The Intertidal Zone

Question

1 of 25

The lower limit of the intertidal zone is the

average high tide.

average middle tide.

lowest tide.

lowest edge of the rocky substrate.

None of the above choices are correct: it varies according to type of substrate.

Question

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

Question

3 of 25

Which of the following strategies is not used to avoid desiccation in the intertidal?

Closing shells

Crowding in areas that are always moist

Burrowing into substrate

Mucus

Moving out of tide pools

Question

4 of 25

Most sessile animals living on rocky shores are which of the following?

Deposit feeders

Carnivores

Detritus feeders

Filter feeders

Grazers

Question

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.

Question

6 of 25

Byssal threads are used by mussels to cope with.

desiccation.

wave shock.

restricted feeding.

salinity changes.

temperature changes.

Question

7 of 25

Vertical zonation on rocky shores is mostly the result of differences in tolerance to

wave action.

exposure.

predation.

light.

salinity.

Question

8 of 25

This organism is typical of the upper intertidal on rocky shores.

Mussels

Barnacles

Sponges

Sea anemones

Periwinkles

Question

9 of 25

The middle intertidal is characterized by which of the following?

Constant wetting by splash and spray

Long exposure to air

Steady immersion

Exposure and immersion on a regular basis

Splashing during high tide and complete exposure at low tide

Question

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

desiccation.

restricted feeding.

wave shock.

salinity changes.

temperature changes.

Question

11 of 25

Predation by sea stars on rocky shores ultimately results in

fewer species.

less wave action.

a decrease in the number of seaweeds.

an increase in the number of mussels.

more species.

Question

12 of 25

Ecological succession ultimately results in

a climax community.

an upper-limit stage.

competitive exclusion.

keystone predation.

vertical zonation.

Question

13 of 25

Which of the following is generally considered to be the greatest limiting resource in the rocky intertidal?

Salinity

Space

Prey

Availability of mates

Light availability

Question

14 of 25

Which of these organisms is typically a very rare component of soft-bottom intertidal communities?

Burrowing organisms

Detritus feeders

Seaweeds

Infauna

Deposit feeders

Question

15 of 25

Most animals living on sandy beaches are included among which of the following?

Infauna

Deposit feeders

Macrofauna

Producers

Grazers

Question

16 of 25

Fine sediments are characteristic of

shores exposed to wave action.

rocky shores.

areas with wide temperature fluctuations.

calm, less exposed shores.

areas that experience considerable water flow.

Question

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.

Question

18 of 25

The main source of food in muddy-bottom intertidal communities is

seaweeds

detritus

plankton

large prey

epifauna

Question

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

temperature.

salinity.

substrate type.

prey availability.

predators.

Question

20 of 25

What organism would be most likely to be found in the upper intertidal zone of a rocky shoreline?

Mussels

Seaweed

Encrusting algae

Barnacles

Irish moss

Question

21 of 25

In soft-bottomed intertidal communities, locations with strong waves and currents are most likely to have which type of bottom?

Gravel

Sand

Silt

Clay

Mud

Question

22 of 25

Meiofauna live

on rocky shores.

on sandy bottoms.

between grains of sediment.

in burrows.

in the water column.

Question

23 of 25

A species that significantly influences the structure and diversity of its community is a ______________.

predator species

keystone species

prey animal

primary producer

apex predator

Question

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

Question

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