Dynamic
Ecosystems 1
EL: To introduce the unit and define
what an ecosystem is
Key knowledge
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components of ecosystems: communities of living organisms, ecological groupings;
ecological niche;
relationships between organisms: feeding including parasite/host, predator/prey, of
mutual benefit, including mutualism and symbiosis;
flow of energy: inputs and outputs of the system; productivity; trophic levels and
trophic efficiency;
cycling of matter: principle of exchange between living and non-living components
of the ecosystem, including inputs and outputs; biogeochemical systems including
those of water, carbon, oxygen, nitrogen; bioaccumulation;
population dynamics: carrying capacity of ecosystems; factors affecting distribution
and abundance of organisms including birth and death rates, migration;
change to ecosystems over time
– scope and intensity of regular and irregular natural changes; succession
– human activity and the sustainability of ecosystems
– historical practices of indigenous peoples and settlers;
techniques for monitoring and maintaining ecosystems.
Key questions
 What are the components of Australian
marine ecosystems and how do they
interact?
 How does matter and energy flow through
the marine ecosystem?
 How has the marine ecosystem changed
over time and how have humans influenced
this?
 How do we monitor and maintain
ecosystems?
Pre-test
 Complete pre test and hand in
 If you finish early, read page 410
“introducing ecosystems” and write
YOUR OWN definition
Activity
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Order from smallest to largest:
ecosystem, cell, organism, community,
population and biosphere
How did you go?
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Cell: smallest living unit.
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Organism: A single living thing.
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Population: A group of the same species living
in the one location at the same time.
Community: The sum of all the species living
in the location at the same time.
Ecosystem: The sum of all abiotic and biotic
factors and their interactions.
Biosphere: All ecosystems combined
Community
Cell
Organism
Ecosystem
Biosphere
Population
What does environment
mean?
 In everyday language ‘environment’ means the space
or surroundings in which we live.
 To a ‘Biologist’ environment means the sum of ALL
the factors that affect an organism.
 All factors that affect organisms can be
classified as ABIOTIC or BIOTIC.
Environment = Abiotic + Biotic factors
What is an ecosystem?
 An ecosystem includes the communities of
living organisms in a given region, interacting
with each other, surrounded by non-living
factors with which they also interact
 An ecosystem consists of a community, its
physical surroundings and the physical
interactions within and between them
 A living part and a non-living part
Abiotic
+
Biotic
+
Interactions
=
ecosystems
Dynamic
Ecosystems 1b
EL: To explore Victorian marine
ecosystems
Naming ecosystems
 Can be named in a variety of ways
 a terrestrial ecosystem can be named in terms of its
plant community and the growth form and the
structure of its dominant vegetation (e.g. forest)
 naming the dominant flora found by its genus (eg:
tall open eucalyptus forest).
Marine ecosystems
 Defined by:
 Types of plants (e.g. kelp, seagrass)
 Tide level
 Type of substrate (sandy, muddy, silty
or rocky)
 Types of Victorian marine ecosystems:
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The coast
Intertidal rocky reef
Subtidal rocky reef
The beach and soft substrate
Seagrass beds
Pelagic (i.e. open sea)
Marine ecosystems
FIRST, COPY THE TABLE BELOW
INTO YOUR BOOKS, LEAVING 5
LINES FOR EACH ECOSYSTEM
Ecosystem
The Coast
Intertidal rocky reef
Subtidal rocky reef
Seagrass beds
Beaches and soft
substrates
Pelagic
Abiotic factors
Biotic factors
Interactions
between them
Instructions
 In groups of 3-4, go to one of the side benches
where there is a marine ecosystem picture
 Use the information and picture to fill out your
table
 You have 15 minutes. At the end, we’ll go
through each ecosystem and each group will
help the others to fill out the rest of the table
The Coast
Intertidal Rocky Reef
Subtidal Rocky Reef
Seagrass Beds
The Beach
Pelagic
Components of ecosystems
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Communities
Surroundings
Populations
Interactions
Diversity
What is a population?
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A group of the same species living in the one
location at the same time.
Name one population in the next picture
The Beach
What is a community
 A community is made up of populations
of various organisms living in the same
location at the same time
 Name the community in the next picture
Intertidal Rocky Reef
Diversity
 Ecosystems can differ in their diversity
 Diversity can be measured considering
two factors:
- The richness or the number of different
species present in the sample community
- The evenness or the relative abundance of
different species in the sample
 Which of the marine ecosystems was
the most diverse and why?
