BIOL 575 Final Exam with 100% correct answers + rationales 2026

The boundary between the continental shelf and the continental rise is the __________.

A. continental margin

B. continental slope

C. deep ocean floor

D. hadal zone

E. mesopelagic

B. continental slope

The bathypelagic region is deeper than the ________ region in the ocean.

A. aphotic

B. hadalpelagic

C. abyssopelagic

D. mesopelagic

E. hadal

D. mesopelagic

In the open ocean, the oxygen minimum zone usually occurs below the ________ zone.

A. nutrient maximum

B. bathypelagic

C. photic

D. abyssopelagic

E. pH maximum

C. photic

The saltmarsh cord grass Spartina alterniflora uses the ______ pathway of photosynthesis.

A. C3

B. C4

C. C2

D. shortest

E. carbonic anhydrase

B. C4

The three major branches on the General Phylogenetic Tree are _______, Bacteria, and Archea.

A. Fungi

B. Eukarya

C. Aracnida

D. Archetypa

E. Eubacteria

B. Eukarya

Most harmful species of phytoplankton are ____.

A. diatoms

B. bacteria

C. cryptophytes

D. viruses

E. dinoflagellates

E. dinoflagellates

The removal of a _____has major impacts on ecosystem function.

A. predator

B. herbivore

C. bacteria

D. keystone species

E. redundant species

D. keystone species

The intensity of intertidal zonation of fauna ______ with decreasing latitude.

A. increases

B. decreases

C. is constant

D. exponentially increases

A. increases

The more closely-related the two competitors, the more ___ the outcome of competition will be.

A. even

B. uneven

C. distinct

D. limited

E. unfortunate

A. even

Why is there such a large difference in the percentage of benthic species vs. pelagic species?

A) More benthic area relative to water volume

B) The benthos is more habitable than the water column

C) Benthic habitats are more easily sampled than the water column D) Mostly due to coral reef species

C) Benthic habitats are more easily sampled than the water column

Intertidal zonation along the coast of South Carolina is due primarily to _____

A. Competition

B. Physical conditions

C.Wave energy

D. Winter temperatures

E. SC doesn't have intertidal zonation

A. Competition

Genetic diversity, species diversity, and diversity of the environment are all components of _________.

A. marine ecology

B. diversity indices

C. biodiversity

D. ecodiversity

E. biotic indices

C. biodiversity

Diatoms are heavy due to their silicified ______.

A. flagella

B. spines

C. frustules

D. skeletons

E. spikes

C. frustules

Two major groups of MOTILE phytoplankton are_____and _______.

A. diatoms, dinoflagellates

B. cyanobacteria, cryptophytes

C. diatoms, cyanobacteria

D. diatoms, cryptophytes

E. chrysophytes, cryptophytes

E. chrysophytes, cryptophytes

A plant or animal species that is restricted to one or a few localities in its distribution is said to be ________.

A. extirpated

B. endemic

C. allopatric

D. expatriated

E. sympatric

B. endemic

Marine species constitute more than ___% of the known species on Earth.

A. 14

B. 8

C. 5

D. 60

A. 14

Cryptic species _______identical but genetically different.

A. morphologically

B. are not

C. morpholy

D. sometimes

E. morphically

A. morphologically

Sea level has been much lower for the last _____ years.

A. 25 million

B. 250,000

C. 25,000

B. 250,000

Plankton ranging in size from 0.2 - 2.0 μm in size are termed ____.

A. femtoplankton

B. picoplankton

C. bacteria

D. nanoplankton

E. microplankton

B. picoplankton

Plants use ___ as the electron acceptor for oxygenic photosynthesis, resulting in O2 as a byproduct.

A. H2O

B. NO2

C. H2S

D. SO4

E. NH4

A. H2O

Long-lived planktonic larvae have __________ rates of endemism than those with limited dispersal.

A. lower

B. higher

C. the same

A. lower

Following the K-T Mass Extinction Event ___ million years ago, almost 11% of marine species went extinct.

A. 250

B. 64

C. 125

D. 3.5

E. 92

B. 64

Major ocean currents have can be classified as thermohaline or _________.

A. wind-driven

B. Eckman transport

C. clockwise

D. tidal

E. reverse

A. wind-driven

The observation that many similar species occur in close proximity in the seemingly uniform environment of the water column is known as "the _____ of the plankton".

A. paradigm

B. paradox

C. principle

D. competition

E. rule

B. paradox

Which of the following is the largest in areal extent?

A. Ecoregion

B. Realm

C. Province

D. Biome

E. Ecosystem

B. Realm

When did the most recent major species radiation begin?

