Energy Flow and Nutrient Cycle - Environment Science Community and Ecosystem Concept Energy flows through an ecosystem from producers to consumers. Energy flows from one trophic level to the next. (troph = feeding) Nutrients (matter) cycle in an ecosystem. The processes of photosynthesis and aerobic respiration are important in nutrient cycling and energy flow.

1. Principles of Ecology
Anand Soni ES-03
Environment Science
Community and ecosystem consept

2. Describe the different
niches organisms occupy
in food chains and
diagram a model of a food
web that includes several
food chains.
1
Compare and contrast
how matter and energy
move through ecosystems
and explain how each
process relates to the laws
of conservation of mass
and energy.
2
Discuss the potential
ecological, environmental,
and social impacts of a
primary plant-based or
primary meat-based diet
in a human society.
3
Identify how living
organisms influence
global and local cycles of
matter (ex. Carbon,
nitrogen, phosphorus, and
water cycles)
4

3.  Energy flows through an
ecosystem from producers to
consumers. Energy flows from
one trophic level to the next.
(troph = feeding)
 Nutrients (matter) cycle in an
ecosystem.
 The processes of photosynthesis
and aerobic respiration are
important in nutrient cycling
and energy flow.

4. Primary Producers – plants, algae, photosynthetic bacteria,
some archaea cells.
Most are photoautotrophs.
Some are chemoautotrophs
(use chemicals in the environment
instead of sunlight to produce food)

5. • Food Chains – show the trophic relationship between
organisms in an ecosystem.
• A single food chain is just one link in a food web
Primary
Producer
Primary
Producer
Primary
Producer
Primary
Consumer
Primary
Consumer
Primary
Consumer
Secondary
Consumer
Secondary
Consumer
Secondary
Consumer
Tertiary
Consumer
Tertiary
Consumer Quaternary Consumer

6.  Food Webs show all the interacting food chains in an ecosystem.

7.  Energy flow in an ecosystem is not efficient between trophic levels,
which can be seen in an energy pyramid.
F
igure 54.11
Tertiary
consumers
Secondary
consumers
Primary
consumers
Primary
producers
1,000,000 J of sunlight
10 J
100 J
1,000 J
10,000 J
The 10% rule
(a) Most biomass pyramids show a sharp decrease in biomass at
Trophic level Dry weight
(g/m2)
Primary producers
Tertiary consumers
Secondary consumers
Primary consumers
1.5
11
37
809
 Biomass pyramids also
decline as the trophic level
increases.
 Why?
 Energy lost in
the form of heat.
 Energy used for
metabolic
purposes.
 Indigestible
material
Only about 10% of all energy is passed
from one trophic level to the next

8.  The dynamics of energy flow through ecosystems have important
implications for the human population.
 Consider the resources needed to grow, feed, process, and transport beef.

9.  Discussion Question: As human populations continue to grow, will
humans be able to sustain a diet that relies on animals for protein?
Trophic level
Secondary
consumers
Primary
consumers
Primary
producers

10.  Decomposers and Detritivores play an important role in recycling
nutrients in an ecosystem.

11.  The chemical cycling in an ecosystem is an essential component of
ecosystem function.
 Also called Biogeochemical Cycles
CO2 in atmosphere
Photosynthesis
Cellular
respiration
Burning of
fossil fuels
and wood Higher-level
consumers
Primary
consumers
Detritus
Carbon compounds
in water
Decomposition
THE CARBON CYCLE
N2 in atmosphere
Denitrifying
bacteria
Nitrifying
bacteria
Nitrifying
bacteria
Nitrification
Nitrogen-fixing
soil bacteria
Nitrogen-fixing
bacteria in root
nodules of legumes
Decomposers
Ammonification
Assimilation
NH3 NH4
+
NO3

NO2

Rain
Plants
Consumption
Decomposition
Geologic
uplift
Weathering
of rocks
Runoff
Sedimentation Plant uptake
of PO4
3
Soil
Leaching
THE NITROGEN CYCLE THE PHOSPHORUS CYCLE

12.  The Carbon Cycle is a global biogeochemical cycle
 What are some living and non-living reservoirs of carbon?
 What are some of the processes that occur that change carbon from one form to another?
 In what form(s) is carbon utilized by living things?

13.  The nitrogen cycle is a global biogeochemical cycle
 What sort of organisms convert nitrogen from one form to another?
 Why are each of these processes essential for an ecosystem food web?