Download Applications and skills

Topic 4: Ecology (12 hours)
4.1 Species, communities and ecosystems: The continued survival of living organisms including humans depends on
sustainable communities.
Nature of science: Looking for patterns, trends and discrepancies—plants and algae are mostly autotrophic but some are not.
Understandings:
 Species are groups of organisms that can potentially interbreed
to produce fertile offspring.
 Members of a species may be reproductively isolated in
separate populations.
 Species have either an autotrophic or heterotrophic method of
nutrition (a few species have both methods).
 Consumers are heterotrophs that feed on living organisms by
ingestion.
 Detritivores are heterotrophs that obtain organic nutrients
from detritus by internal digestion.
 Saprotrophs are heterotrophs that obtain organic nutrients
from dead organisms by external digestion.
 A community is formed by populations of different species
living together and interacting with each other.
 A community forms an ecosystem by its interactions with the
abiotic environment.
 Autotrophs obtain inorganic nutrients from the abiotic
environment.
 The supply of inorganic nutrients is maintained by nutrient
cycling.
 Ecosystems have the potential to be sustainable over long
periods of time.
Applications and skills:
 Skill: Classifying species as autotrophs, consumers,
detritivores or saprotrophs from a knowledge of their
mode of nutrition.
 Skill: Testing for association between two species
using the chi-squared test with data obtained by
quadrat sampling. To obtain data for the chi-squared
test, an ecosystem should be chosen in which one or
more factors affecting the distribution of the chosen
species varies. Sampling should be based on random
numbers. In each quadrat the presence or absence of
the chosen species should be recorded.
 Skill: Recognizing and interpreting statistical
significance.
PRACTICAL
Setting up sealed mesocosms to try to establish
sustainability. Mesocosms can be set up in open tanks, but
sealed glass vessels are preferable because entry and exit
of matter can be prevented but light can enter and heat
can leave. Aquatic systems are likely to be more successful
than terrestrial ones.
International-mindedness: The need for sustainability in human activities could be discussed and the methods needed to
promote this.
Topic 4: Ecology (12 hours)
4.2 Energy flow: Ecosystems require a continuous supply of energy to fuel life processes and to replace energy
lost as heat.
Nature of science: Use theories to explain natural phenomena—the concept of energy flow explains the limited
length of food chains.
Understandings:
Applications and
 Most ecosystems rely on a supply of energy from sunlight. There is a continuous but
skills:
variable supply of energy in the form of sunlight but that the supply of nutrients in an
 Skill:
ecosystem is finite and limited and must be cycled.
Quantitative
 Light energy is converted to chemical energy in carbon compounds by photosynthesis.
representations
 Chemical energy in carbon compounds flows through food chains by means of feeding.
of energy flow
 Energy released from carbon compounds by respiration is used in living organisms and
using pyramids
converted to heat.
of energy.
 Living organisms cannot convert heat to other forms of energy.
 Heat is lost from ecosystems.
 Energy losses between trophic levels restrict the length of food chains and the biomass
of higher trophic levels. Biomass in terrestrial ecosystems diminishes with energy
along food chains due to loss of carbon dioxide, water and other waste products, such
as urea.
 Pyramids of energy should be drawn to scale and should be stepped, not triangular.
The terms producer, first consumer and second consumer and so on should be used,
rather than first trophic level, second trophic level and so on.
International-mindedness: The energetics of food chains is a factor in the efficiency of food production for the
alleviation of world hunger.
Topic 4: Ecology (12 hours)
4.3 Carbon cycling: Continued availability of carbon in ecosystems depends on carbon cycling.
Nature of science: Making accurate, quantitative measurements—it is important to obtain reliable data on the
concentration of carbon dioxide and methane in the atmosphere.
Understandings:
 Autotrophs convert carbon dioxide into carbohydrates and other carbon compounds.
 In aquatic ecosystems carbon is present as dissolved carbon dioxide and hydrogen
carbonate ions.
 Carbon dioxide diffuses from the atmosphere or water into autotrophs.
 Carbon dioxide is produced by respiration and diffuses out of organisms into water or
the atmosphere.
 Methane is produced from organic matter in anaerobic conditions by methanogenic
archaeans and some diffuses into the atmosphere or accumulates in the ground.
 Methane is oxidized to carbon dioxide and water in the atmosphere.
