2. iii
Department of Education ● Republic of the Philippines
Science – Grade 10
Alternative Delivery Mode
Quarter 3 – Module 9: Population Explosion: Its Effect to the Environment
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3. Lesson
1 Population Growth: A Reality
If you take a look around, you would surely notice how each person belongs
to a certain group of people or to a particular population. You would also realize that
the number of people living in a certain place can vary; some regions have a dense
population while some have problems with sparse population. These variations can
actually be studied by experts in what they termed as population growth.
What’s New
ACTIVITY 1.1: PUZZLE: FIND ME
Objective: after performing this activity you should be able to:
1. Define Population
2. Describe the impact of population
Direction:
1. Analyze the guide questions and find the answer forming in the puzzle word
Observation questions: You are given a hint of the first letter of the word for your
answer
1. What do you call a group of organisms of the same species that live in a certain
area? P_________
2. What are living things refer to? O _________
What are the uses of plants and animals?
3. F_________
4. M____________
5. I ____________
4. What Is It
POPULATION GROWTH
Why do some populations grow while some tend to
shrink?
A major component of modern ecological research focuses on
understanding what influences the abundance of organisms within a
population, and why this abundance changes over time. A term called population
dynamics refers to how populations of species change over time.
When conditions are ideal for growth and reproduction, a population
will experience a rapid increase in size. Initially the population grows slowly,
but the larger the population gets, the faster it grows. As more offspring
survive and reproduce, even more offspring are born. The graph on the next
page illustrates a population growth curve of this nature
Figure 1.1 Population Growth Curve
Population growth is based on four fundamental factors: birth rate, death
rate, immigration, and emigration.
F W Y H J M S C F G F W Y H J M S
P O P U L A T I O N B N G T I E K
C F G T H J I N D U S T R Y H D K
F V B N F O O D O Y R V B N M I O
E R L G H N J U R Q Y R F G H C J
F O R G A N I S M S O V B N M I O
E R A G H N C T K C D R F G H N J
F V D N M R O R O F F V B N M E O
F W Y H E M S Y F G F W Y H J M S
5. Using these factors, the formula in determining population growth is as
follows:
Population growth= (births+ immigrants) - (deaths+
emigrants)
If the population growth is less than zero, t h i s s i m p l y m e a n s
t h a t there are more deaths and emigrants (organisms that leave the area)
in the population than there are births and immigrants (organisms that
arrive new to the area). If this is the case, the size of the population will
begin to decline.
The Ups and Downs of Population Growth
Ecologists regularly monitor the number of organisms in many populations
because every population can either potentially grow or decrease. They also observe
the indicators that manifest if some potential problems in the habitat of the
organisms may arise. Each condition will give a warning to the ecologists if something
is off.
An essential question though is why do population sizes have a tendency to
increase or decrease?
There are many factors that can cause a population’s size to change and this
is the reason why there is a need to understand the basic reason why a certain
population increases or decreases. Population of any organisms (humans, animals
or bacteria) will continue to grow if more organisms are being developed (genetically-
modified organisms) or born, than are dying.
More on this topic is presented in the next lesson.
What’s More
ACTIVITY 1.2: LIMITING FACTORS
Objectives: At the end of the activity, you should be able to:
1. Identify limiting factors in a certain area
2. Describe some factors that cause decreased in population of an individual
Directions:
1. Analyze the given area identify and describe each limiting factors
2. Write only letter for your answer and write your answer in your answer sheet.
6. PART A
Guide Questions of observations:
1. How does the four gardens differ of factors needed by the plants?
A. Good weather condition C. Supply of sunlight
B. Water and Fertile soil D. Space of garden
2. How does the LEAST factors affect the population growth of the plants in the
garden?
A. Decreases the population C. Increases population
B. Population growth decline D. Both A and B
PART B
3. How does the fishes survive inside the aquarium? What factor is given in the
sample aquarium?
