1. Scientists
have discovered that when they provide supplemental food for hares, their
density tripled. Based on the figure above, showing cycles of lynx and hare
populations over a century's time, what do you predict would happen to a lynx
population in an area where hares were provided supplemental food? The lynx
population would increase 1-2 years after the hares increased.
2. What
type of populations would be most likely to show resource partitioning? sympatric
populations of species with similar ecological niches
3. How
does the caterpillar benefit from its relationship with the ant? protection from a predator
4. How
does the ant benefit from its relationship with the caterpillar? obtains sugary
droplets as food
5. Suppose
the friendly ants took the sugar from the caterpillar but did nothing to help
or protect the caterpillar. Assuming that it is energetically costly to produce
the sugar and the risk of being attacked by non-friendly ants, what type of
symbiotic relationship is this? Parasitism
6. Suppose
the caterpillar did not feed the ants, but the ants still protected the
caterpillar. Assuming that the ants are not hurt in this role, what type of
relationship is this? Commensalism
7. According
to the video, the tentacles of the caterpillar communicate with the ants via a
chemical. What hypothesis follows logically from this? The ants are able to
detect this chemical in some manner.
8. Caterpillars
of the same species on a large leaf each chew as much leaf as they can. This is
an example of exploitation competition.
9. Secondary
metabolites are produced to deter herbivores.
10. Several
butterfly species that are edible to birds have very similar color patterns to
the generally inedible monarch butterfly. This is best described as an example
of what? Batesian mimicry
11. What
concepts enable two or more species with similar niches to coexist in a
community?
·
Character displacement
·
Resource partitioning
12. What
is an example of a +/- interaction? Predation
13. You
find some rather strange plants in your backyard. They consist only of thin,
pale yellow stems that are wrapped around other species of plants growing
nearby. You experiment by unwrapping some of the strange yellow plants and
planting half of them alone in pots of soil and half in pots with other plants
from your yard. You water and fertilize both sets of pots, but after a few
weeks you find that the yellow plants that were potted alone have died, while
those potted with other plants are thriving. What term would you use to
describe the strange yellow plants? Holoparasitic
14. Sympatric
species are more likely than allopatric species to display character
displacement.
15. What
is an example of a +/+ interaction? Mutualism
16. You
are assigned a research project on a parasitic species. You choose the sea
lamprey (Petromyzon marinus), you discover that juvenile sea lampreys attach
themselves to the outside of fish and 'rasp' away the scales and skin in order
to obtain nutrition from the fish's bodily fluids. You are surprised to find
out that sea lampreys can feed on more than ten different fish species from
several families. You also learn that adult lampreys die after spawning while
eggs hatch into a nonparasitic larvae that inhabit small sand burrows in stream
beds. Based on all these findings, what terms would you use in your research
report to describe the sea lamprey? Polyphagous; Ectoparasitic; macroparasitic
17. For
each of the statements below, indicate whether the statement is true or false.
·
The number of anti-predator tactics that
evolve in prey species supports the hypothesis that predation acts as a strong
selective pressure on prey populations. True
·
Introduced invasive predators frequently
do well in a new environment due to the lack of evolved defenses in the prey
species. True
·
Some herbivores have evolved the
capability of neutralizing toxins produced by plants. True
·
The density of most prey species is
independent of predation levels and is influenced to a greater extent by
competition with other species. False
·
Secondary metabolites are produced by
herbivores to help in the digestion of toxic plant materials. False
·
Large vertebrate herbivores have a
stronger effect on plant species than do small invertebrate herbivores such as
insects. False
·
Batesian mimicry describes a situation
in which poisonous animals evolve similar coloration patterns that facilitate
the effectiveness of the coloration in deterring predation. False
·
If population densities of a prey
species increase upon the removal of predators from the environment, then prey
density is considered to be predator-controlled. True
18. The
relationship of disease-causing organisms to an infected rabbit is one of parasitism.
19. Fill
in the sentences with the appropriate words.
·
The competitive exclusion hypothesis
states that two species with overlapping niches cannot survive together. One
species will be driven to local extinction.
·
In order for complete exclusion from n
area to be avoided, resource partitioning can occur whereby similar sympatric
species evolve slightly different ecological niches.
·
If the evolution of different niches is
the result of morphological changes, then character displacement has occurred.
·
The evolution of morphological
differences between two species should be greater when they are sympatric than
when they are allopatric, due to selective pressures to diversify niches in the
face of competition.
20. Animals
have evolved many different antipredator strategies. Match the animal pictured
with its antipredator strategy.
·
Chemical defense: jellyfish toxin
·
Intimidation: hissing cat
·
Cryptic coloration: walking stick
·
Armor: tortoise shell
·
Aposematic coloration: brightly-colored
poisonous Lionfish
·
Masting: mass hatching of locusts
21. Fleas
are endoparasites. False
22. The
ideal biotic and abiotic environment a species can inhabit is referred to as
the fundamental niche, while the realized niche refers to the environment that
an animal actually inhabits after accounting for interactions with other
species.
23. Two
species of barnacles overlap in their niches within the intertidal zone.
