INTRODUCTION TO Biology
Biology: The Science of Life
Biology as a Science
Definition of Biology - Greek words: bios - meaning “life” + logos - meaning “study of”

the science of life
 the study of living things
 deals with the investigation of the origin, history, structure, function,
identification, classification, distribution, development, inheritance, and
significance of living things as well as their relationships and interaction with the
environment.
History of Biology
The history of biology can be summarized in four stages namely:
1. Primitive period – characterized by uncritical accumulation of information,
accumulated knowledge was not recorded.
2. Classical Period – began with Greeks and continued with the Romans. Marked
by great curiosity about natural phenomena and ability to organized biological
knowledge and recorded it.
3. Renaissance Period – took place during the 14th – 16th century. Anatomy,
physiology, botany and zoology were established in the middle of this period.
4. Modern Era – introduction of microscope marked the start of modern biology.
1
Some World Famous Biologist
1. Andreas Vesalius (1543) – worked on human anatomy and published the book
“The structure of the Human body”
2. William Harvey (1628) – discovered the mechanics of human blood circulation
which contributes to physiology.
3. Marcello Malphigi (1661) – worked on blood capillaries and completed the path
between the arteries and veins.
4. Robert Hooke (1966) – first coined the word cell.
5. Antoni Van Leeuwenhoek – worked on microscopy.
6. Theodore Schwann (1883), Matthias Scheiden (1839) – established the “Cell
Theory”.
7. Charles Darwin – an English naturalist, proposed the “Theory ofevolution through
natural Selection and published “The Origin of Species” in 1859.
8. Gregor Mendel – made studies on genetics, the “Father of Modern Genetics
9. Louis Pasteur – introduced pasteurization and rabies vaccination, the “Father of
Modern Microbiology.
10. Robert Koch – discovered bacteria that causes anthrax, tuberculosis and cholera
11. Sir Alexander Fleming – discovered penicilin
Some Filipino Biologist
1. Angel Alcala, Ph.D. – contributed in marine ecology through conservation of coral
reefs and captive breeding of Philippine crocodile.
2. William G. Padolina, Ph. D. – multi-awarded in his excellent pioneering
researches in biotechnology and chemistry of natural resources.
3. Eduardo a. Quisumbing, Ph.D. – Father of Modern Orchidology.
4. Carmen C. Velasquez, Ph.D. – (National Artist) researched on parasitic worms.
2
Major Branches of Biology
1. Botany – study of plant life.
2. Zoology – study of animal life
3. Microbiology – study of microorganisms
Branches according to subject matter or concepts of study:
1. Biosystematics – deals with the identification, naming and classification of
organisms. This is the modern term for taxonomy. (plant, animal, microbial
systematics)
2. Biogeography – the study of biographical distribution of organisms.
a. Phytogeography – plant geography
b. Zoogeography – animal geography
3. Molecular Biology or Biochemistry – the study of chemistry of living things.
Molecular Biology includes gene biology and aspect of organic chemistry.
4. Cell Biology or Cytology – the study of cells.
5. Histology – the study of tissues.
6. Organismic Biology – the study of organ system.
7. Ecology – the study of interrelationship of organisms and their environment.
8. Morphoanatomy – the study of the gross structure of living organisms.
9. Physiology – the study of biological function.
10. Genetics – the study of heredity and variation.
11. Reproductive Biology – the study of various aspect of reproduction.
12. Developmental Biology – the study of the development of organisms from
gamete formation to birth, (embryology) and other developmental processes.
13. Paleontology – the study of fossil records.
14. Evolution – study the origin and differentiation of life.
3
15. Ethology – study of behavior of organisms.
16. Pathology – study of diseases, its nature, causes and symptoms.
Subdivisions according to type of organism:
Phycology – study of algae
Pomology – study of fruit trees
Dendrology – study of trees
Horticulture – study of vegetable
Floriculture – study of flowers
Bryology – study of mosses and
liverworts
7. Entomology – study of insects
8. Helmintology – study of worms
9. Ichthyology – study of fishes
1.
2.
3.
4.
5.
6.
