Exam Questions / Community

The oceanic zone is divided into many different zones based on depth. The zone representing the top layer of the ocean, where the majority of ocean photosynthesis occurs, and where plankton, floating seaweed, jellyfish, tuna, sharks, dolphins are commonly found, is referred to as the...

a) Epipelagic

Which marine ecosystem occurs in the littoral zone, is characterized by interaction between saltwater and freshwater (i.e., it has a strong and fluctuating salinity gradient), has high levels of emergent non-woody vegetation, and includes hatcheries for many species of commercially and ecologically important fish?

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• b)  Salt marsh

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The intertidal zone of the ocean is strongly influenced by ocean tides, which are driven by the gravitational attraction of the sun and moon on oceanwater. Which of the following is the name given to tides when the earth, moon and sun form a right angle within the plane of the elliptic (hint: this name describes the scenario where there are 4 tides per day with 6-hour intervals between each).

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• b)  Neap tides

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Which of the following marine ecosystems is located in the Neritic zone at tropical latitudes, has the highest species diversity of all marine ecosystems, and is under extreme threat due to rising water temperatures as a result of global warming?

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• c)  Coral reefs

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The deepest zone of the ocean, which includes the Mariana Trench, can have water pressure in excess of 16,000 pounds per square inch (PSI), and which was once thought to be uninhabitable, is referred to as the ...

c) Hadalpelagic 

How do oceanic gyres influence climate around the world?

b) They moderate temperature extremes; they do so by transporting cool water from the poles to the equator and warm water from the equator to the poles

Which of the following statements about populations is false?

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• c)  Populations exhibit static behavior, changing very little through time

You need to estimate the density of a population of the Pine Barrens Pitcher Plant within a large bog. You divide the bog into 200 equal-sized plots, and you count the number of individuals you find in a random sample of 15 of those plots. If the total number of Pitcher Plants found in the 15 sampled plots is 45, then what is your best estimate of the total population size of the pitcher plants within the bog?

b) 600

With respect to plants, which type of spatial dispersion of individual plants in a population is often caused by density dependent mortality (i.e., where the ability of individuals to survive is a function of the number of individuals per unit area in the population)?

• a)  Evenly spaced dispersion

According to Levin’s metapopulation model, if the extinction rate of metapopulation patches is 0.2 and the colonization rate of metapopulation patches is 0.4, then the metapopulation....

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• c)  will persist, and the equilibrium number of patches occupied will be 0.5 (or 50%).

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A population of invasive Green Crab from England exhibits exponential population growth. If the initial crab population size is 10, and the intrinsic per capita growth rate is 0.5 per year, what would the approximate crab population size be after 20 years of growth?

e) 221,660

According to the logistic model of population growth, if the current population abundance of a species is above carrying capacity, we would expect the population to do which of the following in the future?

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• b)  Decline until reaching carrying capacity

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Changes in the structure of food chains tend to cause trophic cascades. If the producer in a food chain dramatically increases in abundance, we would expect which of the following to occur?

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• b)  The first, second and third order consumers in the food chain would all increase in abundance.

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According to the theory of Lindeman’s Biomass Pyramid, approximately what percentage of energy consumed at one level of a food chain becomes biomass in the next level of the food chain?

c) 10% 

When grown together in a common garden experiment, grass A restricts the abundance of grass B, and grass B restricts the abundance of grass A. The interaction between these two species is best described as ...

a) Competition

Which of the following describes the distribution of a species net of the effects of competition?

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• b)  Realized niche

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Leibig’s law of the minimum states that limitations on growth are determined by...

• d)  availability of the scarcest resource.

If the average number of species in an ecosystem over time follows the intermediate disturbance hypothesis, which of the following statements would be correct?

d) Lower levels of disturbance would result in lower species diversity than intermediate levels of disturbance.

Scientists hypothesize that the first forms of life on earth (roughly dating to 3.7 BYA) were...

• b)  Chemosynthetic bacteria.

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Classes of Plants 

Annuals

• Complete their entire life cycle (germination, growth, flowering, seed production, and death) within one growing season

Perennials

• Live for more than two years, often many years. 

• Shrubs

• Live for more than two years, often many years. 

• Trees 

Early stage succession

• Pioneer species: The first species to colonize an area after a disturbance or on newly formed land. 

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• Rapid growth and reproduction: These species are often "r-selected" and thrive in harsh conditions, quickly colonizing the area. 

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• Simple ecosystems: Early successional communities have lower species diversity and simpler food webs. 

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• Examples: Grasses, weeds, and other fast-growing plants. 

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Late stage succession 

• Climax community: The final stage of succession, where the ecosystem is relatively stable and self-sustaining.

• Slower growth and reproduction: Species are often "K-selected" and have longer lifespans.

• High biodiversity: Late successional communities have a greater variety of species and more complex food webs.

• Examples: Mature forests, old-growth forests, and tall-grass prairies.