Ecology Test 1 (52-54) Flashcards
(305 cards)
1
Q
What is Ecology?
A
is the scientific study of the interactions between organisms and the living and nonliving components of their environment
2
Q
what does ecology determine
A
the distribution of organisms and their abundance
3
Q
what are examples of abiotic factors
A
temperature, light, water, and nutrients
4
Q
what are examples of biotic factors
A
organisms that are part of an individual’s environment
5
Q
what are abiotic factors
A
nonliving factors
6
Q
what are biotic factors
A
living
7
Q
what is organismal ecology
A
how an organism’s structure, physiology, and (for animals) behavior meet environmental challenges
8
Q
what is population ecology
A
focuses on factors affecting population size over time
9
Q
what is community ecology
A
examines how interactions between species affect community structure and organization
10
Q
what is ecosystem ecology
A
emphasizes energy flow and chemical cycling between organisms and the environment
11
Q
what is landscape ecology
A
focuses on the exchanges of energy, materials, and organisms across multiple ecosystems
12
Q
what is a population
A
a group of the same species living in an area
13
Q
what is a ecosystem
A
interaction between the community of organisms in an and their environment
14
Q
what is a landscape/seascape
A
connected ecosystems
15
Q
what is the biosphere
A
the global ecosystem
16
Q
what is a community
A
a group of populations of different species in an area
17
Q
what is global ecology
A
examines how the regional exchange of energy and materials influences the function and distribution of organisms across the biosphere
18
Q
what is climate
A
the long-term average weather of a particular locality
19
Q
what is weather
A
the daily change in temperature, precipitation, wind, etc.
20
Q
what are the four major physical components of climate
A
temperature, precipitation, sunlight, and wind
21
Q
what are global climate patterns determined by
A
solar energy and Earth’s movement in space
22
Q
what does the warming effect of the sun on earth cause
A
temperature variations, circulation of air and water, and evaporation of water
23
Q
why does the intensity of solar radiation vary seasonally
A
because the Earth is tilted on its axis
24
Q
what do global climate patterns cause
A
latitudinal variations in climate
25
the angle at which sunlight hits Earth affects what
its intensity
26
where is sunlight most intense
in the tropics (between 30 degrees north and south latitude)
27
why is sunlight most intense in the tropics
because the sun is overhead at the equinoxes while at the poles sunlight becomes slanted
28
what are the three circulation cells
polar cell, Ferrell cell, and Hadley cell
29
what three major climatic zones do the three circulation cells result in
tropical, temperate, and polar zones
30
what is the Hadley cell
found in the tropics, the wind currents flow east to west towards the equator
31
what is the polar cell
occurs at the North and South poles-high pressure zones with little precipitation-"polar deserts", flow east to west
32
what is the Ferrell cell
exist at mid-latitudes, air flows eastward and towards the poles
33
what do rising air masses do
they release water and cause high precipitation
34
what do global air circulation and precipitation patterns cause
climate patterns
35
when water evaporates in the tropics where does that warm, wet air flow to
the poles
36
what climate does dry, descending air create
arid, especially near 30 degrees north and south
37
air that flows close to Earth's surface creates what kind of global wind patterns
predictable
38
where do westerlies winds blow from
west to east in the temperate zones
39
what natural formations modify the climate
large bodies of water and mountain ranges
40
how does climate vary
seasonally
41
what is seasonality
seasonal variations in day length, solar radiation, and temperature increase steadily toward the poles
42
what is focused on in population ecology
the fitness of the species (reproduction)
43
what causes seasonality at high latitudes
by the tilt of Earth's axis of rotation and its annual passage around the sun
44
the changing angle of the sun affects what kind of environments
local
45
regions at 20 degrees N and 20 degrees S latitudes have wet and dry seasons due to what
the changing angle of the sun
