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Ecology and Our Ecosystem
Characteristics of the Biosphere
• Ecology is the study of
organisms and their
interactions with the
environment. (eco-home)
• The biosphere is the lifesupporting region of the
earth. It includes all the
land, air and water in
which organisms live.
Parts of the environment
• Abiotic factors- non- • Biotic factors- living
living parts of the
parts of the
environment.
environment.
• A-without, bio-life
• Ex: plants, animals
and other organisms.
• Ex: water, soil, light ,
temperature, wind, and
physical space.
1.43 Understand that and describe how organisms are influenced by
a particular combination of living and non-living components in the
environment.
Habitats
• Every species in a
habitat has
characteristics that
enable it to function in
the unique abiotic and
biotic factors.
• It provides the
members of a species
with food, shelter,
water, and whatever
else they need to
survive.
Species, Populations and
Communities
• Species are a group of
•
organisms so similar to one
another, they can breed and
produce fertile offspring.
• Populations are all of the
members of a single species •
that live in one area.
• Populations of different
organisms share a living space
and interact with one another.
All of the populations
that live and interact in
one environment make
up the community.
Can you give an
example of a species,
population and
community where you
live?
The Ecosystem
• All of the populations
and abiotic factors in
an area make up the
ecosystem.
• It can be a large
(forest, ocean, desert)
or small area (garden,
pond.)
• Healthy ecosystems
are very diverse.
Let’s Review the Organization of
Life in Ecology
From smallest to biggest
1. Organisms- ecologists study behaviors.
2. Populations- ecologists study the effects of them on the
environment and growth rates.
3. Communities- study the effects on a community when new
species are added or removed.
4. Ecosystem- ecologists are concerned with the stability of
the ecosystem.
5. Biosphere- ecologists are concerned with all interactions.
Ecological Methods
• Regardless of the tools
they use, scientists
conduct modern
research using 3 basic
approaches.
• 1. Observing
• 2. Experimenting
• 3. Modeling.
How Organisms Interact: Feeding
Relationships
Autotrophs- use energy
from the sun or stored
energy to make their
own food. They are
also called producers.
All organisms rely on
autotrophs for food.
Ex: plants.
• Heterotrophs- depend
on autotrophs and
their source of
nutrients and energy.
They are also known
as consumers.
• They include animals.
Photosynthesis vs. Chemosynthesis
• Photosynthesis- uses
light to make food
6CO2 + 6H20 
C6H12O6 + 6O2
• Chemosynthesis
• Hydrogen sulfide and
oxygen combine to form
sulfur compounds. Using
chemical energy, cells
make carbohydrates using
CO2 from sea water.
• Where are these bacteria
found?
Autotrophs
• Get their energy from the • Chemosynthesis is
sun through
when organisms use
photosynthesis.
chemical energy to
produce carbohydrates
• Use light energy to
when there is no light
power chemical reactions
present.
that convert carbon
dioxide and water into
• Bacteria- vents at
oxygen and sugar.
bottom of ocean is an
example.
• 6CO2 + 6H2O 
C6H12O6 + 6O2
Photosynthesis vs. Cellular
Respiration
• Photosynthesis
Captures energy
Chloroplasts
• Cellular Respiration
Releases energy
Mitochondria
• 6CO2 + 6H2O 
C6H12O6 + 6O2
• C6H12O6 + 6O2 
6CO2 + 6H2O
1.3, 1.4, 1.9, 1.43
Heterotrophs:
Carnivores and Scavengers
• Carnivores eat only
“meat”.
• What are some
examples of
carnivores?
• Scavengers eat
animals that are
already dead, they
don’t kill for food.
• What are some
examples?
• Why are they
important?
Herbivores
• Eat Plants
Omnivores and Decomposers
• Omnivores eat both
plants and animals.
• What are some
examples?
• Decomposers are
organisms that break
down and absorb
nutrients from dead
organisms.
• Ex: bacteria, some
protozoans, fungi.
• Why are they
important?
Detritivores
• Feed on plant and animal remains and other
dead matter called detritis
• Earthworms, crabs, mites, snails
Matter and Energy in Ecosystems
• When you pick an apple from a
tree and eat it, you are
consuming C, N and other
elements, and well as energy.
• Matter and energy are
constantly cycling through the
ecosystems.
• Conservation of mass and
energy laws: can’t be created
or destroyed. They are
transformed into different
forms.
Food Chain
• It is a simple model that scientists use to show how
matter and energy move through an ecosystem.
• Nutrients and energy flow from autotroph to
heterotroph to decomposers.
• They consist of 3 links, but no more than 5 because
the amount of energy by the 5th link is only a small
portion. Energy is lost as heat at each link.
• Ex: Algae Fish Bird
Trophic levels
• Each organism in a
food chain represents
a feeding step, or
trophic level, in the
passage of energy and
materials.
• They are many
“routes”.
• 1st level- photosynthetic
autotrophs- (producers.)
• 2nd level- first order consumers
(herbivores/omnivore)
• 3rd level- second order
consumers (carnivores.)
