Chapter 3 * The Biosphere

Chapter 3 – The Biosphere
All organisms __________with
the environment  to
understand these_______________,
interactions we study ecology
_________= the scientific study of interactions among organisms
and between organisms and their environment (surroundings)
Ecology is all about ________________
this leads to a better
understanding of the interactions that take place
_____________ = the combined
portions of the planet in which
all life exists, including land,
water, air, or atmosphere
There are 5 levels of organization within the biosphere; a
species, populations, communities, ecosystems, and biomes
1. Species
Species = a group of organisms so similar to one another that
they can breed and produce offspring
an individual most
This levels of organization looks at just _________________
of the time
2. Population
Population = a group of individuals that belong to the
same species and live in the same area at the same time
3. Communities
Communities = assemblages of different populations
that live together in the same area at the same time
4. Ecosystem
Ecosystem = collection of all the organisms that live in a certain
area, together with the nonliving (physical) environment
5. Biome
Biome = a group of ecosystems that have the
same climate and similar dominant communities
Ecologists use a wide range of tools and techniques to study
the living world
The 3 basic approaches ecologist use are _____________,
__________________, and ____________
In order for organisms to interact, they need energy!
Sunlight is the main source of energy for life on Earth
Some types of organisms rely on energy stored in ___________
chemical compounds
Autotrophs = organisms that can capture energy from the
sun or chemicals to produce food
They are also called ______________
Includes plants, some algae, since they make their own food
and certain bacteria
Producers help _______the
flow of
energy through the biosphere
photosynthesis to use light
Most autotrophs we think of use ___________________
energy to power chemical reactions that produce carbs
Photosynthesis adds
oxygen to the
atmosphere and removes
Land plants, as well as algae
that remain in the sunlit
portion of aquatic
environments use
Some autotrophs use ____________________
(chemical reactions) to produce carbs
Many ___________
bacteria use
Heterotrophs = organisms that rely on other organisms
for energy and food supply
They are also called consumers
There are several different types of heterotrophs
1. ______________
Herbivores – only eat plants
(cows, caterpillars, deer)
2. Carnivores
_____________ – only eat
animals (lions, snakes, owls)
Omnivores – eat both plants and
3. ______________
animals (humans, bears, crows)
4. ________________(scavengers)
– feed on animal and
plant remains and other dead matter (vultures)
5. _________________–
Decomposers break down
organic matter (bacteria and fungi)
Energy flows through ecosystems in one direction;
sun/inorganic compounds  autotrophs  heterotrophs
chain = a series of steps in which organisms
transfer energy by eating or being eaten
In a food chain, the arrows point in
direction in which energy is
The amount of energy remaining is _______________
only a portion
of what was available at the first transfer
Ex. Grass  antelope  coyote
web = shows the complex network of
interactions within an ecosystem
Food webs link the food chains
in an ecosystem together
Food webs can be
very complex because 1
producer can be food for
several consumers and 1
consumer can feed on several
types of producers as well as
other consumers
level = each step in a food chain or food web
Producers are the 1st trophic level
Consumers make up the 2nd, 3rd,
or higher trophic levels
Each consumer depends on the
trophic level below for energy
Ecologist have come up with ecological
to model energy or matter in an ecosystem
pyramids = a diagram that shows the
relative amounts of energy or matter within each
trophic level in a food chain or web
There are 3 types of pyramids;
energy, biomass, numbers
1. Energy pyramid – shows the amount
of energy available at each trophic level
10% of the energy gets passed from one trophic
Only about _______
level to the next
The transfer amount is small because organisms use much of
the energy they obtain for basic processes like ______________,
_____________, and ________________
The more trophic levels, the ______
less energy reaches the top
2. Biomass pyramid – shows the total amount of
living mass (biomass) in a given trophic level
Biomass is usually expressed in grams per unit area
It represents the amount of potential ______
food available
for each trophic level
3. Pyramid of numbers – shows the
number of individuals at each trophic level
Sometimes the shape of the numbers and biomass pyramid are
the same because ______________________
lots of individuals produce food for a
lesser number of consumers
Sometimes a numbers pyramid can be upside down when ____
producer can be food for ____________________
many consumers (Ex. one trees
feeds many insects)
Section 3-3:
Cycles of Matter
Organisms need more than just energy to
survive  they need nutrients too!
Energy only flows one way, but
matter is _________________________
recycled within and
between ecosystems
cycles = connect
biological geological, and
chemical aspects of the biosphere
to help recycle matter
Matter is never used up, it is transformed
 that is why it can be recycled
The water cycle is very important because
all living things require water to live!
evaporates (liquid to gas) from lakes and oceans
Water _______________
and becomes ________________
water vapor
Plants release water vapor through transpiration
breathe (also when
Animals release water vapor when they __________
they perspire/urinate)
As water cools high in the atmosphere, it condenses on dust
in the air to form clouds
Eventually the water vapor _____________
condenses enough to fall as
Nutrients = all chemical substances
that an organism needs to sustain life
Every living organism needs nutrients to build tissues and
carry out essential life functions
carbon ____________,
nitrogen and _______________
phosphorus cycles are
important nutrient cycles (oxygen is involved in each)
The carbon cycle! – we have already learned that carbon is a
very important element
Carbon takes many forms and is
a key ingredient of _______________
living tissue
4 main processes move carbon through its cycle
Biological processes like
1. _____________
photosynthesis, respiration, decomposition
Geochemical processes like erosion and volcanic activity
2. _________________
3. ____________________________
Mixed biogeochemical processes like burial
and decomposition of dead organisms
4. _____________________
Human activities like mining, cutting/burning
forests, and burning fuels
The nitrogen cycle! – nitrogen is essential for
amino acids and protein building
There are many different naturally occurring forms of nitrogen
78% nitrogen, most plants can’t use it
– even though the air is _____
Certain bacteria
_________ on plant roots can help convert the nitrogen
in the air to usable nitrogen in ammonia (_____________________)
nitrogen fixation
Animals eat plants and use the nitrogen proteins for various
form muscles
uses (__________________)
When animals _________,
urinate nitrogen is released back into the soil
for plant use (the same thing happens when an animal ______)
Some soil bacteria convert nitrates into nitrogen gas through
The phosphorus cycle! – phosphorus is
important in the formation of DNA and RNA
Phosphorus cycles in 2 ways
______________ – when animals die, phosphorus is returned to
the soil to be used again
Long-term – phosphates get incorporated into rock and
other insoluble compounds – millions of years later that rock
becomes exposed and erodes, releasing the phosphorus back
into the local system
Since nutrients are so important to ecosystems, they can
sometimes be limiting
Primary productivity of an
ecosystem = the rate at which organic
matter is created by producers
Sometimes an ecosystem is
limited by a single nutrient
Primary productivity is limited by (_____________________)
limiting nutrient
available nutrients
Oceans are considered __________________
nutrient-poor compared to land
An _______________
algal bloom can occur
when a large amount of the
limiting nutrient is introduced
to an aquatic ecosystem
These blooms can disrupt the
equilibrium of a system
Grand Lake on July 1st, 2011
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