Exemplar for internal assessment resource Science for Achievement Standard 90953
Exemplar for Internal Achievement Standard
Science Level 1
This exemplar supports assessment against:
Achievement Standard 90953
Demonstrate understanding of carbon cycling.
An annotated exemplar is an extract of student evidence, with a commentary, to explain key
aspects of the standard. These will assist teachers to make assessment judgements at the
grade boundaries.
New Zealand Qualification Authority
To support internal assessment from 2014
© NZQA 2014
Exemplar for internal assessment resource Science for Achievement Standard 90953
Grade Boundary: Low Excellence
1.
For Excellence, the student needs to demonstrate comprehensive understanding of
carbon cycling. This involves explaining thoroughly links between the addition, removal
and storage of carbon, using information which could include visual representations
and data.
The student has explained comprehensively the addition of carbon (1) and removal of
carbon (2), and explained its short term and long term storage (3) in a forest
ecosystem.
For example, the student has explained that when wood is converted to coal it is buried
away from the weather and is converted to carbon where it remains undisturbed for
millions of years. When coal is burnt it releases the carbon dioxide which enters the
atmosphere again.
For a more secure Excellence, the student could provide more evidence to explain
comprehensively how carbon is stored, long term, in a forest ecosystem.
For example, the student could explain that carbon storage could occur in the
environmental conditions where oxygen levels are low. In those conditions wood can
be converted to lignite and, over a longer period of time, be converted to coal and
stored for millions of years. These long term stores become fossil fuels which humans
may burn and release CO2.
© NZQA 2014
AS 90953
Student 1
Student 1: Low Excellence
The travels of carbon C12 in a forest ecosystem.
Carbon is a finite resource on this planet. There is only so much carbon. This means for life
to continue carbon must be recycled again and again. All the carbon atoms have been used
millions of time in the 4.5 billion year age of the Earth. Carbon is found in the atmosphere
and is added to a biological system, removed from a biological system and is stored in a
biological system both long and short term. This tends to keep the levels of carbon dioxide in
the atmosphere at a constant level. This is essential for life to continue as we know it.
The addition of carbon to a forest ecosystem from the atmosphere.
Carbon occurs in the atmosphere as the gas carbon dioxide. It enters the ecosystem during
the process of photosynthesis where it is initially converted to sugar (glucose) and it then
converted to other key compounds like fats and proteins. This process involves carbon
dioxide being combined with water in the presence of sunlight to make the sugar. This takes
carbon dioxide from the atmosphere and incorporates it into the plant. (1)
The removal of carbon from a forest ecosystem to the atmosphere
Plants can return carbon dioxide to the atmosphere from the ecosystem by the process of
respiration as plants “burn” sugar to release energy. Carbon dioxide is also lost as leaves fall
to the ground in autumn and are decomposed. If people burn wood or there is a forest fire
then carbon dioxide is released directly back into the atmosphere. (2)
The short and long term storage of carbon from a forest ecosystem.
The key method of storing carbon dioxide in plants is to incorporate the carbon into wood
that supports a tree and locks up the carbon short term. This stage can last for 1 year for
annual plants or for thousands of years for mature hard wood forests. This is called short
term storage because the carbon is locked up for the life of a tree and only released on the
death of the tree. Long term storage can also occur where plants when they die don’t decay.
Over time they can be converted to lignite and then coal. The carbon dioxide is only released
on burning. This time period can last millions of years. (3)
Humans are now releasing carbon dioxide from long term stores faster than any time in the
past. This has caused the amount of carbon dioxide in the atmosphere to jump from 280ppm
to 400ppm in 150 years. This will change the Earth’s climate.
Exemplar for internal assessment resource Science for Achievement Standard 90953
Grade Boundary: High Merit
2.
For Merit, the student needs to demonstrate in-depth understanding of carbon cycling.
This involves explaining the addition, removal and storage of carbon, using information
which could include visual representations and data.
The student has explained, in depth, reasons for the addition of carbon (1) and removal
of carbon (2), and explained carbon’s short term storage and long term storage (3) in a
forest ecosystem.
For example, the student has explained that photosynthesis removes carbon dioxide
and this is converted to wood. Wood can last for thousands of years before being
converted back to carbon dioxide. Tree trunks store carbon dioxide as wood, and tie up
the carbon dioxide for thousands of years.
To reach Excellence, the student could provide more evidence to explain in depth how
carbon is stored, long term, in a forest ecosystem.
For example, the student could explain how, in the environmental conditions where
oxygen levels are low, wood can be converted to lignite, and over a longer period of
time be converted to coal and stored for millions of years. These long term stores
become fossil fuels.
© NZQA 2014
AS 90953
Student 2
Student 2: High Merit
The travels of carbon C12 in a forest ecosystem.
