This document discusses several theories on the origin of life on Earth: 1. The Theory of Special Creation proposed that all life forms were directly created by God in their present form, without evolution or adaptation. It lacked experimental evidence. 2. The Theory of Panspermia suggested that life came to Earth from space, carried by meteors and dust. 3. The Theory of Spontaneous Generation was an ancient belief that living organisms could arise from non-living matter, but it was disproven by Pasteur. 4. The Theory of Biochemical Evolution, proposed by Oparin and Haldane, suggested organic compounds could form from simple gases through energy like lightning. Miller

1. INTRODUCTION TO LIFE
SCIENCE

2. 1. One theory to explain the origin of life is called chemical
evolution. According to this theory, which of the following events
would need to occur first for life to evolve?
A. origin of genetic material
B. onset of photosynthesis
C. Synthesis of organic molecules
D. formation of the plasma membrane

3. 1. One theory to explain the origin of life is called chemical
evolution. According to this theory, which of the following events
would need to occur first for life to evolve?
A. origin of genetic material
B. onset of photosynthesis
C. Synthesis of organic molecules
D. formation of the plasma membrane

4. 2. Which of the following describes why the Miller-Urey theory
is widely accepted today?
A. The process of synthesizing organic molecules from a mixture
of gases has been successfully modeled in the laboratory.
B. Organic molecules are present today in extremely high
concentrations.
C. No other alternative hypotheses have been introduced.
D. Amino acids spontaneously form from molecules in the
atmosphere today.

5. 2. Which of the following describes why the Miller-Urey theory
is widely accepted today?
A. The process of synthesizing organic molecules from a mixture
of gases has been successfully modeled in the laboratory.
B. Organic molecules are present today in extremely high
concentrations.
C. No other alternative hypotheses have been introduced.
D. Amino acids spontaneously form from molecules in the
atmosphere today.

6. 3. Who among the following first discarded the theory of
spontaneous creation and gave that life originates from
pre-existing life ?
A. Stanley Miller
B. Louis Pasteur
C. Lamarck
D. Charles Darwin

7. 3. Who among the following first discarded the theory of
spontaneous creation and gave that life originates from
pre-existing life ?
A. Stanley Miller
B. Louis Pasteur
C. Lamarck
D. Charles Darwin

8. 4. Panspermia is the name given to the theory that life come
from where?
A. the ocean
B. undersea thermal vents
C. an extraterrestrial source
D. a primordial soup

9. 4. Panspermia is the name given to the theory that life come
from where?
A. the ocean
B. undersea thermal vents
C. an extraterrestrial source
D. a primordial soup

10. 5. Which theory of the origin of life proposed that all different
forms of life are created by God?
A. Theory of Panspermia
B. Theory of Special Creation
C. Theory of Biochemical Evolution
D. Theory of spontaneous generation

11. 5. Which theory of the origin of life proposed that all different
forms of life are created by God?
A. Theory of Panspermia
B. Theory of Special Creation
C. Theory of Biochemical Evolution
D. Theory of spontaneous generation

13. Have you ever wondered how the first life on earth came
into existence?

14. Theories of the Origin of Life

15. Objectives:
1. Identify the different theories of Origin of Life.
2. Explain the evolving concept of life based on emerging
pieces of evidence.
3. Appreciate the contribution of the proponents towards
their ideas about the origin of life and the importance of
life.

16. THEORY OF SPECIAL CREATIONS

17. • The theory of special creation is proposed that life
on earth is created by a supernatural power, the GOD.

18. A. All living organisms were created same day
[NO DIFFERENCE IN THEIR APPEARANCE]
B. They were created in the present form
[NO EVOLUTION]
C. Their bodies and organs are fully developed to meet the
requirement to run the life
[NO ADAPTATION]

19. Comparison to other theories.:
•It was purely based on religious belief.
•There was no experimental evidences to support the
assumptions.
•The age of different fossils proves that living organism
appear on earth in different time frame.

20. THEORY OF PANSPERMIA

21. •Life had come to earth from other planets of the universe,
in the form of resistant spores.
•British astronomers Fred Hoyle and Chandra
Wickramasinghe proposed:
•interstellar dust and comets contain organic
compounds.
•comets, which are largely made of water-ice,
carry bacterial life across galaxies and protect
it from radiation damage along the way.

22. THEORY OF SPONTANEOUS
GENERATIONS

23. In ancient
Egypt, it was
believe that
frog, snake,
crocodiles in
the mud of
Nile
River warmed
with sun.
Theory of spontaneous
generations

24. Fly larvae
develops
on rotten
meat.

25. Mice from the
dirty shirt and
handful of
wheat grains
kept in dark
cupboard in 3
weeks.

26. The theory of spontaneous generation or
abiogenesis assumes that non-living material in
a spontaneous manner give rise to life.

27. Is spontaneous generation similar to abiogenesis?

28. THEORY OF BIOCHEMICAL
EVOLUTION

29. Alexander Oparin (in 1924), and John Haldane (in 1929)
Oparin-Haldane Hypothesis
independently suggested that if the primitive atmosphere was
reducing (as opposed to oxygen-rich), and if there was an
appropriate supply of energy, such as lightning or ultraviolet
light, then a wide range of organic compounds might be
synthesised.

30. Stanley L. Miller and Harold C. Urey
Miller-Urey experiment
was an experiment that simulated hypothetical conditions
present on the early Earth in order to test what kind of
environment would be needed to allow life to begin.

31. Guide Questions:
1. What was he idea of spontaneous generation?
2. How Charles Darwin explain the existence of rats, maggots, and
microbes?

32. Choose one theory that you think the most
acceptable for you. Explain why.