The lower limit of the intertidal zone is the
average high tide.
average middle tide.
lowest edge of the rocky substrate.
None of the above choices are correct: it varies according to type of substrate.
2 of 25
The particular characteristic most widely used in classifying intertidal communities is which of the following?
Type of tides
Relative exposure to air
Type of substrate
Type of seaweeds
Relative immersion by water
3 of 25
Which of the following strategies is not used to avoid desiccation in the intertidal?
Crowding in areas that are always moist
Burrowing into substrate
Moving out of tide pools
4 of 25
Most sessile animals living on rocky shores are which of the following?
5 of 25
If a rocky shore highly exposed to wave action is compared to a similar rocky shore that is a lot less exposed to wave action, one should expect that barnacles living on the more exposed shore show a
wider vertical distribution.
narrower tolerance to salinity.
narrower tolerance to temperature.
narrower vertical distribution.
higher resistance to predators.
6 of 25
Byssal threads are used by mussels to cope with.
7 of 25
Vertical zonation on rocky shores is mostly the result of differences in tolerance to
8 of 25
This organism is typical of the upper intertidal on rocky shores.
9 of 25
The middle intertidal is characterized by which of the following?
Constant wetting by splash and spray
Long exposure to air
Exposure and immersion on a regular basis
Splashing during high tide and complete exposure at low tide
10 of 25
Intertidal organisms from exposed areas sometimes have thicker shells than their counterparts from less exposed areas. This is thought to be an adaptation to
11 of 25
Predation by sea stars on rocky shores ultimately results in
less wave action.
a decrease in the number of seaweeds.
an increase in the number of mussels.
12 of 25
Ecological succession ultimately results in
a climax community.
an upper-limit stage.
13 of 25
Which of the following is generally considered to be the greatest limiting resource in the rocky intertidal?
Availability of mates
14 of 25
Which of these organisms is typically a very rare component of soft-bottom intertidal communities?
15 of 25
Most animals living on sandy beaches are included among which of the following?
16 of 25
Fine sediments are characteristic of
shores exposed to wave action.
areas with wide temperature fluctuations.
calm, less exposed shores.
areas that experience considerable water flow.
17 of 25
The interstitial water in muddy bottoms
has plenty of oxygen since temperature is much higher than in the water column.
accumulates oxygen as a result of photosynthesis by inhabitants of the sediment.
recirculates oxygen very frequently so it is high.
is deficient in oxygen.
is deficient in oxygen but only during the day.
18 of 25
The main source of food in muddy-bottom intertidal communities is
19 of 25
On Atlantic shores, the dog whelk (Nucella lapillus) has two color forms: white-shelled and brown-shelled. Survival of one form over the other form in a region appears to be related to
20 of 25
What organism would be most likely to be found in the upper intertidal zone of a rocky shoreline?
21 of 25
In soft-bottomed intertidal communities, locations with strong waves and currents are most likely to have which type of bottom?
22 of 25
on rocky shores.
on sandy bottoms.
between grains of sediment.
in the water column.
23 of 25
A species that significantly influences the structure and diversity of its community is a ______________.
24 of 25
The best reason for putting a cage over certain organisms in an intertidal study area is so that __________________.
other organisms can be kept out of the study area
biologists can control when certain animals mate
their respiration rates can be measured
they can be removed from the area
body measurements can be taken
25 of 25
Two sediments that are very rich in detritus are ______________.
sand and gravel
sand and clay
silt and gravel
clay and sand
silt and clay