Ecology
 the study of the interactions of living
things with each other and their physical
environment
Activity/homework – ch 13
 Read pages 409 + 410 and answer quick
check questions 1&2 on page 411
 Copy Key ideas on page 411 into your
notebooks
 Read page 411-413 about littoral
communities and make an annotated
diagram summarising the main points
Reflection
 Define your ecosystem, including the
population, community and diversity.
Dynamic
Ecosystems 2
EL: To explore ecological groupings
and interactions
Ecological Groups
 Although environments can differ vastly
all organisms within an ecosystem
belong to one of the following groups:
 Producer/autotroph
 Consumer/heterotroph (primary, secondary,
tertiary)
 Decomposer
 Detritivore
Producers or Autotrophs
 Producers manufacture organic compounds
from simple inorganic compounds, such as
carbon dioxide, using an abiotic energy source
such as sunlight through PHOTSYNTHESIS
 Producers use these organic compounds
themselves for energy and for all other
members within that ecosystem
What are the producers in
the marine environment?
Consumers or Heterotrophs
 obtain their energy by eating other organisms
or parts of them
 All animals are consumers – what are some of
the categories of
consumers?
Consumers or Heterotrophs
Consumer organisms can be sub divided into the following
groups:
Herbivores that eat plants (animals and insects)
Carnivores that eat animals (living animals and insects)
Omnivores that chow down on both plants and animals
such as (most) humans
Detritivores that eat decomposing organic matter, such as
rotting leaves or decaying animal remains, for example
earthworms, crabs and dung beetles
 Nb. Detritivores differ from decomposers in that decomposers
first break down the organic matter outside their bodies by
releasing enzymes and then they absorb some of the products
Australian Herbivore
Australian Carnivore
Omnivore (Stupidous
Americanus)
Detrivore
Pelagic
Interactions within
ecosystems
In ecosystems, interactions are continually
occurring:
Between the living community and abiotic
surroundings
Within the abiotic surroundings
Within the living community
Inputs and outputs
Inputs and outputs?
Activity
 Go outside and choose an ecosystem
 Draw annotated diagram of the biotic
factors (include inputs and outputs),
abiotic factors and the interactions
between them (try to include at least 10)
 You have 15 minutes
Interactions within a living
community
 Can involve members of the same
(intraspecific) or other (interspecific)
species
 Can be classified ways such as:
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Competition (page 421-22, 433)
Predator- prey/Herbivore-plant (page
422-425)
Parasite-host (page 425-430)
Mutualism (page 430-31)
Commensalism (page 431-432)
Activity
 In four groups, read the relevant section
on your topic and come up with a 10
minute interactive lesson on it for the
next class (you’ll get 20 mins at the start
of next class to finalise it)
 It can involved some multimedia (no more
than 3 minutes)
 It should use egs from the marine
environment to demonstrate
Homework
 Read pages 415-418
 Copy down key ideas on page 418
 Complete quick check questions on 419
Reflection
 Name your inputs and outputs and two
other ways you interact with the biotic or
abiotic factors in your ecosystem
Dynamic
Ecosystems 3
EL: To further explore ecological
interactions
Activity
 You have 20 minutes to finalise your
lesson and 10 minutes to present it
 After the lessons, complete the feeding relationships
worksheet
 After the lessons (or if your group is
ready early) and for homework, please:
 Copy key ideas pg 433 into your books and
complete qu 5&6
 Complete biochallenge pg 434 qu 1-3
 Chapter review qu 2-7
Reflection
 Which lesson did you enjoy the most and
why?
OR
 Were you happy with your groups
lesson? Why/why not?
Dynamic
Ecosystems 7
EL: To learn about trophic levels
and energy flow
A Day in the Life of Krill
 Read “a day in the life of krill on page
438-440. Use the information to
construct a flow chart of the feeding
relationships.
 Read page 443-446 – add the terms and
types of energy in the krill story to your
flow chart
Role play
Group of 4
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Person 1 = grass
Person 2 = grasshopper
Person 3 = bird
Person 4 = cat/sun
Plants capture about 1% of the energy they
receive from the sun
Person 1 – get a meter length of paper to
represent this as energy that’s been converted
to biomass
The grasshopper consumes the entire plant.
Person 1, pass the energy onto person 2.
Person 2: drop 60% of the paper as energy was
required to find and consume the grass
Question: What processes in this cost energy?
Person 2: drop 20% of the energy taken from
the grass, burned while avoiding predators
Question: What parts of the environment might
you make use of, in avoiding predators?
Person 2: An infection by flukes has cost you a
further 5% of your energy intake.
