Earth and Life Science

1. 1
THE CONCEPT OF LIFE BASED ON
EMERGING PIECES OF EVIDENCE
for Earth and Life Science Grade 11
Quarter 2 / Week 1

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FOREWORD
The diversity of life on Earth today is the result of evolution.
Life began on Earth at least 3.5 to 4 billion years ago, and it has
been evolving ever since. Theories and studies have been
established and conducted to better understand the origin of life.
This Self Learning Kit will serve as guide to students as they
explore the various theories of origin that seeks to explain the
evolution of life based on emerging pieces of evidence
This will be an exciting lesson as learners try to relate their
prior knowledge and experiences to various claims, theories and
laws that governs the very existence of life in this planet.

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LEARNING COMPETENCY
Explain the evolving concept of life based on emerging pieces of
evidence (S11/12LT-IIa-1)
I. WHAT HAPPENED
PRE-ACTIVITY
Directions: Answer the following question in your own idea and
write in on your activity notebook. Be able to support your claim
by citing evidence
1. How did life begin and evolve on Earth?
Rubrics:
Content------------------------5
Cohesiveness----------------3
Organization ---------------2
______________________________________
Total 10 pts.
OBJECTIVE:
This self-learning kit aims to:
K- Explain the evolving concept of life based on
emerging pieces of evidence
S- Describe the conditions on early Earth that made the
origin of life possible and the first life forms
A- Cite ways on how to preserve and conserve various life
forms.

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II. WHAT I NEED TO KNOW
DISCUSSION
What was the first form of life?
Life is believed to have existed on earth for billions of years
now. Scientists do not know exactly when life began on Earth.
However, they can trace how life developed and evolved
using some pieces of evidence. Earth is much older than life.
Based on radioactive decay studies of rocks, it was revealed
that Earth is around 4.5 billion years old – 1 billion years older
than the oldest fossils. So how did life begin? Where did it
come from?
https://link.quipper.com/en/organizations/59487b1ca8a9ff7fe3000007/curriculum#curriculum
Theories on how life could have begun:
1. Extraterrestrial origin- The hypothesis explains that life originated
on another planet outside our Solar System. Life was then
carried to Earth on a meteorite or an asteroid and colonized
Earth. However, this hypothesis has not been proven.

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http://micetimes.asia/scientists-have-proved-the-possibility-of-an-extraterrestrial-origin-of-life/
2. Panspermia- The theory presumes that the “seed” of life exists all
over the universe and can be propagated through space, and
that life on Earth originated from those seeds.
https://astrobiology.nasa.gov/news/in-search-of-panspermia/
3. Divine creation- Many people believe that life was put on Earth
by divine forces. Creation theories are common to many of the
world’s religions and cultures.

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https://en.wikipedia.org/wiki/Creationism
4. Origin from nonliving matter- Scientist believed that life arose on
Earth from inanimate matter after Earth had cooled. They stated
that random events probably produced stable molecule that
could self-replicate. Then, natural selection favored changes in
the rate of reproduction which eventually led to the first cell.
https://futurism.com/abiogenesis-life-may-have-evolved-from-non-living-matter-with-relative-ease
There are many theories about the origin of life. Some
believed that living organisms were put to Earth by some divine
forces. Others say that life did not originate from Earth but from
other planets. But among scientists, the most accepted theory is
that life came from inanimate matter.
According to the primordial soup theory proposed by
Alexander Oparin and John Haldane, life started in a primordial
soup of organic molecules. Some form of energy from lightning
combined with the chemicals in the atmosphere to make the
building blocks of protein known as the amino acids.

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Evidence on the first forms of life:
A. Experiment
American chemist Stanley Miller performed an experiment
replicated early Earth conditions. Together with Harold Urey, he
provided proof that amino acids and other organic molecules
could be formed.
Miller-Urey experiment:
The atmosphere that
Miller and Urey
introduced into the flasks
contained simple
molecules that were
probably present in the
early Earth’s atmosphere:
hydrogen, CO2,
methane, water vapor,
nitrogen, ammonia, and
carbon monoxide.
https://simple.wikipedia.org/wiki/Miller%E2%80%93Urey_experiment
STANLEY MILLER HAROLD UREY

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They heated the mixture and zapped it with electrical sparks to
stimulate lightning. Within days, a dark, smelly mixture
developed.
https://en.wikipedia.org/wiki/Miller%E2%80%93Urey_experiment
When this mixture was analyzed, they found that many complex
molecules had formed, including some amino acids, which are
the building blocks of proteins.
 Using slightly different combinations of starting molecules, Miller
and other scientist where able to generate many amino acids,
RNA and DNA nucleotides, lipids, carbohydrates, and
adenosine triphosphate (ATP).
B. FOSSILS
 One of the strongest pieces of evidence that show many life
forms existed in the Earth in the past 3.5 billion years.
1. Bone Fossil
https://www.slideshare.net/RuwyneAkkeanObedient/the-historical-development-of-the-concept-of-life
2. Shell Fossil

