Ch 20 Ecology Cain, Bowman, Hacker

Front 1

PCBs =
POPs =
called so because...

Back 1

PolyChlorinated Biphenyls
Persistent Organic Pollutants
they remain in the environment for a long time.

Front 2

POPs produced at __ latitudes enter the atmosphere (they are in gaseous form at the temperatures there). They are carried by atmospheric ____ ____ to the Arctic, where they...

Back 2

low
circulation patterns
where they condense to liquid forms & fall from the atmosphere.

Front 3

Feeding Relationships
CONCEPT 20.1
_____ _____ describe the feeding positions of groups of organisms in ecosystems.

Back 3

Trophic levels

Front 4

20.1
what organisms eat & what eats them...is called

Back 4

trophic interactions

Front 5

20.1
All organisms in an ecosystem are either consumed by other organisms or enter the ___ of dead organic matter (___).

Back 5

pool
(detritus)

Front 6

20.1
In terrestrial ecosystems, only a small portion of the ___ is consumed, & most of the ___ ___ passes through the detritus.

Back 6

biomass
energy flow

Front 7

20.1
Detritus is consumed by many organisms, including ____, & ___, such as the common wood louse.
Most of the NPP in terrestrial & aquatic systems ends up as ____.

Back 7

fungi, & crustaceans
detritus.

Front 8

20.1
First (primary producers) are ____
Second (primary consumers) are ____
Third (secondary consumers) are ___
Fourth (tertiary consumers) are ___

Back 8

Autotrophs
Herbivores
Primary carnivores
Secondary carnivores

Front 9

20.1
In trophic studies, detritus is considered part of the ___ trophic level, & detritivores are grouped with ___ in the ___ trophic level.

Back 9

first trophic level,
detritivores grouped with herbivores in the second trophic level.

Front 10

20.1
%of NPP consumed by herbivores
On avg, about ___% of terrestrial NPP is consumed;
in aquatic ecosytems, an avg of about __% NPP is consumed.

Back 10

13%
35%
Only a small proportion of NPP is consumed by herbivores.

Front 11

Energy Flow among Trophic Levels
CONCEPT 20.2
The amount of energy transferred from one trophic level to the next depends on ___ quality & _____ abundance & ______.

Back 11

food quality
consumer abundance
physiology.

Front 12

20.2
The 2nd law of thermodynamics states that during any _____ _ ___, some is lost due to the tendency toward an increase in disorder (entropy). Energy will ___ with each trophic level.

Back 12

transfer of energy,
decrease
(a proportion of the biomass at each trophic level is not consumed, & a proportion of the energy at each trophic level is lost in the transfer to the next trophic level.)

Front 13

20.2
A ___ ___ is a graphic representation of trophic relationships.
A series of rectangles portray the relative amounts of ____ or ___ of each level

Back 13

trophic pyramid
energy or biomass

Front 14

20.2
In aquatic ecosystems, the biomass pyramid may be ___

Back 14

inverted

Front 15

There is a _____ relationship between net primary production & the amount of biomass consumed by herbivores.

Back 15

positive

Front 16

20.2
Inverted pyramids in aquatic ecosystems are more common in ______ waters with __ autotrophic biomass.

Back 16

nutrient-poor
low

Front 17

20.2
The amount of autotrophic biomass consumed is significantly ____ in aquatic than in terrestrial ecosystems.

Back 17

higher

Front 18

20.2
The amount of energy at one trophic level divided by the amount of energy at the trophic level immediately below it = __

Back 18

trophic efficiency

Front 19

20.2
___efficiency is the proportion of available biomass that's ingested by consumers.

Back 19

Consumption

Front 20

20.2
The proportion of energy transferred between trophic levels depends on efficiencies of ____, ____, & _____.

Back 20

consumption,
assimilation,
& production.

Front 21

20.2
_____efficiency is the proportion of the ingested biomass that consumers ____ by digestion.

Back 21

Assimilation
assimilate

Front 22

20.2
___efficiency is the proportion of assimilated biomass used to ___ new consumer biomass.

Back 22

Production
produce

Front 23

20.2
Trophic efficiencies can influence ____ _____.

Back 23

population dynamics.

Front 24

Trophic Cascades
CONCEPT 20.3
Changes in the abundances of organisms at one trophic level can influence ____ ____ at multiple trophic levels.

Back 24

energy flow

Front 25

20.3
A trophic cascade is a series of trophic interactions that result in ___ in energy & species _____.

Back 25

change in energy &
species composition.

Front 26

20.3
The amount of production in an ecosystem can be viewed as being controlled by limiting resources (____ _____) or by controls exerted on the composition & abundance of autotrophs due to consumption by ____ trophic levels.

Back 26

(Bottom-up control)
higher (Top-down control)

Front 27

20.3
Rates of consumption by predators at the highest trophic lvls determine species ___ & abundances at ___ trophic levels, which in turn determine rates of _____ ______.

Back 27

species composition &
lower
primary production.

