Science 10th grade
LEARNING UNIT
What is everything around us
made from?
S/K
Language
Socio cultural context of
the LO
Curricular axis
Standard competencies
Background Knowledge
English Review topic
Vocabulary box
LEARNING OBJECT
How does energy flow in
ecosystems?
•
Describe
systems
ecosystems
as
open
•
Identify ecosystems’ main source of energy
•
Identify the mechanisms
by
transferred in an ecosystem.
•
Differentiate
ecosystems’ biotic components
according to the source of energy they use.
•
Compare
aquatic
productivity.
•
Relate an ecosystem’s
resilience capacity.
and
thermodynamic
which
land
renewal
energy
is
ecosystems’
rate
with
its
English
Colombia
Living Environment
Explain the relationship between matter and energy
in food chains.
General knowledge of ecology, biotic and abiotic
systems, energy and thermodynamics.
Difference between ‘such as’ and ‘like’.
Cassava: Known as ‘yuca’ in Spanish, cassava is a
woody shrub native to South America of the spurge
family, Euphorbiaceae. It is extensively cultivated as
an annual crop in tropical and subtropical regions for
its edible starchy tuberous root, a major source of
carbohydrates.
Retrieved from Wikipedia.
Plankton: are a diverse group of organisms that live
in the water column of large bodies of water and that
cannot swim against a current.[1] They provide a
crucial source of food to many large aquatic
organisms, such as fish and whales.
Retrieved from Wikipedia.
Matter: Atoms and molecules are all composed of
matter. Matter is anything that has mass and takes up
space. If you are new to the idea of mass, it is the
amount of stuff in an object.
NAME: ____________________________________________________
GRADE: ___________________________________________________
INTRODUCTION
When visiting different places such as the beach, the jungle, a moor or a desert, it is
possible to notice how different they are from each other.
The scenarios above have specialized weather conditions with their own fauna and
flora. Due to their own specific features, those places are called ecosystems.
Ecosystems home different populations (animals, plants, and microscopic beings) that
live together and relate to each other and to the abiotic elements or their environment.
Energy travels from the main luminous source in our solar system, the sun, to the
Earth, to be transformed into chemical energy through photosynthesis.
Figure 1. Shows the basics of photosynthesis, in which the solar energy is converted into
chemical energy due to substrates such as CO2 and water. Plants generate their own carbon
compounds and then releases oxygen to the environment. Retrieved from:
http://www.dreamstime.com/free-photos-images/photosynthesis.html
Then, said energy flows in an ecosystem to transform again through food or trophic
chains.
Energy flows more in some ecosystems, making them more productive and fostering
relations among their members. Due to these interrelations, many ecosystems can
endure disturbances and then go back to their initial setting.
OBJECTIVES
ü To identify energy sources in several ecosystems and how they can be transformed.
ü To appreciate the importance of energy and how it influences ecosystems.
ü To compare the rate of energy of aquatic and terrestrial ecosystems and how it can
vary depending on the factors related to said ecosystems.
ü To understand what energy is and how it can be transformed in any type of
ecosystem.
ACTIVITY 1
SKILL 1: Describe ecosystems as open thermodynamic systems
SKILL 2: Identify ecosystems’ main source of energy
OPEN SYSTEMS AND ENERGY SOURCES
Introduction
When watching a documentary on how a jaguar hunts a turtle, for instance, what you see
in the background is the place where these species live surrounded by natural elements
that interact and are related among them (an ecosystem).
Ecosystems can be open or closed systems. Open ecosystems are all the natural
systems where matter and energy flow (they come in, flow, and then go out) among
the beings forming it (Figure 2) and its abiotic factors.
Closed systems are artificial; otherwise, energy could not flow and transform within
those systems.
