Food Chains, Webs and Nutrient Cycles
The 10% rule (see diagram on previous outline page)
The _______________ in energy as you travel up the pyramid of up the food chain is called the ___________________.
It’s called the 10% rule because at each level of the food chain or food pyramid has only _______________ of the level below it.
For example, when a grasshopper eats grass it only gets ________% of the energy in the grass. When a bird eats the grasshopper
the bird gets only _____________ of the energy in the grasshopper.
Food Chains & Food Webs
_____________ chain – a _________________ model that shows how matter and ________________ move through an ecosystem
Draw a sample food chain that you might see here in Texas: include a producer, a primary consumer, a secondary consumer, a
tertiary consumer, and a decomposer.
________________
(producer)
_________________
________________
(primary consumer)
(secondary consumer)
_________________
(tertiary consumer)
_______________
(decomposer)
Food ___________- shows __________ possible feeding ___________________ in a community at each _______________ level.
Essentially it represents a _________________ of interconnected food _________________.
So a Food chain shows just _____________ path of energy, whereas a Food Web shows ______________ possible energy paths.
From the food web at right find an example of the following:
A producer: ___________________________
A primary consumer: _______________________
A secondary consumer: _______________________
A tertiary consumer: ________________________
A decomposer: ___________________________
A herbivore: ____________________________
A carnivore: _____________________________
What type of feeder is always at the base of every food chain?
Circle one: producer, consumer or decomposer
Toxins in the food chains:
While the amount of energy available to consumers ____________________ as it moves up the food chain, any toxins in the
ecosystems will _________________ in concentration. This is called ________________________ _______________________.
Nutrient Cycles
Nutrient cycling maintains ___________________________ (balance) in the environment by allowing important resources to be
____________________________.
There are ____________ important cycles that keep ecosystems alive and healthy:
1. The Water Cycle:
Water turns into clouds (water vapor) through ________________________________ (from the oceans) and
___________________________ (from plants). Water returns to liquid form by ______________________________ and
forming __________________________ (rain) which then falls back to earth. The cycle continues.
2. The Carbon Cycle:
All living things are made mostly of ____________________________ so recycling it is very _____________________________!
The process of ___________________________ & _______________________________ and the decomposition of living things
by ____________________________________ cycles carbon through the environment.
3. The Nitrogen Cycle:
__________________________ is super important to life because it is a major component of _________________________ and of
the nitrogenous bases that make up ________________________.
__________________________ nitrogen (N2) makes up nearly ___________% to _________% of air.
Organisms CANNOT use nitrogen in that gaseous form, but fortunately __________________________ and
____________________________ can convert nitrogen forms useable to life.
Nitrogen Fixation: The process by which ____________________ convert atmospheric nitrogen (N2) into useable form
ammonium (NH4+).
N2  NH4+
Some nitrogen fixing bacteria live in the soil _____________________, while others live in a symbiotic relationship
(_____________________________) with certain plants
Nitrogen that is inside living creatures returns to the soil after they die by decomposers like __________________________ and
______________________________. The nitrogen can now be used again by ____________________________.