Summary of Rationalism

1. An Introduction to
Life Science
Group 3

2. In this module, you will be able to:
 Identify organisms and the conditions that enable them to exist
(enrichment);
 Explain the evolution of life based on emerging pieces of
evidence;
 Describe classic experiments that model conditions which may
have enabled the first life-forms to evolve;
 Describe the unifying themes in the study of life; and
 Show the connections among living things and how they
interact with each other and with their environment

3. In April 2009, a novel
influenza virus – the A (H1N1)
was first detected in the
United States.
This new viral strain was originally
referred to as “swine flu” since
laboratory analysis showed that its gene
segments were similar to influenza
viruses present among pigs.

4. Scientist believed that this
strain was the result of gene
reassortment, a process by which
influenza viruses swap gene
segments.
Due to the segmented nature of the virus,
genetic exchange between two different
influenza viruses coinfecting a cell is
possible. This reassortment results in the
generation of a new viral strain.

6. - refers to the outbreak of a disease that occurs over a wide geographic
area at an exceptionally high proportion of the population.
The new viruses that emerged from such gene reassortment showed major differences
from the parent viruses. This phenomenon is an example of evolution at work.
Evolution is considered the core theme of biology. It is focused on
how life forms adopt to a constantly changing environment in order to
survive.

7. Life and
Its Remarkable
Beginnings

8. Paleontologists are scientist
who collect, identify, and study pieces of
evidence about earlier life-forms and try
to determine how these have evolved into
the organisms of today.
A fossil is a remnant or trace of a plant, animal, or
another organism that may have been replaced by
a rock material or left imprinted on a sedimentary
rock deposited in riverbeds or on the ocean floor.

9. Are very small fossils and can be
seen only with the aid of a
microscope.
Fossils that are considered the
oldest on Earth.
Microfossils
These layers of sheetlike sedimentary rocks that were created by layers upon layers of
cyanobacteria, single celled photosynthetic mircobes. Bacteria are considered to be the
first life-form that existed on Earth over two billion years ago.
Stromatolites

10. 1. The use and carry of chemical energy to
help organisms perform activities and carry
out chemical reactions
2. The ability of individuals to adapt to
their environment (evolutionary
adaptation)
3. The consistent growth and
development controlled by the
inherited gene
5. The ability of organisms to control their
internal environment (regulation)
4. The systematic and highly ordered
structure of organisms
6. The ability of organisms to respond to
environmental stimuli
7. The ability of every organism to reproduce
its own kind

11. HIERARCHY
OF
ORGANISM
Biosphere – highest level in the hierarchy

14. 3 MAJOR FIELDS IN
BIOLOGY
GENETICS, EVOLUTION, BIOCHEMISTRY

15. Genetics is the branch of biology
that studies heredity and variation.
The biological or genetic information and characteristics of
an organism are contained in there genes, chemically known
as deoxyribonucleic acid (DNA).

17. Biologists classify organisms into 3 categories called domains:

18. A prokaryotic cell or
prokaryote is a simple, single-
celled organism that lacks a
nucleus and membrane-bound
organelles.
Eukaryotes possess true nuclei
and membrane-bound organelles

19. 1. Individuals with traits
suited to the
environment are more
likely to survive than less
suited individuals
3. The process of natural
selection from one generation to
another will lead to a continuing
gradual change which may
result in evolutionary
adaptations or production of
new species.
2. Survival for existence
depends on the
hereditary constitutions
of survivors, and that
this is part of the
process of natural
selection.
Evolution
Charles Darwin published the book On the Origin Species by Means of Natural Selection in 1859.

20. Cells are composed of chemical
substances.
All organisms are made up of
elements or a combination of elements called
compounds.
Organisms are made up of matter that occupies
spaces and has mass (weight). About 25 elements
are essential to organisms. Four of these element
make up about 96% of the weight of most
organisms. These elements are carbon, hydrogen,
oxygen, and nitrogen.