Carbon is a finite resource on this planet. There is only so much carbon. This means for life
to continue carbon must be recycled again and again. All the carbon atoms have been used
millions of time in the 4.5 billion year age of the Earth. Carbon is found in the atmosphere
and is added to a biological system, removed from a biological system and is stored in a
biological system. This tends to keep the levels of carbon dioxide in the atmosphere at a
constant level. This is essential for life to continue as we know it.
The addition of carbon to a forest ecosystem from the atmosphere.
Carbon occurs in the atmosphere as the gas carbon dioxide. It enters the ecosystem during
the process of photosynthesis where it is initially converted to sugar (glucose) and it then
converted to other key compounds like fats and proteins. This process involves carbon
dioxide being combined with water in the presence of sunlight to make the sugar. This takes
carbon dioxide from the atmosphere and incorporates it into the plant. (1)
The removal of carbon from a forest ecosystem to the atmosphere
Plants can return carbon dioxide to the atmosphere from the ecosystem by the process of
respiration as plants “burn” sugar to release energy. Carbon dioxide is also lost as leaves fall
to the ground in autumn and are decomposed. If people burn wood or there is a forest fire
then carbon dioxide is released directly back into the atmosphere. (2)
The short and long term storage of carbon from a forest ecosystem.
The key method of storing carbon dioxide in plants is to incorporate the carbon into wood
that supports a tree and locks up the carbon short term. This stage can last for 1 year for
annual plants or for thousands of years for mature hard wood forests. This is called short
term storage because the carbon is locked up for the life of a tree and only released on the
death of the tree. Coal is long term storage. (3)
Humans are now releasing carbon dioxide from long term stores faster than any time in the
past. This has caused the amount of carbon dioxide in the atmosphere to jump from 280ppm
to 400ppm in 150 years. This will change the Earth’s climate.
Exemplar for internal assessment resource Science for Achievement Standard 90953
Grade Boundary: Low Merit
3.
For Merit, the student needs to demonstrate in-depth understanding of carbon cycling.
This involves explaining the addition, removal and storage of carbon, using information
which could include visual representations and data.
The student has explained, in depth, the addition of carbon (1) and removal of carbon
(2), and explained carbon’s short term storage (3) in a forest ecosystem. For example,
the student has explained how photosynthesis removes carbon dioxide and this is
converted to wood. Wood can last thousands of years before being converted back to
carbon dioxide.
For a more secure Merit, the student could provide more evidence to explain in depth
how carbon is stored, both long and short term, in a forest ecosystem. For example,
the student could explain how, in the correct conditions, wood can be converted to
lignite and coal and stored for millions of years. This is long term storage. Burning fossil
fuels release CO2.
© NZQA 2014
AS 90953
Student 3
Student 3: Low Merit
The travels of carbon C12 in a forest ecosystem.
Carbon is a finite resource on this planet. There is only so much carbon. This means for life
to continue carbon must be recycled again and again. All the carbon atoms have been used
millions of time in the 4.5 billion year age of the Earth. Carbon is found in the atmosphere
and is added to a biological system, removed from a biological system and is stored in a
biological system.
The addition of carbon to a forest ecosystem from the atmosphere.
Carbon occurs in the atmosphere as the gas carbon dioxide. It enters the ecosystem during
the process of photosynthesis where it is initially converted to sugar (glucose) and it then
converted to other key compounds like fats and proteins. This process involves carbon
dioxide being combined with water in the presence of sunlight to make the sugar. This takes
carbon dioxide from the atmosphere and incorporates it into the plant. (1)
The removal of carbon from a forest ecosystem to the atmosphere
Plants can return carbon dioxide to the atmosphere from the ecosystem by the process of
respiration as plants “burn” sugar to release energy. If people burn wood or there is a forest
fire then carbon dioxide is released directly back into the atmosphere. (2)
The short and long term storage of carbon from a forest ecosystem.
The key method of storing carbon dioxide in plants is to incorporate the carbon into wood
that supports a tree and locks up the carbon short term. This stage can last for 1 year for
annual plants or for thousands of years for mature hard wood forests. This is called short
term storage because the carbon is locked up for the life of a tree and only released on the
death of the tree. (3)
Humans are now releasing carbon dioxide from long term stores faster than any time in the
past. This has caused the amount of carbon dioxide in the atmosphere to jump from 280ppm
to 400ppm in 150 years. This will change the Earth’s climate.
Exemplar for internal assessment resource Science for Achievement Standard 90953
Grade Boundary: High Achieved
4.
For Achieved, the student needs to demonstrate understanding of carbon cycling. This
involves describing the addition, removal and storage of carbon, using information
which could include visual representations and data.
The student has described the addition of carbon (1) and removal of carbon (2), and its
short term storage (3) in a forest ecosystem. For example the student has described
how carbon can be retained within a tree.