 Peat forms when organic matter is not fully decomposed because of acidic and/or
anaerobic conditions in waterlogged soils.
 Partially decomposed organic matter from past geological eras was converted either
into coal or into oil and gas that accumulate in porous rocks.
 Carbon dioxide is produced by the combustion of biomass and fossilized organic
matter.
 Animals such as reef-building corals and mollusca have hard parts that are composed
of calcium carbonate and can become fossilized in limestone.
Applications and
skills:
 Application:
Estimation of
carbon fluxes
(measured in
gigatons) due to
processes in the
carbon cycle.
 Application:
Analysis of data
from air
monitoring
stations to
explain annual
fluctuations.
 Skill: Construct a
diagram of the
carbon cycle.
Aims: The ethical implications of diverting crops such as maize from a food to a fuel crop could be considered.
Topic 4: Ecology (12 hours)
4.4 Climate change: Concentrations of gases in the atmosphere affect climates experienced at the Earth’s surface.
Nature of science: Assessing claims—assessment of the claims that human activities are producing climate change.
Understandings:
 Carbon dioxide and water vapour are the most significant greenhouse gases.
 Other gases including methane and nitrogen oxides have less impact.
 The impact of a gas depends on its ability to absorb long wave radiation as well as
on its concentration in the atmosphere.
 The warmed Earth emits longer wavelength radiation (heat).
 Longer wave radiation is absorbed by greenhouse gases that retain the heat in
the atmosphere.
 Global temperatures and climate patterns are influenced by concentrations of
greenhouse gases.
 There is a correlation between rising atmospheric concentrations of carbon
dioxide since the start of the industrial revolution 200 years ago and average
global temperatures.
 Ozone depletion ≠ enhanced greenhouse effect
 Recent increases in atmospheric carbon dioxide are largely due to increases in
the combustion of fossilized organic matter.



Applications and skills:
 Application: Threats to coral
reefs from increasing
concentrations of dissolved
carbon dioxide.
 Application: Correlations
between global
temperatures and carbon
dioxide concentrations on
Earth. Databases can be
used to analyse
concentrations of
greenhouse gases.
 Application: Evaluating
claims that human activities
are not causing climate
change.
International-mindedness: Release of greenhouse gases occurs locally but has a global impact, so international
cooperation to reduce emissions is essential.
Theory of knowledge: The precautionary principle is meant to guide decision-making in conditions where a lack of
certainty exists. Is certainty ever possible in the natural sciences?
Aims: There are interesting parallels between humans that are unwilling to reduce their carbon footprint and
cheating in social animals. When the level of cheating rises above a certain level, social behaviour breaks down.
Science Journal 2/29/2016
Do any of
these
statistics
surprise
you?
What do you
think most
Americans
base their
beliefs on?
How could
these statics
be biased?
International Climate
Change Concern Survey
Perceived Causes of Climate
Change in USA
Biology Journal 3/8/2016
This graphic shows movements of carbon, called carbon flux,
on the Earth. Answer these questions.
1.
2.
3.
4.
Where is most of the
carbon on Earth found?
How much (include
units)?
How much carbon is
stored as plant material
on Earth?
What amount of carbon
dioxide gets added by
humans every year?
Does all of the
photosynthesis balance
out all of the cellular
respiration?
Ecology
Whiteboard Review!
What are the 3 fossil fuels?
Oil, coal, and natural gas
What is the difference between an
autotroph and a heterotroph?
Autotrophs make their own food through photosynthesis
(usually) and heterotrophs do not make their own food, they
must eat another living thing.
How is a population defined?
A population is organisms
of the same species that
live in the same area and
can interbreed.
What tool can be used to estimate a
population size?
A quadrat is used to
measure the population
of a small area, and
then multiplied to
estimate a larger area.
What does an ecosystem
include, that a community does
not include?
An ecosystem include the
abiotic factors of a system,
such as temperature, H2O,
and nutrients.
A community is limited to
all of the living things.
Write out the chemical reaction
for photosynthesis.
Write it using out the formulas (like “H2O”)
Below the formulas, write out the words (like “water”)
H 2O
+
water
plus
CO2 → O2 + C6H12O6
carbon
dioxide
yields
(or turns into)
oxygen
plus
sugar
(or glucose)
What would each of these processes be called?