10. Herpetology – study of reptiles and
amphibians
11. Mammology – study of mammals
12. Ornithology – study of birds
13. Parasitology – study of parasites
14. Protozoology – study of singlecelled animals or protozoa
15. Bacteriology – study of bacteria
16. Mycology – study of fungi
17. Virology – study of viruses
Unifying Theories of Biology
Modern biology is based on several great ideas, or theories:
1.
The Cell Theory (Scheiden, 1838, Schwann, 1839, and Virchow, 1858)
All organisms are made up of cells, and these cells come from pre-existing
cells.
2.
Biogenesis (Pasteur, 1865)
Life comes only from life.
3.
Homoestasis (Bernard, 1858)
The internal environment remains within a normal rage.
4.
Theory of Evolution by Natural Selection (Darwin, 1858)
All the living things have a common ancestor and are adapted to a particular
way of life.
5.
Gene Theory (Mendel, 1866, Franklin, Watson and Crick, 1953)
Organisms contain coded information that dictates their structure, function
and behavior.
4
Method of Biology
As a science, biology also uses the scientific method in solving or investigating
a biological problem.
Scientific Method - a systematic method in finding the truth making careful
observations and experiments and later using the data
obtained to formulate general principle or theories.
Steps of Scientific Method
1. Identification of the Problem
any scientific process starts with observation using all the senses
from the observation a problem may be identified
2. Formulation of the Hypothesis
a set of assumption or possible explanation to the problem will be
formulated
Hypothesis – a set of assumptions or possible explanations to the problem
-
preliminary conclusion or a scientific/educated guess, tentative or
casual explanation for a group of observations.
3. Testing of the hypothesis or experimentation
Experiment – is a special procedure used to test the hypothesis
2 Sets of Experiments
a. control set-up
b. experimental set-up – similar to the control set-up in every aspect except the
presence of variable
Variable – the factor or parameter to be tested
5
4. Analysis and interpretation of data and results
data/results must be gathered during and after the experimentation
data include records collected while making observation during an
experiment
one way to analyze or interpret records of observation is b using tables or
graphs
5. Generalization or Formulation of conclusion
based from the analyzed data, a theory may be formulated supported by
experimental evidence
this theory may be developed into a scientific law or into a principle
Theory – a hypothesis that has been repeatedly and rigorously tested.
Observation
Statement of the Problem
Formulation of Hypothesis
Testing of the Hypothesis
Results
Expected Results
Unexpected Results
Generalization
Figure 1. The Scientific Method
6
Limitations of the scientific method
1. Existence of God
2. Beauty appreciation
3. Moral Issues
4. Value judgment
Nature of Life
Life – the sum total of all bodily activities of an organisms. It is sometimes a fork of
energy from which all the different worlds of activity could be expressed.
Theories on the Origin of Life
1. Divine Creation or Special Creation Theory
This theory states that life was presumed to have been created by
supernatural power whom we call God.
2. Abiogenesis or Spontaneous Generation Theory
Life originated spontaneously from non-living things. Disproved by
Francesco Redi, an Italian scientist in 1668, and by Louis Pasteur, a French
chemist in 1865
3. Cosmozoic or Interplanetary Theory
Life originated from outer planets in the form of a resistant spore propelled
by radiation or pressure, reached the earth and started the first form of life.
4. Philosophical Theory of Eternity
Life has no beginning and no end. It states that whatever forms of life we
have now have actually been here right from the beginning of time.
7
5. Marine Theory
Life originated from the sea.
6. Naturalistic or Evolutionary or Physico-chemical Theory
The most scientific and the most accepted theory.
a. Life came about as a result of a chain of chemical reactions that gave
rise to a mass of living protoplasm which then gradually modified, giving
rise to the present forms of life.
b. This chemical evolution has never been duplicated.
Characteristics of Living Things
1. Living things can respond to stimuli.
Although all living things respond differently to stimuli, the capacity to respond to
those changes in both internal and external environment is the basic function of
living things.
Stimuli – the physical or chemical changes in the environment.
2. Living things are capable of reproduction.
Generation after generation, in order for life to continue, living things must be
able to produce other living things of their kind.
Reproduction – ability of the organism to create another of the same kind.
3. Living things are capable of adapting to their environment.
Living things not suited to a new condition either moves to a better environment
or change (evolution). A change cannot occur in one generation but over many
generations. Adaptation results into unity and diversity of life.
Adaptation – traits that are enhance the individual’s ability to survive in a particular
environment.
