The document provides an overview of key concepts in biology by summarizing 7 points: 1) New properties emerge at higher levels of biological organization from molecules to ecosystems. 2) Organisms interact with their physical environment and other organisms in complex relationships. 3) Life requires the transfer and transformation of energy to carry out functions. 4) Structure and function are closely related at all levels from cells to organisms. 5) The cell is the basic unit of structure and function in organisms. 6) The continuity of life is based on heritable DNA containing genetic information. 7) Feedback mechanisms allow biological processes to self-regulate themselves.

1. CHAPTER 1
INTRODUCTION TO
THE STUDY OF LIFE
INTRODUCTORY
BIOLOGY

2. • Biology is the scientific study of life
• Biologists ask questions such as
– How does a single cell develop into an organism?
– How does the human mind work?
– How do living things interact in communities?
• How do we know if something is living? Is a virus alive
or dead?
INTRODUCTION :

3. Order
Adaptation
Response
to the
environment
Reproduction
Growth and
development
Energy processing
Regulation
Some
properties
of life

4. To know what is biology, we need to understand:
1. New properties emerge at each level in the biological
hierarchy
2. Organisms interact with other organisms and the physical
environment
3. Life requires energy transfer and transformation
4. Structure and function are correlated at all levels of
biological organization
5. The cell is an organism’s basic unit of structure and
function
6. The continuity of life is based on heritable information in
the form of DNA
7. Feedback mechanisms regulate biological systems

5. 1. New Properties Emerge at Each Level
in the Biological Hierarchy
• Life can be studied at different levels, from molecules
of microscopic scale to global scale of the entire living
planet
• The study of life can be divided into different levels of
biological organization

6. The biosphere
Ecosystems
Tissues
Organs and
organ systems
Communities
Populations
Organisms
Organelles
Cells
Atoms
Molecules

7. Emergent Properties
• Emergent properties result from the arrangement and
interaction of parts within a system
• Emergent properties characterize non-biological entities
as well
– For example, a functioning bicycle emerges only when
all of the necessary parts connect in the correct way

8. • These emergent properties are due to the
arrangement and interaction of parts as
complexity increases :
 a cell is much more than a bag of molecules
eg: components of a chloroplast & photosynthesis
 our thoughts and memories are emergent properties
of a complex network of neurons
• This show the importance of structural
arrangements
• Emergent properties of life reflect a hierarchy of
structural organization

9. • The complex organization of life makes it difficult to
study the biological processes.
• cannot fully explain higher level of organization by
breaking down into its components (a dissected
animal no longer functions)
• at the same time, it is futile to analyze an organism or
cells without taking it apart
• This is where ‘Reductionism’ plays an important role
in understanding the biological processes of complex
organization.
• Reductionism = the reduction of complex systems
to simpler components that are more manageable to
study.

10. The Power and Limitations of Reductionism
• Reductionism is the reduction of complex systems to
simpler components that are more manageable to
study
– For example, studying the molecular structure of DNA
helps us to understand the chemical basis of
inheritance
• An understanding of biology balances reductionism
with the study of emergent properties
– For example, new understanding comes from studying
the interactions of DNA with other molecules

11. • To understand the larger scale how parts of
cells, organisms and higher levels of orders
such as ecosystems work together an
approach called system biology was used

12. Systems Biology
• A system is a combination of components that
function together
• Systems biology constructs models for the dynamic
behavior of whole biological systems
• The systems approach poses questions such as
– How does a drug for blood pressure affect other
organs?
– How does increasing CO2 alter the biosphere?
• A successful model predicts how a change in one or
more variables affect other components and the
whole system

13. 2. Organisms Interact with Other
Organisms and the Physical Environment
• Every organism interacts with its environment,
including non-living factors and other organisms
• Both organisms and their environments are affected by
the interactions between them
– For example, a tree takes up water and minerals from
the soil and carbon dioxide from the air; the tree
releases oxygen to the air and roots help form soil

14. Animals eat
leaves and fruit
from the tree.
Leaves take in
carbon dioxide
from the air
and release
oxygen.
Sunlight
CO2
O2
Cycling
of
chemical
nutrients
Leaves fall to
the ground and
are decomposed
by organisms
that return
minerals to the
soil.
Water and
minerals in
the soil are
taken up by
the tree
through
its roots.
Leaves absorb
light energy from
the sun.

15. • Humans have modified our environment
– For example, half the human-generated CO2 stays in
the atmosphere and contributes to global warming
• Global warming is a major aspect of global climate
change
• It is important to understand the effects of global
climate change on the Earth and its populations

16. 3. Life Requires Energy Transfer and
Transformation
• A fundamental characteristic of living organisms is their use of
energy to carry out life’s activities
• Work, including moving, growing, and reproducing, requires a
source of energy
• Living organisms transform energy from one form to another
• Energy flows through an ecosystem, usually entering as light and
exiting as heat
For example,
– plant absorb light energy and convert it to chemical energy
stored in sugar molecules
– animals convert chemical energy (consume plant products) to
kinetic energy (motion)
– some of this energy is converted to thermal energy (heat)

17. Figure 1.6
Heat
Producers absorb light
energy and transform it into
chemical energy.
Chemical
energy
Chemical energy in
food is transferred
from plants to
consumers.
(b) Using energy to do work
(a) Energy flow from sunlight to
producers to consumers
Sunlight
An animal’s muscle
cells convert
chemical energy
from food to kinetic
energy, the energy
of motion.
When energy is used
to do work, some
energy is converted to
thermal energy, which
is lost as heat.
A plant’s cells use
chemical energy to do
work such as growing
new leaves.