21. The 3 Domains need to reproduce (genetics), adapt (evolution),
and metabolize (biochemistry).

22. Similarities in the molecular
characteristics of cells serve as basis
of scientists to hypothesize that cells
are descended from a common
ancestral cell or last universal
common ancestor. (LUCA)

23. It was anoxic (deficient in oxygen)
with limited gases present. Only microorganisms
that were capable of surviving in the absence of
oxygen (anaerobic) survived, including
methanogens (methane-producing organisms).
The atmosphere during the first 3 billion
years was rich in nitrogen and carbon
dioxide.
Organisms that were-light
dependent survived as they got energy
from sunlight (phototrophic organisms).
The first group of phototrophs such as
purple bacteria were simple, while others
were anoxygenic (nonoxygen-producing
phototrophs).

25. The theory of spontaneous generation
Spontaneous generation states that vital
forces or organic matter can create organisms from
inanimate objects
Aristotle claimed that some classes of
organisms generate spontaneously For example, the
apperance of maggots in meat that was left in the open
area

26. Robert Hooke (1635-1703)
An english scientist who wrote the
book Micrographia (1665),
illuatrated small organisms such as
the fruiting structure of molds
His first illustrations and
descriptions of small oraganisms
became the first description of
micro organisms

27. In 1684, leewenhoek further
developed a simple microscope to
investigate the natural substances
present in microbes.
He discovered bacteria
while studying a pepper-water fussion
and called those small organisms
“wee animalcules”
Antonie van
leeuwenhoek (1632-
1723)

28. An italian sceintist. In 1668, Redi
designed a scientific experiment to
demonstrate that maggots do not just
appear spontaneously but are produced
from eggs of flies .
Francesco Redi (1626-1697)

29. Redi’s Experiment
To test the hypothesis, Francesco Redi placed fresh
meat in open containers [left, above]. As expected,
the rotting meat attracted flies, and the meat was
soon swarming with maggots, which hatched into flies
[left, below]. When the jars were tightly covered so
that flies could not get in [middle, above], no maggots
were produced [middle, below]. To answer the
objection that the cover cut off fresh air necessary for
spontaneous generation, Redi covered the jars with
several layers of porous gauze [right, above] instead
of an air-tight cover. Flies were attracted to the smell
of the rotting meat, clustered on the gauze, which was
soon swarming with maggots, but the meat itself
remained free of maggots [right, below]. Thus flies are
necessary to produce flies: they do not arise
spontaneously from rotting meat.

30. In 1750, John Turberville Needham, an
english biologist attempted to test the relevance of
redi’s experiment to prove that spontaneous
generation can occur under the right conditions. At
that time, it was beleived that heat could kill even the
tinest organisms
John Turberville Needham (1713-1781)

31. Needham’s Experiment
Needham conducted an experiment
wherein he put some chicken broth in an open
container, let it cool, and then covered the continer
and kept it at room temperature.Needham claimed
that, when the broth was boiled, all the organisms in it
had died from the heat. Days later, when needham
examined the broth, he noticed that a thick solution
had formed on the broth and concluded that this was
made up of microorganisms that had been generated
spontaneously

32. Lazaro Spallanzani was an italian scholar
who sought to verify Needham’s test in 1767.
Spallanzani believed that Needham had not heated
the broth enough to kill the organisms in it.
Lazaro Spallanzani (1729-1799)

33. Spallanzani’s Experiment
He repeated Needdham’s experiment by
boiling equal amounts of chicken broth in two
containers, with one container being sealed and the
other left open. after a few days spallanzani observed
that the container that had been left open was
teeming with microorganisms while the sealed
container remained free of microbial growth

34. Louis Pasteur opposed the concept of
spontaneous generation. he believed that
microorganisms that decay or spoil materials are
present in the air or might have been existing on the
surface where decaying materials are found.
Louis Pasteur (1822-1895)

35. Pasteur’s Experiment
Pasteur filled a swan- necked flask with a nutrient
solution that he boiled and sterilized, after heating, the
flask was cooled and the air was allowed to re enter,
but the bend in the neck prevented particulate matter
such as microorganisms from entering and mixing
with the nutrient solution that would eventually cause
rotting. teeming microorganisms were observed when
particulate matter was allowed to enter.

36. THANK YOU