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https://www.slideshare.net/RuwyneAkkeanObedient/the-historical-development-of-the-concept-of-life
3. Plant Fossil
https://www.slideshare.net/RuwyneAkkeanObedient/the-historical-development-of-the-concept-of-life
How do fossil forms:
 Over long periods of time, particles piled up on the remains of
organisms and eventually became sedimentary rocks,
preserving the original body patterns of organism.
 Microfossils
 Fossil fragments that can only be
seen by microscope
 Existed in mats and formed layered
structures called stromatolites.
https://www.slideshare.net/Ru
wyneAkkeanObedient/the-
historical development-of-the-
concept-of-life
 Stromatolites
 a calcareous mound built up of
layers of lime- secreting
prokaryotes, or single-celled
organisms, called cyanobacteria
(the blue-green algae) and trapped
sediment, found in Precambrian
rocks as the earliest known fossils,
and still being formed https://www.slideshare.net/Ruwy
neAkkeanObedient/the-
historical-development-of-the-
concept-of-life

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in lagoons in Australasia.
 Cyanobacteria
 Believed by scientists to be the
first oxygen- producing
organisms that helped evolve
the Earth’s early atmosphere
into one that can support early
life forms
 As these microorganisms continued generating oxygen,
other photosynthetic organisms evolved and increased
the level of oxygen in the atmosphere.
 This increased the chance of more and more oxygen
reaction ammonia, a reaction that results in the release
of nitrogen into atmosphere
 This resulted in the formation of the ozone layer!
 A rapid evolution of life occurred after oxygen became
abundant.
Early Forms of Life
The first form of life is believed to have appeared some 3.5
billion years ago. The first evidence of life is found in microfossils.
Microfossils are fossils that contain the remains of tiny plants
and animals. They are very small and can be measured in
millimeters, and some could only be identified under a
microscope. Some of the remains of organisms do not have a
nucleus so they were called prokaryotes. They are known to be
the earliest forms of life. They have survived the extreme
conditions of the early environment. They started to make their
own food by utilizing the energy from the sun and the carbon
dioxide in the atmosphere. These are the photosynthetic
organisms.
https://www.microscopemaster.
com/cyanobacteria.html

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The process of photosynthesis produced more oxygen that
changed the Earth’s early atmosphere. This change in the
atmosphere allowed oxygen-breathing organisms to exist.
The cyanobacteria are the first photosynthetic organisms to
form. Their microfossils are among the easiest to recognize. Their
morphology remained the same and they left chemical fossils in
the form of broken products from pigments. The first microfossil
that showed remains of organisms with differences in structure
from the simple form of life was seen in rocks about 1.5 billion
years old. They are larger than bacteria and have internal
membranes and thicker wall. These findings marked the
beginning of eukaryotic organisms on Earth.
How did multicellular organisms evolve?
Multicellular organisms are believed to have evolved from
unicellular eukaryotes. Some single eukaryotic cells, like unicellular
algae, formed multicellular aggregates through association with
another cell producing colonies. From colonial aggregates, the
organisms evolved to form multicellular organisms through cell
specialization.
Protozoans, sponges, and fungi came to being. The first
fossilized animals which were discovered 580 million years ago
were soft-bodied. The continuous process of cell specialization
brought the emergence of complex and diverse plants and
animals, including human beings. Evidence from fossil layers
proved that different forms of life were present and have evolved
through time. According to Charles Darwin, organisms change
over time because of adaptation to their environment to survive.

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Performance Task:
POST ACTIVITY
Directions: Essay. Write your answer in your activity notebook.
Do not write anything in this module.
1. Your mother bought some meat from the market one day.
She placed the meat in a pan but forgot to place it in the
freezer. After some time, maggots were seen crawling from the
meat. What can you say about these outcomes?
Rubrics:
Content------------------------5
Cohesiveness----------------3
Organization ----------------2
______________________________________
Total 10 pts.
III. WHAT I HAVE LEARNED
EVALUATION/POST-TEST
Directions: Multiple choice. Choose the answer correctly. Write
the answers in your activity notebook. Do not write anything on
this module.
1. When did the early forms of life exist?
A. 1.5 billion years ago
B. 2.5 billion years ago
C. 4.5 billion years ago
D. 3.5 billion years ago
2. Where is the first form of life seen?
A. microfossils
B. layers of rocks
C. oceanic crusts

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D. sediments
3. Which of the following is the first photosynthetic organism to
form?
A. cyanobacteria
B. algae
C. fungi
D. gymnosperm
4. Which is not true about the prokaryotes?
A. They are simple in structure, small, and unicellular.
B. They do not have nucleus.
C. They survive in extreme conditions.
D. They are not capable of making their own food.
5. Which of the following processes brought changes in the early
atmosphere?
A. earthquake
B. extreme condition
C. photosynthesis
D. volcanic eruption
6. The following are multicellular organisms first evolved from
colonial aggregates except:
A. fungi
B. protozoans
C. sponges
D. mollusks
7. Which of the following statements is not correct?
A. Photosynthetic organisms decreased the amount of
oxygen in the atmosphere.
B. Organisms change over time because of adaptation for
survival.
C. Multicellular organisms evolved from unicellular
eukaryotes.
D. The earliest forms of life were the prokaryotes.