• 4th level- third order consumers
(carnivores that feed on second
order carnivores)
1.44 Describe the flow of energy within ecosystems.
Food Webs
• Food Webs
represent a
network on
interconnected
food chains.
• They express all
the possible
feeding
relationships at
each trophic
level in a
community.
Ecological Pyramids- show the relative
amounts of energy or matter contained
within each trophic level.
• Energy Pyramid- • Biomass Pyramid- shows
total amount of living
only 10% of the
tissue within a given
energy available
trophic level.
within one trophic
level is transferred • Pyramid of Numbersto organisms at the
shows relative numbers of
next.
individual organisms at
each trophic level.
Which pyramid is shown?
Some pyramids of energy use numbers to represent the number of
animals/plants there are for each level. If you had a tree that fed 50,000
insects, what would the pyramid look like?
Others use grams.
Cycling Maintains Homeostasis
• Energy is lost as heat to
the environment by body
processes at each level. It
flows one way.
• Sunlight is the source of
all energy.
• Matter also moves through
the trophic levels, but can’t
be replinished like
sunlight.
• Matter is constantly
recycled.
• Biological systems do
not use up matter, they
transform it into living
tissue, or passed out as
waste.
1.44 Describe the flow of matter and nutrients within ecosystems.
Why do we need the following?
•
•
•
•
Water
Carbon
Nitrogen
Phosphorus
• Water- liquid or solid on Earth and gas in the atmosphere.
The water cycle
• Evaporation of water from water bodies, animals and
plants.(liquid to gas)
• Condensation- gas to liquid in form of precipitation.
• Transpiration- loss of water vapor from plants.
• Respiration- gaseous exchange of oxygen and carbon
dioxide between organisms and environment. (Organisms
also lose water through excretion.)
• After an organism dies, decomposition releases water
back into the environment.
The Carbon Cycle
Carbon Cycle
• Carbon is found in the environment in the form of CO2
in the atmosphere and ocean.
• From the atmosphere, CO2 moves to aquatic and
terrestrial producers.
• Producers use CO2 in photosynthesis to make sugar, a
higher energy form.
• Organisms eat C when they consume “plants”.
• Respiration returns C to atmosphere in form of CO2 and
decay returns C to the environment.
• If decay occurs without O, the C can be bound up in a
fossil fuels that are burned and returned to the
atmosphere.
Fossil Fuels Formation
• Fossil fuels are made when plants and other organic
organisms die and decompose in the ground. Layers upon
layers are formed over many years. Through chemical
processes and pressure, fossil fuels are made.
• 1.42 Sometimes, the environmental conditions are such that
plants and marine organisms grow faster than decomposers
can recycle them back to the environment. Layers of energy
rich organic material thus laid down have gradually been
turned into great coal beds and oil pools by the pressure of
the overlying earth. Burning these fossil fuels, people are
passing most of the stored energy back into the environment
as had and release large amounts of CO2.
Nitrogen Cycle
Nitrogen Cycle
• Atmospheric N2 makes up nearly 78% of air.
• Living things can’t use N in atmospheric form.
• Lightning and some bacteria convert atmospheric N2 into
usable N-containing compounds. (nitrogen-fixing bacteria)
• Plants take up nitrates made from bacteria and lightning and
convert them into N-compounds.
• Herbivores eat the plants and convert N-plant proteins into
N animal proteins.During digestion, plant and animal
proteins are made into human proteins.
• Organisms return N to the atmosphere when they die and
decay.(denitrification)
• Fertilizers from farming are taken up by plants or runoff
into body of waters.
Phosphorus Cycle
Phosphorus Cycle
• Plants use P from the soil in their body tissues.
• Animals get P by eating plants.
• When the animals die, they decompose and the P is
returned to the soil to be used again. (Short-term cycle.)
• Phosphate washed into the sea become incorporated into
rock as insoluable compounds. Millions of years later, as
the environment changes, the rock is exposed and made
part of the ecological system. (long-term cycle.)
Nutrient Limitation
• Primary productivity
is the rate at which
organic matter is
created by producers.
• Controlled by amount
of available nutrients.
• When an organism is
limited by a single
nutrient that is scarce
or cycles slowly, the
substance is a limited
nutrient.
• Why would this be
important to
ecologists?
Algal Bloom
• If there is too much of a limiting nutrient (ie.
Fertilizer from field) that flows into water, this can
cause an immediate increase in the amount of
algae and other producers called an algal bloom.
• Why do they occur?
• This increases the number of producers, and
disrupt the ecosystem, if not enough consumers.
• Eutrophication- too much algae, takes up all of
the oxygen things die
Invasive Species
• In 1988, small
freshwater zebra
mussels were
introduced to Lake
Erie from Europe.
• They spread to all
great lakes in less than
10 years.
• They compete with
other species for food.
• They clog up waterintake pipes and farmirrigation pipes.
• One benefit- filterfeeding action h as
made water cleaner.
• Gypsy moths
1.38
Biosphere Review
• Click on the following link and choose your
text book. Review the links and take the
self-test.
• Ch. 3 Review