Semibalanus outcompetes Chthamalus where their niches overlap, excluding
Chthamalus. Examine the two barnacle species in the figure and then label their appropriate niches,
showing the differences between the fundamental and realized niches of these
species.
·
Chthamalus
realized niche
·
Chthamalus
fundamental niche
·
Semibalanus
fundamental and realized niche
24. Milkweed
plants contain cardiac glycosides, substances that are toxic to many species.
However, the caterpillars of the monarch butterfly have evolved to feed on
milkweed, and are thus able to tolerate the toxins and even sequester them for
protection from predators. Milkweed also produces a sticky substance called
latex, which can entrap and kill small monarch caterpillars. It has recently
been discovered that monarch caterpillars often nibble through a leaf's petiole
(attachment point) before feeding on the leaf - this cuts off the supply of
latex to the leaf. If you could travel far into the future, what development do
you think you would be most likely to find in the milkweed/monarch interaction?
Milkweed plants have evolved to have tougher petioles; most monarchs are unable
to chew through them prior to feeding on leaves.
25. Resource
partitioning occurs between allopatric species. False
26. Many
species of ants "farm" aphids, protecting them from predation and
collecting concentrated sugars (i.e. honeydew) from them. This type of
ant/aphid relationship is known as defensive mutualism.
27. Two
species that occupy identical realized niches will not be able to co-exist for
an extended period of time. True
28. You
are studying the feeding habits of a group of four closely related bird
species. You observe that all four species feed on insects. However, you notice
that the species do not feed at the same time of day: one species feeds most
actively at dawn, another during the middle of the day, another at dusk, and
the last species feeds at night. What term would you use to describe this
behavior? resource partitioning
29. In
a hypothetical situation, a bacterium lives on the surface of a leaf where it
obtains nutrients from the leaf's nonliving waxy covering, which the leaf
continually produces. The plant is not hurt or harmed by this feeding. Once the
number of bacteria reaches a critical mass, they inhibit the growth of other
microbes that damage the plant. Occasionally, these bacteria can gain access to
the interior of the leaf, for example, if there is weather-related leaf breakage
the exposes the plant's interior tissues. If this occurs, the bacteria feed on
the plant's living tissue, causing minor damage. What sequences best describes
the ecological roles played by the bacterium in this situation? commensalism→ mutualism→ parasitism
30. Resource
partitioning enables species that are better competitors to exclude similar
species from a community. False
31. Competition
among individuals of different species is called interspecific competition.
32. Character
displacement is driven by competition. True
33. Place
each of the following into the appropriate category of competition.
·
Interspecific-interference competition
¨ An
eastern bluebird and a European starling compete for nest cavities by physical
confrontations.
¨ If
given the opportunity, a bald eagle will steal a fish that an osprey has caught
rather than catching a fish itself.
·
Intraspecific-exploitation competition
¨ In
late fall, American red squirrels scurry around the base of a white oak
collecting as many acorns as possible for their individual winter food caches.
·
Interspecific-exploitation
¨ White-tailed
deer browse the understory of a deciduous forest, eating the vegetation that
numerous other species depend on.
¨ Paramecium
caudatum and P. bursaria both show a drop in population densitites when housed
together.
·
Intraspecific-interference
¨ During
the breeding season, male elephant seals engage in vicious battles for control
of a harem of females.
34. Oak
trees and many other plant species have years in which they have synchronous
production of many progeny by all individuals in a population. This is known as
masting.
35. Polyphagous
parasites feed on many different host species.
36. Place
each scenario into the appropriate type of mutualism. Labels may be used more
than once.
§ Trophic
mutualism
·
Mycorrhizae fungus grow on plant roots,
receiving carbohydrates from the plant’s photosynthetic products. The fungal
strands help the plant to better absorb water and nutrients. Neither plant nor
fungus can survive on their own.
§ Obligate
mutualism
·
Mycorrhizae fungus grow on plant roots,
receiving carbohydrates from the plant’s photosynthetic products. The fungal
strands help the plant to better absorb water and nutrients. Neither plant nor
fungus can survive on their own.
·
The senita cactus moth can only lay its
eggs on the senita cactus. It is the sole pollinator for the cactus.
§ Dispersive
mutualism
·
The senita cactus moth can only lay its
eggs on the senita cactus. It is the sole pollinator for the cactus.
§ Defensive
mutualism
·
An ant species collects nectar from
special glands on a plant’s leaves. The ants will often kill or remove insect
herbivores that attempt to attack the plant.
§ Facultative
mutualism
·
An ant species collects nectar from
special glands on a plant’s leaves. The ants will often kill or remove insect herbivores
that attempt to attack the plant.
37. For
each pair of organisms, indicate whether the relationship is parasitic,
mutualistic, or commensal.
§ Mutualism
·
Hummingbirds / plants with tube-shaped
flowers
·
Leaf-cutter ants / fungus
·
Ants / acacia plants
·
Squirrels / oak trees
§ Commensalism
·
Orchids with no nectar / bees
·
Plants with hooked seeds / mammals
·
Epiphytes / tropical trees
·
Egrets / cattle in field
§ Parasitism
·
Mosquito / mammal
·
Leeches / fish
·
Plant without chlorophyll / growing
plant with chlorophyll
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