Eumetazoa, Metazoa, Protostomia, Ecdysozoa
b) Parazoa, Radiata, Lophotrochozoa, Deuterstomia
c) Metazoan Eumetazoa, Bilateria, Protostomia
d) Radiata, Eumetazoa, Deuterstomia, Ecdysozoa
2) Naturally occurring identical twins are possible only in animals that
a) have spiral cleavage
b) have determinate cleavage fate of embryonic cells is determined very early
c) are protostomes
d) have indeterminate cleavage each cell produced by early cleavage retains the
ability to develop into a complete embryo
e) a,b and c
3) A major difference between the molecular phylogeny of animals and traditional
phylogeny of animals is that
a) the presence or absence of the mesoderm is not important in molecular phylogeny
b) molecular phylogeny suggests that al animals do not share a single common ancestor
c) body symmetry, whether radial or bilateral, is not important determinant in
molecular phylogeny
d) a molecular phylogeny does not include the echinoderms in the deuterstome clade
e) molecular phylogeny suggests that the presence or absence of a coelom is not
important for classification
4) Parazoa includes the animals that lack ____true tissues_____. This includes the Phylum
_____Porifera____.
5) How can sponges feed, have structure, or produce gametes if the lack true tissues?
They have specialized cells
6) Describe the following:
Choanocytes- feeding
Mesophyl- functions as structure and holds body together.
Amebocytes- absorb food (from choanocytes)
Spicules- structure
Spongin- fibers of tough protein
7) How do sponges reproduce?
Sexually hermaphrodites (produce sperm and eggs)
Asexually by budding or fragmentation
8) How do sponges form gametes?
They are derived from amebocytes or choanocytes
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9) List some important characteristics of Radiata, and list some examples
includes cnidarian and ctenophore
radially symmetrical
mostly marine
diploblastic
mesoglea connects the 2 dermis layers. The jelly in jellyfish
hydra, anemones and jellyfish
10) Describe the 2 body forms of a Cnidarian
Polyp-> sessile, tentacles facing up
Medusa-> motile tentacles facing down
11) True or False, Cnidarians and Ctenophorans lack a circulatory, respiratory, and
excretory systems
True.
12) Why can’t you train a jellyfish?
Because they lack a true nervous system, they have a nerve net which is nerve cells
arranged in a net formation
13) What are the stinging cells in Cnidarians called?
Cnidocytes ( cnidocytes contain nematocysts which are powerful capsules with an
inverted coiled and barbed thread)