46
what alters ocean currents
changes in wind patterns (and temperatures)
47
what changes do wind patterns (and temperature) create in the ocean
-can cause upwelling of cold, nutrient rich water from deep ocean layers
-this causes prevailing circulation patterns of water to be produced
48
do ocean currents influence the climate of nearby terrestrial environments
yes
49
what do currents flowing toward the equator carry what temp of water from the poles
cold
50
currents flowing away from the equator carry what temperature of water towards the poles
warm
51
what do ocean currents create
circulation patterns of water
52
how do ocean currents affect air
it cools or warms air before passing over land
53
how do large bodies of water moderate the climate of nearby land
during the day, air rises over warm land and draws a breeze from the cooler water; at night, the pattern is reversed
54
do large bodies of water moderate the climate of nearby land
yes
55
explain a rain shadow
-warm air cools as it rises up a mountain and releases moisture on the windward side
-cool, dry air absorbs moisture from the land as it descends, creating a rain shadow on the leeward side
56
in the northern hemisphere, south-facing slopes receive ____ sunlight than north-facing slopes
more
57
as elevation increases what happens to the temperature
it drops
58
what does a microclimate mean
localized patterns in climate
59
what is an example of a microclimate
forests trees, influence surrounding areas by casting shade, altering evaporation from the soil, or changing wind patterns
60
what is climate change
is a directional change to the global climate lasting three decades or more
61
what is the greenhouse effect
when greenhouse gas molecules absorb thermal infrared energy, their temperature rises. these gas molecules radiate infrared energy back to Earth's surface which causes its temperature to rise
62
what keeps Earth at a relatively stable temperature
that close to the same amount of energy that enters the Earth, is released
63
do species shift their geographic ranges in response to climate changes
yes
64
what could cause a species to have a smaller range or become extinct due of climate changes
species that have difficulty dispersing or face a shortage of suitable habitat
65
what are biomes characterized by
vegetation types (terrestrial biomes) or by physical environment (aquatic biomes)
66
what is a major factor in determining the locations of terrestrial biomes
climate
67
why is climate a major factor in determining the locations of terrestrial biomes
because it strongly influences the distribution of plants
68
what are biomes affected by
changes in temperature and precipitation through the year
69
what are the layers of vertical layering
upper canopy, low-tree layer, shrub understory, ground layer of herbaceous plants, forest floor, and root layer
70
what is a disturbance
an event such as:
-a storm, fire, or human activity that changes a community
71
what type of disturbance is optimal for diversity
intermediate disturbance frequency
72
tropical forest
tropical rain forests: rainfall is relatively constant, the temperature is 25-29 degrees C, and has little variation
tropical dry forests: precipitation is highly seasonal, the temperature is 25-29 degrees C, and has little variation
tropical forests: vertically layered, competition for light is intense, animal diversity is high
73
desert biome climate
-found around equator
-precipitation is low and highly variable
-the temperature is variable seasonally and daily
-deserts may be hot or cold
74
desert biome plants/animals
-plant adaptations include heat and desiccation tolerance, water storage, and reduced leaf surface area
-many animals are nocturnal, and adaptated for water conservation
75
savanna biome
-found around the equator
-precipitation is seasonal
-have dry seasons
-hot
76
savanna biome plants/animals
-scattered trees, with plant species that are fire-adpated and tolerant of seasonal drought
-grasses and forbs make up most of the ground cover
-large gerbivores are common, but insects are the dominate herbivores
77
chaparral biome
-occurs in midlatitude coastal regions on several continents
-precipitation is highly seasonal with rainy winters and dry summers
-summer is hot ; fall, winter, and spring are cool
78
