BIOLOGY: The Science of Our Lives

1. BIOLOGY:
The Science
of Our Lives

2. Learning Objectives
Define biology and explain its
importance
Explore the evolving concept of life
based of life based on emerging
evidence
Describe classic experiments that
model conditions that may have
enabled the first life forms to evolve

3. • Biology deals with structures,
functions, and relationships of
organisms with their environment.
• How do biologists study life and
explore its complexities?

4. • Biology- “study of life”
Greek words, “ bios” means life
and “logos” means reason or
study
Biology is the science that deals
with structures, functions, and
relationships of living things and
their environment.

5. Major divisions in Biological Science
Microbiology- study of
microorganisms
Botany- study of plants
Zoology- study of animals

6. Branches of Biology
 Taxonomy- naming and classifying
organisms
 Cytology-structures and functions of cells
 Embryology- formation and development
of organisms
 Anatomy- structures and parts of
organisms.
 Physiology- functions of living organisms
and their parts

7. • Biochemistry- biochemical
composition of living things
• Genetics- heredity and variation
• Evolution- origin and differentiation
of various organisms
• Ecology- relationships of organisms
with their environment.

8. Modern Branches of Biology
• Molecular biology- molecules that make up
the cells of living organisms
• Genomics- genetic material(genome) of an
organisms
• Proteomics-different proteins (proteome)
found in a living organism.
• Immunology- immune system
• Bioinformatics- biological data using
computer program.

9. Life and Its Beginnings
The study of the origin of life
is viewed from different
perspective.

10. Early Beliefs About the Origin of Life
• Spontaneous generation or
abiogenesis- is the idea that life could
appear from nonliving material.
This idea was proposed by Aristotle

11. People in the past
believed that flies
could grow from cattle
manure, mice from
wheat stored in the
dark, maggots from
decaying meat, fish
from mud of
previously dried lakes,

12. • Biogenesis- is the belief that life
originates from preexisting life.

13. Redi’s Experiment

14. • Francesco Redi, Italian Physician,
conducted an experiment that
challenged the idea of spontaneous
generation- disproving spontaneous
generation using maggots that
arose in decaying meat.

15. • Redi observed that flies were attracted to
both jars but settled only on the meat of
the open jar since the gauze blocked
flies from hovering onto the meat in the
other jar.
• After several days, Redi observed that
maggots arose from eggs laid by flies on
the rotten meat but not on the meat in

16. Needham’s Experiment
John Needham, 1748, English priest
challenged Redi’s experiment. It is common
knowledge at that time that boiling could kill
microorganism.

17. • He placed a solution of boiled mutton broth
in a container and heated it. Then he sealed it
with corks proving that it could prevent
anything from the broth turned cloudy and
full of microorganisms.
• He concluded that life in the broth was
caused by spontaneous generation.
• Actually, he did not heat it long enough to kill
all the microbes in the broth.

18. Spallanzani’s Experiment
• Lazzaro Spallanzani, Italian scientist (1767)
challenged Needham’s experiment. Spallanzi boiled
a broth containing meat and vegetables placed in
clean glass containers.

19. • Both containers were boiled but one setup
was not sealed, allowing air to enter the flask.
Several days later, the open container was
filled with a population of microorganisms but
the sealed container remained sterile.
• He concluded that life occurred from
something that entered the unsealed flask
and that it was the one responsible for life to
grow.

20. • The results were not taken
completely by the believers of
abiogenesis who even stated that
Spallanzani excluded air from his
sealed flasks, which they believed
was needed for spontaneous
generation to occur.

21. Pasteur’s Experiment
• Louis Pasteur’s experiment that
most scientists were convinced
that spontaneous generation could
not occur.
• Pasteur designed an experiment to
test the idea that a vital element
from air was necessary for life to
occur.
• He boiled sugar solution with yeast
in flasks with long neck

23. • The flask were left open to allow the vital
element in air to enter but no organisms
developed in the mixture. It was because
the microorganism settled on the bottom
of the curved neck of the flask and could
not each the mixture.
• He also cut the neck of the flask and
within 2 days, the solution was teeming
with microorganisms because airborne
microorganisms could easily enter the
flask

24. • This experiment
supported the theory
of biogenesis and
disproved
spontaneous
generation. This
evidence suggest
that new bacteria
appear only when
they are produced
by existing bacteria.

25. CURRENT BELIEFS ABOUT
THE ORIGIN OF LIFE

26. Divine Creation
Belief is believed that life forms and
everything in the universe were created
through a supernatural power rather than
naturalistic. The belief that life arose from
nothing but the power of a divine being is
called creationism. Creationists believe
that everything was made by God in 6
days.