A. In the Triassic Period

B.In the Jurassic Period

C. 65,000 years ago

D. 65,000,000 years ago

E. During the Cretaceous Period

D. 65,000,000 years ago

Why is there such a large difference in the percentage of benthic species vs. pelagic species?

A. More benthic area relative to water volume

B. The benthos is more habitable than the water column

C. Benthic habitats are more easily sampled than the water column D. Mostly due to coral reef species

C. Benthic habitats are more easily sampled than the water column

Major ocean currents have a ________ rotation in the northern hemisphere.

A. cyclonic

B. anticyclonic

C. counterclockwise

D. tidal

E. reverse

B. anticyclonic

______ prevents taxa from evolving locally and spreading into other regions.

A. currents

B. insolation

C. planktotrophic larvae

D. competition

E. isolation

E. isolation

Marine and Terrestrial primary production are approximately equal at _____ Pg C y-1 .

A. 5

B. 50

C. 500

D. 5000

E. 0.5

B. 50

_________ is the most successful and most abundant genus on Earth.

A. Synechococcus

B. Homo

C. Prochlorococcus

D. Trichodesmium

E. Microcystis

C. Prochlorococcus

Micromonas is the smallest known ________ phytoplankton species in the world's oceans.

A. virus

B. eukaryote

C. diatom

D. dinoflagellate

E. prokaryote

B. eukaryote

According to biogeographic theory, species richness _____ with increasing island area.

A. increases

B. decreases

C. varies with

D. has no relation to

E. dissipates with

A. increases

Ecosystems are composed of _______.

A. populations

B. species

C. communities

D. communities and the abiotic features of the seascape

E. biospheres

D. communities and the abiotic features of the seascape

The Optimal Foraging Theory and the Time in Patch Model are generally applied to explain the costs vs. benefits of different _____ strategies.

A. reproductive

B. predation

C. mating

D. swimming

E. parasitic

B. predation

Many species use ______ coloration to defend themselves against predation.

A. danger

B. inverse

C. imposematic

D. aposematic

E. aposentic

D. aposematic

The _____ Effect may occur when population sizes are small and result in extinction.

A. Founder

B. Allele

C. Allee

D. Hardy

E. Paradox

C. Allee

_____ are habitat determining species that substantially alter, sometimes even create, the structural habitat on which other species depend.

A. Founders

B. Foundation species

C. Turnkey species

D. Structural species

E. Cryptic species

B. Foundation species

The "larval bottleneck" is used to describe _______ of larvae that eventually reach adulthood.

A. high survival rates

B. low survival rates

C. predation

D. immortality

E. settlement

B. low survival rates

Interference competition, exploitation competition, and _____ are the primary modes of interspecific competition.

A. competitive exclusion

B. predation

C. resource

D. parasitism

E. mimicry

A. competitive exclusion

Disturbance that occurs at intermediate levels usually ____ species diversity.

A. inhibits

B. increases

C. negatively affects

D. has no effect on

E. hinders

B. increases

The termination of some phytoplankton blooms may be caused by ______.

A. too much sunlight

B. high nutrient concentrations

C. a reduction in herbivore biomass

D.viruses

E. sinking out of the photic zone

D.viruses

_____ is said to occur when positive interactions between species lead to enhanced survival.

A. Cooperation

B. Synergy

C. Facilitation

D. Commensalism

E. Vacillation

C. Facilitation

The Intermediate Disturbance, Equal Chance, and Gradual Change Hypothesis assume that species composition is seldom in a ______.

A. state of equilibrium

B. competitive network

C. closed system

D. tipping point

E. transition

A. state of equilibrium

Niche Diversification, Circular Networks, and Compensatory Mortality Hypotheses assume that high diversity is maintained _____ continual changes in species composition.

A. with

B. without

C. under

D. constantly

E. suboptimal but

B. without

Nutrient controls of phytoplankton growth would be an example of a _____ effect.

A. web

B. top-down

C. bottom-up

D. Allee

E. Arrhenius

C. bottom-up

Diatom vegetative sizes are maintained by ____ reproduction.

A. sexual

B. asexual

C. binary fission

B. asexual

The Calvin Cycle of photosynthesis can only occur in the dark.

A. True

B. False

B. False

The intensity of competition between species in the intertidal zone generally ____ with increasing latitude.

A. stays constant

B. increases

C. decreases

D. grows exponentially

E. becomes more important

C. decreases

_________ phytoplankton usually grow well under wellmixed conditions, while ________ phytoplankton prefer stratified water columns.

A. flagellated, non-motile

B.non-motile, flagellated

C. eukaryotic, prokaryotic

D. diazotrophic, non-diazotrophic

B.non-motile, flagellated

_____ light is attenuated more quickly than _____light in near coastal and estuarine waters.

A. blue, red

B. black, white

C. infrared, ultraviolet

D. red, blue

E. reflected, absorbed

A. blue, red

Respiration increases the concentration of dissolved CO2 and results in ______ in pH.