Chaparral biome plants/animals
-dominated by shrubs, small trees, grasses, and herbs; many plants are adapted to fire and drought
-animals include amphibians, birds, and other reptiles, insects, browsing mammals, and a diversity of small mammals
79
temperate grassland biome
-found on many coninents
-precipitation is highly seasonal
-winters are cold and dry; summers are hot and wet
80
temperate grasslands biome plants/animals
-the dominant plants, grasses and forbs, are adapted to droughts and fire
-native mammals include grazers such as bison and wild horses and small borrowers such as prairie dogs
81
northern coniferous forest biome
-spans northern North America and Eurasia: the largest terrestrial biome on Earth
-precipitation varies; some forests have periodic droughts and other, especially near coasts, are wet
-Winters are cold; summers may be hot (e.g., Siberia ranges from –50ºC to 20ºC)
82
northern coniferous forest biome plants/animals
-Conifers such as pine, spruce, fir, and hemlock dominate
-Animals include migratory and resident birds and large mammals such as moose, brown bears, and Siberian tigers
-Periodic insect outbreaks kill vast areas of forest
83
temperate broadleaf forest biome
-lots of rain during all seasons
-cold winter, hot and humid summer
84
temperate broadleaf forest biome plants/animals
-has vertical layers
-The dominant plants are deciduous trees in the Northern Hemisphere and evergreen eucalyptus in Australia
In the Northern Hemisphere, many mammals hibernate and many birds migrate in the winter
85
tundra biomes
-found in Artic
-low precipitation
-cold
86
tundra biome plants/animals
-Vegetation is herbaceous (mosses, grasses, forbs, dwarf shrubs and trees, and lichen)
-Permafrost, a permanently frozen layer of soil, restricts the growth of plant roots
-Mammals include musk oxen, caribou, reindeer, bears, wolves, and foxes; many migratory bird species nest in the summer
87
what is the photic zone
the narrow top layer of an ocean or lake
88
how much light does the photic zone receive
has sufficient light for photosynthesis
89
what is the aphotic zone
the part of an ocean or lake beneath the photic zone
90
how much light does the lower aphotic zone receive
little light
91
what do the photic and aphotic zones make up
the pelagic zone (open water)
92
where is the benthic zone found
at the bottom of all these aquatic zones
93
what makes up the benthic zone
sand and organic and inorganic sediments
94
is the benthic zone shallow or deep
it can be either
95
what are benthos
the communities of organisms that live in the benthic zone
96
what is the abyssal zone
is located in the aphotic zone with a depth of 2,000 to 6,000m
97
what is the thermocline
a temperature boundry that separates the warm upper layer from the cold deeper water in oceans and most lakes
98
what does a turnover of water do
it mixes oxygenated water from the surface with nutrient-rich water from the bottom
99
what is a turnover
a semiannual mixing of water (lakes)
100
in marine communities, most organisms occur where
in the relatively shallow photic zone
101
does the aphotic zone harbor the majority of marine life or the minority
minority
102
what kind of thermocline does a temperate lake have
seasonal
103
what kind of thermocline do tropical lowland lakes have
a year-round thermocline
104
what is a oligotrophic lake
are nutrient-poor and generally oxygen-rich
105
what is a eutrophic lakes
are nutrient-rich and often depleted of oxygen in deep zones or throughout if ice covered in winter
106
what lives in the littoral zone close to the shore
rooted and floating aquatic plants
107
what zone do phytoplankton inhabit
limnetic zone
108
can the limnetic zone support plants
no, it's too deep to support rooted plants
109
what zone do invertebrates live in
the benthic zone
110
what zones do fish live in
all zones with suffiecient oxygen
111
what can nutrient enrichment of a lake lead to
algal blooms, oxygen depletion, and fish kills
112
what are zooplankton and what do they feed upon
are drifting heterotrophs that graze on the phytoplankton
113
what is the most prominent physical characteristic of streams and rivers
the current
114
what are the characteristics of headwaters
generally cold, clear, turbulent, swift, and oxygen-rich; they are often narrow and rocky
115