Figure 2. Shows an open system, in which the border can be represented as the Earth’s
atmosphere that allows energy and matter to come in and out. (Image retrieved from
mechteacher.com, 2016. Retrieved from: http://mechteacher.com/thermodynamicsystem/)
The Earth depends on solar energy and its transformation through photosynthesis
(from luminous energy to chemical energy). After that, chemical energy is harnessed by
all the beings (through feeding) that return and release consumed energy in the form
of heat.
Living beings are open systems and depend on solar energy as their main source. All
living beings need energy and, on its part, energy depends on constant flow,
having its origin in the sun. In other words, ecosystems’ main source of energy is the
sunlight, which is later transformed.
Solar energy arrives in the Earth in the form of light and heat to be harnessed in
photosynthesis and regulate the temperature in our planet.
The first law of conservation of energy (first law of states that: “energy can be
transformed from one form to another, but cannot be created or destroyed”. However,
the flow and transformation of energy is not always evident in an ecosystem, since
most of the reactions are invisible to the eye. Said reactions take place at molecular
level in cellular organelles: chloroplasts in plants (photosynthesis) and mitochondria in
animals (oxidative metabolism).
Exercise 1
The purpose of the following activity is to identify if students understand the concept of
open and closed systems occurring in nature. Please use it with the purpose of
implementing Skill 2.
Instructions:
1. Conduct a survey with your classmates: Ask at least five of them to answer the
following two questions and to provide you with an example:
ü What do you understand by open system? Give an example.
ü What do you understand by closed system? Give an example.
2. In your notebook, write the answers of five of your classmates.
3. Organize the results and share them with the class: To do so, briefly read out the
answers given by your partners.
4. You can use words such as matter, energy, heat, and photosynthesis, that may
help you understand said biological systems.
Did you know that…?
ü The sun is 330,330 time bigger than the Earth.
ü It would take 20 years to reach the sun on a plane at 644 Km/h from the Earth.
Thanks to the transformation of energy, all the living beings are able to use it in their
life process. It is to say that living beings obtain energy from the environment
surrounding them and transform them in work to make their basic functions and satisfy
their own needs in that way. The rest of the energy that is not used is transformed in
heat that dissipates in the ecosystem and flows within the ecosystem and out of the
Earth back to the universe.
Exercise 1
This activity allows the identification and conceptualization of the most important terms
related to the flow of energy through ecosystems so that you can implement the Skills
specified for this unit and you can widen your specific knowledge.
Instructions:
1. Make a word search that includes the following words about ecosystems. Choose
five of the words and find out more about them:
Species
Heat
Population
Energy
Community
Chloroplast
Ecosystem
Sun
Abiotic
Thermodynamics
Biotic
System
Photosynthesis
Mitochondrion
2. Remember to put the words to be found under the word search as well as those that
are familiar to you. Once you have your word search ready, share it with your partners
so that they can solve it.
3. At the end, share with your partners the meaning of the five words that you have
previously chosen.
Help: to make your word search, place the words in any order from right to left or from
the top to the bottom, as you prefer.
Conclusion
Through the activities above, it has been revealed the importance of the open systems
in nature and how they are clearly represented in ecosystems (the settings where
energy enters, flows, and leaves). All systems are open and they completely depend on
their main energy source: the sunlight.
ACTIVITY 2
SKILL 3: Identify the mechanisms by which energy is transferred in an ecosystem.
SKILL 4: Differentiate ecosystems’ biotic components according to the source of
energy they use.
ENERGY TRANSFER AND BIOTIC COMPONENTS
Introduction
In a day in the country, you can see the light, feel the air and heat, and see animals
having vegetables, in addition to other unnoticed events. This is the result of the
energy flowing through such ecosystem.
Energy enters ecosystems through the sun to be transformed and taken to all the
species therein. Energy flows in an ecosystem throughout four components: producers
(plants), primary consumers (herbivores), secondary and tertiary consumers
(carnivorous) and decomposers (microorganisms) (Figure 4).
Said components exchange energy and materials within the system they live. Part of
said energy is accumulated or leaves the ecosystem (heat).
