Transcript Unit Two Ecological Interactions

Unit Two
Ecological Interactions
Chapter 4
Matter and Energy in the Ecosystem
ROLES OF LIVING THINGS
Producers
Decomposers
Consumers
Producers – Autotrophs
• Organisms that make their
own food from inorganic
molecules and energy
from the sun
• auto = self troph = feed
• Photosynthesis – the
chemical process that
produces sugar from CO2
and energy from sunlight
protists – phytoplankton
plants – corn, rice, grass,
wheat)
Consumers – Heterotrophs
 Organisms that must eat
food for energy
 hetero = other
troph = feed
 Herbivores – organisms
that eat only plants (cows)
 Carnivores – organisms
that eat only herbivores or
other carnivores (wolves)
 Omnivores – organisms
that eat both plants and
animals (bears; humans)
Decomposers
Wood ear
• Bacteria and fungi that
consume the bodies of
dead organisms and
organic wastes
• Decomposers complete
the cycle of matter in the
ecosystem
Ex:
Portobello
Fungi: wood ear, portabella
Bacteria: E. coli, Salmonella
E. coli
Salmonella
Trophic Levels
• A layer of the feeding
relationships in an
ecosystem
• First level – producers
• Second level – herbivores
• Third level – first order
carnivores
• Fourth level – second
order carnivores
• Each level completely
depends on the level
below it
Ecosystem Structure
Food Chain
• A series of organisms that
transfer food between
trophic levels of an
ecosystem
• Always begins with
producers
• Decomposers supply the
nutrients that begin the
cycle
Ecosystem Structure
Food Web
• A network of food
chains representing the
feeding relationships
among organisms in
an ecosystem
• Changes in any
organism affects the
other populations
FACTORS THAT AFFECT THE
ECOSYSTEM
ABIOTIC
• WEATHER
• CLIMATE
• SOIL QUALITY
• AVAILABLILITY OF
FRESH WATER
• POLLUTION
• CONTAMINATION
BIOTIC
• PLANT LIFE
• BIODIVERSITY
• ANIMAL POPULATIONS
• HUMAN ACTIVITY
BIOTIC FACTOR: BIODIVERSITY
• The number of
connections in a food
web varies in every
ecosystem (few
species in the polar ice
caps to many in the
tropical rain forest)
• The older or more
complex food webs
are more stable and
are more resistant to
natural or man-made
disasters
ABIOTIC FACTOR: BIOMAGNIFICATION
• Ex: The pesticide DDT
was used to control the
mosquito population.
Fish ate the sprayed
mosquitos and their
larvae which
concentrated the DDT in
the bodies of the fish.
Eagles ate the
contaminated fish. This
caused the eagles to have
defective shells and eggs
broke decreasing the
number of eagles being
born.
• Pollution or chemical
contamination that can
be magnified in a food
web
• The concentration of a
pollutant in organisms
increases as it moves up
the trophic levels in a
food chain.
Energy in the Ecosystem
• Ecological pyramids –
show the relative energy
in each trophic level
• Energy is NOT a
renewable resource
• Energy, biomass or
number pyramids
decrease in value as you
move up the trophic levels
• This means each trophic
level gets less energy fro
the food they consume
than the previous level
Energy in the ecosystem
• BIOMASS – shows • 10% LAW –
total amount of
producers store
organic matter
30% or LESS of
(energy) present in
sun’s energy, each
a trophic level
trophic level after
that only gets 10%
• Energy travels
of the available
between one
energy from the
trophic level and
trophic level
the next in the form
before.
of food.
Chemical Cycles
• 96% of your body is
made up of four
elements: carbon,
oxygen, hydrogen,
nitrogen
• Elements move the
ecosystem in cycles
• Matter cycles
repeatedly through the
ecosystem
• The amount of matter
that enters and leaves
each cycle is small
Water Cycle
• Water Cycle – water
moves between ocean,
atmosphere and land
• Evaporation – water
changes from liquid to a
gas, moves into
atmosphere
• Transpiration –
evaporation of water from
leaves of plants
• All of the fresh water we
will ever have is already
here
Carbon Cycle
• Producers (plants,
bacteria and plankton)
produce sugar using
energy from the sun in
a process called
photosynthesis
• H2O + CO2 = C6H12O6 + O2
• Consumers use the
energy from food in a
process called
respiration
• C6H12O6 + O2 = H2O + CO2
Nitrogen Cycle
• Nitrogen is necessary to
make amino acids – the
building blocks of proteins
• Nitrogen is usually found
as a gas in our atmosphere
• Bacteria help to convert
nitrogen gas to ammonia
and nitrates
• Legumes (peas, beans,
peanuts) have specialized
bacteria in their roots that
covert nitrogen gas from
the atmosphere into
nitrates which can be used
by plants to make amino
acids