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8. All the following statements are true about the evolution of
multicellular organisms except:
A. They are formed from multicellular colonial aggregates
through cell specialization.
B. They are believed to have evolved from single-celled
prokaryotes.
C. The process of continuous specialization brought more
complex organisms.
D. The single-celled organisms that formed multicellular
aggregates were like the cells of algae.
9. Why do you think the emergence of plants and animals
came later than simple living organisms?
A. They are too big and take time to form.
B. They are the least important factor in the environment.
C. Their cell structures are more complex.
D. They contain more nucleus compared to lower forms of
organisms
10. Considering the present condition of the environment, do
you think living organisms are still evolving today?
A. Yes, because humans continuously alter the
environment that triggers evolution among living organisms
to survive.
B. No because the environment remains favorable to living
organisms.
C. Yes because it is a natural phenomenon which we
cannot stop from happening.
D. No because there is no condition outside their bodies
that will trigger evolution.

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REFERENCES
Quipper “Introduction to Life Science, Earth and Life Science”.
The Evolving Concept of Life.
https://link.quipper.com/en/organizations/59487b1ca8a9ff7fe30
00007/curriculum#curriculum
Teaching Guide for Senior High School. EARTH AND LIFE SCIENCE
CORE SUBJECT. “Introduction to Life Science” pg.167-172
Slideshare. “The Historical Development of the Concept of Life”
https://www.slideshare.net/RuwyneAkkeanObedient/the-
historical-development-of-the-concept-of-life
Teresita F. Religioso and Lilia G. Vengco. YOU AND THE NATURAL
WORLD SERIES EARTH AND LIFE SCIENCE” The Concept of Life”
pg.161-164

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DEPARTMENT OF EDUCATION
SCHOOLS DIVISION OF NEGROS ORIENTAL
SENEN PRISCILLO P. PAULIN, CESO V
Schools Division Superintendent
FAY C. LUAREZ, TM, EdD, PhD
OIC - Assistant Schools Division Superintendent
Acting CID Chief
NILITA L. RAGAY, EdD
OIC - Assistant Schools Division Superintendent
ROSELA R. ABIERA
Education Program Supervisor – (LRMS)
ARNOLD R. JUNGCO
Education Program Supervisor – (SCIENCE & MATH)
MARICEL S. RASID
Librarian II (LRMDS)
ELMAR L. CABRERA
PDO II (LRMDS)
CRAYDON T. ABENDAN
Writer
MELISA PRECYFEL B. QUIÑANOLA
Lay-out Artist
_________________________________
ALPHA QA TEAM
LIEZEL A. AGOR
EUFRATES G. ANSOK JR.
JOAN Y. BUBULI
MA. OFELIA I. BUSCATO
LIELIN A. DE LA ZERNA
THOMAS JOGIE U. TOLEDO
BETA QA TEAM
JUSTIN PAUL ARSENIO C. KINAMOT
PETER PAUL A. PATRON
LIEZEL A. AGOR
THOMAS JOGIE U. TOLEDO
MARY JOYCEN A. ALAM-ALAM
DISCLAIMER
The information, activities and assessments used in this material are designed to provide
accessible learning modality to the teachers and learners of the Division of Negros Oriental. The
contents of this module are carefully researched, chosen, and evaluated to comply with the set
learning competencies. The writers and evaluator were clearly instructed to give credits to
information and illustrations used to substantiate this material. All content is subject to copyright
and may not be reproduced in any form without expressed written consent from the division.

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ANSWERS KEY
Pre activity:
1.Answers may vary
Post activity
1.Answers may vary
Evaluation/Post-test:
I.
1. D
2. A
3. A
4. D
5. C
6. D
7. A
8. B
9. D
10.C
SYNOPSIS
Life is believed to have existed
on earth for billions of years now.
Scientists do not know exactly when
life began on Earth. However, they
can trace how life developed and
evolved using some pieces of
evidence.
Learners are expected to
explain the evolving concept of life
based on emerging pieces of
evidence.
ABOUT THE AUTHOR
CRAYDON T. ABENDAN finished his Bachelor of
Science in Nursing at the University of Negros
Occidental- Recoletos and finished his Bachelor of
Science in Secondary Education major in General
Sciences at Central Negros College, San Carlos City
and just passed hi CAR MAED major in General
Science at Central Philippine State University. He is
currently teaching at Jose B. Cardenas Memorial
High School Senior High School Department. He is
also a Grade 11 Coordinator, Science Department
Head, Schools’ Prefect of Discipline and District
Health Coordinator.
ANSWERS
KEY
Pre
activity:
1.Answers
may
vary
Post
activity
1.Answers
may
vary
Evaluation/Post-test:
I.
1.
D
2.
A
3.
A
4.
D
5.
C
6.
D
7.
A
8.
B
9.
D
10.C