4. Living things can grow and develop
8
From zygote, a living thing develops changes and grows into a mature organism
through several differentiations. They may increase in size accompanied by
differentiation of body parts.
Growth – increase in the size of cell or number of cell or both
Development – slow process of progress change in the organism.
5. All living things can carry on metabolisms.
Process required in maintaining their organization, growth and reproduction.
Metabolism – the sum of all chemical activities in living organisms.
Two phases of metabolism:
a.
b.
Anabolism – forms more complex substances from simpler one resulting
in the storage of energy and production of new cellular material.
Catabolism – breaks down complex substances to release energy.
6. Living things can maintain homoestasis.
Homoestasis – the process by which an organism maintains the constant internal
conditions necessary for life.
7. Living things maintain a definite chemical composition
All organisms are basically made up of similar inorganic (water, salts, minerals,
gases) and organic molecules (carbohydrates, lipids, proteins and nucleic acids.)
8. Living things are capable of movement
Animals exhibit this characteristic obviously. Although plants do not move wholly,
the organelles inside the cell do move. This is called cyclosis.
9. Living things are capable of taking in energy from the environment and transferring
this into another form of energy.
Assimilation – the process of converting non-living inorganic and organic
molecules into living cell that can be done inside a living cell.
10. Living things are highly organized.
9
Parts of living things are arranged in a particular way. There are levels of
biological organization – biochemical, structural, structural, physiological and
ecological organization.
Levels of Organization
Atoms: smallest particle of matter non-divisible by chemical means.
Molecules: form when two or more atoms of the same element react with one another
or combine with atoms of another element
Organelle: A subunit of a cell, an organelle is involved in a specific subcellular function,
for example the ribosome (the site of protein synthesis) or mitochondrion (the site of
ATP generation in eukaryotes).
Cell: The fundamental unit of living things. Each cell has some sort of hereditary
material (either DNA or more rarely RNA), energy acquiring chemicals, structures, etc.
Living things, by definition, must have the metabolic chemicals plus a nucleic acid
hereditary information molecule.
Tissue: (in multicellular organisms). A group of cells performing a specific function. For
example heart muscle tissue is found in the heart and its unique contraction properties
aid the heart's functioning as a pump.
Organ: (in multicellular organisms). A group of cells or tissues performing an overall
function. For example: the heart is an organ that pumps blood within the cardiovascular
system.
Organ System: (in multicellular organisms). A group of cells, tissues, and organs that
perform a specific major function. For example: the cardiovascular system functions in
circulation of blood.
Individuals/Organism: One or more cells characterized by a unique arrangement of
DNA "information". These can be unicellular or multicellular. The multicellular individual
exhibits specialization of cell types and division of labor into tissues, organs, and organ
systems.
Populations: Groups of similar individuals who tend to mate with each other in a limited
geographic area. This can be as simple as a field of flowers, which is separated from
another field by a hill or other area where none of these flowers occur.
10
Species: Groups of similar individuals who tend to mate and produce viable, fertile
offspring. We often find species described not by their reproduction (a biological
species) but rather by their form (anatomical or form species).
Community: The relationships between groups of different species. For example, the
desert communities consist of rabbits, coyotes, snakes, birds, mice and such plants as
sahuaro cactus (Carnegia gigantea), Ocotillo, creosote bush, etc. Community structure
can be disturbed by such things as fire, human activity, and over-population.
Ecosystem: The relationships of a smaller group of organisms with each other and
their environment.
Biosphere: The sum of all living things taken in conjunction with their environment. In
essence, where life occurs, from the upper reaches of the atmosphere to the top few
meters of soil, to the bottoms of the oceans. We divide the earth into atmosphere (air),
lithosphere (earth), hydrosphere (water), and biosphere (life).
ATOM
hydrogen, oxygen
MOLECULE
H2O
CELL
neuron
ORGAN SYSTEM
Nervous system
ORGAN
brain
TISSUE
ganglion
ORGANISM
horse
POPULATION
Group of horse
COMMUNITY
horse + insects +
trees
BIOSPHERE
planet + all organisms
ECOSYSTEM
Horse + other organisms + nonliving organisms
Figure 2. LEVEL OF BIOLOGICAL ORGANIZATION
11