To reach Merit, the student could provide more evidence to explain how carbon is
added, removed and stored, both long and short term, in a forest ecosystem. For
example, the student could identify the correct conditions for wood to be converted to
lignite and coal, and stored for millions of years.
© NZQA 2014
AS 90953
Student 4
Student 4: High Achieved
The travels of carbon C12 in a forest ecosystem.
Carbon is a finite resource on this planet. There is only so much carbon. This means for life
to continue carbon must be recycled again and again. All the carbon atoms have been used
millions of time in the 4.5 billion year age of the Earth. Carbon is found in the atmosphere
and is added to a biological system, removed from a biological system and is stored in a
biological system.
The addition of carbon to a forest ecosystem from the atmosphere.
Carbon occurs in the atmosphere as the gas carbon dioxide. It enters the ecosystem during
the process of photosynthesis where it is initially converted to sugar (glucose) and it then
converted to other key compounds like fats and proteins to build the plant. This process
involves carbon dioxide being combined with water in the presence of sunlight to make the
sugar. (1)
The removal of carbon from a forest ecosystem to the atmosphere
Plants can return carbon dioxide to the atmosphere from the ecosystem by the process of
respiration as plants “burn” sugar to release energy. If people burn wood or there is a forest
fire then carbon dioxide is released directly back into the atmosphere. (2)
The short and long term storage of carbon from a forest ecosystem.
The key method of storing carbon dioxide in plants is to incorporate the carbon into wood
that supports a tree and locks up the carbon short term. This stage can last for 1 year for
annual plants or for thousands of years for mature hard wood forests. This is called storage.
(3)
Humans are now releasing carbon dioxide from long term stores faster than any time in the
past. This has caused the amount of carbon dioxide in the atmosphere to jump from 280ppm
to 400ppm in 150 years. This will change the Earth’s climate.
Exemplar for internal assessment resource Science for Achievement Standard 90953
Grade Boundary: Low Achieved
5.
For Achieved, the student needs to demonstrate an understanding of carbon cycling.
This involves describing the addition, removal and storage of carbon, using information
which could include visual representations and data.
The student has described the addition of carbon (1) and removal of carbon (2) in a
forest ecosystem. Photosynthesis and respiration have been inferred.
For a more secure Achieved, the student could provide more evidence describing how
carbon is stored short term in a forest ecosystem. For example, the student could
explain how a well-established forest can tie up carbon for over a thousand years.
© NZQA 2014
AS 90953
Student 5
Student 5: Low Achieved
The travels of carbon C12 in a forest ecosystem.
Carbon is a finite resource on this planet. There is only so much carbon. This means for life
to continue carbon must be recycled again and again. All the carbon atoms have been used
millions of time in the 4.5 billion year age of the Earth. Carbon is found in the atmosphere
and is added to a biological system and can be removed from a biological system.
The addition of carbon to a forest ecosystem from the atmosphere.
Carbon occurs in the atmosphere as the gas carbon dioxide. It enters the ecosystem during
the process of photosynthesis where it is initially converted to sugar (glucose) and it then
converted to other key compounds like fats and proteins to build the plant. (1)
The removal of carbon from a forest ecosystem to the atmosphere
Plants can return carbon dioxide to the atmosphere from the ecosystem by the process of
respiration as plants “burn” sugar to release energy. If people burn wood or there is a forest
fire then carbon dioxide is released directly back into the atmosphere. (2)
Humans are now releasing carbon dioxide faster than any time in the past. This will change
the Earth’s climate.
Exemplar for internal assessment resource Science for Achievement Standard 90953
Grade Boundary: High Not Achieved
6.
For Achieved, the student needs to demonstrate an understanding of carbon cycling.
This involves describing the addition, removal and storage of carbon, using information
which could include visual representations and data.
The student has described the addition of carbon in a forest system (1). For example,
the description includes how pine trees store carbon as wood, and sugars in their trunk
and leaves.
To reach Achieved, the student could provide more evidence describing how carbon is
added to a forest ecosystem and removed from that same system. For example, the
role of photosynthesis in tying up carbon could be described.
© NZQA 2014
AS 90953
Student 6
The travels of carbon C12 in a forest ecosystem.
Student 6: High Not Achieved
Carbon is a finite resource on this planet. There is only so much carbon. This means for life
to continue carbon must be recycled again and again. All the carbon atoms have been used
millions of time in the 4.5 billion year age of the Earth. Carbon is found in the atmosphere
and is added to a biological system and can be removed from a biological system.
The addition of carbon to a forest ecosystem from the atmosphere.
Carbon occurs in the atmosphere as the gas carbon dioxide. It enters the ecosystem during
the process of photosynthesis where it is initially converted to sugar (glucose) and it then
converted to other key compounds like fats and proteins to build the plant. This stores and
hides carbon from the atmosphere. (1)
Humans are now releasing carbon dioxide from plants faster than any time in the past. This
will cause global warming.