ecology chp 16
estimates show that oceans absorb about______of all the atmospheric CO2
48%
trophic cascade
A change in the rate of consumption at one trophic level that results in a series of changes in species abundance or composition at lower trophic levels.
interaction web
A concept that describes both the trophic (vertical) and non-trophic (horizontal) interactions among the species in a traditional food web.
species accumulation curve
A graph that plots species richness as a function of the total number of individuals that have accumulated with each additional sample.
rank abundance curve
A graph that plots the proportional abundance of each species in a community relative to the others in rank order, from most abundant to least abundant.
interaction strength
A measure of the effect of one species (the interactor) on the abundance of another species (the target species).
foundation species
A species that has large, community-wide effects on the habitat or food of other species by virtue of its size or abundance.
ecosystem engineers
A species that influences its community by creating, modifying, or maintaining physical habitat for itself and other species.
functional group
A subset of a community that includes species that function in similar ways, but do not necessarily use the same resources.
trophic facilitation
An interaction in which a consumer is indirectly facilitated by a positive interaction between its prey or food plant and another species.
indirect interaction
An interaction in which the relationship between two species is mediated by a third (or more) species.
direct interaction
An interaction that occurs between two species, such as competition, exploitation, or a positive interaction.
redundant species
Having the same function in a community as other species in that community within a larger functional group.
Most food webs do not include information about symbiotic relationships.
In a competitive hierarchy, one species dominates the interaction; in an interaction network, no one species dominates the interaction.
Which statement best describes the difference between the theoretical concept of a community and the ways in which communities are delineated in practice?
In theory, communities consist of all species present; in practice, biologists usually study only a subset of the species.
Which statement describes a limitation of a species accumulation curve in terms of its ability to determine whether species diversity has been adequately sampled?
It assumes that the sampling methods are consistent throughout the study.
In their studies of a salt marsh community, Sally Hacker and colleagues found that removing _______ led to a(n) _______.
Juncus; decrease in the abundance of aphids through indirect effects
Which statement about food webs is true?
Most food webs do not include information about symbiotic relationships.
horizontal interactions
Non-trophic interactions, such as competition and some positive interactions, that occur within a trophic level.
competitive networks
Sets of competitive interactions involving multiple species in which every species negatively interacts with every other species, thus promoting species coexistence.
Which statement about the studies by Mary Power and colleagues on California rivers is true?
Species, such as the steelhead, that are keystone predators during normal years are minor players in the food web during drought years.
shannon index
The index most commonly used to describe species diversity quantitatively.
Which statement about keystone predators is true?
They usually influence primary producers indirectly.
food web
a diagram showing the connection between organisms and the food they consume
community
a group of interacting species that occur together at the same place and time
trophic level
a group of species that obtain energy in similar ways classified by the number of feeding steps by which the group is removed from primary producers, which are the first trophic level
species diversity
a measure that combines the number of species ( species richness) in a community and their relative abundances compared with one another (species evenness)
In the study by Jennifer Hughes and colleagues, in which community did it appear that the species richness had been adequately sampled?
a plant community from a forest in Michigan
guild
a subset of a community that includes species that use the same resource whether or not they are taxonomically related
An experiment by Alsterberg and colleagues showed that with ocean acidification and warming, the biomass of benthic microalgae
both a and b ( did not change with omnivores/ declined without omnivores)
Although beavers are relatively rare, they have considerable influence over species interactions in communities in which they are present because of the dams that they construct. The beaver is thus an example of a(n)
both b and c (ecosystem engineer/ keystone species)
Ecologists are concerned about the establishment of invasive species in new areas because invasive species
can have large ecological effects in their new communities
which conclusion was the primary finding of buss and Jackson's study of coral- associated invertebrates and algae in Jamaica?
competitive networks can be circular
Cougars prey on both white-tailed deer and mule deer. Because of their shared predator, each deer species' abundance is affected by the presence of the other deer species. The white-tailed and mule deer are engaged in a(n)
indirect interaction
what is the primary difference between interaction webs and food webs?
interaction webs include non-trophic interactions; food webs do not
Which statement about the "killer alga," Caulerpa taxifolia, is false?
it is toxic to humans and other mammals
Menge and colleagues performed experiments in which they exposed some populations of mussels to sea stars and excluded sea stars from other mussel populations. Suppose two populations of mussels are the same size prior to treatment, and after treatment there are 600 mussels in the treatment without sea stars and 200 mussels in the treatment with sea stars. Suppose further that the sea star population consists of 10 individuals. What is the per capita interaction strength of sea stars on mussels?
ln (0.33/10)
Members of the same functional group must belong to the same
none of the above
Species that feed on more than one trophic level are called
omnivores
Lions prey on animals such as zebras and wildebeest, which feed primarily on grasses. Lions thus should be considered
secondary consumers
the shannon index is a measure of
species diversity
Which value can be measured the most easily?
species richness
biodiversity
the diversity of important ecological entities that span multiple spatial scales, from genes to species to communities
species richness
the number of species in a community
species evenness
the relative abundances of different species compared to one another in a community
community structure
the set of characteristics that shape a community, including the number, compositions, and abundance of species