what are the characteristics of downstream waters
-generally warmer, more turbid, and well oxygenated; they are often wide and meandering and have silty bottoms
-form rivers
116
can headwater streams be rich in phytoplankton or rooted aquatic plants
yes
117
what is the intertidal zone
is periodically submerged and exposed by the tides
118
what challenges do intertidal organisms face
variations in temperature and salinity and by the mechanical forces of wave action
119
are oxygen and nutrient levels high or low in intertidal zones
high
120
what substrates appear in the intertidal zones
either rocky or sandy
121
what life do the sandy zones of the intertidal zones support
sea grasses and algae
122
what life do the rocky zones of the intertidal zones support
attached marine life and algae
123
in rocky zones in intertidal zones what adaptation have animals formed
structural adaptations for attaching to the hard substrate
124
in the sandy zones of the intertidal zone what animals live there
worms, clams, and crustaceans bury themselves in the sand
125
what types of animals live in the intertidal zone
sponges, sea anemones, echinoderms, and small fishes
126
what is the oceanic pelagic zone constantly mixed by
wind-driven oceanic currents
127
are oxygen levels high or low in the oceanic pelagic zone
high
128
what does seasonal turnover in temperate oceans renew
nutrients in the photic zones
129
why are nutrient concentrations lower in tropical oceans
year-round thermal stratification (cold water sinks, warm water stays on top)
130
how much of Earths surface does the oceanic pelagic zone cover
70%
131
what are the dominate organisms of the oceanic pelagic zone
Phytoplankton and zooplankton
132
what other animals exist in the oceanic pelagic zone
Fish, squid, turtles, and marine mammals also occupy the pelagic zone
133
what are coral reefs formed from
the calcium carbonate skeletons of corals (cnidarians)
134
what temperatures do coral reefs exist at
Shallow reef-building corals live in the photic zone in warm (about 20–30ºC), clear water; deep-sea corals live at depths of 200–1,500 m
135
what requirements do coral reefs have to grow
high oxygen concentrations and a solid substrate for attachment
136
what does algae provide coral with
organic molecules
137
what does the marine benthic zone consist of
the seafloor below the surface waters of the coastal, or neritic zone and the offshore pelagic zone
138
what have organisms that live in the very deep benthic (abyssal) zone adapted to
continuous cold and extremely high water pressure
139
what is the substrate like in the marine benthic zone
mainly soft sediments; some areas are rocky
140
what do the shallow areas of the marine benthic zone contain
seaweeds and filamentous algae
141
what life do hydrothermal vents support in the marine benthic zone
unique chemoautotrophic prokaryotes, as well as echinoderms and arthropods
142
what animals do neritic benthic communities include
invertebrates and fishes
143
what is dispersal
is the movement of individuals or gametes away from centers of high population density or from their area of origin
144
what does dispersal contribute to
the global distribution of organisms
145
what are species transplants
include organisms that are intentionally or accidentally relocated from their original distribution
146
what is range expansion
when organisms reach an area where they did not exist previously
147
if a species transplant is successful what does that indicate
indicates that the potential range of a species is larger than its actual range
148
what impact can species transplants have
can disrupt the communities or ecosystems to which they have been introduced
149
what biotic factors affect the distribution of organisms
-Predation
-Herbivory
-Competition
-Mutualism
-Parasitism
150
what abiotic factors affected the distribution of organisms
-Temperature
-Water
-Oxygen
-Salinity
-Sunlight
-Soil
151
can ecological interactions cause evolutionary change and vice versa
yes
152
how does ecological change alter evolutionary change
alters selective pressures in population
153
how does evolutionary change alter ecological change
alters outcome of ecological interactions
154
what is a population
-is a group of individuals of a single species living in the same general area
-are described by their boundaries and size.