Figure 4. Shows a food chain and its basic components: Producer, primary,
secondary, and tertiary consumers, and decomposers (Image retrieved from
openwindowlearning.com, 2016. Retrieved from:
http://www.openwindowlearning.com/topic/food-chains/)
Producers, when catching part of the light can reflect, transfer, lose, or absorb it to
generate photosynthesis (transformation of luminous energy in chemical energy). Part
of said energy is transferred to primary consumers (feeding), and the energy that is not
used is eliminated (excrement).
Secondary and tertiary consumers consume energy in lower quantities as in each stage of
the food chain energy is lost in the form of heat. Since energy is more dispersed for
them, they make more efforts to obtain it.
Decomposers (bacteria and fungi) are in charge of harnessing the remaining energy,
and with it, plants will use it again to form its compounds, and start a new cycle.
Finally, the elements of an ecosystem are classified mainly in biotic and abiotic (Figure
5).
Figure 5. Shows the corresponding classification of an ecosystem’s components: biotic factors
(living) and abiotic factors (inert) (Image retrieved from Quora, 2015.
Retrieved from: https://www.quora.com/What-is-the-difference-between-biotic-and- abiotic)
Did you know that…?
Herbivore populations depend on the abundance of vegetables and carnivorous
populations, on their part, depend on herbivores. However, carnivorous regulate the
amount of vegetal material available in an ecosystem by hunting herbivores
In ecosystems, energy management is linked to the proper flow of energy therein.
Ecosystems have trophic levels, which are the levels whereby energy flows. Plants are
the basis of said levels as they are in charge of supplying energy to the whole ecosystem.
In the Amazon region, it is possible to see large pasture areas and/or cassava crops
where livestock (that damage this ecosystem) have been in increase in the past years.
Said pasture regions or cassava crops are classified as primary producers due to the
photosynthetic action of the sun. On its part, livestock is considered as the primary
consumer (or herbivore) since it feeds from it.
Jaguars are an active part of said ecosystem since it is the most representative predator
of the Amazon region, and it is considered as a secondary consumer as it gets really
close to the crops and pastures to hunt cows. Vultures, tertiary consumers, eat the rest
of the cow pieces left behind by jaguars.
Finally, the smallest leftovers, blood, and any other microscopic components are
decomposed by bacteria and fungi (decomposers) to finish the energy transformation
cycle. Therefore, they are actors in charge of fixing most needed elements (nutrients) by
plants to start the cycle over again.
At the same time, abiotic factors are the indirect basis for such energy relations to
prevail through biotic factors.
Exercise 1
By developing this activity, the contents proposed in this unit can be complemented.
Instructions:
1. In pairs, draw in your notebooks the following elements:
Eagle
Sol
Corn plant
Mouse
Microorganisms
Snake
2. Make a trophic chain with the drawings you made, and identify the consumers
(primary, secondary, and tertiary). Start with the energy produced by the sun. Do not
forget to include decomposers in your food chain.
3. Share your designs and trophic chains with your classmates.
Conclusion
All the species in an ecosystem generate relationships among them. The larger the
number of interactions, the better the ecosystem. Therefore, each of the species of a
system have their own energy transformation mechanisms, although all of them depend
on energy. Each component of the ecosystem has a role in the transformation of
energy, either by storing it or generating heat, because of the energy they can
consume or release to the environment.
ACTIVITY 3
SKILL 5: Compare aquatic and land ecosystems’ productivity.
SKILL 6: Relate an ecosystem’s renewal rate with its resilience capacity.
PRODUCTIVITY AND RENEWAL RATE OF ECOSYSTEMS
Introduction
There are several differences between a river and the jungle (Amazon region, for
instance) since it is possible to identify a higher number of species, both plants and
animals, in a terrestrial ecosystem. In contrast, an aquatic ecosystem does not offer a
high, specific productivity.