Burning (combustion)
1
Photosynthesis
2
CO2
(in atmosphere)
Cellular Respiration
3
Decomposition
4
Diffusion
5
CO2
(in ocean as carbonic acid)
Deposition (becomes fossil fuels over a6
long time
If the first consumers of a square kilometer of
temperate forest ecosystem have a biomass of 1,490
kilograms, what is the biomass of the third level
consumers?
Answer!
14.9 kg
149 kg
x 0.1
(which is 10%)
x 0.1
1490 kg
(which is 10%)
You don’t start here!
Compare and contrast saprotrphs and
detritovores in a Venn diagram.
Saprotroph
Both
Detritovore
Compare and contrast saprotrphs and
detritovores in a Venn diagram.
Saprotroph
Both
• Decomposers
• Digests its food
• Important for
externally, then
recycling
absorbs it
matter (not
• Fungi
energy!)
Detritovore
• Consumes its
food the breaks
it down and
absorbs it.
• Bacteria,
earthworms
Here is a graph of atmospheric CO2 concentration at
Mauna Loa, Hawaii over 60 years.
1. Summarize the trend.
Positive correlation. CO2 concentration
increases as time increases.
2. Explain why CO2 concentration “zig-zags.”
When it is summer (in the Northern hemisphere) plants do more
photosynthesis, reducing CO2; when it is winter (in the Northern
hemisphere) plants do less photosynthesis, and CO2 builds up.
Photosynthesis (mostly) can’t happen in
the winter. Why not?
The sunlight is dim,
and days are short
CO2 + H2O
→
C6H12O6 + O2
Water is frozen, and thus
inaccessible
Write out the formula for
cellular respiration.
Write it using out the formulas (like “H2O”)
Below the formulas, write out the words (like “water”)
C6H12O6 + O2 →
sugar
(or glucose)
plus
oxygen
yields
(or turns into)
CO2 + H2O
carbon
dioxide
plus
water
Explain the greenhouse effect
The sun causes infrared rays to hit the Earth. Some
of these rays bounce off, and don’t heat the earth.
Some rays are absorbed in the atmosphere by
greenhouse gasses, warming the Earth.
On this food web, name all of the…
1. Producers Bladderwrack, microscopic algae
2. 2nd consumers Crab, lobster, seal, herring gull
3. Decomposers None are shown!
4. Autotrophs Bladderwrack, microscopic algae
5. Heterotrophs Everything except the autotrophs
How long does it take for fossil fuels to form?
300,000,000 years
Prehistoric Fern Plants fossilized in coal samples
Name at least 4 greenhouse
gasses found in the atmosphere
Greenhouse Gasses






H2O (water)
These are the
most significant!
CO2 (carbon dioxide)
CH4 (methane or “natural gas”)
O3 (ozone)
N2O (nitrous oxide)
CFCs (chlorofluorocarbons)
What happens to the energy in a food
web? What happens to the matter?
The energy is continually lost. Only 10% of energy
is passed from any organism when it is eaten. The
matter is never lost. It is recycled by decomposers
and by other processes.
What do these 2 have in common?
A coal power plant
Weightlifting
Both of these…






Create CO2
Create H2O
Consume O2
Burn calories
Consume / release energy
Break down organic (carbon-based) molecules to
get energy
 The energy for these molecules at one point came
from the sun (either food or fossil fuels)
True or False?
Write out the numbers 1 through 6. Then, write “true”
or “false” for each one.
1. Plants do photosynthesis.
2. Plants do cellular respiration.
3. Plants create O2.
4. Plants remove CO2 from the air.
5. Plants cause global warming.
6.Plants get the energy for photosynthesis
from water.
True or False?
1. Plants do photosynthesis. True!
2. Plants do cellular respiration. True!
3. Plants create O2. True!
4. Plants remove CO2 from the air. True!
5. Plants cause global warming. False!
6.Plants get the energy for photosynthesis
from water. False!
True or False?
Write out the numbers 1 through 4. Then, write “true”
or “false” for each one.
1. Animals do photosynthesis.
2. Animals do cellular respiration.
3. Animals depend on plants as a source of O2
and a source of energy.
4. Animals create CO2.
True or False?
1. Animals do photosynthesis. False!
2. Animals do cellular respiration. True!
3. Animals depend on plants as a source of O2
and a source of energy. True!
4. Animals create CO2. True!
Where does the energy to build the food
molecules in photosynthesis come from?
The Sun
Apollo, god of the sun and Greek restaurants