155
what is density
is the number of individuals per unit area or volume
156
what is dispersion
is the pattern of spacing among individuals within the boundaries of the population
157
what causes a change in population
-births
-deaths
-immigration
-emigration
158
what increases the amount of individuals in a population
births and immigration
159
what causes a decrease in the amount of individuals in a population
deaths and emigration
160
what influences the spacing of individuals in a population
environmental and social factors
161
what is the most common pattern of dispersion
clumped: in which individuals aggregate in patches
162
what are clumped dispersions influenced by
-resource availability
-mating behavior and group defense
163
what is uniform dispersion
one in which individuals are evenly distributed
164
what is uniform dispersion influenced by
territoriality
165
what is random dispersion
the position of each individual is independent of other individuals
166
what is demography
is the study of these vital statistics of a population and how they change over time
167
what is a life table
is an age-specific summary of the survival and reproductive rates within a population
168
what is a survivorship curve
is a graphic way of representing the data in a life table
169
what is type 1 of the survivorship curve
Low death rates during early and middle life and an increase in death rates among older age groups
170
what is type 2 of the survivor ship curve
A constant death rate over the organism’s life span
171
what is type 3 of the survivorship curve
High death rates for the young and a lower death rate for survivors
172
can organisms be intermediate between the survivorship types
yes
173
are males or females looked at when studying sexually reproducing species
females, because they are the only ones that produce offspring
174
if immigration and emigration are ignored, the change in population size equals what
births minus deaths
175
the per capita (per individual) change in population size represents what
the contribution that an average member of the population makes to the population size during the time interval
176
what is exponential population growth
is population increase under idealized conditions
177
what happens to populations that are under idealized conditions
may increase in size by a constant proportion at each instant
178
exponential population growth results in what shape of curve
a J shaped curve
179
what are the results of growth in an exponential growing population
The rate of increase is constant, but the population accumulates more new individuals per unit time when it is large than when it is small
180
what type of growth characterizes some rebounding populations
the J-shaped curve of exponential growth
181
the logistic model of population growth produces what shape
sigmoid (S-shaped) curve
182
new individuals are added to the population most rapidly at what population size
intermediate
183
what is population chaos
when the population looses all equilibrium and becomes unstable
184
what do scientists use the logistic model to predict
-rates of population recovery,
-estimate sustainable harvest rates
-estimate the population size below which leads to extinct
185
An organism’s life history comprises the traits that affect its schedule of what
reproduction and survival
186
life history traits are outcomes reflected in what of an organism
development, physiology, and behavior
187
An organism’s life history entails what three key components
-The age at first reproduction (maturity)
-How often the organism reproduces
-How many offspring are produced per reproductive episode
188
what are semelparity species
species that reproduce once and die
189
what are iteroparity species
produce offspring repeatedly
190
species that produce one or few offspring may do what better than species that produce many offspring
provide for their young
191
what is r-selection
-is selection for life history traits that maximize reproductive success at low density with little competition for resources
- r = rate of population increase
192
what is k-selection
-is selection for life history traits that are advantageous at high population densities; resources are low, and competition is strong
-k = carrying capacity
193
what does r-selection and k-selection represent
two extremes in a range of actual life histories.
194
in density-independent populations what is the relationship between birth rate and death rate
they do not change with population density
195
in density-dependent populations what is the relationship between birth and death rates
fall and increase with rising population density
196
only desnity-dependent factors can regulate population size
density-independent can cause a decrease in population but doesn't regulate
197
factors that cause a change in density-dependant population
-disease
-medical care
-food availability
198
factors that cause a change density-independent population
-natural disaster
-
199
what is an example of negative feedback that regulates population growth
density-dependent birth and death rates
200
what factors affect density-dependent birth and death rates
-competition for resources
-territoriality
-disease
-predation
-intrinsic factors
-toxic wastes
201
The study of population dynamics focuses on complex interactions between biotic and abiotic factors that cause what
variation in population size
202
what factors can affect population size of large mammals over time
abiotic and biotic
203
when a population becomes crowded and resource competition increases, what increases
emigration
204
what are metapopulations
are groups of populations linked by immigration and emigration
205
what do local populations in a metapopulation occupy
patches of suitable habitat surrounded by unsuitable habitat
206
what can happen to local populations lost through extinctions
they can be recolonized by immigration from other patches
207
to maintain population stability what are the two configurations that the population can exist in
-Zero population growth = High birth rate - High death rate
-Zero population growth =Low birth rate - Low death rate
208
what is the demographic transition
is the move from the first state to the second state
209
can a population grow indefinity
no
210
what is age structure
is the relative number of individuals of each age in a population
211
what can age-structure diagrams (pyramids) can help predict what
population's growth trends
212
what is the ecological footprint concept
summarizes the aggregate land and water area needed to sustain a person, city, or nation
213
what influences carrying capacity
food, space, nonrenewable resources, or buildup of wastes
214
can humans regulate population growth through social changes
yes
215
what happens when the density of a population is low
it will increase until the density reaches equilibrium
216
what happens when the density is high
the population shrinks until the density reaches equilibrium
217
what is a biological community
is an assemblage of populations of various species living close enough for potential interaction
218
what are interspecific interactions
Ecologists call relationships between species in a community
219
what are examples of interspecific interactions
competition, predation, herbivory, parasitism, mutualism, and commensalism
220
how can the effects of interspecific interactions be summarized
-positive (+)
-negative (-)
-no effect (0)
221
when does competition occur
when species compete for a resource that limits survival and reproduction
222
strong competition can lead to what
competitive exclusion (local elimination of a competing species)
223
can two species competing for the same limiting resources coexist permanently in the same place
no
224
what is an ecological niche
is the sum of an organism’s use of biotic and abiotic resources; it can be thought of as an organism’s ecological role
225
can ecologically similar species coexist in a community if there are one or more significant differences in their niches
yes
226
what is resource partitioning
is differentiation of ecological niches, enabling similar species to coexist in a community.