A. Food B. Water C. Space D. Sunlight
4. How does the four aquarium differ?
A. Aquarium 1 fishes has enough food to survive, while aquarium 2,3 and 4
has limited food supply
B. Aquarium 2 fishes has enough food to survive, while aquarium 1,3 and 4
has limited food supply
C. Aquarium 3 fishes has enough food to survive, while aquarium 1, 2 and 4
has limited food supply
D. Aquarium 4 fishes has enough food to survive, while aquarium 1, 2 and 3
has limited food supply
PART C
Garden 1
*Space @ 5 m2
*10 Vegetable
plants
* 100 % supply of
Sunlight, water
and fertile soil
* Good weather
condition
Garden 3
* Space @ 3m2
*10 vegetable
plants
* 100 % supply
of Sunlight, water
and fertile soil
* Good weather
condition
Garden 2
* Space @ 4m2
*10 vegetable
plants
* 100 % supply of
Sunlight, water and
fertile soil
* Good weather
condition
Garden 4
* Space @ 2m2
*10 vegetable plants
* 100 % supply of
Sunlight, water and
fertile soil
* Good weather
condition
Aquarium 1
20 fishes
20 pieces
seaweeds
Aquarium 4
20 fishes
5 pieces
seaweeds
Aquarium 3
20 fishes
10 pieces
seaweeds
Aquarium 2
20 fishes
15 pieces
seaweeds
FOREST 1
20 Plants and
animals
Poor weather
condition
FOREST 1
20 Plants and
animals
Good weather
condition
FOREST 3
100 Plants and
animals
100 % water
supply
100% water
supply
n
FOREST 4
100 Plants and
animals
80 % water
supply
7. 5. How does the plants and animals survive in both forest 1 and 2
A. Food B. Water C. weather condition D. Sunlight
6. What limiting factor are found in forest 1 compare to forest 2?
A. 80% water supply C. 100% water supply
B. Poor weather condition D. Good weather condition
7. How does forest 4 plants and animals differ from forest 3?
A. Forest 3 has enough water supply, while forest 4 has limited supply of water
B. Forest 3 has limited water supply than forest 4
C. Forest 3 has more plants and animals than forest 4
D. Forest 3 and 4 has the same water supply
What I Have Learned
ACTIVITY 1.3: MY VEGETABLE GARDEN: WHO WILL SURVIVE?
Objectives: at the end of the activity you should be able to:
1. Describe factors affecting the growth of a plant
Observation Questions: Read and analyze the guide questions. Choose only one
letter for your answer. Write your answer in your answer sheet.
1. Based on the figure above, what are the basic needs / factors for a plant to survive?
A. Sunlight, Water C. Sunlight, Water and Fertile soil
B. Sunlight, Fertile soil D. Sunlight only
2. Which garden has MORE space for plants to survive?
A. Garden 1 B. Garden 2 C. Garden 3 D. Garden 4
3. Which garden has LEAST space for plants to survive?
A. Garden 1 B. Garden 2 C. Garden 3 D. Garden 4
4. Which garden of plants survive the most? Why?
A. Garden 1, because of enough space and complete factors needed for
plants to survive.
Garden 1 @ 1m2
*10 Vegetable
plants
* 100 % supply of
Sunlight, water
and fertile soil
Garden 4 @ 1m2
*40 vegetable plants
* 100 % supply of
Sunlight, water and
fertile soil
Garden 3 @ 1m2
*30 vegetable
plants
* 100 % supply of
Sunlight, water
and fertile soil
Garden 2 @ 1m2
*20 vegetable
plants
* 100 % supply of
Sunlight, water
and fertile soil
8. B. Garden 2, because of enough space and complete factors needed for
plants to survive.
C. Garden 3, because of enough space and complete factors needed for
plants to survive.
D. Garden 4, because of enough space and complete factors needed for
plants to survive.
What I Can Do
ACTIVITY 1.4: INTERPRETING GRAPH OF POPULATION
GROWTH
Objectives: At the end of the activity you should be able to:
1. Describe the changes in population growth
2. Analyze graph of population growth
Instruction:
1. Examine the graph below, answer questions 1-3 and write the letter only for
your answer. Write your answer in your answer sheet.
Graph A
Observation guide questions:
1. What type of growth does this graph represent?
A. The population increases from A to C, it remains unchanged from C to D
B. The population decreases from A to C, it increases from B to D
C. The population increases from C to D, while decreases from A to B
2. Which of the following is true of the time interval marked D on the graph?
a. The carrying capacity has been reached.
b. The population is growing.
c. The population is declining.
d. The birth rate is higher than the death rate.
e. The emigration is greater than immigration.