27. Spontaneous Origin
• Some scientist believe that life
came from a spontaneous origin
or life evolved from inanimate
matter. Before life could evolve,
simple molecules combined to
form complex one.

28. • The energy that drove these chemical
processes may come from lightning or
some form of geothermal energy,
culminating in the evolution of cells from
simple to multicellular forms.
• Electric sparks can produce amino acids
and sugars from an atmosphere loaded
with preexisting materials like, water,
methane, ammonia, and hydrogen.

29. Scientists also tried to explain various
scenarios where life molecules could have
first assembled such as in underwater
volcanic vents, surface of clay sediments,
deep in Earth’s crust or under frozen ocean.
Another hypothesis deals with the
primordial soup that complex biological
compounds were randomly assembled by
chance in an organic broth on Earth’s early

30. Panspermia
• The Swedish scientists Svante Arrhenius
popularized the idea that life arose
outside Earth and life that forms were
transported from another planet to seed
life on Earth.
• Panspermia proposes that a meteor or
cosmic dust may have carried to Earth
significant amounts of organic
molecules, which started the evolution of

31. • In 1966, a meteorite that has found in
Antarctica, suggested that it had been
ejected from Mars possibly by a
collision with an asteroid.
• The meteorite contained presence of
complex organic molecules and small
globules, which resemble those found
on Earth.

32. UNIFYING THEMES ABOUT LIFE

33. What characteristics do all
living things share?

34. Gathering and Using Energy
One unique characteristic of living things is
the ability to use energy an matter to
ensure survival.
Energy is the ability of organisms to do
work that allows them to move.
Green plants obtain energy from sunlight
by means of photosynthesis.

35. The process by which energy is released
by the breakdown of food substances is
called cellular respiration.
All chemical processes, reactions, and
energy changes happening inside the
body of an organism are referred to as
metabolism.

36. Nutrient Uptake and Processing
All living organisms need to feed in order to
survive, grow, and reproduce. The process by
which organism acquire food is called nutrition.

37. Waste Elimination
Enzymes help regulate the rate at which
these reactions occur including the amount
of nutrients to be processed into other
forms.
The different organ systems help control the
internal environment and maintain normal
processes such as heart rate, body
temperature, and fluid environment of cells.
The maintenance of the body’s internal

38. Adapting and Evolving
• Certain responsive processes
allow organisms to react to
changes in their surroundings
in a predictable and meaningful
way. Categories of response
include movement, irritability,
individual adaptation, and
evolution.

39. Motility
Most animals can move from one place
to another by walking, flying, swimming,
gliding, or jumping. Such movement is
called locomotion or motility.

40. Irritability
External factors or stimuli such as light, sound,
temperature, pressure, food sources, or presence
of chemical substances affect living things. The
reaction to stimuli is called tropism or reponse.
The ability of an organism to respond
appropriately against a stimulus is called
sensitivity or irritability.

41. Adaptation
For living things to survive and
perform normal functions, the ability
to adjust to changes in the
environment is a must.

42. Evolution
Evolution refers to the changes in characteristics
of a group of organism (population) over time.
Evolutionary Adaptation is a gradual or rapid
change in a body structure or behaviour to be
better suited and to survive a new environment.

43. Reproducing and Continuing Life
• Certain life properties relate to an
increase in the size of the organism
or increase in the number of
organisms.
• Growth, development, and
reproduction are processes that
require metabolism because they
cannot occur without nutrient uptake

44. Growth
Growth is an increase in size and by converting
food to become a part of body cells.
Living things exhibit growth from within the cells
in a process called intussusception.
Among multicellular organisms, growth involves
more complex processes of cell differentiation
and formation of new organs or organogenesis.
Non living things grow but only by accretion,
which is growth by external addition of
substances.

46. Development and Reproduction
• Development- stages in life cycle
which starts with birth and ends in
death.
• Reproduction- is a process by
which genetic information is
passed on from one generation to
another as organisms produce
offspring that resemble their

48. Heredity : Unity Amidst Diversity
• Animals, plants, and
microorganisms carry
the common genetic
material DNA, which is
the molecule of life that
carries the instructions
for assembling protein
that is responsible for
forming a variety of
structures.

49. Organization of Life

50. • The organism interacts with other
organisms of the same kind known as
population, while an array of populations
sharing their habitat compose a
community.
• These communities exist in an
environment affected by both living and
nonliving components known as
ecosystem. All ecosystems on Earth
whether they support life on land, water,
or lower atmosphere make up what we
call the biosphere.

53. • Activity- Biology in Our Lives
(112A)