227
what is a species’ fundamental niche
is the niche potentially occupied by that species
228
what is a species' realized niche
is the niche actually occupied by that species
229
can a species' fundamental niche differ from its realize niche
yes
230
how can species partition their niche
-time
-space
231
what is character displacement
is a tendency for characteristics to be more divergent in sympatric populations of two species than in allopatric populations of the same two species
232
what is a allopatric population
species that are geographically separated from each other
233
what is a sympatric population
species that are in the same geographic area
234
what is an example of character displacement
is variation in beak size between populations of two species of Galápagos finches
235
what is exploitation
refers to any positive or negative interaction in which one species benefits by feeding on the other species
236
what interactions include predation, herbivory, and parasitism
exploitation
237
what is predation
(positive or negative interaction) refers to an interaction in which one species, the predator, kills and eats the other, the prey
238
what types of adaptations do predators have that enable them to find, identify, catch, and subdue their prey
-morphological and physiological adaptations
Ex. claws, fangs, or poison
239
what adaptations do prey display to avoid being eaten
-behavioral defenses
-morphological and physiological defense adaptations
240
what behavioral defenses do prey have
include hiding, fleeing, and forming herds or schools
241
what are examples of defensive adaptations that prey have
-Cryptic coloration
-Mechanical defense
-Müllerian mimicry
-Batesian mimicry
-Chemical defense
-Aposematic coloration
242
what is aposematic coloration
warning coloration
243
what defenses do animals with aposematic coloration
chemical defenses
244
what is cryptic coloration
camouflage
245
what is Batesian mimicry
a palatable or harmless species mimics an unpalatable or harmful model
246
what is Müllerian mimicry
two unpalatable species mimic each other
247
what has evolved in many predators to enable them to approach prey
mimicry
248
what is an example of mimicry
the mimic octopus can take on the appearance and movement of more than a dozen marine animals
249
what is herbivory
(positive or negative interaction) refers to an interaction in which an herbivore eats parts of a plant or alga
250
what specialized adaptations do herbivores (and plants) have
-many herbivores have specialized teeth or digestive systems for processing vegetation
-Plants may produce toxic or distasteful chemicals or mechanical defenses, such as spines or thorn
251
what is parasitism
(+/– interaction), one organism, the parasite, derives nourishment from another organism, its host, which is harmed in the process
252
what are endoparasites
Parasites that live within the body of their host
253
what are ectoparasites
Parasites that live on the external surface of a host
254
do some parasites change that would increase the likelihood that the parasite will be transmitted to the next host
change the behavior of the host
255
how can parasites affect the hosts' population
the survival, reproduction, and density of their host population, directly or indirectly
256
what are positive interactions
where at least one species benefits and neither is harmed
257
what are examples of positive interactions
Mutualism (+/+) and commensalism (+/0) are positive interactions
258
what type of interactions heavily influences ecological communities
positive interactions
259
what is mutualism
(+/+ interaction) is a common interspecific interaction that benefits both species
260
what is the cost to mutualism
both species incur costs, but the benefits to each partner exceed the costs
261
in mutualism, each species depends on the other for what
their survival and reproduction; in others, both species can survive alone
262
what is commensalism
(+/0 interaction) is another common interaction in which one species benefits and the other is neither harmed nor helped
263
what is an example of commensalism
shade-tolerant wildflowers depend on the shade provided by forest trees, but the trees are not affected by the wildflowers
264
can interactions that are typically commensal become, at times, mutualistic
yes
265
what is an example of where a commensal relationship becomes mutualistic
