The document discusses key concepts in ecosystems including biotic and abiotic factors, producers, consumers, decomposers, food chains, food webs, energy transfer between trophic levels, and nutrient cycling. It also describes how human activities like deforestation, pollution, overfishing, and misuse of fertilizers and insecticides can negatively impact ecosystems. Maintaining clean environments, sustainably managing resources, and protecting wildlife are identified as important ways to conserve the natural world.

1. ECOSYSTEM
LESSON 15

2. CONTENT STANDARDS
2

3. LEVELS of
INTERACTIONS
01 02
03 04
SCENARIOS:
Imagine you are stranded on an island
where there is a snall cornfield and 50
chickens. You are not sure when you
will be rescued. Remember, you need
to stay alive until rescue arrived.
3

4. What should I eat to stay alive for
a longer period?
4
Eat the corn first, then eat the chicken Eat the chicken first, then eat the corn
Pros: Pros:
Cons: Cons:
OPTIONS
OPTION 2
OPTION 1

5. 5
ECOSYSTEM
-Is an ecological formed by the
interaction of living organisms and their
non-living environment in a particular
area.
-- It comprises biotic (living) and abiotic
(non-living) factors that an organisms
interacts with in its habitat.

6. BIOTIC FACTORS
- Composes all the organisms
6
ABIOTIC FACTORS
- Are physical and chemical features
such as light, temperature, water, type
of soil, oxygen content and others

7. HABITAT
Is the place where organism lives
such as pond , a stream, a river
, a forest or a desert.

8. 8
- It is the same species living in
a particular area make up a
population.
Group of Organisms

9. How do energy and
nutrients flow through an
ecosystem?
9
Organisms compromise the
producers, consumers, and
decomposers. Energy and nutrients
are transferred from producers to
consumers to decomposer through
feeding.

10. 10
PRODUCERS
They can make or produce
food to provide energy an
oxygen for the living
organisms.

11. CONSUMERS
11
Obtain their energy by feeding on other organisms
as we discussed in biodiversity. All animals are
consumers. Herbivores or the plant –eaters feed
directly on plant also known as primary
consumers. Meat-eaters or carnivores feed on
other animals, hence they are known as
secondary consumers. Carnivores that feed on
other carnivores are called tertiary consumers.

12. DECOMPOSERS
12
Obtain energy by breaking down dead
organisms, feces and other excretory
products. The broken down materials
such as carbon and nitrogen
compounds return to the environment
and used again by plants.

13. FOOD CHAIN
13
13
Is a series of eaten-eater relationship in
which energy is transferred.

14. Food WEB
15.3
Is made up of two or
more overlapping food
chains that are linked
together.

15. FOOD WEB
15

16. Why are short food
chains more efficient
in energy transfer?

17. A shorter food chain means more
energy is available to the final
consumer because less energy is
lost to the environment. For instance,
more energy will be available to a
man if he feeds directly on crop
plants grown in a given area, rather
than eating the meat of the cattle
that feed on his crop. 17

18. 15.4 PYRAMID ENERGY
18
In food web, eenrgy is lost when one
organisms eats another. The transfer of
energy and biomass in food from one
trophic level to an other is not one
hundred percent used. Biomass- is the
total mass of organisms in a food cahin
or food web.

20. In a typical terrestrial
ecosystem, the greatest
biomass is the producers. There
is a progressive decrease of
biomass from lower (base) to
higher trophic levels. Thus, the
pyramid of biomass is upright.
20
20

21. 21
Web design principles
Mars is actually a very
cold place
Mercury is the closest
planet to the Sun
Venus is the second
planet from the Sun
Neptune is very far away
from us
White space
Jupiter is the biggest
planet of them all
Saturn is a gas giant and
has rings
Movement Unity

22. 22
The first source of energy is the sun.
The 10% Rule describes how energy is
lost when it is passed in an ecosystem
from one trophic level to the next.
Roughly, only ten percent of energy
will be passed on. Energy that is lost
as heat cannot be recycled. Hence,
energy (in the form of light energy) has
to be constantly supplied through the
producers.

23. 15.5 NUTRIENT CYCLING IN
AN ECOSYSTEM
23
Nutrient cycle or ecological
recycling is the movement and
exchange of organic and
inorganic materials back into
the production of living matter.

24. Detritivores and decomposers play an
important role in assuring the survival of
producers such as plants, and thus all life, by
recycling nutrients back to them. The process is
regulated by food web pathways that
decompose matter into mineral nutrients.
Nutrients cycles occur within ecosystems.
The nutrient cycle describes the use,
movement and recycling nutrients in the
environment. Important elements like carbon,
oxygen, hydrogen and phosphorus and
nitrogen are essential to life and must be
recycled in order for organisms to exists and
survive. In balanced ecosystem, nutrients are
never lost but are continually recycled.
Nutrients cycles involve living and non-living
components of the environment. We shall now
study some of these cycles to understand the

25. THE CARBON CYCLE
25
CARBON, in the form of CARBON
DIOXIDE, is constantly being
removed from and released into the
environment. Organisms use and
produce gases through various
processes that makes up the carbon
cycle.

