chapter 5 Grade 7 Even Semester

1. ECOSYSTEM
Created by Alfi_MSK, a Biology teacher of GIS JH

2. What is ecosystem?
• Ecosystem is interaction between
organism or indivuals and the abiotic
environment.
Created by Alfi_MSK, a Biology teacher of
GIS JH

3. According to the process of its
establishment, there are 2 types of
ecosystem ;
1. Natural ecosystem
made by nature
ex. Forest, oceans, lakes, swamps, etc
2. Artificial ecosystem
made by human
ex. Rice fields, aquarium, etc
Created by Alfi_MSK, a Biology teacher of
GIS JH

4. 2 kinds of ecosystem components
1. The biotic components
consist of all organism such as plants,
animals, and microorganisms
grouped into 3 kinds ; producers,
consumers, decomposers
2. The abiotic components
consist of physical or non-living factors
ex. Sunlight, air, water, temperature, etc
Created by Alfi_MSK, a Biology teacher of
GIS JH

5. Producers
• Producers are organisms that produce food
for both themselves and other organisms
• Producers are all plants and photosynthetic
organisms, because they can
photosynthesize
• During the photosynthesis, H₂O and CO₂
are converted into C₆H₁₂O₆ and O₂
• Due to their ability to manufacture their
own food, plants are called autotroph
organism Created by Alfi_MSK, a Biology teacher of
GIS JH

6. Consumers
• Consumers are organisms that eat other organisms,
because they can’t manufacture their own food
• Consumers are categorized into primary consumer,
secondary consumer, tertiary consumer, etc
• The primary consumers directly eat the producers
• The organisms that indirectly depend on producers
and eat other consumers are called secondary and
tertiary consumers
• Base on their foods, animals in ecosystem are
categorized into 3 groups namely herbivore,
carnivore, and omnivore a Biology teacher of
Created by Alfi_MSK,
GIS JH

7. Decomposers
• Decomposers are organisms that decompose
organic materials of dead organism into
inorganic ones
• The inorganic materials resulted from this
process fertilize the land since they are rich
of nutrients necessary for the soil
• The decomposers include bacteria and fungi
• If there were no decomposers, the earth
would be full of stocks of garbage and
remnants of organisms
Created by Alfi_MSK, a Biology teacher of GIS JH

8. Sunlight
• Sunlight is the main source of energy for all
organisms on earth
• H₂O and CO₂ are transformed into C₆H₁₂O₆
and O₂ during photosynthesis by using
sunlight
Created by Alfi_MSK, a Biology teacher of
GIS JH

9. Air
• Air is composed of different types of gases such
as oxygen, hydrogen, carbon dioxide, and
nitrogen
• All organisms need air for their activities, for
ex. Oxygen is required during the respiration
that oxides (burn) carbohydrate to generate
energy
• Plants use carbon dioxide as the raw material
to produce carbohydrate and nitrogen to
produce protein
Created by Alfi_MSK, a Biology teacher of
GIS JH

10. Water
• All organisms on earth need water to survive
• Plants will dehydrate and die if they lack of
water
• In human body, water functions as dissolver
dissolving all the materials eaten by organisms
• Water is also a habitat for fish and frogs
Created by Alfi_MSK, a Biology teacher of GIS
JH

11. Temperature
• Temperature is one of important
components for the organisms to survive on
earth
• Each organism needs a certain range of
temperature to survive
• Therefore, plants living in hot area as cactus
will die or grow poorly if they are planted in
cold area and vice-versa
Created by Alfi_MSK, a Biology teacher of
GIS JH

12. Interaction between abiotic and biotic components
• All organisms on earth need water for their survivals
• The water on earth will form a water cycle
• On a clear day, seawater evaporates and forms a mass of
condensed water in the atmosphere
• The condensed water form clouds which also condense and
result in rain
• The rain-water is absorbed by the soil
• Then, the water accumulates into water springs and flows to the
rivers and ends up in seas
• This process is called water cycle
Created by Alfi_MSK, a Biology teacher of GIS JH

13. Water Cycle
Created by Alfi_MSK, a Biology teacher of
GIS JH

14. Carbon Cycle
Created by Alfi_MSK, a Biology teacher of
GIS JH

15. Interactions within biotic components
• The interaction within biotic components in the ecosystem can
be seen in the rank of food consumption in the organism, which
is called food chain
• For ex. the plants are eaten by the herbivores, then the
herbivores are eaten by the 1st carnivores which are finally eaten
by other carnivores
• In the end, all producers and consumers will die and they will be
decomposed by the decomposers
• The plants will use the decomposed materials as nutrients for
their growth
• If an ecosystem has several related food chains, those food
chains will form food web
Created by Alfi_MSK, a Biology teacher of GIS JH

16.  in food web, one consumer can have more
than one role, for example the role as a first
level consumer and also as a second level
consumer.
 in food chain, energy in food can be
tranferred from one organism to another, but
the energy tranferred is only a small amount.
 in food chain, some of the energy is utilized
for growth, some is excreted as residue, and
some is released as heat.
 Only 10% of energy is stored inside the body
of an organism.
Created by Alfi_MSK, a Biology teacher of GIS JH