-cattle egrets typically benefit from the insects flushed out of the grass by bison and have no effect on the bison
-At times, they may remove and eat ectoparasites from the bison’s skin, making the interaction mutualistic
266
what is species diversity of a community
is the variety of organisms that make up the community
267
what are the two components of species diversity
-species richness
-relative abundance
268
what is species richness
is the number of different species in the community
269
what is relative abundance
is the proportion each species represents of all individuals in the community
270
can two communities can have the same species richness but a different relative abundance
yes
271
what is a food web
is a group of food chains linked together forming complex trophic interactions
272
can a species play a role at more than one trophic level
yes
273
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
274
what does the energetic hypothesis suggest
that length is limited by inefficient energy transfer
275
how much energy is stored in organic matter at each trophic level that is then converted to organic matter at the next trophic level
10%
276
what is an example of an energetic hypothesis
a producer level consisting of 100 kg of plant material can support about 10 kg of herbivore biomass and 1 kg of carnivore biomass
277
how can the energetic hypothesis be tested
manipulating productivity
278
because carnivores tend to be larger at higher trophic levels, how does this affect the food chain length
it can limit it
279
are large carnivores able to obtain enough food from small prey efficiently enough to meet their metabolic needs
no
280
what are dominate species
are those that are most abundant or have the highest biomass
281
what are the two hypotheses on how dominant species are dominant
-dominant species are most competitive in exploiting resources
-they are most successful at avoiding predators or disease
282
what can happen when an invasive species is introduced to a new environment
may become dominant because they lack natural predators or parasites
283
how can you study the impact of species
to remove it from the community
284
what is a keystone species
exert strong control on a community by their ecological roles, or niches
285
are keystone species abundant in a community like dominant species are
no
286
how do keystone predators effect the ecosystem
maintain ecosystem equilibrium
287
what feeding type dominates the food web
predation
288
how does a keystone species population size compare to their impact
their population size is small and their effect is large
289
what changes do ecosystem engineers (foundation species)
cause physical changes in the environment that affect community structure
290
what is bottom-up control
Nutrient supply or the availability of food at lower trophic levels limits the abundance of organisms at higher trophic levels.
291
what is top-down control
The abundance of organisms at higher trophic levels controls the abundance of organisms at lower trophic levels.
292
The bottom-up model of community organization proposes what influence
a unidirectional influence from lower to higher trophic levels
293
The top-down model, also called the trophic cascade model proposes what
that control comes from the trophic level above
294
in the top-down model what limits what
predators limit herbivores, herbivores limit plants, and plants limit nutrient levels
295
what is bio manipulation
can help restore polluted communities
296
what is biomass
total mass of all living organisms in a system
297
why do oceans and large lakes tend to moderate the climate of nearby land
the high specific heat of water
298
how do forests affect the climate
-forests reduce Earth's surface temperature
-they increase precipitation rates
299
what is a biome
major life zones characterized by vegetation type in terrestrial biomes
300
what does layering of vegetation provide animals with
many different habitats
301
what is a disturbance to a biome
storm, fire, or human activity that changes a community
302
what makes up the largest marine biome
oceans
303
what provides most the planet's rainfall
water evaporated from oceans
304
what supplies most of the planet's oxygen
marine algae and photosynthetic bacteria
305
what are examples of biotic limitations
-predation and herbivory
-presence or absence of pollinators
-food resources
-parasites
-pathogens
-competing organisms