Most of our planet is water and one might think most of the productivity lies there, but
that is not the case as no much nutrients are available in aquatic systems. Terrestrial
ecosystems have a larger flow of nutrients, light, and oxygen, and that is why their
productivity is higher (Figure 6).
Figure 6. Shows the biotic components of terrestrial and aquatic ecosystems, as well as the
trophic, related chains of each system (Image retrieved from Gloobal.net., 2016. Retrieved
from:
http://www.gloobal.net/iepala/gloobal/fichas/ficha.php?entidad=Textos&id=1548&opci
on=documento).
After a fire wipes the fauna and flora of a forest, ecosystems are damaged and they
must recover (resilience).
The equilibrium was then affected and the existing interactions between biotic and
abiotic means were altered. Therefore, ecosystems use resilience (or the capacity to
recover) against possible disturbances (Figure 7).
Figure 7. Shows a clear example of resilience, where a plant grows in the middle of a road
(Image retrieved from Urbanismo y Transporte, 2015. Retrieved
from:http://urbanismoytransporte.com/ciudades-resilientes-un-nuevo-enfoque-para- lasostenibilidad-urbana/)
The more interactions related to an ecosystem, the faster resilience takes place. The
recovery of an ecosystem starts by a succession (natural process) of changes whereby
plants and animals take their place in sequence over time.
Later, succession will promote the arrival of the original species, over time, and the
objective is to establish the altered order and restore the equilibrium of the ecosystem
(Figure 8).
Figure 8. Shows an event known as ecological succession, in which recovery takes place by
stages until the ecosystem is completely restored (Image retrieved from Pertuz, 2012. Retrieved
from: http://sucesioneseco.blogspot.com.co/).
Exercise 1
Ecosystems are characterized by the fact they can produce biomass (amount of living
matter an individual or ecosystem can produce), that can be produced in several
quantities (depending on the type of ecosystem and their level of equilibrium). A good
example of biomass is the Amazon region, or even a small crop, where a huge
abundance of biomass and vegetal material is evident.
Therefore, in case of an event that affects the ecosystem (for example, a massive
clearing of trees), said system tends to recover, although it will take a long time before
it fully recovers. Then, the term ‘renewal rate of an ecosystem’, which is the relation
between its production and the biomass of said system
For instance, when the mountains around Bogotá catch fire, there is a disturbance
event that alters the ecosystem and the location where the fire takes place is evident. It
will take time before the ecosystem recovers, but it will happen and the mountains will
be green again, and many of the animal and plant species will also return.
This activity attempts to boost the concept of productivity of an ecosystem based on a
reading. For the activity to be successful, it is necessary to have read the whole
contents of the unit as well as the examples and visual aids proposed.
Instructions:
1. In pairs, read the following (Datateca.unad.edu.co., 2016). Productividad de los
Ecosistemas (Ecosystems’ Productivity): Retrieved from: Datateca.unad.edu.co.,
2016:
http://datateca.unad.edu.co/contenidos/102021/AntiguasVersiones/cont
enidolinea/productividad_de_los_ecosystems.html Read only the text in the first
tab of the title “Productividad de los Ecosistemas (Ecosystems’ Productivity)”
2. Once read and understood, identify the main idea and write it in your notebooks.
To do so, write only three lines and use the following words: comparison,
relation, and productivity. All of them are common when talking about
ecosystems.
3. Once the paragraph is written, choose a representative to read it out in class.
Help: A terrestrial ecosystem has much more productivity than an aquatic one.
Did you Know that…?
The plankton in the oceans produce 75% of the oxygen we breath, and absorbs 25% of
the carbon dioxide released to the atmosphere.
Conclusion
The flow of energy in an ecosystem is key and final for the members of said
ecosystem. If any of the members is missing, the system fails and the ecosystem gets
unbalanced. Therefore, it is important to allow ecosystems to recover themselves, even
though it takes longer.