3. At which time interval do you begin to see the effects of limiting factors (such as
limited food, water, space, etc.) on the population?
A. at point A B. at point B C. at point C D. at point D
9. Lesson
2
Carrying Capacity: Limit
to Everything
What’s New
ACTIVITY 2.1: MATCH MY GROWTH
Objectives: At the end of the activity, you should be able to:
1. Describe the population growth of individual
2. Differentiate Exponential from Logistic Growth
Instruction:
1. Analyze the graph of population growth and describe how are they differ from
each other
2. Explore how population growth affected with different factors
3. Answer the guide questions. Write letter only for your answer and write your
answer in your answer sheet.
Description A
This is a description of idealized
population growth that is slowed by
limiting factors. When resources are
limited, populations exhibit this type of
growth. In logistic growth, population
expansion decreases as resources
become scarce and it levels off when the
carrying capacity of the environment is
reached, resulting in an S-shaped curve.
Description B
During this period, there are plenty of
resources available for all organisms, so
more births are recorded than deaths
among the organisms. When resources
are unlimited, populations exhibit
exponential growth, resulting in a J-
shaped curve.
Graph 1 Graph 2
10. Observations Guide Questions:
1. Which description is match with Graph?
A. Graph 1 is match with description A, while graph 2 is match with description
B
B. Graph 2 is match with description A, while graph 1 is match with description
B
2. Which graph has a population resulting in a J shaped curved?
A. Graph 1 B. Graph 2
3. What kind of population growth when resources are unlimited?
A. Logistic Growth B. Exponential Growth
4. How will you describe Logistic growth?
A. Available and plenty of resources for all organisms in a given environment
B. More births are recorded than deaths among organisms in a certain
environment
C. Organism in the environment has unlimited resources
D. Resources are limited and scarce for organism and carrying capacity of the
environment is reached.
5. Why does population exhibit logistic growth?
A. population growth become slower due to limited resources
B. population growth increases due to unlimited resources
C. population growth become bigger due to unlimited resources
D. population growth become slower due to available resources
What Is It
Read on to have a deeper understanding on population fluctuations.
11. Crossword puzzle made from: https://crosswordlabs.com/embed/species-
diversity-aptation-and-survival-2
Studying population growth can help the scientists understand what causes
changes in population sizes and growth rates. For example, fish experts know that a
certain fish population is declining but they do not necessarily know the reason why.
Is this particular fish population declining because it has been overfished?
Or could it be that their habitat disappeared? There is a need for experts to know the
reason why there is a decline or increase of a population to be able to answer these
questions. Knowing this information contributes greatly to their research.
In addition, studying population growth also gives scientists insight into how
organisms interact with each other and with their environment. This is especially
meaningful when considering the potential impacts of climate change and other
changes in environmental factors. How will populations respond to changing
temperatures? To drought? Will one population prosper after another declines?
As a population grows in an area, a population may experience the effects of
increased densities. The maximum population size of species that the environment
can sustain is called the carrying capacity which is determined by the amount of
available resources (food, habitat, water).
DENSITY-DEPENDENT LIMITING FACTORS
A factor that regulates a population’s growth and is influenced by population
density is called a density-dependent limiting factor. This will come into play when
the population reaches a certain number or organisms and there is a lack of enough
resources (shelter, water, food) for all the organisms.
This event can cause the population to stop growing when it reaches the
maximum number of organisms that can be supported by the environment. This
number is known as the population’s carrying capacity in an environment. Each
population of organisms has a different carrying capacity depending on the amount
of resources available in the area in which they live.
DENSITY-INDEPENDENT LIMITING FACTORS
Density-independent limiting factors that can stop a population from growing can
be such things as natural disasters, temperature, sunlight, and the activities of
humans in the environment. Natural disasters such as tropical cyclones, floods,
earthquakes and fires will stop a population from growing no matter how many
organisms are living in a certain area.
As an example, global warming is proven to increase the temperature of an
area and the amount of sunlight it receives. This phenomenon can cause a decrease
in a population’s number, regardless of how large or small the population was to
begin with. This simply means that human activities that alter the environment,
global warming for example, can definitely decrease the number of organisms in a
population regardless of the size of a population.
