During the 19th century, sea otters were hunted almost to the point of
extinction. When the number of sea otters became very low, it was
noticed that the ecosystem of kelp bed "forests" was also
disappearing. It was discovered that the sea otters were predators of
sea urchins, which were, in turn, predators of the kelp. When sea
otters declined, the sea urchin populations grew, destroying the kelp
ecosystem and the many species that depended on it. It was then
understood that sea otters were _____ in this ecosystem
A. a keystone species
B. parasites
C. competitors
D. producers - ANSWERS-keystone species
To address the problem of preserving biodiversity, biologists have
identified various "hotspots" around the world. What exactly is a
hotspot
A. areas of the world where extinction rates are significantly higher
than "background" rates of extinction
B. areas around the globe where the climate and geologic events have
resulted in a large number of species
C. geographic areas that are warm year-round and never experience
freezing temperatures
,D. geographic regions where endangered species and humans come in
contact with - ANSWERS-areas around the globe where the climate
and geologic events have resulted in a large number of species
In a particular county, there are 30 births and 20 deaths for every 1000
residents. What is the annual growth rate of this population
A. 1.0%
B. 30%
C. 3.0%
D. 10% - ANSWERS-1.0%
The data presented above, the reason for the increase in the
population of wolves 2004-2005 would be
A. moose weakened by a budding tick population are easy preys
B. an increase in the populations' carrying capacity due to
urbanization
C. none of the answers are correct
D. a decrease in the population of the moose
E. a decrease in the tick population - ANSWERS-moose weakened by
a budding tick population are easy preys
Which of the following statements are true
,A. the population of the three species are interconnected
B. wolves have a direct influence on the number of ticks
C. all statements are true
D. moose are influenced by the population of ticks not wolves
E. the growth of the three populations are independent - ANSWERS-
the population of the three species are interconnected
Which of the following best demonstrates the use of mimicry as a
defense strategy by certain organisms
A. a harmful species gradually evolves into a harmless species
B. a harmless species gradually evolves into a harmful species
C. a harmful species assumes a known characteristics of a harmless
species
D. a harmless species assumes a known characteristics of a harmful
species - ANSWERS-a harmless species assumes a known
characteristics of a harmful species
Birds nestling in the trees; protozoa in the guts of termites; tapeworms
in humans are examples of ____ symbiotic relationships respectively
A. commensalism, parasitism, and mutualism
B. commensalism, mutualism, and parasitism
C. mutualism, parasitism, and commensalism
D. parasitism, mutualism, and commensalism
, E. mutualism, commensalism, and paratisim - ANSWERS-
commensalism, mutualism, parasitism
The benefits of wetlands include
A. increasing rate of water flow to bodies of water
B. production of sediment that is useful for fertilizer
C. protection from flooding
D. storage of drinking water - ANSWERS-protection from flooding
When a patch of land is cleared in a tropical rainforest, the vegetation
is often burned to enrich the soil with nutrients from the burned plant
material. This
A. isn't necessary because tropical soils are filled with nutrients
B. helps to promote long-term sustainable agricultural
C. works well long term because so many nutrients are trapped in
tropical plants
D. works for a few years, but the soil is soon depleted of nutrients -
ANSWERS-works for a few years, but the soil is soon depleted of
nutrients
During the last few years, scientists have observed that caribou have
had difficulty migrating due to the melting of the ____ creating
impassable wetlands where there was once solid ground