Even though, there are mechanisms that may help the succession process to run faster
by intervening the system by planting some of the original species. In that way, the
system can recover its equilibrium faster and the fauna once inhabiting it returns.
ABSTRACT
Ecosystems are settings characterized by having specific weather conditions, as well as
specific fauna and flora. Several populations inhabit them as they relate to each other
and to the abiotic elements around them.
Ecosystems are considered to be open systems. There is nothing in nature that is
closed and life is only possible in open systems.
Energy enters, flows, is transformed throughout the ecosystems, and among all the
members therein. Living beings are open systems and depend on solar energy as their
main source.
Energy flows in an ecosystem throughout four components: producers (plants),
primary consumers (herbivores), secondary and tertiary consumers (carnivorous), and
decomposers (microorganisms).
Producers are the basis of trophic chains as they transform luminous energy in
chemical energy through photosynthesis.
The elements of an ecosystem are classified in biotic (living) and abiotic (inert)
Aquatic ecosystems are characterized by having a lower production rate in comparison
to terrestrial ecosystems, since they have a lower availability of nutrients.
An ecosystem can recover through resilience (or the capacity to recover) against the
several events that affects it. Then, succession events take place until the ecosystem is
fully recovered.
HOMEWORK
To do homework, students must use the contents and concepts studied throughout unit
2, implementing Skills 3 and 4. If necessary, clarify concepts with your teacher or do all
the activities of the unit.
Instructions:
1. Form groups of five students.
2. Each group must record a video-clip, no longer than five minutes, using a cellphone,
a tablet or a video camera.
3. The contents in the video must be narrated.
4. In the video, explain in a creative way, situations to show the entrance, flow, and
release of energy in an ecosystem (e.g., represent a trophic chain).
5. Once you have recorded your video, upload it to YouTube to show it to your class.
Students may also use the following links for reference:
Cadenas Alimenticias en la Naturaleza (Trophic Chains in Nature):
from:http://aula-abiertabormujos.wikispaces.com/file/view/Cadenas+alimenticias+(clase+2).pdf
Cadena Alimenticia (Trophic Chain): Retrieved
http://www.ecologiahoy.com/cadena-alimenticia
from:
Retrieved
Ecologiahoy.com.
(2016):
Transferencia de Energía en los Ecosistemas (Energy Transfer in Ecosystems):
Retrieved
from:
Quimi-ciencias
SismayG
(2016):
https://www.youtube.com/watch?v=FV0eL2Hgt3o
BIBLIOGRAPHY
Areaciencias.com. (2016). Fotosíntesis en las Plantas. Explicado Fácilmente:
http://www.areaciencias.com/VIDEOS%20YOUTUBE/la%20fotosintesis.htm [Retrieved
on March 25, 2016].
Burgos, G., Sevilla, L. (2008). Ecología y Salud. Tercera Edición. México. McGraw-Hill
Interamericana.
Datateca.unad.edu.co. (2016). Productividad de los Ecosistemas (Ecosystems’
Productivity):
http://datateca.unad.edu.co/contenidos/102021/AntiguasVersiones/contenidoli
nea/productividad_de_los_ecosystems.html [Retrieved on March 22, 2016].
Ecologiahoy.com.
(2016).
Cadena
Alimenticia
(Trophic
Chain):
http://www.ecologiahoy.com/cadena-alimenticia [Retrieved on March 22, 2016].
Gloobal.net. (2016). Gloobal - Guía de conocimiento sobre desarrollo sostenible:
http://www.gloobal.net/iepala/gloobal/fichas/ficha.php?entidad=Textos&id=15
48&opcion=documento [Retrieved on March 20, 2016].
Martínez, C. (2016). Cadenas alimentarias en la naturaleza: http://aula-abiertabormujos.wikispaces.com/file/view/Cadenas+alimenticias+(clase+2).pdf [Retrieved on
March 29, 2016].
Pertuz,
J.
(2012).
Sucesiones
ecológicas:
http://sucesioneseco.blogspot.com.co/ [Retrieved on March 20, 2016].
