Science grade11 onsts newton empowerment

Science

1. THE CONCEPT OF
LIFE BASED ON
EMERGING PIECES
OF EVIDENCE
Prepared by: EVA MAE ADLAO

2. 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-----------------------10
Cohesiveness----------------6
Organization ---------------4
______________________________________
Total 20 pts.

3. A quick review:
A. What are the branches of Biology based on the pictures?
B. Have you been curious of when and where did life possibly
start on Earth?
C. What was the first form of life?

4. What was the
first form of life?

5. 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 itcome from?

7. 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.
Theories on
how life could
have begun:

8. Theories on
how life could
have begun:
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.

9. Theories on
how life could
have begun:
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.

10. Theories on
how life could
have begun:
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.

11. 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.

12. 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.

13. Miller-Urey experiment:
•They heated the mixture and zapped it with
electrical sparks to stimulate lightning.
Within days, a dark, smelly mixture
developed.
•When this mixture was analyzed, they found
that many complex molecules had formed,
including some amino acids, which are the
building blocks of proteins.

14. Miller-Urey experiment:
•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).

15. Evidence on the first forms of life:
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.

16. Evidence on the first forms of life:
B. FOSSILS
1.Bone Fossil
2. Shell Fossil
3. Plant Fossil

17. 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.

18. How do
fossil forms:
•Microfossils
Fossil fragments that can
only be seen by
microscope
Existed in mats and
formed layered structures
called stromatolites.

19. How do
fossil forms:
•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

20. How do
fossil forms:
•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

21. •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.

22. 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.

23. Early Forms of Life
The earliest life forms we
know of were microscopic
organisms (microbes) that
left signals of their presence
in rocks about 3.7 billion
years old. The signals
consisted of a type of
carbon molecule that is
produced by living things.
https://naturalhistory.si.edu/education/teaching-resources/life-science/early-life-earth-animal-
origins#:~:text=The%20earliest%20life%20forms%20we,is%20produced%20by%20living%20thin
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