Study Guide for Energy and Cycles in Ecosystems Quiz
Ecology is the study of the interactions between organisms and their environment.
Ecosystem is a community of organisms and their nonliving environment.
Biotic describes all of the living factors in an environment examples would include;
bacteria, fungi, plants and animals.
Abiotic describes all of the nonliving factors in an environment examples would include; clouds, wind,
water and rocks.
Biosphere is the part of Earth where life exists.
Predator – an organism that eats other organisms.
Prey – an organism that is eaten by another organism.
Carrying capacity – the largest population that a qiven environment can support over a long period of
time.
Niche – an organism’s way of life and its relationships with its abiotic and biotic environments.
Sunlight is a primary source of energy for most living things on Earth.
Food Chains: One pathway that shows how energy in food molecules flow from one organism to the
next.
Grass
Producer
Rabbit
Fox
Coyote
scavenger decomposer
Herbivore/Consumer Carnivore/Consumer Top Predator
Producers/Autotrophs use the suns energy to make their own food which is then eaten by herbivores.
Herbivores/consumers eat plants. Secondary consumers/carnivores then eat the herbivores.
Decomposers and scavengers are consumers who will then feed on the remains of dead organisms and
recycle nutrients back to the earth.
Food Webs
Is a complex diagram showing the many energy pathways
(includes many food chains) in a real ecosystem.
Energy Pyramid - is a diagram shaped like a triangle
that shows the loss of energy at each level of the
food chain.
-Producers are the plants that convert sunlight
energy into chemical energy in sugar
-Primary Consumers or herbivores eat the producers
-Secondary consumers or carnivores eat the primary
consumers.
-Tertiary consumers eat secondary consumers. If
there were as many tertiary consumers as the
number of producers then there would not be
enough food for all the higher level consumers.
Carbon Cycle – The diagram to the left represents the carbon cycle.
Every living thing is made up of carbon and carbon plays an important
role in the cells of all living things.
Carbon enters the environment by:
 Decomposing of dead plants and animals
 Respiration of plants and animals
 Burning of fossil fuels
If too much carbon enters the atmosphere in a form that is not useable
(gas), then it accumulates and causes an imbalance in the
environment. Some scientists believe carbon emissions are the major
cause of our ocean and land temperatures increasing. Scientists call
this global warming.
Water Cycle
Rain, sleet, snow, hail are all forms of
precipitation that fall to earth and collect in
oceans, lakes, ponds, rivers and streams.
Ground water and surface water evaporates
and rises into the atmosphere. Plants lose
water to the atmosphere through
transpiration.
Evaporated water collects in the clouds and
condenses and eventually falls to the
ground in the form of precipitation.
Nitrogen Cycle
All plants and animals need nitrogen to make amino acids, protein and DNA. The nitrogen in the air is not
in a form that is useable to plants and animals. The nitrogen gas must be changed by a process known as
nitrogen fixation. What happen is bacteria in the soil and algae in water can fix (change) nitrogen into a
form that is useable for plants, animals and all living things.
Humans use fertilizers with nitrates in it on their lawns to help grass grow. This fertilizer washes off
the grass and flows into waterways where it causes water plants to grow too quickly. These plants
eventually die, decompose and deplete the water of available oxygen. This affects the entire food chain
because it decreases the amount of available food and oxygen for living organisms which can lead to the
death of these organisms.