Transcript PowerPoint: Ecosystems and the Biosphere Part 1

Ecosystems
and the
Biosphere
© Amy Brown Science Stuff, June 2012
Part 1: Energy Flow and
the Recycling of Matter.
An ecosystem is….
….all the living organisms in a given
area as well as the abiotic factors
with which they interact.
Overview
All of the organisms living on
energy to carry
Earth need ______
out life processes such as
growth, movement, and
reproduction.
In an ecosystem, the ultimate
sun
source of energy is the ____.
The sun’s energy is _________
converted from one
passed through the
form to another and _______
various levels of the ecosystem.
The flow of energy through an
ecosystem is crucial to the
ecosystem’s ability to sustain
life.
Energy Flow Through the Ecosystem
Sunlight is the main energy
source for life on Earth.
Without this energy from the sun:
life on Earth could not exist.
Of all the sun’s
energy that reaches
the earth, less than
1% is actually
____
used by:
living organisms.
This 1% is used by the organisms that are
photosynthesis
capable of ______________.
Photosynthesis is the process by which:
green plants (and a few other organisms)
use the light energy from the sun to convert
water and carbon dioxide into glucose and
oxygen.
The organisms on Earth
that cannot carry out
photosynthesis rely on:
the energy that has been
stored in the organic
compound glucose (a
type of sugar) as their
source of energy.
food in the form
Not only does photosynthesis provide _____
sugars and starches for many of the organisms on
of _________________
carbon dioxide from the
Earth, but it also removes _____________
oxygen into the atmosphere.
atmosphere and releases _______
Autotrophs are organisms that
have the ability to:
use energy from the sun to
convert simple inorganic
substances into complex
organic substances.
Autotrophs convert:
carbon dioxide and water into carbohydrates (glucose).
A few protists
Green plants
A few species of
bacteria
The algae
On land, the ___________
green plants are the main autotrophs.
algae are the main autotrophs.
In aquatic ecosystems, _____
Photosynthetic bacteria (cyanobacteria) are also important
_________________________________
oxygen producers.
_______
Autotrophs are also called “_________”.
producers
The autotrophs are essential to the
energy through the
flow of ______
ecosystem.
Our very life is
on these autotrophs.
Without them, we would
not have…..
……food to eat……
…….or oxygen to breathe.
Many organisms cannot
directly use the energy
from the sun as the
autotrophs do.
These organisms
acquire their energy
from:
other organisms.
Heterotrophs are organisms that:
cannot make their own food.
They rely on other organisms for their:
energy and food supply.
Heterotrophs are also called “__________.”
consumers
There are many types of heterotrophs:
Herbivores
obtain
energy by
eating only
plants.
Carnivores
obtain
energy by
eating
other
animals.
Omnivores
obtain
energy by
eating both
plants and
animals.
Decomposers
Decomposers are a class of detritivores that cause:
decay by breaking down organic compounds.
Decomposers include bacteria and fungi.
Some of the molecules released during decay are consumed
by the ___________,
decomposer and some of these molecules are
the soil or water
returned to _______________.
The action of the decomposers
nutrients contained in
makes the ________
the dead bodies and wastes of
organisms available to __________.
autotrophs
The process of decomposition…..
…..recycles chemical nutrients.
All life on Earth would
cease as detritus
______
dead organic matter
(__________________)
piled up and the supply of
chemical elements
_________________
needed to build new
organisms was exhausted.
_________
What would happen
if there was no
decomposition?
Chemical elements such as carbon,
nitrogen, and phosphorus must be
recycled to be used again in new
organisms.
In summary,
energy
______ enters the
ecosystem in the
__________
form of ________.
sunlight
It is converted to ________
chemical energy
autotrophs and passed to
by ___________
heterotrophs in the form of:
____________
organic compounds (molecules of glucose).
Feeding Relationships
What happens to
energy in an
ecosystem as one
organism eats
another?
The energy flows in a
one-way
_______ path through the
ecosystem.
Energy enters the ecosystem
sunlight
in the form of ________.
Photosynthetic organisms convert the sun’s energy into
glucose
molecules of _______.
This energy is then passed on to the animals that eat the
plants and to the animals that eat other animals.
I must repeat this
one more time!
Energy flows through an
one direction
ecosystem in ____________,
from the ____
sun to __________
autotrophs
and then to various
heterotrophs
____________.
Food Chains
The energy stored by producers in the form of
glucose molecules can be passed through an
ecosystem along a __________.
food chain
A food chain is…..
…..a series of steps in which organisms transfer
energy from one organism to another by eating
and by being eaten.
All food chains begin with an
_________.
autotroph
Examples of Food
Chains:
a) grass  mouse  snake  hawk
b) marine algae  zooplankton  small
minnow  squid  whale
In an ecosystem, the
feeding relationships
between organisms are
much too complex to be
shown in a …..