Quimi-ciencias SismayG. (2016). Transferencia de Energía en los Ecosistemas (Energy
Transfer
in
Ecosystems):
https://www.youtube.com/watch?v=FV0eL2Hgt3o [Retrieved on March 26, 2016].
Tideca.net.
(2016).
CASO
REAL
N°
1
|
Tideca:
http://www.tideca.net/content/caso-real-01 [Retrieved on March 12, 2016].
Transformaciones Educativas del Medio Ambiente. (2010). FACTORES BIOTICS Y
ABIOTICS
DEL
MEDIO
AMBIENTE:
https://licenciadascnambientalistas.wordpress.com/contenidos/ [Retrieved on March
20, 2016].
Urbanismo y Transporte. (2015). Ciudades resilientes: un nuevo enfoque para la
sostenibilidad urbana: http://urbanismoytransporte.com/ciudades- resilientes-unnuevo-enfoque-para-la-sostenibilidad-urbana/ [Retrieved on March 20, 2016].
Web.educastur.princast.es.
(2016).
La
vida
en
acción:
http://web.educastur.princast.es/proyectos/formadultos/unidades/la_vida_en_
accion/ud2/3_2.html [Retrieved on March 12, 2016].
GLOSSARY
Autotroph: Organism that can produce its own energy.
Biomass: Quantity of matter of an individual or an ecosystem.
Trophic Chain: Representative system of the flow of energy in an ecosystem.
Constituted by producers, consumers, and decomposers.
Carnivorous: Individual that obtains its energy exclusively from the meat of other
individual in an ecosystem.
Biogeochemical Cycle: Cycle of the most representative chemical elements of the
planet (nitrogen, carbon, phosphorus, sulphur, oxygen).
Primary Consumer: Individuals that exclusively eat plants.
Secondary Consumer: Individuals that exclusively eat plants and animals
(omnivores).
Tertiary Consumer: Exclusively carnivorous individuals.
Decomposers: Microorganisms such as bacteria and fungi that decompose organic
matter.
Photosynthesis: Process to transform luminous energy in chemical energy,
exclusively performed by plants and some green algae.
Herbivorous: Individual that eats plants only.
Heterotroph: Organism that cannot produce its own energy.
Trophic Level: Category in which certain individuals can be classified as they perform
a key role during the flow of energy.
Producer: Individuals characterized by being the basis of the trophic chains in nature,
such as plants.
EVALUATION
To develop this evaluation, you must have prior studied this whole Learning Object, so
that you show how much you learnt along the three units worked so far. Otherwise,
review all the activities and do the corresponding homework.
Instructions:
The following evaluation will test the students’ performance on the contents through 10
easy questions. This evaluation is subdivided in different types of questions: true or
false, correct answer, and matching.
To take this evaluation you need to understand the whole Learning Object.
I. CHOOSE FALSE (F) OR TRUE (T):
1. Ecosystems are specifically considered Opens Systems:
A. True
B. False
2. Energy flows through an ecosystem according to the following components:
producers, primary, secondary, and tertiary consumers, and decomposers.
A. True
B. False
3. The main energy source of our planet is Photosynthesis:
A. True
B. False
4. Energy can be created but cannot be destroyed when it is captured by
decomposers:
A. True
B. False
II. CHOOSE THE RIGHT OPTION.
5. Process by which luminous energy is transformed in chemical energy:
A. Respiration
B. Krebs Cycle
C. Phosphorylation
D. Photosynthesis
6. From the following, which is not an abiotic element:
A. Water
B. Air
C. Virus
D. Heat
7. Which of the following ecosystems is the least productive:
A. Forests
B. Jungles
C. Moors
D. Rivers
III. MATCH THE COLUMNS AS CORRESPONDS.
A. Chloroplasts
Bird ( )
B. Resilience
Photosynthesis ( )
C. Heterotrophs
Reparation ( )