Chapter 9 Flashcards
what are three basic components of ecosystem?
Producers (P), Consumers (C) and the Abiotic component (A)
define flux of energy?
Energy flows through ecosystems,
ends up as heat (IR radiation)
what is primary production?
The rate at which solar energy is stored by photo-
synthetic activity; unit dry mass production per area
and time. (Also includes chemosynthesis)
What does GPP stand for?
Gross primary productivity (GPP)
Total rate of photosynthesis (and chemosynthesis)
What is Net Primary productivity?
Net primary productivity (NPP):
Gross production less respiration by the plants.
Energy and matter available for consumers.
T/F:Most of the products of photosynthesis are used by
autotrophs themselves and by heterotrophs
True
T/F: Chemotrophy is globally a less important part of
primary production than phototrophy, but can be
locally important.
True
what are some examples of chemotrophy?
Acid mine drainage, deep ocean hydrothermal vents, hot volcanic springs
what are the factors affecting Net primary productivity of an ecosystem?
temp & precipitation
what is the best condition for precipitation ?
the more rain, the more productivity. thus moist & warm
T/F: Net Primary Production
(NPP) of various
ecosystems shows a
close relationship with
the actual
evapotranspiration
True
the actual evapotranspiration is actually based on temperature and precipitation
True
the cooler it is the less net primary production
true
what is the average yearly net primary productivity of north america
2.17 kg C/m^2/year
High agricultural productivity in the
prairies often achieved by irrigation.
true
prevailing winds coming from south west(monsoon)
??
nutrient availability depends on…
- nutrient mineralization rate
- imports
what is Mineralization rate?
rate at which
nitrate, ammonium and other
nutrient ions are set free from
decomposing organic matter
pines grow on rather poor nutrient environment
true
for oceans precipitation is limited, and temperature varies. thus nutrients availability varies
why does oceans have highest highest productivity along
coastal regions?
high nutrient availability
what would we expect for high net primary productivity?
high mineral nutrient supply
define Eutrophic
Productive ecosystem with a
high nutrient availability
what is Oligotrophic?
Nutrient-poor ecosystem with
a low productivity
Mesotrophic
Intermediate nutrient availability
what terms are used to refer to aquatic ecosystem?
Eutrophic, Oligotrophic, Mesotrophic
what is carrying capacity?
The maximum number of organisms of a given species
(consumers) that can be supported in a given area
T/F: Carrying capacity does not depend on the net primary production
False- it does depend on it
both Secondary production and Carrying capacity depend on net primary production
true
if the population is too large what happens to carrying capacity?
Too large population with respect to carrying capacity leads to a
(temporary) population collapse. This may lead to oscillating populations
rabbits in sudbury increased due to carrying capacity years ago.
??
Population overshoot of
consumers can reduce
the carrying capacity
True
What happens to energy in the grass
that is eaten by an elk?
part of it :
1. leaves the body in form of heat, undigested, or it exuded.
2. part of it is gained(weight gain)
why dung is important?
Dung contains energy.
It can be used for heating and cooking.
In a treeless environment, dung
is often the only available fuel.
which animals rely on dung for energy?
Anellaria sepulchralis(fungus), slugs ( feeding on fox scat), Dung beetles
how much does a white-tailed deer eat?
17% : gained (secondary production)
48%: Respiration (( heat production)
5%: Urine, Methane
5%:
quadric or more percent of all energy is used and stored in feces.
how does weights loss pill affect the energy system?
some targets digestible energy(reduce), some targets metabolizable energy(increase heat production)
what is secondary production?
Production of tissue by heterotrophic organisms,
including their offspring
Secondary production depends on the
animal ‘ s growth rate and reproductive rate
True
Secondary production is the greatest for
fast-growing animals with a high birth-rate
true
why small mammals are important food for secondary consumers?
- hight productiviyt
- reproduc fast
3.grow fast - grow fast
- high mortality rate
American Robin has a fast growing rate , around 13 days
true
Body mass of a young robin increases during
its first 10 days by about a factor of 8.
To do that, human babies need 10 years
true
what is the affect of agricultural meat production?
maximizes body weight gain
why eating insects are more sustainable?
Eating insects instead of beef is environmentally more sustainable,
as small ectothermic organisms have a higher secondary
production for a given amount of resources used
insects…
have higher protein production efficiency which is better for insects.
assimilation efficiency?
T/F: Ectotherms gain heat from the environment:
variable body temperature
True
why endotherm have a high assimilation efficiency?
high AND constant body temperatures
why endotherms have low net production efficiency?
their use of energy for heating.
why endotherms have a high assimilation efficiency due to the
high AND constant body temperatures?
- Digestive reactions fast at high temperatures
- Enzyme functioning optimized at constant temperatures
how much energy is passed to the next level in tropical level?
10%
it takes 10,000 pounds primary
production to produce one pound of cat.
true
Eating corn utilizes primary
production more efficiently than
eating corn-fed beef
true
Grass-fed beef is, however, a
good way to utilize primary
production in areas which
cannot be used as arable land.
Humans cannot eat grass.
But! Carrying capacity is small
true
percentage of agricultural production is higher in western world.
true
In some ecosystem humans can live only by eating
heterotrophic organisms
true
what happens to herbivores/vegeteriansat limited primary production?
At limited primary production,
herbivores/vegetarians have a higher
carrying capacity than carnivores
Environmental sustainability depends on where the production takes
place and what the critical environmental issues are in that region(california)
what happens ro primary production ?/
Primary production is either eaten (herbivory) or
it dies and is being decomposed
Primary production leads to what?
Grazing food chain or Detrital food chain
describe detrital food chain
The percentage of primary
production consumed by
herbivores is often quite
small, e.g., 3% in a deciduous
forest. The rest is consumed
by decomposers.
describe Grazing food chain?
In heavily grazed pastures
herbivores may consume
up to 50% of the production.
Commonly, major part of primary production
dies without being eaten.
Detrital foodchain is the major pathway of
energy flow in most terrestrial ecosystems
based on the ecological pyramide
Is it possible that an ecosystem has a larger
biomass of carnivores than herbivores, and a larger
biomass of herbivores than plants
Yes, because the energy flow (production) is
more important than the standing crop
In low-productive lakes, heterotrophic biomass exceeds autotrophic biomass.
This can be explained by longevity of the heterotrophs and/or additional food
sources such as imported organic carbon
what is trophic cascade?
Consumer effect on primary producers
Grazing by wilderbeest stimulates grass
growth in Serengeti.
example of trophic cascade
top down / bottom up