12. CARRYING CAPACITY
As mentioned earlier, each population of
organisms has a different carrying capacity
depending on the amount of resources available in
the area. There is a limit to the number of
individuals in a population that an environment can
maintain.
Before a population reaches its carrying
capacity, it experiences a period of rapid growth.
This period of growth is called exponential
population growth. During this period, there are
plenty of resources available for all organisms, so
more births are recorded than deaths among the
organisms. When resources are unlimited,
populations exhibit exponential growth, resulting
in a J-shaped curve.
Another type of
growth pattern is logistic growth. This is a description
of idealized population growth that is slowed by limiting
factors. When resources are limited, populations
exhibit this type of growth. In logistic growth,
population expansion decreases as resources become
scarce and it levels off when the carrying capacity of the
environment is reached, resulting in an S-shaped
curve.
In conclusion, as long as individuals are able to successfully reproduce
and raise multiple young, a population will grow in number until it reaches
the carrying capacity of its ecosystem.
Activity 2.2: ASSESSING A SITUATION
Objectives: At the end of the activity, you should be able:
1. to identify factors have direct effects to the pattern of population growth
What’s More
13. Directions:
1. Use the knowledge you gained from the previous reading and activities
to answer the following situational questions.
2. Choose letter only for your answer. Write your answer in your answer sheet
Observation Guide Questions:
1. What factor have direct effect to the population growth for Situation A?
A. Predation C. Competition
B. Emigration D. Disease/ parasites
2. Which situation has a direct effect to the population growth of Emigration?
A. Situation A and B C. Situation F and B
B. Situation A and F D. Situation E and C
3. Which among the situation has similar limiting factors of population growth?
A. Situation A, B and C C. Situation C, D and E
B. Situation D, E and F D. Situation A , D and F
4. What kind of limiting factors are natural disasters, temperature, sunlight and
human activities?
A. Density- Independent limiting factor C. Density- Dependent limiting factor
B. Density limiting factor D. Dependent limiting factor
5. Which of the following are natural disasters?
A. Tropical cyclones, sunlight, temperature and fires
B. Floods, Earthquakes, Fires, and tropical cyclones
C. Temperature, floods, fires and sunlight
D. Sunlight, Fires, floods and temperatures
Situation A
COVID 19 – Over 254
thousand OFWS flown
home amid pandemic
Situation C
Taal volcano erupted on the
afternoon of January 12, 2020,
43 years after its previous
eruption in 1997.
Philippines
Situation B
COVID 19 : updates
October 18,2020
Total cases: 354 thousand
Recovered: 295 thousand
Deaths: 6,603
Situation D
Philippines Floods: latest
news, heavy rain
deepened flood misery
in farming and
mountainous regions of
the northern Philippines.
Situation E
Oct 17,2020 Cebu city floods
blamed on trash, clogged
waterways.
Philippines
Situation F
Over 800 people were
displaced by flooding in the
province of Cebu in the region
of central Visayas, Philippines
after heavy rain on Oct. 4
2020
Philippines
14. What I Have Learned
Activity 2.3: LIMITING FACTORS: GIVE ME MY SPACE!
Direction: Read and understand the selection. Afterward, answer the
succeeding questions.
Limiting factors cover both biotic (living) and abiotic (non-living) things in an
ecosystem that prevent a population from growing any larger. For example, a
population of 100 deer may live in an ecosystem that has enough water and space to
support a group of 200 deer, but if there is only enough food for 100 deer, the
population will not grow any larger. In this example, food is the limiting factor.
Food though is not the only factor that can limit population growth. For example,
sometimes there is enough food in an ecosystem for a large population, but only a small
amount of suitable shelter for the organism. Or maybe there is plenty of food, water,
shelter and space to support a larger population in an area, but there are so many
predators that limit the number of the organisms.
Observation Guide Questions: Choose only one letter for your answer. Write your
answer in your answer sheet:
1. How can the area of available space have an impact to an organism?
A. Organism need enough space for them to grow better and survive
B. Organism with limited resources will increase their population
C. Organism with enough food decreases their population
D. Organism need good weather condition thus decrease population
2. In the selection, what does “limit” mean?
A. availability of enough supply resources
B. availability of least supply resources
C. Organism has no supply of resources
D. Organism need more supply of resources
3. Differentiate dependent from independent limiting factors.
A. Dependent limiting factor regulates a population’s growth, while
independent factor stop population from growing
B. Dependent limiting factor decreases population, while independent
factor increases population
C. Independent limiting factor decreases population, while dependent
limiting factor the population remain unchanged
D. Independent limiting factor fluctuate population, while dependent
decreases population
15. .