….. single food chain.
Food Webs
There are many complex
interactions between many
different food chains.
Many consumers eat:
more than one type of food.
More than one species may
feed on:
the same organism.
Food web
Food web:
The network of complex
interactions formed by the
feeding relationships among
the various organisms in an
ecosystem.
A food web links all
the food chains in an
ecosystem together.
Each step in a food chain is called
trophic level
a ___________.
The trophic level indicates:
the organism’s position in the
sequence of energy transfers.
Trophic Levels
The first trophic level in a food chain is always made up of
producersThese organisms are referred to as
_________.
primary producers
_________________.
The second trophic level is occupied by the herbivores
__________ that producers
feed on the _________. These
primary consumers
organisms are referred
to as _________________.
Predators of herbivores
____________________
belong to the third level.
These organisms are
referred to as:
secondary consumers.
Each consumer depends
on the:
trophic level below it for
energy.
Most ecosystems contain
only ____________
three or four
trophic levels.
What does the
plant do with
the glucose it
produces?
half of the glucose
About ____
is used immediately in
cellular respiration
_________________.
Respiration is the
conversion of:
glucose into molecules of
ATP, the energy source for
a cell.
Some of the glucose molecules are
used as ________________________
for the building of
other_______compounds within the
cell.
Much of the glucose is…..
…..stored by the plant for future use.
Biomass is a term that is
used to describe:
the amount of organic
material in an ecosystem.
Producers add biomass to
an ecosystem by making
organic compounds
_________________.
Energy Transfer Between Trophic Levels
The amount of energy or matter
in an ecosystem can be
represented by an:
…..ecological pyramid.
Ecological pyramid:
A diagram that shows the
relative amounts of energy or
matter contained within each
trophic level in a food chain or
a food web.
10% of the total energy _________
Roughly ____
consumed
in one trophic level is passed to the
next trophic level
organisms in the ________________.
The pyramid shape of
the diagram to the right
represents the low
percentage of energy
transfer from one
trophic level to the
next.
Why is the transfer of energy to the next
trophic level so low?
energy possessed by the organisms at one trophic level
Not all of the ______
passed up to the next trophic level.
will be _______
consume for their own
use much of the energy they ________
Organisms ____
life processes such as respiration, movement, or reproduction.
___________
Many organisms at one trophic
escape being eaten
level will _________________
predators at the next
by the _________
level.
energy of these escapees
The _______
“_______” will not be passed to
higher
the organisms at the
_______
level.
Finally, no energy
100%
transformation is _____
efficient.
At each trophic level
some energy will be lost
to the environment in
heat
the form of _____.
Even if the organism is
eaten by a predator some of
_________________,
the molecules in its body will be
in a form that the consumer
cannot:
break down and use.
An example might be the
antlers and hooves of an
__________________
antelope eaten by a lion.
Any energy consumed in
cellular respiration cannot
________________
passed up to the next
be _________
trophic level.
10% of the
Because each ___________
trophic level receives only _____
below it can support only
energy from the trophic level ______,
one tenth the amount of ___________.
living tissue
about _________
In the following diagram, label each trophic level.
Tertiary consumers
Secondary consumers
Primary consumers
Primary producers
10 J
100 J
1000 J
10,000 J
1,000,000 Joules of sunlight
If the ecosystem is
receiving 1,000,000
Joules of energy from
the sun, how much
energy will be passed
to each trophic level?
Remember:
1. Only 1% of the sun’s
energy is converted to
glucose by the
producers.
2. Energy transfer between
trophic levels is 10%
efficient.
The following is a hypothetical food chain:
grass ---> grasshopper ---> toad ---> black snake ---> hawk
The grass occupies what trophic
level?
It is the producer.
The grasshopper occupies what
trophic level?
The grasshopper is the primary
consumer.
The toad occupies what trophic
level?
Secondary consumer
The black snake occupies what
trophic level?
Tertiary consumer
The hawk occupies what trophic
level?
Quaternary consumer
If the energy content of grass is approximately 5,000
calories per square meter of land surface, then the
energy content of the black snakes should be
approximately how many calories per square meter?
Answer: About 5 calories per square meter.
The low rate of energy transfer
between trophic levels explains
why:
food chains rarely contain more
than a few trophic levels.
Organisms occupying the lower
trophic levels are usually much
abundant than organisms
more _________
belonging to the highest level.
There are many more grasses,
shrubs, and trees than there are
herbivores
__________.
There are many herbivores (deer,
antelope, gazelles) for each
carnivore (lion)
______________.
Higher trophic levels
energy and
contain less ______,
therefore, they can support
individuals
fewer _________.