Question: What is the name of the biotic
relationship in this case?
Person 2: 5% of the energy you took from the
grass is spent in reproductive activities.
Question: What type of energy would be
required?
Bad luck person 2! You weren't quite good
enough at avoiding predators. You've been
eaten by a bird - give your remaining energy
over to person 3.
Lucky you'd already reproduced!
Person 3: as a bird you use 50% of your energy
to stay warm.
Question: Why does staying warm require
energy?
Ants rummaging around and scare up insects.
Person 3 - finding and consuming food only
takes 20% of the energy you took from the
grasshopper.
Question 7: What example of symbiosis is this?
Apart from this, why might food consumption be
less draining for a bird than a grasshopper?
Birds need to care for their offspring while they
mature. Person 3, drop 20% of your energy
uptake.
Question: How is this reproduction strategy
different to that of the grasshopper?
Bad luck person 3! What goes around comes
around. You've been eaten by a cat.
Pass on your energy to person 4.
Staying warm is draining business. Lose 50% of
your energy.
Question: What do we call organisms like birds
and cats that generate their own body heat?
You need to groom yourself carefully to avoid
fleas. This takes time; time you aren't eating
birds. Lose 25% of your energy.
What percentage remains of the initial solar
energy captured by the grass?
Hypothetical:
If a tertiary consumer was preying on cats, what
percentage of your initial energy would it
receive?
If that consumer needed 1% of the initial energy
captured, how many cats would it need to eat?
Is this viable?
Homework
 Copy key ideas page 446
 Quick check qu 446 page 446
 Read pages 447-449 and summarise
Reflection
 Were you surprised by the amount of
energy lost in our role play?
Dynamic
Ecosystems 8
EL: To learn about food chains and
webs and demonstrate them with a
game!
 http://www.youtube.com/watch?v=rJ2oF
D9-WVc&feature=related
 http://www.youtube.com/watch?v=_BCq8qym_w&feature=related
Activity
 Food web game
Activity
 Use the pictures to construct a marine
food web. You can add your own
drawings in too
 Make sure you label each organism with
its trophic level
Homework
 Read pages 450-52
 Copy key ideas on pg 452 into your book
 Quick check qu on pg 452
Reflection
 What key knowledge about energy
transfers in ecosystems and ecosystem
interactions did the game demonstrate?
Dynamic
Ecosystems 9
EL: To learn about ecological pyramids
and ecosystem productivity
Organism abundance
 Take a look at your food web poster from
yesterday. Next to each organism, write
an estimated number of that organism
using terms like “lots”, “few” etc
 Which organisms are there more and
less of and why?
Ecological pyramids
 Show the number of organisms at each
trophic level (except detritivores and
decomposers)
 Pyramid of numbers = number of organisms
per unit area
Pyramid of numbers
Ecological pyramids
 Show the number of organisms at each
trophic level (except detritivores and
decomposers)
 Pyramid of numbers = number of organisms per unit
area
 Pyramid of biomass = total dry organic
matter of organisms at each trophic level in
a given area
Pyramid of biomass
Ecological pyramids
 Show the number of organisms at each
trophic level (except detritivores and
decomposers)
 Pyramid of numbers = number of organisms per unit
area
 Pyramid of biomass = total dry organic matter of
organisms at each trophic level in a given area
 A pyramid of energy shows the amount of
energy input to each trophic level in a given
area of an ecosystem over an extended
period, often one year
Pyramid of energy
Activity
 Construct a pyramid of numbers for your
marine food web. Try to then construct a
pyramid of biomass or energy.
 Complete the food pyramid worksheet
 Copy down key ideas on page 454 and
complete quick check questions
Ecosystem productivity
 Productivity = rate of chemical energy
production in an ecosystem, expressed in
“grams or organic matter per square
meter per year”
Ecosystem productivity
 List in order from least productive to most
productive:
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Swamp
Desert scrub
Temperate grassland
Temperate forest
Tropical forest
Continental shelf
Open ocean
Upwelling zones
Algae beds and coral reefs
Ecosystem productivity
Why are some ecosystems more productive than others?
Activity/homework
 Finish any work not yet finished from
earlier in the lesson
 Copy down key ideas on page 457 and
complete quick check questions on page
458
Reflection
 Thinking about human population and
our food production, what shape do you
think our pyramid of numbers might take?
Is this sustainable?
Dynamic
Ecosystems 10
EL: To understand that unlike energy
matter is never lost and needs to be
recycled and how to create a matter
cycle map.
