Lesson 2 (Chapter 54, Community Ecology) Flashcards
(120 cards)
1
Q
an assemblage of populations of various species living close enough for potential interaction
A
community
2
Q
relationships between species
A
interspecific interactions
3
Q
can affect the survival and reproduction of each species, in which the effects can be summarized as positive (+), negative (-), or no effect (0)
A
interspecific interactions
4
Q
examples of interspecific interactions
A
competition, predation, herbivory, symbiosis (parasitism, mutualism, commensalism), facilitation
5
Q
occurs when species compete for a resource in short supply (-/-)
A
competition
6
Q
strong competition can lead to this phenomenon
A
competitive exclusion
7
Q
local elimination of a competing species
A
competitive exclusion
8
Q
states that two species competing for the same limiting resources cannot coexist in the same place
A
competitive exclusion principle
9
Q
total of a species’ use of biotic and abiotic resources
A
ecological niche
10
Q
can also be thought of as an organism’s ecological role
A
ecological niche
11
Q
can coexist in a community if there are one or more significant differences in their niches
A
ecologically similar species
12
Q
differentiation of ecological niches, enabling similar species to coexist in a community
A
resource partitioning
13
Q
a niche potentially occupied by a species
A
fundamental niche
14
Q
the niche actually occupied by a species
A
realized niche
15
Q
a species’ fundamental niche may differ from its realized niche due to this
A
competition
16
Q
behavior in which an organism is active during nighttime
A
nocturnal
17
Q
behavior in which an organism is active during daytime
A
diurnal
18
Q
a tendency for characteristics to be more divergent in sympatric populations of two species than in allopatric populations of the same two species
A
character displacement
19
Q
evolution of a new species from a surviving ancestral species while both continue to inhabit the same geographic region
A
sympatric speciation
20
Q
speciation that occurs when biological populations of the same species become isolated due to geographical changes
A
allopatric speciation
21
Q
interaction in which one species, the predator, kills and eats the other, the prey (+/-)
A
predation
22
Q
some feeding adaptations of predators
A
claws, teeth, fangs, stingers, poison
23
Q
defensive adaptations of prey
A
behavioral adaptations such as hiding, fleeing, forming herds or schools, self-defense, alarm calls; morphological adaptations; physiological adaptations
24
Q
makes prey difficult to spot
A
cryptic coloration or camouflage
25
bright warning coloration exhibited by animals with effective chemical defense
aposematic coloration
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predators are particularly cautious in dealing with prey that display such coloration
aposematic coloration
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in which a prey species may gain significant protection by mimicking the appearance of another species
Batesian mimicry
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in which a palatable or harmless species mimics an unpalatable or harmful model
Batesian mimicry
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in which two or more unpalatable species resemble each other
Müllerian mimicry
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interaction in which an herbivore eats parts of a plant or alga (+/-)
herbivory
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has led to evolution of plant mechanical and chemical defenses and adaptations by herbivores
herbivory
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a relationship where two or more species live in direct and intimate contact with one another
symbiosis
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in which one organism, the parasite, derived nourishment from another organism, its host, which is harmed in the process (+/-)
parasitism
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a parasite that lives within the body of its host
endoparasite
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a parasite that lives on the external surface of a host
ectoparasite
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true or false: many parasites do not have a complex life cycle involving a number of hosts
false
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true or false: some parasites change the behavior of the host in a way that increases the parasites' fitness
true
38
an interspecific interaction that benefits both species (+/+)
mutualism
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mutualism in which one species cannot survive without the other
obligate mutualism
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mutualism in which both species can survive alone
facultative mutualism
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interaction in which one species benefits and the other is neither harmed nor helped (+/0)
commensalism
42
why commensal interactions are hard to document in nature
any close association likely affects both species
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interaction in which one species has positive effects on another species without direct and intimate contact (+/+) or (+/0)
facilitation
44
true or false: in general, a few species in a community exert strong control on that community's structure
true
45
two fundamental features of community structure
species diversity, feeding relationships
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the variety of organisms that make up the community
species diversity
47
two components of species diversity
species richness, relative abundance
48
the number of different species in the community
species richness
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the proportion each species represents of all individuals in the community
relative abundance
50
diversity can be compared using this device
Shannon diversity index (H)
51
formula of the Shannon diversity index
H = -(p_A[ln p_A] + p_B[ln p_AB] + p_C[ln p_C] + ...)
