Mastering Biology Chapter 33
The animal phylum most like the protists that gave rise to the animal kingdom is _____.
- answer Porifera
Which of the following is a characteristic of cnidarians? - answer gastrovascular cavity
Which of the following is characteristic of the phylum Platyhelminthes? - answer They
are dorsoventrally flattened.
Members of the phylum Mollusca _____. - answer are soft-bodied and often covered by
a shell
Which of the following is true of annelids? - answer They perform gas exchange across
their skin.
A marine biologist dredges up a small animal from the bottom of the ocean. It is
uniformly segmented, with short, stiff appendages and soft, flexible skin. It has a
complete digestive system and a closed circulatory system, plus multiple true coeloms.
Based on this, you determine that the animal must be a(n) _____. - answer annelid
Which of the following is a hypothesis the researchers were testing in this study? -
answer Through evolution, periwinkle populations with a history of predation by crabs
have become less vulnerable to crab predation.
Identify an independent variable in this experiment. - answer the source of the
periwinkles (northern or southern sites in the Gulf of Maine)
Identify the dependent variable in this experiment. - answer the number of periwinkles
killed by crabs
Why did the researchers set up four treatments? - answer to test whether the origin
(northern site or southern site) of the crabs and periwinkles affected their interactions
Why did the researchers present unshelled northern and southern periwinkles to
northern and southern crabs in the second experiment? - answer to test if either
population of periwinkles was unpalatable to either population of crabs
Which of the following best summarizes the results shown in the graph? - answer Crabs
are more successful in preying on northern periwinkles.
The animal phylum most like the protists that gave rise to the animal kingdom is _____.
- answer Porifera
Which of the following is a characteristic of cnidarians? - answer gastrovascular cavity
Which of the following is characteristic of the phylum Platyhelminthes? - answer They
are dorsoventrally flattened.
Members of the phylum Mollusca _____. - answer are soft-bodied and often covered by
a shell
Which of the following is true of annelids? - answer They perform gas exchange across
their skin.
A marine biologist dredges up a small animal from the bottom of the ocean. It is
uniformly segmented, with short, stiff appendages and soft, flexible skin. It has a
complete digestive system and a closed circulatory system, plus multiple true coeloms.
Based on this, you determine that the animal must be a(n) _____. - answer annelid
Which of the following is a hypothesis the researchers were testing in this study? -
answer Through evolution, periwinkle populations with a history of predation by crabs
have become less vulnerable to crab predation.
Identify an independent variable in this experiment. - answer the source of the
periwinkles (northern or southern sites in the Gulf of Maine)
Identify the dependent variable in this experiment. - answer the number of periwinkles
killed by crabs
Why did the researchers set up four treatments? - answer to test whether the origin
(northern site or southern site) of the crabs and periwinkles affected their interactions
Why did the researchers present unshelled northern and southern periwinkles to
northern and southern crabs in the second experiment? - answer to test if either
population of periwinkles was unpalatable to either population of crabs
Which of the following best summarizes the results shown in the graph? - answer Crabs
are more successful in preying on northern periwinkles.