26. 1. During the photosynthesis, carbon dioxide
removed by plants from atmosphere to be used in
manufacturing of food, for example, the
carbohydrates-glucose.
2. When animals feed on plants, the carbon
compounds become part of their bodies. These
compounds may also be stored in fossil fuels such
as coal, natural gas and oil.
3. Then, carbon dioxide is released and returned
into environment through respiration, combustion
and decomposition.
26
26

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Mercury is the closest
planet to the Sun
Neptune is the farthest
planet from the Sun
Despite being red, Mars is
a cold place

28. The cycling of water happens around the environment
including the oceans, land, air and living things. It
involves the following events.
1. When sunlight warms the surface of the earth,
water evaporates from the land, lakes rivers and
oceans (evaporations)
2. The escape of water through leaf ( transpiration)
adds water vapor to the atmosphere.
3. Upon cooling at high altitude, water vapor
condenses which forms clouds ( condensation).
4. Eventually, rain or snow forms (precipitation). On
land, water is absorbed by plant roots and replenish
the ground. The excess water finally overflows into
oceans and the water cycle continues.
THE WATER CYCLE
28

29. Extra skills
29
Mercury is the closest planet to the Sun and
the smallest one in the Solar System
Venus has a beautiful name and is the second
planet from the Sun
Coding
Editing
Despite being red, Mars is actually a cold
place. It's full of iron oxide dust
Managing

30. The NITROGEN CYCLE
30
Organisms use nitrogen gas to build proteins and nucleic
acids necessary for life. The cycling of nitrogen happen
whens:
1. Nitrogen-fixing bacteria which can be found in the
nodules of legumes, convert nitrogen to ammonia. This
process is called nitrogen fixation.
2. In the nitrogen cycle, nitrifying bacteria use ammonia,
converting it into nitrate and nitrate by products. These
steps are named ammonification and nitrification. These
bacteria are essential to ecosystem because they bring
nitrogen into the soil for plants to use.

31. 3. Animals consume
plants and return
nitrogen to the soil
through waste products
and upon death,
denitrifying bacteria
return nitrogen to the
atmosphere which is
referred as
denitrification process.
Then the recycle
continues.

32. 15.6 How do we affect the
ecosystem?
32
Human activities must be
carefully monitored to
preserve and conserve the
environment for the future.
Here are some human
activities that affects the
ecosystem.

33. 33
With modern technology,
trees are being cleared at
a faster rate than they can
replaced. This lead to loss
of habitats, wildlife lose
their homes. Effects are
soil erosion, flooding and
climate change.
Deforestation

34. 34
Some method of fishing such as use of
cyanide also destroy seabed and marine
habitat. Eventually some species may
become endangered or even extinct.
Uncontrolled fishing practices

35. Most product of technology are toxic
including factories. These toxic
wastes are collected through air and
water., threatening the lives in the
ecosystem. For examples, chemical
fertilizers containing nitrates and
phosphate are used to increased the
yield of crops. However, the overuse
of these fertilizer may cause water
pollution.
35
POLLUTION

36. 36
Insecticides are used to kill insects. However,
this may end up affecting other organisms
as well. For example, an insecticide named
DDt (dichlorodiphenyltrichloroethane) are
non-biodegradable. This means they
cannot be broke down by microorganisms
like bacteria. DDt is insoluble in water and
is not excreted. This means it accumulate
in the body of the organism which cause
the top consumer to suffer toxic effects in
the long run.
USE of INSECTICIDES

37. USE of FERTILIZER
Uncontrolled use of chemical
fertilizers may increase soil
acidity which can destroy the
soil beneficial structure to
plants. Fertilizers run off to
rivers, ponds and lakes that
may cause the death of these
water gradually.
37

38. Generally to
conserve the
environment,
we should:

39. 39
1. Keep the environment clean
2. Effectively manage the use of
natural resources
3. Protect wildlife

40. 40
40
Taking steps to conserve is a
willful act. Doing our part by
changing daily habits can be
good contribution. Here are
some tips to help save our
environment.

41. 41
1. Try decreasing energy and
water consumption.
2. You may create a compost
heap in your garden or use a
compost bin. This helps recycle
food waste and other
biodegradeable materials.
3. Bring your own eco-bags and
avoid plastic bags as much as
possible.

42. 42
4. Separate biodegradable and
recyclable waste from non-
biodegradable and work to
reduce the amount of non-
biodegradable or recyclable
waste.
5. You may join many tree
planting trips as you can!