17.  This one tenth energy is available for the organism
which becomes a predator.
 The 90% reduction of energy at every trophic level
is the answer to the question “why are there more
plants compared to herbivores, and more
herbivores compared to carnivores?”
 in other words, in order for a food chain to last,
the number of producers have to be higher than
the number of 1st level consumers, the number of
1st consumers have to be higher than the 2nd
consumers, and so on.
Created by Alfi_MSK, a Biology teacher of GIS JH

18. Food Chain
Created by Alfi_MSK, a Biology teacher of
GIS JH

19. Food Web
Created by Alfi_MSK, a Biology teacher of
GIS JH

20. Food Pyramid
Created by Alfi_MSK, a Biology teacher of
GIS JH

21. The interaction within biotic components can
occur in several form
A. Symbiosis
symbiosis is a close relation between 2 different types of
organisms.
symbiosis classified into;
1. Mutualism is an association that benefits all the
participants.
ex. An association between the wasp and flower
2. Commensalism is an association of organisms of different
types where one organisms gains benefit without causing
loss to the other.
ex. An association between sharks and remora fish
3. Parasitism is an association between 2 organisms of
different species where one organism gains benefit and the
other suffers losses.
ex. An association between bacteria and the human body
Created by Alfi_MSK, a Biology teacher of
GIS JH

22. Mutualism Symbiosis Commensalism Symbiosis
Created by Alfi_MSK, a Biology teacher of
GIS JH

23. Parasitism Symbiosis
Created by Alfi_MSK, a Biology teacher of
GIS JH

24. B. Competition
organisms in an ecosystem compete with each
other to gain things they need to survive.
ex. The competition between zebra, horse, buffalo,
and deer to obtain grass in savannah ecosystem
C. Predation
predation is an association between the eater and
the eaten.
ex. The association between deer and lion
D. Antibiotic
antibiotic is an association of 2 organisms where
one organism resists the growth of the other one.
ex. The association between penicillium notatum
and pathogenic bacteria
Created by Alfi_MSK, a Biology teacher of
GIS JH

25. Competition Predation
Created by Alfi_MSK, a Biology teacher of
GIS JH

26. Anti biosis Netral
Created by Alfi_MSK, a Biology teacher of
GIS JH

27. Material Cycle and Energy Flow
• Material Cycle
 it is a continual cycle of material from abiotic component
to biotic one and then back to the biotic one.
 Material cycle starts from abiotic component, for ex. the
water and mineral cycles
 On land ecosystem, matrials such as water and mineral
from the ground go through plant body, then the plants
transform the water and the minerals into different
substances such as glucose, protein, and fat, which is
consumed by herbivores
 to biotic component by Alfi_MSK, athen going back to abiotic
Created
and Biology teacher of
components GIS JH

28. Then the herbivores are eaten by the carnivores.
Finally , the plants, herbivores, and carnivores
are decomposed by the decomposers.
The materials in those bodies are transformed
into water and nutrients which then return to
the soils.
The materials will keep cycling from abiotic
component
Created by Alfi_MSK, a Biology teacher of
GIS JH

29. • Energy Flow
 In nature the energy flows from the outside of the ecosystem
into the ecosystem and then exits from the ecosystem.
 Energy flow starts from outside, for example from the sun
energy
 The source of energy on the Earth is the Sun. It enters the
ecosystem through the plants.
 The plants capture sunlight energy and convert it into
chemical energy.
 Chemical energy from the plant flows into the body of
herbivores in the forms of food such as leaves, fruits, and
seeds.
Created by Alfi_MSK, a Biology teacher of
GIS JH

30.  where do living organisms obtain their energy to live from?
 Through photosynthesis, green plants use energy from sunlight
to produce energy stored in the form of food or nutrients.
 if plants are eaten by 1st consumers, the energy stored within
the plants is transferred into the 1st level consumers.
 furthermore, if 1st level consumers have been eaten by 2nd level
consumers, energy from 1st consumer is transferred into the
bodies of 2nd level consumers, and so on.
 this phenomenon is called a transfer of energy.
Created by Alfi_MSK, a Biology teacher of GIS JH

31.  Chemical energy in herbivores flows to the body of
carnivores in the form of food such as meat.
 The chemical energy in the plants, herbivores, and
carnivores then flow into the microorganisms.
 Beside flowing from one organism to other organisms, some
energy is transformed into heat that in the end exits from
the ecosystem.
 Each level of the energy flow in an ecosystem is called
trophic level.
 The producers are in the 1st trophic level, the herbivores are
in the 2nd trophic level, the carnivores eating herbivores are
in the 3rd trophic level, and the carnivores eating other
carnivores are in the 4th trophic level.
Created by Alfi_MSK, a Biology teacher of
GIS JH

32. You can download this slide on
http://www.slideshare.net/alfikesturi
Or on
http://www.authorstream.com/kesturi
Created by Alfi_MSK, a Biology teacher of
GIS JH