A. a decrease

B. an increase

C. no change

D. buffering

E. a stable

A. a decrease

When the Mixing Depth is less than the Critical Depth, there is _______ net phytoplankton growth.

A. positive

B. reduced

C. zero

D. negative

E. alternative

A. positive

Prokaryotes use ______ to convert N2 gas to organic N and ammonium.

A. denitrification

B. nitrification

C. ammonification

D. nitrate fixation

E. nitrogen fixation

E. nitrogen fixation

Photoacclimation can be achieved by __________ of photosynthetic units (PSUs).

A. increasing the size

B. increasing the number

C. turning off

D. A or B

E. A, B, or C

D. A or B

Nitrate concentrations are usually _____ below the permanent thermocline.

A. high

B. low

C. the same as surface waters

D. in the form of ammonium

E. C and D

A. high

The complete nitrogen cycle requires _________ environments.

A. low pH

B. dark

C. anoxic

D. oxic

E. C and D

E. C and D

Nitrification and denitrification are said to be _______ processes.

A. oxic

B. anoxic

C. uncoupled

D. coupled

E. A and C

D. coupled

____ is usually the most abundant form of combined inorganic N in runoff, riverine input, groundwater discharge, and atmospheric deposition due to rapid oxidation of ammonium.

A. nitrite

B. nitrate

C. ammonium

D. urea

E. amines

B. nitrate

In terms of the total amount of nitrogen fixed, the most important nitrogen fixer (diazotroph) in the open ocean is probably_______.

A. Trichocystous

B. Oscillatoria

C. Trichodesmium

D. Prochlorococcus

E. Synechococcus

C. Trichodesmium

The compensation depth is the depth at which ______ equals the rate of gross primary production.

A. the respiration rate

B. the photic zone

C. the mixing depth

D. nutricline

E. grazing rate

A. the respiration rate

______ is the most abundant (non-gaseous) chemical species of BIOAVAILABLE nitrogen in deep ocean waters.

A. nitrite

B. nitrate

C. ammonium

D. A and C only

E. urea

B. nitrate

Why is the rapidly increasing concentration of atmospheric CO2 a problem for calcareous organisms?

A. It lowers dissolved oxygen concentrations

B. It enhances calcification

C. It affects the grazing rates of zooplankton

D. It causes dissolution of calcium carbonate

E. It not a real problem

D. It causes dissolution of calcium carbonate

A SCUBA diver was at a depth of 50 m (150 ft) in clear ocean waters and accidently sliced his finger on an angry coral. What is the color of the liquid oozing out of the injured finger?

A. Red

B. Ultraviolet

C. Blue

D. Orange

E. Yellow

C. Blue

As the attenuation coefficient for PAR increases, the depth of the photic zone ______.

A. decreases

B. increases

C. stays the same

A. decreases

It is possible for the critical depth to be shallower than the compensation depth.

A. True

B. False

B. False

Chloroplast stacking (pigment packaging) is a method used by phytoplankton for _______.

A. nutrient uptake

B. photosynthesis

C. respiration

D. buoyancy

E. photoacclimation

E. photoacclimation

Most open ocean species of phytoplankton are picoplankton (0.2 - 2 µm). This is likely due to ______.

A. low temperatures

B. turbulence

C. low sunlight

D. low nutrient concentrations

E. high grazing

D. low nutrient concentrations

The primary wavelengths for light absorption by chlorophyll a are _____ and _____.

A. green, red

B. blue, green

C. yellow, green

D. orange, yellow

E. blue, red

E. blue, red

_________ phytoplankton usually grow well under mixed conditions, while ________ phytoplankton prefer stratified water columns.

A. flagellated, non-motile

B. non-motile, flagellated

C. eukaryotic, prokaryotic

D. diazotrophic, non-diazotrophic

E. diatoms, cyanobacteria

B. non-motile, flagellated

Oligotrophic phytoplankton species with larger cells usually have a ____ half-saturation constant (Kt) than smaller cells for nutrient uptake.

A. higher

B. lower

C. constant

A. higher

The only "true" pelagic macroalga in the open ocean is _______.

A. Pycnococcus

B. Ulva

C. Sargassum

D. Prochloroccus

E. Spartina

C. Sargassum

In Michaelis-Menten kinetics, Vmax is the maximum __________ rate.

A. uptake

B. growth rate

C. velocity parameter

D. excretion

E. volumetric

A. uptake

_____ can exist in solid, liquid, and gas states under normal environmental conditions on Earth.

A. N

B. P

C. S

D. Fe

E. A and C

E. A and C

A high kt for a phytoplankter suggests that it would grow faster when nutrient concentrations are low.

