BIOL 212 - Quiz 6 Short Answer
How do animals obtain nutrients? - ANS-Using directed movement to find food. Then ingest
prey and digest it with their bodies.
What are the traits that make animals unique (i.e., that are not seen in other organisms)? -
ANS-Muscle and Nervous Cells
What organism is the evolutionary ancestor of animals, and what evidence do we have for this
relationship? - ANS-Choanoflagellates. They are identical to "collar cells" in sponges, which is
the basal group of animals.
What phylum is the basal (earliest evolving) group of animals? - ANS-Phylum Porifera
What are the characteristics of Phylum Porifera (sponges), and in what ways are organisms in
this phylum simpler than other animals? - ANS-Sedentary, filter-feeders, simpler than other
animals because they use collar cells to capture food from water drawn in through pores. They
are also asymmetric and lack true tissue
What type of lifestyle would favor radial symmetry and what type of lifestyle would favor bilateral
symmetry? - ANS-Radial symmetry is best suited for a sessile or planktonic lifestyle.
Bilateral symmetry is best suited for an active lifestyle
What is the difference between diploblastic and triploblastic embryonic development -
ANS-Diploblastic: having two embryonic layers, endoderm (internal organs) and ectoderm (outer
covering and nervous system)
Triploblastic: having a third embryonic layer, mesoderm (body cavity and muscles)
What types of tissues arise from ectoderm, mesoderm, and endoderm in triploblastic
organisms? - ANS-Endoderm: internal organs
Mesoderm: body cavity and muscles
Ectoderm: outer covering and nervous system
What are the advantages of having a body cavity? - ANS-Allows external body wall and internal
organs to move independently
Cushions internal organs
Can act as a "skeleton" against which muscles work
What are the advantages of deuterostome development? - ANS-Allows for embryonic cells to
retain capacity to develop into a complete embryo.
How do animals obtain nutrients? - ANS-Using directed movement to find food. Then ingest
prey and digest it with their bodies.
What are the traits that make animals unique (i.e., that are not seen in other organisms)? -
ANS-Muscle and Nervous Cells
What organism is the evolutionary ancestor of animals, and what evidence do we have for this
relationship? - ANS-Choanoflagellates. They are identical to "collar cells" in sponges, which is
the basal group of animals.
What phylum is the basal (earliest evolving) group of animals? - ANS-Phylum Porifera
What are the characteristics of Phylum Porifera (sponges), and in what ways are organisms in
this phylum simpler than other animals? - ANS-Sedentary, filter-feeders, simpler than other
animals because they use collar cells to capture food from water drawn in through pores. They
are also asymmetric and lack true tissue
What type of lifestyle would favor radial symmetry and what type of lifestyle would favor bilateral
symmetry? - ANS-Radial symmetry is best suited for a sessile or planktonic lifestyle.
Bilateral symmetry is best suited for an active lifestyle
What is the difference between diploblastic and triploblastic embryonic development -
ANS-Diploblastic: having two embryonic layers, endoderm (internal organs) and ectoderm (outer
covering and nervous system)
Triploblastic: having a third embryonic layer, mesoderm (body cavity and muscles)
What types of tissues arise from ectoderm, mesoderm, and endoderm in triploblastic
organisms? - ANS-Endoderm: internal organs
Mesoderm: body cavity and muscles
Ectoderm: outer covering and nervous system
What are the advantages of having a body cavity? - ANS-Allows external body wall and internal
organs to move independently
Cushions internal organs
Can act as a "skeleton" against which muscles work
What are the advantages of deuterostome development? - ANS-Allows for embryonic cells to
retain capacity to develop into a complete embryo.