Front 28

20.3
Brown trout ____ total invertebrate density by 40% more than the galaxias did.

Back 28

reduced

Front 29

20.3
4 trophic lvls: Piper cenocladum trees; herbivores; ants (Pheidole) that live in the pentioles of the Piper trees and eat herbivores; and beetles (Tarsobaenus) that eat the ___

Back 29

ants

Front 30

20.3
If production by Piper trees was ____ primarily by resource supply, the beetle predator should have ____ effect.

Back 30

limited
little

Front 31

20.3
Addition of beetles ____ ant abundance fivefold,
Addition of beetles ____ herbivory threefold,
Addition of beetles ___ leaf production by half.

Back 31

reduced
increased
decreased
Thus, it's clear that top-down trophic cascades do occur in diverse terrestrial ecosystems, although they may require strong interactions between specialist predators&their prey.

Front 32

20.3
What determines # trophic levels in an ecosystem?
There are 3 basic, interacting controls. 1. 2.
3. The _____ _ ____ or other agents of change can determine whether populations of top predators can be sustained.

Back 32

1. Dispersal ability may constrain the ability of top predators to enter an ecosystem.
2. The amount of energy entering an ecosystem through primary production.
3. frequency of disturbances

Front 33

20.3
____ trophic levels sustain ____ trophic levels, so there is a longer time lag to reestablish ____ trophic levels.

Back 33

lower
higher
higher

Front 34

20.3
The constraints imposed on ___ ___ to higher trophic levels by trophic efficiency & disturbance dynamics are manifested in a rarity of _____

Back 34

energy transfer
"big, fierce animals"
(Colinvaux 1978). (These constraints explain why carnivores are the most common threatened&enadegrd mammals.

Front 35

Food Webs
CONCEPT 20.4
Food webs are conceptual models of the trophic interactions of organisms in an ecosystem.

Back 35

A food web is a diagram showing the connections between organisms & the food they consume.

Front 36

20.4
Food webs are ___descriptions of energy flow&trophic interactions.
Actual trophic interactions can ___ over time.
Some organisms ____ feeding patterns over their lifetime.

Back 36

static
change
change

Front 37

20.4
Some organisms, such as migratory birds, are components of ____ food webs.
Most food webs ___ include other types of interactions, such as pollination.

Back 37

multiple
don't

Front 38

20.4
Some species are ___ important in food webs than their numbers would indicate.

Back 38

more

Front 39

Case Study Revisited: Toxins in Remote Places
They may not be metabolized or excreted for a variety of reasons, so they become progressively more concentrated over the organism's lifetime, _____

Back 39

Bioaccumulation

Front 40

Process where concentration of chemical compounds increases in animals at higher trophic levels, as animals at each trophic level consume prey with higher concentrations of the compounds.

Back 40

Biomagnification

Front 41

____pollutants have been reported in all environments on Earth.
Organisms in ___ areas have high concentrations of these pollutants, related to the trophic positions of the animals.
Consumers at the highest trophic levels(polar bears, seals, & birds of prey), contain the ___ amounts of pollutants.

Back 41

Anthropogenic
remote
highest

Front 42

20.1
Omnivores feed at _____ trophic levels, although their diets can be partitioned to reflect their consumption at each level.

Back 42

multiple

Front 43

20.2
____ and _____ pyramids portray the relative amounts of energy or biomass at different trophic levels.

Back 43

Energy and Biomass

Front 44

20.2
The high ____ of autotroph biomass in aquatic ecosystems can result in biomass pyramids that are inverted relative to energy pyramids.

Back 44

turnover

Front 45

20.2
The proportion of autotroph biomass consumed in terrestrial ecosystems tends to be ____ than that in aquatic ecosystems.

Back 45

lower

Front 46

20.2
The efficiency of energy transfer from one trophic level to the next is determined by ____ quality and the ______ of consumers.

Back 46

food equality
physiology of consumers.

Front 47

20.3
Changes in the numbers and types of consumers at higher trophic levels can _____ primary production through ______ on the consumption of herbivores.

Back 47

influence
influences

Front 48

20.3
Trophic cascades tend to be more ______ in aquatic ecosystems than in terrestrial ecosystems, but they've been demonstrated in complex terrestrial ecosystems as well.

Back 48

apparent

Front 49

20.3
The number of trophic levels that can be sustained in an ecosystem is determined by the ____ability of organisms, the amount of ____ ____ the ecosystem through primary production, and the ______ _ ______.

Back 49

dispersal
energy entering
frequency of disturbance

Front 50

20.4
Although trophic interactions are extremely complex, food webs can be simplified by focusing on the _____ interactions among the component organisms.

Back 50

strongest

Front 51

20.4
_____ ______ have greater effects on energy flow and species composition in their communities than their abundance or biomass would indicate.

Back 51

Keystone species

Front 52

20.4
______ effects of a consumer on a target prey species, including effects on other species that compete with, facilitate, or modify the environment of the target species, can negate or reinforce the direct effects of consumption. These indirect effects may have important stabilizing effects on inherently unstable food webs.

Back 52

Indirect