18. 4. Structure and Function Are Correlated
at All Levels of Biological Organization
• Analyzing a biological structure gives clue about what
its function
• Knowing a function of something provides insights of
its structure

19. • Structure and function of living organisms are closely
related
– For example, a leaf is thin and flat, maximizing the
capture of light by chloroplasts
– For example, the structure of a bird’s wing is adapted
to flight (shape of wing & structure of bones)

20. 5. The Cell Is an Organism’s Basic Unit of
Structure and Function
• The cell is the lowest level of organization that can
perform all activities required for life
• All cells
– Are enclosed by a membrane
– Use DNA as their genetic information
• Two main forms of cells :
– prokaryotic (bacteria)
– eukaryotic (plants, animals)

21. 6. The Continuity of Life Is Based on
Heritable Information in the Form of
DNA
• Chromosomes contain most of a cell’s genetic
material in the form of DNA (deoxyribonucleic acid)
• DNA is the substance of genes
• Genes are the units of inheritance that transmit
information from parents to offspring
• The ability of cells to divide is the basis of all
reproduction, growth, and repair of multicellular
organisms

22. 7. Feedback Mechanisms Regulate
Biological Systems
• Feedback mechanisms allow biological processes to self-
regulate
• Common to life at all levels, from molecules to
ecosystems and the biosphere
• Negative feedback means that as more of a product
accumulates, the process that creates it slows and less of
the product is produced
• Positive feedback means that as more of a product
accumulates, the process that creates it speeds up and
more of the product is produced

23. E.g.: When excess ATP being produced by cells due to the
generation of energy, ATP “feeds back” and inhibit an enzyme
near the beginning of the pathway

24. E.g.: When blood vessel is damaged due to open wound,
platelets begin to aggregate at the site. Positive feedback occurs
as chemical released by the platelets to attract more platelets to
seal the wound.

25. The Diversity of Life
• Approximately 1.8 million species have been identified
and named to date
• This diversity include :
– 6,300 species of prokaryotes
– 100,000 fungi
– 290,000 plants
– 52,000 vertebrates
– 1 million insects
• Thousands more are identified each year
• Estimates of the total number of species that actually
exist range from 10 million to over 100 million

26. Grouping Species: The Basic Idea
• To help organize the diversity of life, biologist classify
species into groups.
• Taxonomy is the branch of biology that names and
classifies species into groups, formalizes the ordering
of species
• Domains, followed by kingdoms, are the broadest
units of classification

27. Species
Ursus
Ursidae
Carnivora
Mammalia
Ursus americanus
(American black bear)
Chordata
Animalia
Eukarya
Genus Family Order Class Phylum Kingdom Domain
Figure 1.14

28. FORMS OF INQUIRY TO EXPLORE LIFE
• Science derived from the Latin verb = to know
• The heart of science = inquiry
• Two types of scientific inquiry:
- discovery science (describing nature)
- hypothesis-based science (explaining nature)
* Most scientific inquiries combine these two approaches

29. 1) Discovery Science :
Describes natural structures and processes as accurately
as possible through careful observation and analysis of
data
- discovery science build our understanding of cell
structures and is expending our databases of
genomes of diverse species
2) Types of Data
Observation is the use of the senses to gather
information, which is recorded as data

30. Hypothesis-Based Science
• In science , inquiry usually involves the proposing and
testing of hypotheses
• A hypothesis is a tentative answer to a well-framed
question
• A scientific hypothesis leads to predictions that can be
tested by additional observation or by experiments
• A type of logic called deduction is built into hypothesis-
based science

31. Example of
hypothesis-
based inquiry
Deduction:
If the dead battery
hypothesis is correct,
and you replace the
batteries with new
ones, then the
flashlight should
work

32. • A Hypothesis must be :
i) Testable – some way to check validity of idea
ii) Falsifiable – some observation or experiment that
could reveal if such idea is actually not
true
• The ideal in hypothesis-based science is to frame two or
more alternative hypotheses and design experiments to
falsify them
• No amount of experimental testing can prove a
hypothesis because it is impossible to test all alternative
hypotheses
• A hypothesis gains credibility by surviving experiments
that could falsify it, while testing falsifies alternative
hypotheses

33. • Scientific method
- idealized process of inquiry
- basic steps in Scientific method
> make observations, may come from others or results
of previous tests
> ask questions about the observations : How? Why?
When?
> generate hypotheses : phrased in such a was as to be
testable
> derive predictions : logical, testable outcomes of the
hypotheses
> developed by the use of deductive reasoning

34. • Scientific method
- basic steps in Scientific method
> predictions take the form of
“if (statement of hypothesis) is true, then
(predictions)
> test predictions: to determine if the predictions are
supported (fail to falsify) or falsified
> a hypothesis becomes credible when repeated tests
to falsify fail
- not all scientific inquiries need to follow rigidly the steps
above

35. • Scientific method
- not all scientific inquiries need to follow rigidly the steps
- discovery science has contributed much to our
understanding of nature without most of the steps of
scientific method
• Limitation of science
- these limits are set by science’s requirements that
> hypotheses be testable and falsifiable
> observations and experimental results be
repeatable

36. • Theories in Science
- a scientific theory is much more broader scope than
hypothesis
- Hypothesis : “Mimicking poisonous snakes is an
adaptation that protects nonpoisonous
snakes from predators”
- A theory is general enough to generate many new
specific hypotheses that can be tested
- A theory is generally supported by a much more greater
body of evidence

37. • Theories in Science
- theories that become widely adopted in science explain
many observations and are supported by a great deal of
evidence
- scientist may have to modify or reject theories when
new evidence is found, in spite of the body evidence
supporting a widely accepted theory
- if there is “truth” in science, it is based on a
preponderance of the available evidence

38. THE SCIENTIFIC METHOD
• https://www.youtube.com/watch?v=pGGCek
UDQKc