where A, B, C, ... are the species, p is the relative abundance of each species, and ln is the natural logarithm
52
true or false: determining the number and abundance of species in a community is difficult, especially for small organisms
true
53
can be used to help determine microbial diversity
molecular tools
54
why do ecologists manipulate diversity in experimental communities
to study the potential benefits of diversity
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benefits of having communities with higher diversity
more productive and more stable in their productivity
better able to withstand and recover from environmental stresses
more resistant to invasive species
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organisms that become established outside their native range
invasive species
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the feeding relationships between organisms in a community
trophic structure
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a key factor in community dynamics
trophic structure
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link trophic levels from producers to top carnivores
food chains
60
a branching food chain with complex trophic interactions
food web
61
true or false: species cannot play a role at more than one trophic level
false
62
how can food webs be simplified
grouping species with similar trophic relationships into broad functional groups
isolating a portion of a community that interacts very little with the rest of the community
63
true or false: each food chain in a food web is usually only a few links long
true
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two hypotheses that attempt to explain food chain length
energetic hypothesis, dynamic stability hypothesis
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hypothesis in which length is limited by inefficient energy transfer
energetic hypothesis
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most data support this hypothesis
energetic hypothesis
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total mass of all individuals in a population
biomass
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hypothesis in which long food chains are less stable than short ones
dynamic stability hypothesis
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species with large impact
highly abundant species, species that play a pivotal role in community dynamics
70
species that are most abundant or have the highest biomass
dominant species
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species that exert powerful control over the occurrence and distribution of other species
dominant species
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one hypothesis suggests that they are most competitive in exploiting resources
dominant species
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one hypothesis is that they are most successful at avoiding predators
dominant species
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typically introduced to a new environment by humans, often lack predators or disease
invasive species
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species that exert strong control on a community by their ecological roles or niches
keystone species
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species that are not necessarily abundant in a community, in contrast to dominant species
keystone species
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species that cause physical changes in the environment that affect community structure, also known as ecosystem engineers
foundation species
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a model of community organization that proposes a unidirectional influence from lower to higher trophic levels
bottom-up model
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in which the presence or absence of mineral nutrients determines community structure, including the abundance of primary producers
bottom-up model
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a model of community organization that proposes that control comes from the trophic level above, also called the trophic cascade model
top-down model
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in which the predators control herbivores, which in turn control primary producers
top-down model
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a method that can help restore polluted communities
biomanipulation
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decades ago, most ecologists favored this viewpoint
communities are in a state of equilibrium
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suggested that species in a climax community function as a superorganism
F. E. Clements
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challenged whether communities were at equilibrium
A. G. Tansley, H. A. Gleason
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describes communities as constantly changing after being buffeted by disturbances
nonequilibrium model
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an event that changes a community, removes organisms from it, and alters resource availability
disturbance
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what characterizes a high level of disturbance
high intensity, high frequency of disturbance
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suggests that moderate levels of disturbance can foster greater diversity than either high or low levels of disturbance
intermediate disturbance hypothesis
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effect of high levels of disturbance
exclude many slow-growing species
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low levels of disturbance
dominant species exclude less competitive species
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the sequence of community and ecosystem changes after a disturbance
ecological succession
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occurs where no soil exists when succession begins
primary succession
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occurs where soil remains after a disturbance
secondary succession
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three possible links between early-arriving species and late-arriving species
early arrivals may:
facilitate
inhibit
tolerate
the appearance of later species
96
have the greatest impact on biological communities worldwide
human disturbance
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usually reduces species diversity
human disturbance
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two key factors that affect a community's species diversity
latitude, area
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area with high species richness
tropics
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decline of species richness
along an equatorial-polar gradient
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two key factors in species richness in equatorial-polar gradients
evolutionary history, climate
102
communities in these regions have started over repeatedly following glaciations
temperate, polar
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greater species richness may be attributed to this characteristic
greater age of tropical environment
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growing season is longer and biological time runs faster in these regions
tropical
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primary cause of the latitudinal gradient in biodiversity
climate
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two main climatic factors correlated with biodiversity
solar energy, water availability
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the evaporation of water from soil plus transpiration of water from plants
evapotranspiration
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solar energy and water availability can be simultaneously measured through this activity
evapotranspiration
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quantifies the idea that, all other factors being equal. a larger geographic area has more species
species-area curve
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factors affecting species richness on islands
island size, distance from mainland, immigration, extinction
111
species richness on an ecological island levels off at a dynamic equilibrium point
equilibrium model of island biogeography
112
examples of pathogens
microorganisms, viruses, viroids, prions
113
can alter community structure quickly and extensively
pathogens
114
responsible for transporting pathogens around the world at unprecedented rates
human activities
115
needed to help study and combat pathogens
community ecology
116
pathogens that have been transferred from other animals to humans
zoonotic pathogens
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many of today's emerging human diseases are caused by these pathogens
zoonotic pathogens
118
intermediate species that can transfer pathogens
vector
119
methods in which pathogens can be transmitted
direct transmission, vector transmission
120
significance of identifying the community of hosts and vectors for a pathogen
can help the spread of contagious diseases within a community