What I Can Do
ACTIVITY 2.4: GONE AND NEVER COMING BACK!
When you think of Philippine wildlife, which kind of animals
enter your mind? Do you imagine crocs, tamaraws, or perhaps the Philippine Eagle?
Well, would you believe that elephants, rhinoceroses, and giant tortoises once lived
in our country? The roar of wild tigers even reverberated over the mountains of
Palawan!
Paleontologist Sylvio Lopez excavated the molar of a Stegodon, an extinct
relative of modern-day elephants, between Cagayan and Kalinga Apayao in 1973.
Then in 2008, the University of the Philippines Archaeological Studies Program
announced the discovery of tiger bones in Palawan’s El Nido!
Mighty stegodon (Stegodon luzonensis) were the extinct cousins of modern-day elephants who once
roamed the plains of the Cagayan Valley in Northern Luzon. They died out just 4,000 years ago during the time
when the Pharaohs ruled Egypt. (Photo credit: National Museum)
As humans rose to dominate life on Earth, many species fell by the wayside.
Gone are the wild elephants, rhinoceroses, and the tigers of the Philippines.
However, what’s more worrying is the unnatural rate of extinction over the
course of years. Over 200 species are now disappearing daily. By the time you
finished reading this column, other organisms have already vanished.
Observation Guide Questions:
1. Why the Stegodon became extinct in the Philippines?
A. Due to both dependent and independent limiting factors
B. Due to independent limiting factor only
C. Due to dependent limiting factor only
D. Due to population density
16. 2. Do you think educating the public about the plight of the Stegodon can have
a possible influence to the increase of the bald eagle’s population? If so, in
what ways can this certain influence be manifested?
A. Yes, preserving, conserving and protecting the environment for
survival of organism
B. Yes, conserving the environment by tree planting organism will
survive
C. Yes, protecting the environment in maintaining the good practices
in farming
D. Yes, people should have to preserve the area or space for plants and
animals
3. Considering the events that had happened to the extinction of some Philippine
animals, what predictions can you make about the future of all our
endangered species in the present time?
A. Endangered species should have given priority to preserve their
environment
B. Endangered species will be taken care of all mankind
C. Endangered species should have protection from dependent and
independent limiting factor
D. Endangered species will be vanished if not given needed supply of
resources
4. Research on other extinct Philippine animals and cite the reasons why they
vanished from our country.
A. Some extinct animals has least supply of resources and has
dependent and independent limiting factor
B. Some extinct animals has more supply of resources
C. Some extinct animals has limited supply of resources
D. Some extinct animals has abundant supply of resources
17. Answer Key
Lesson 1: Population Growth: A Reality
Lesson 2: Carrying Capacity: Limit to Everything
18. References
Ronald Diana, Grade 8 Science Modules, 2015 edition (Tru-copy Publishing House, Inc.
2015).pp.2-7.
H. Acosta, et al., (Science 10 Learners Material (Pasig City: Rex Bookstore, 2015) pp. 299-
319.
https://populationeducation.org/wp-content/uploads/2017/10/crowding_can_be_seedy.pdf
https://www.publicdomainpictures.net/
https://onlinedegrees.kent.edu/geography/geographic-information-
science/community/human-impact-on-the-environment
https://www.carbonindependent.org/
https://www.nature.com/scitable/knowledge/library/an-introduction-to-population-growth-
84225544/
https://slideplayer.com/slide/8481924/
https://illustoon.com/?id=3084
https://www.redlandsusd.net/site/handlers/filedownload.ashx?moduleinstanceid=6825&datai
d=21751&FileName=Evidence-for-Evolution-Worksheet%20a.pdf
http://www.iq.poquoson.org
http://animalscene.ph/2018/10/09/extinct-animals-of-the-philippines/
https://www.cpalms.org/Public/PreviewResourceLesson/Preview/127741
