Ecology – Ch. 13
Energy and Nutrients
Warm Up

Draw as much of the water cycle as you can
remember from middle school.
Learning Goals





I can describe how energy moves in an
ecosystem.
I can describe how water moves through the
water cycle.
I can describe how carbon moves from one
part of the carbon cycle to another.
I can describe how nitrogen moves through the
ecosystem.
I can draw and explain a food web.
Ecology



Study of the interaction living things and their
environment
Links living systems and non-living systems
Important for understanding how human
actions can affect the environment and what
can/should be done to fix various issues
between people and the environment
Energy Transfer


All of life’s processes require energy
The primary source of energy for life is the sun

Primary producers use energy from the sun to turn
simple atoms and molecules into living tissues



AKA: autotrophs
Ie: Plants
Consumers feed off the producers

Aka: heterotrophs
Energy Transfer

Energy flows from producers to
consumers, then to decomposers


Each step is a trophic level
As energy flows through the
trophic levels, available energy
diminishes


Gets used to create biomass,
released as heat, etc.
Takes more mass of a lower trophic
level to support a higher level
organism
Nutrient Recycling


Just like energy, nutrients must pass from one
trophic level to another
According to the law of conservation of
matter, matter can not be created or destroyed



Thus nutrients must be recycled through the
biosphere or they will run out
Will limit size of populations
Types: Carbon Cycle, Nitrogen Cycle, Water,
cycle, etc.
Water Cycle


Cycle of Evaporation,
condensation,
precipitation,
transpiration and use and
return by plants and
animals
Transpiration –
evaporation off of the
leaves of plants
Carbon Cycle

Plants convert CO2 in the atmosphere into
sugars, used by heterotrophs, and returned to
atmosphere as waste


Also stored in fossil fuels and in dissolved CO2 in
water.
Major Carbon Pathways



Bio – photosynthesis, respiration, death and decay of
tissue
Biochemical – burial and conservation of once living
organisms into fossil fuels (which are then burned)
Geochemical – volcanic activity, weathering of rocks,
CO2 exchange btn ocean and atmosphere.
Carbon Cycle
Nitrogen Cycle


Nitrogen is used to make proteins and other living
tissues, returned to the atmosphere as waste, then
fixed back into a useable form by bacteria
Major Nitrogen Pathways



Nitrogen Fixation – microorganisms convert N2 into usable
nitrogenous compounds
Nitrification – ammonium (NH4+) is oxidized to nitrite,
then nitrate (NO3-).
Denitrification – bacteria get the oxygen they need from
nitrate, rather than from O2
Nitrogen Cycle
Food Chains and Webs
Linking Trophic Levels Together


Food Chain – Show simple
relationships of Who eats whom?
Food Webs - Several food chains
linked together


Can be very complicated
Shows how energy and nutrients
flows though an ecosystem
 Producers  Primary Consumers
(herbivores)  Secondary
Consumers
(carnivores/omnivores) 
Tertiary Consumers (carnivores)
 Nutrients recycled by
Detritivores/Decomposers