AICE Marine Science A Level Exam Questions with Correct Answers
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Course
Marine Science
Institution
Marine Science
Primary producers - Answer-fix carbon, in the process of photosynthesis, making organic substances which are then made available to higher trophic levels.
Primary producers in marine ecosystems - Answer-phytoplankton, larger algae such as Sargassum, and flowering plants such as the sea grasses.
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AICE Marine Science A Level Exam
Questions with Correct Answers
Primary producers - Answer-fix carbon, in the process of photosynthesis, making
organic substances which are then made available to higher trophic levels.
Primary producers in marine ecosystems - Answer-phytoplankton, larger algae such as
Sargassum, and flowering plants such as the sea grasses.
Function of sea grasses - Answer-provides food for primary consumers, a habitat for
many other organisms, and shelter for juvenile fish. help to reduce water current speed
and increase sedimentation. their roots and rhizomes stabilize the substrate, and
therefore reduce coastal erosion.
Types of phytoplankton - Answer-diatoms, dinoflagellates, cyanobacteria
Sargassum - Answer-widely distributed in tropical and temperate oceans. typically
grows in shallow water and coral reefs, but there are also free-floating planktonic
species.
Sea grasses - Answer-grow in shallow, sheltered areas, rooted in a muddy or sandy
substrate.
Kelp forests - Answer-occur in cool, clear waters in depths of up to about 40 m.
Chemosynthesis - Answer-using energy derived from the oxidation of inorganic
substances such as hydrogen sulfide and ammonia. occurs in the deep ocean around
hydrothermal vents. the total fixation of carbon by chemosynthesis is small compared
with photosynthesis.
Chloroplasts - Answer-organelles in which photosynthesis occurs. contain a number of
pigments which absorb light energy and start the process of photosynthesis.
Factors affecting the rate of photosynthesis - Answer-light intensity, light wavelength,
concentration of carbon dioxide, temperature
Light intensity - Answer-in the absence of light, no photosynthesis occurs, but
respiration continues. as the light intensity increases, the rate of photosynthesis
increases. eventually, the rate of photosynthesis levels out and reaches a plateau.
Temperature - Answer-as temperature increases, the rate of photosynthesis increases
up to an optimum. above this temperature, the rate of photosynthesis declines as the
temperature increased. different species of phytoplankton are adapted to different
temperature ranges.
, Light wavelengths - Answer-the surface layer of the ocean is where there is sufficient
light for photosynthesis and is referred to as the photic zone, reaching 30-150 m from
the surface. the longer wavelengths of light, in the red, orange and yellow part of the
spectrum penetrate to about 15-50 m. shorter wavelengths in the blue or green parts of
the spectrum can penetrate to greater depths, reaching 100 m or lower.
Aerobic respiration - Answer-the process by which almost all living organisms obtain the
energy they need, by the oxidation of organic molecules such as glucose.
Aerobic respiration formula - Answer-glucose + oxygen ---> carbon dioxide + water
Surface area to volume ratio - Answer-as the size of an organism increases, its surface
area decreases in relation to its volume. very small organisms, therefore, have a
relatively large surface area in relation to their volume.
Transport systems - Answer-larger animals have internal transport systems to ensure
that substances are delivered efficiently to cells and tissues, and waste products are
transported away. these transport systems usually consist of blood, pumped around the
body by one or more muscular hearts.
Concentration of oxygen - Answer-marine animals are adapted to live in water which, in
comparison with air, contain low and variable concentrations of oxygen. atmospheric air
contains 21% of oxygen, but the concentration of oxygen dissolved in water is relatively
low. the solubility of oxygen in water decreases as the temperature increases.
Diffusion - Answer-Many small marine animals obtain the oxygen they require by
diffusion across their body surface. larger, more complex animals have a specialized
gas exchange surface.
Pumped ventilation - Answer-the process of maintaining an almost constant flow of
water through their gills by the use of a pumping action of the mouth and operculum.
Ram ventilation - Answer-the process of maintaining a continuous flow of water over
their gills by swimming continuously with an open mouth.
Osmoregulation - Answer-the process by which living organisms maintain the solute
and water content in their blood and body fluids.
Osmoconformer - Answer-their internal osmotic concentration is the same as that of
their surrounding medium. (mussels are osmoconformers)
Euryhaline - Answer-organisms are able to tolerate a range of salinities, for example
animals that are adapted to live in estuarine conditions. (salmon are euryhaline)
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