A. True

B. False

B. False

If the water column is anoxic, sediments will be a source for ________ diffusing into the water column.

A. oxygen

B. phosphate

C. silicate

D. bacteria

E. A, B, C, and D

B. phosphate

According to Stokes' Law, a sphere will increase its sinking speed in proportion to the ____ of the radius.

A) inverse

B) square

C) cube

D) square root

E) reciprocal

B) square

When phytoplankton cells age or die, the C:N ratio _____.

A) increases

B) decreases

C) stays constant

A) increases

Water column stratification favors the growth of _________ phytoplankton cells.

A) small and motile

B) large

C) diatom

D) senescent

E) light-limited

A) small and motile

Silica may be the limiting nutrient for _______ growth if N and P concentrations are in excess.

A. cyanobacteria

B. dinoflagellates

C. cryptophytes

D. diatoms

E. A and D

D. diatoms

Atmospheric dust can be a major source of _________ for the open ocean.

A. iron

B. silica

C. microbes

D. phosphorus

E. A, B, C, and D

E. A, B, C, and D

The Redfield ratio is _________ C:N:P

A. 106:1:16 moles

B. 106:16:1 grams

C. 106:16:1 moles

D. 106:1:16 grams

E. A and B

C. 106:16:1 moles

Sulfate (SO4) is the ____ most abundant ion in seawater.

A) 2nd

B) 3rd

C) 4th

D) 5th

E) 6th

B) 3rd

Under oxic conditions, _______ readily adsorbs (binds) to particles and calcium carbonate.

A. nitrate

B. nitrite

C. ammonium

D. phosphate

E. A, B, and C

D. phosphate

Black and smelly marsh sediments are highly reduced and rich in ________

A. hydrogen sulfide (H2S)

B. adsorbed phosphate (PO4)

C. oxygen (O2)

D. hydrogen sulfate (SO4)

A. hydrogen sulfide (H2S)

The primary sink for silica in the world's ocean is __________ environments.

A. atmospheric

B. terrestrial

C. deep ocean

D. diatoms

E. C and D

E. C and D

Small Reynolds Numbers (Re) indicate that viscosity can be ignored. A) True

B) False

B) False

The surface area of a cell is important for biogeochemical cycling because....

A. Rates are directly proportional to surface area

B. Rates are inversely proportional to surface area

C. Only small cells are important for biogeochemical cycling

D. Smaller cells have lower uptake rates

A. Rates are directly proportional to surface area

Under oxic conditions, phosphate adsorbs (sticks to) onto__.

A) oxyhydrides

B) calcium carbonate

C) clay minerals

D) A,B and C

D) A,B and C

_____ allow nitrogen fixation by some cyanobacteria in oxic environments.

A. nodules

B. heterocysts

C. homocysts

D. filaments

E. nodes

B. heterocysts

Dissimilative sulfate reduction is a major source of hydrogen sulfide (H2S) in ______ environments.

A. oxic

B. anoxic

C. pelagic

D. oligotrophic

E. polluted

B. anoxic

In ocean basins located large distances from continents, _____ may be a limiting nutrient for phytoplankton.

A. phosphorus

B. organic matter

C. sulfur

D. iron

E. molybdenum

D. iron

A major source of "new" iron for the oligotrophic North Atlantic Ocean is ______.

A. regeneration

B. upwelling

C. downwelling

D. river input

E. atmospheric dust

E. atmospheric dust

Usually, fixed ____ is the limiting nutrient for freshwater systems and fixed _____ limits primary production in ocean habitats.

A. N, P

B. P, N

C. P, Fe

D. Fe, P

E. Fe, N

B. P, N

The concentration GRADIENT (dC/dZ) in the diffusive boundary layer ______ as flow around a particle increases.

A. increases

B. decreases

C. does not change

A. increases

A low Reynolds number indicates that ______ is more important for organism movement than inertial forces.

A. salinity

B. temperature

C. pressure

D. viscosity

E. turbulence

D. viscosity

Nitrate reductase is an enzyme that converts nitrate to ________.

A. amino acids

B. nitrite

C. nitrile

D. proteins

E. urea

B. nitrite

Most of the dissolved organic matter (DOM) pool in the marine environment is ________.

A. edible

B. labile

C. refractory

D. bioavailable

E. precipitated

C. refractory

An N:P molar ratio less than 16 usually indicates _______ limitation.

A. P

B. N

C. S

D. Si

E. A and D

B. N

_____ is usually used to infer estimated sinking rates for phytoplankton and other small cells.

A. the Reynolds number

B. Fick's Law

C. Stokes' Law

D. temperature

E. the Redfield Ratio

C. Stokes' Law