Matter cycles
 Matter such as carbon, nitrogen,
phosphorus, oxygen, hydrogen etc
continually cycles through an ecosystem,
and are sometimes found in biotic
components of the ecosystem
 Use the information in the example on
page 461 to construct a diagram of a
carbon cycle
Biogeochemical cycles
 Bio = through living things
 Geo = through geological things
 Chemical = C, N, P and H2O
Activity
 In four groups, use the flip cameras to
make a 2 minute video about the life of a
carbon, nitrogen or phosphorus atom or
water molecule
 It must be told from the point of view of
the atom/molecule and be suitable for a
grade 3-4 audience – keep it simple and
make it engaging
Reflection
 Which video was more suitable to its
target audience and why?
Dynamic
Ecosystems 13
EL: To begin exploring population
dynamics.
Bioaccumulation
 The progressive
accumulation of nonbiodegradable/persista
nt chemicals in living
organisms, becoming
more concentrated in
higher trophic levels
 http://www.youtube.com/watch
?v=052MQM3-tTc
Homework
 Complete bioaccumulation worksheet
 Copy key ideas on page 466
 Complete quick check questions on page
467 and the biochallenge question
Figure 15.2 page 472
 How many populations can you see?
 How many individuals are there?
 Would you say this area is species rich?
Why/why not?
Figure 15.4 page 473
 Where would Australia sit on the graph?
 number of species: 147 579
 Area: 7 692 024 km2
Species Richness
 The number of different populations in
terrestrial communities in the same
region is related to the physical size of
the available area.
 The number of different populations in a
terrestrial area is also related to the
latitude or distance from the equator.
 As we move from the poles to the equator, in
general, species richness of terrestrial
communities increases.
Activity
 Copy key ideas and complete quick
check questions page 475
Human populations
 Think about a population of humans –
what are some ways we can describe it?
 Look at list on page 475 – did we get
them all?
 Refer back to figure 15.2 on page 472 –
how would you now describe the
abundance of the penguins?
Population abundance
 Abundance or density is defined as the
number of individuals of a given species
per unit area.
 Abundance can also be expressed
qualitatively:
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scarce or rare
infrequent
frequent
abundant
very abundant (see figure 15.9).
Our population abundance
 How would you describe the year 11
biology class population abundance
 Quantitatively?
 Qualitatively?
Activity/Homework
 Read pages 476-478 (stop at pop.
distribution)
 Answer the following questions:
 How do we measure population abundance?
 Why can’t population abundance be based
on just one sampling period?
 Outline 2 reasons why we want to know
population abundance.
 Page 497 qu 5
Reflection
 Summarise in one sentence your main
learning from today.
Dynamic
Ecosystems 14
EL: To explore population distribution
and population growth.
What is a population
distribution?
 Refers to the spread of members of a
population over space.
 Populations may have identical densities but
their distributions can differ.
What is a population
distribution?
 three populations with identical
densities but their horizontal
distributions differ
 Clumped and uniform distributions are
both non-random patterns.
 The most common pattern observed in
populations is a clumped distribution.
 Changes in the distribution of
populations can occur over time.
What type of population
distribution?
Activity/Homework
 Read page 480 and summarise the
conditions suitable for the three types of
population distribution
 Copy key ideas page 481
 Quick check 3-6 page 482
 Complete population dynamic worksheet
Population dynamics
 Population dynamics deals with changes
in population size over time.
 Models of growth in closed populations
include:
 exponential or unlimited growth model
 logistic or density-dependent growth model.
.
Population
Exponential growth
 Exponential growth is
the unlimited growth of a
population.
 This pattern of growth can
occur for several
generations at least as
long as resources are
abundant
Logistic growth
 Population growth in the presence
of limiting factors follows a pattern
that is termed logistic growth,
also known as density-dependent
growth.
 When the population size is well
below the carrying capacity (K), the
growth of the population is rapid,
but as the population size
approaches carrying capacity,
growth slows and stops.
How much is too much?
Carrying capacity
The carrying capacity is the maximum
population size that a habitat can support in
a sustained manner
When you can’t stop increasing.
When you really can’t stop
increasing.
We have looked at distribution of animals over space but how about time?
Why is there a lag between the peak in biomass of foxes compared to hares?
Activity/Homework
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Copy key ideas page 492
Quick check 12-16
Read 492-494
Copy key ideas page 495
Quick check 17-19
Biochallenge
Chapter Review qu 2, 3, 6-8, 10
Reflection
 What are 3 key ideas I learnt about
today?