A PowerPoint Presentation about the introduction to Life Science as part of the 2nd quarter curriculum of Earth and Life Science subject in Senior High School.

2. Introduction to Life Science
Maricriz S. Bioco

3. Biology
 a science that deals with all
forms of life, including their
classification, physiology, chemistry,
and interactions. The term was
introduced in Germany in 1800
and popularized by the French naturalist
Jean-Baptiste de Lamarck as a means of
encompassing the growing number of
disciplines involved with the study of
living forms.

4. Where did life begin?

5. Theory of SPECIAL CREATION
 in accordance with the Book of Genesis,
that every species was individually created
by God in the form in which it
exists today and is not capable of
undergoing any change.

6. Cosmozoic Theory (Panspermia Theory)
 the idea proposed by Richter in 1865 and supported by
Arrhenius (1908). According to this theory, life has
reached the planet Earth from other heavenly
bodies such as meteorites, in the form of highly
resistant spores of some microorganisms. The spores of
some microorganisms are called cosmozoa or panspermia
because they are preserved inside meteorites coming to
the earth from the outer space. These meteorites struck
the barren earth to release the cosmozoa and they
developed into different creatures on the earth.

7. Theory of Spontaneous Generation also
known as Abiogenesis
the idea that life arose
from nonlife more than 3.5
billion years ago on Earth.
Abiogenesis proposes that
the first life-forms
generated were very
simple and through a
gradual process became
increasingly complex.

8. Biogenesis Theory
life is derived from the
reproduction of other life,
was presumably preceded
by abiogenesis, which
became impossible once
Earth’s atmosphere
assumed its present
composition.

9. Primordial Soup Theory
According to 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.

10. Coacervate theory
 it is expressed by the Russian
biochemist A.I. Oparin in 1936
suggesting that the origin of life was
preceded by the formation of mixed
colloidal units called coacervates. These
are particles composed of two or more
colloids which might be protein, lipid or
nucleic acid. He proposed that while
these molecules were not living, they
behaved like biological systems in the
ancient seas. They were subject to
natural selection in terms of constant
size and chemical properties, there was
a selective accumulation of material,
and they reproduced by fragmentation.

11. Miller-Urey Hypothesis

12. FOSSIL EVIDENCE
 Fossil evidence indicates that life
on Earth appeared about 3.5
billion years ago in the oceans
 Provided protection from
Ultraviolet (UV) rays
 Allowed multidirectional
movement
 Served as a medium for essential
chemical reactions.
 Anaerobic prokaryotes

13. Early forms of life
 The first forms of life are believed to have
appeared some 3.5 billion years ago.
 Photosynthetic organisms are organisms
who make their own food by utilizing the
energy from the sun and the carbon
dioxide in the atmosphere. The
process of photosynthesis produced
more oxygen that changed the Earth’s
early atmosphere, allowed oxygen-
breathing organisms to exist.
 Cyanobacteria (blue-green algae) are the
first photosynthetic organisms to form.

14. The Early Life
The formation of planets did not use up all the
materials orbiting the sun, so the early Earth received
shower of meteorites and was struck by many
asteroids. These extraterrestrial materials and the
recurring volcanic eruptions paved the way for the
formation of Earth’s land, seas, and atmosphere.

15. The Early Life
 It is still a matter of discussion, but geological evidence
suggests that the early Earth began with little or no free
Oxygen (O2)—had O2 been present iron oxidation (rust
formation) in most ancient rocks would have been
observed, but no such sign of oxidation was found. Had O2
been present, small organic compounds would have
broken apart as quickly as they formed due
oxidation reactions.

16. The Early Life
We know that water is essential to life because molecules
that are parts of life-sustaining processes would have to
be dissolved in water. The Earth’s lithosphere did not exist
then, but it was covered by molted rock, hence water was
in the form of vapor. But as evidence from ancient rocks
suggests, Earth had cooled down 4.3 billion years ago
causing pools of water to arise

17. The Early Life
 Chemists thought that organic molecules were only
made by living organisms and it possessed a special
vital force. But in the early 1900, a chemist was able to
make urea the organic molecule found in urine. Then
another was able to synthesized and amino acid called
alanine. The synthesis of these molecules showed the
possibility that organic molecules can be formed
synthetically.

18. The Early Life
In the present, there are three (3) main hypotheses that
explain the mechanism on how the organic monomers
came about in early Earth. These mechanisms are not
mutually exclusive and might have set off
simultaneously contributing to the formation of the
simple organic compounds in Earth’s early seas—where
early life could have started.

19. Extraterrestrial Materials
At present, meteorites that fall to Earth are often analyzed and
was found out that some contains amino acids, sugars, and
nucleotide bases. These compounds (or their precursors) have
been found in gas clouds that surrounds nearby star. Thus, the
third hypothesis—that early life may have been brought about
by the extraterrestrial materials that fell on the early Earth
received—was created. This hypothesis suggests that materials
from space carried with them organic monomers that were
formed from outer space.

20. Extraterrestrial Materials
At present, meteorites that fall to Earth are often analyzed and
was found out that some contains amino acids, sugars, and
nucleotide bases. These compounds (or their precursors) have
been found in gas clouds that surrounds nearby star. Thus, the
third hypothesis—that early life may have been brought about
by the extraterrestrial materials that fell on the early Earth
received—was created. This hypothesis suggests that materials
from space carried with them organic monomers that were
formed from outer space.