Chapter 1: Biology Today
Chapter 1 Objectives:
Chapter 1 Objectives:
1. List & describe the characteristics of living things
2. List out & explain the hierarchical levels of biological organization
3. List the 3 components of the Cell Theory
4. Be able to list the steps of the scientific method and describe key points for each step.
5. Describe what a theory is in a scientific context. How is the scientific definition of theory different than
the general use of the word?
6. Vocabulary to know: homeostasis, eukaryotic, prokaryotic, species, population, science, & theory
I. The Scope of Life
A. Biology is the scientific study of life, but what is life? THE CHARACTERISTICS OF LIVING THINGS
1. Living things are highly organized compared to non-living things and new properties emerge at each
level – a hierarchy: SMALL TO LARGE
Atom  Molecule  Cell  Tissue  Organ  Organ System  Organism  Species
 Population  Community  Ecosystem  Biosphere
a) Organization begins w/ atoms, which make up basic building blocks of matter called
elements
b) ATOMS COMBINE TO FORM MOLECULES
c) Organic molecules combine to form a cell - the basic structural & functional unit of all living
things
d) Different cells combine to make up tissues (ex: myocardial tissue)
e) TISSUES COMBINE TO MAKE UPAN ORGAN (EX: THE HEART)
f) Specific organs work together as an organ system (ex: the heart, arteries, veins, etc)
g) In multi-cellular organisms, each an individual contain several organs systems (ex:
cardiovascular, digestive, respiratory, etc.)
h) A group of similar organisms capable of reproducing and producing a viable, fertile offspring
is called a species
I) a group of organisms of the same species living in the same geographic area is called a
population
j) INTERACTING POPULATIOINS IN A POPULAR AREA COMPRISE COMMUNITY
k) A COMMUNITY + ITS PHYSICAL ENVIORNMENT = AN ECOSYSTEM
l) The biosphere is comprised of regions of the Earth’s crust, waters, & atmosphere
inhabited by organisms
m) Each level is more complex than the previous
- Emergent properties: new novel properties emerge at each higher level due to the
arrangement & interactions of parts as complexity increases
n) Fig 1.2 Zooming in on Life
2. ALL ORGANELLES MUST MAINTAIN A STATE OF BIOLOGICAL BALANCE CALLED
HOMEOSTASIS
a) Temperature, moisture level, pH, etc must be maintained w/in the tolerance range for that
organism
b) Organisms have intricate feedback & control mechanisms to maintain homeostatic balance
c) NEGATIVE FEEDBACK
- Most common form of regulation
- An accumulation of an end product of a process slows that process
- Ex: Build of ATP – the energy currency of the cell
d) POSITIVE FEEDBACK
- The buildup of an end product of a process speeds up its production
- Ex: Clotting of platelets in the blood
3. LIVING THINGS REPRODUCE & (& GROW) DEVELOP
a) Reproduction is the ability to give rise to another organism like oneself
b) The instructions for an organism’s organization and development are encoded in genes
- Genes = long molecules of DNA (deoxyribonucleic acid) - the genetic code in all living
things
4. LIVING THINGS INTERACT WITH THEIR ENVIORNMENTS
a) Living things respond to their environment & to other living things
- The collective responses of an organism = the behavior of the organism
5.
a) Conducting life-sustaining processes require an outside source of energy
- Energy = the capacity to do “work”
b) Metabolism is all the chemical reactions that occur in a cell
c) THE SUN IS THE ULTIMATE SOURCE OF MOST OF THE ENERGY ON THE EARTH
- Plants & other organisms convert solar energy into chemical energy by the process of
photosynthesis
- This chemical energy is converted to kinetic energy when organisms consume plants
– thus energy flows through the community
d) Nutrients also cycle through the biosphere
e) Fig 1.3
6. LIVING THINGS HAVE EVOLVED FROM OTHER LIVING THING
a) The addition of adaptations & modifications through evolution creates organisms suited for
their environment
b) Evolution is the unifying concept of Biology
7. Fig 1.1 Some of the properties of Life
B. More on Cells
1. CELLS ARE THE BASIC UNIT OF LIFE
a) The cell is the lowest level of biological organization that can perform all of the
activities of life
b) 1800’S VIRCHOW COMES UP WITH THE CELL THEORY 3- PARTS
- All organisms are composed of cells
- Cells are the basic living unit of organization
- All cells arise from pre-existing cells
c) All cells are surrounded by an outer membrane
d) All cells use DNA as their genetic information
e) 2 TYPES OF CELLS
- Eukaryotic: cells that store their DNA in a membrane-bound structure called a
nucleus
- Prokaryotic: DNA is NOT contained in a nucleus
f) Fig 1.4 & Fig 1.5
II. The Process of Science
A. The word science is derived from a Latin verb meaning “to know”
1. SCIENCE IS THE WAY OF KNOWING
a) Science developed from people’s curiosity about themselves and the world around them
b) Fig 1.14
2. Science is also a body of knowledge about our world - a collection of theories
a) IN GENERAL SPEECH, THEORY MEARS A HUNCH OR GUESS
b) In science, a theory is a general set of principles, supported by scientific evidence that
explains some aspect of our world
3. Science does not seek to find facts but to support theories
a) Science is in the “theory building business, not the fact finding business”
B. Science is also a process and has defined steps called the Scientific Method
- 1. MAKE OBSERVATION
- You observe the world to work in a certain way and you wish to explain this phenomenon
- Observations begin the scientific method & also occur throughout the process
- 2. ASK QUESTIONS
- Develop a What, Why, or how question about your observation
- It must be a testable question
- 3. DEVELOP HYPOTHESIS
- A hypothesis is a testable explanation for the observation
- It is often formulated after much research
- Often referred to as an educated guess - but it is more than that
- 4. MAKE PREDICTIONS
- The hypothesis is used to make predictions
- Specific statements that can be directly or unequivocally tested
- Often worded “If __________, then ___________”
- 5. TEST PREDICTIONS - EXPREIMENTATION
- An experiment is an activity designed to test the validity of a hypothesis
- Experimentation involves manipulating variables - an adjustable condition in an experiment
that can affect its outcome
- Only one condition can be adjusted between experimental groups, all other conditions must be
controlled
- 6. ANALIZE AND INTERPRATE DATA
- Scientists collect data - information from their studies
- Quantitative data is the most valuable b/c #’s provide precision & allow data to be compared
- Data is analyzed using statistical tests
- Conclusions are drawn which may support or refute the hypothesis
- 7. REPORT YOUR FINDINGS
- Publication in peer-reviewed, scientific journals and presentations at scientific conferences
- Your methods, data analysis, & conclusions are critiqued by experts/specialists in your field
- 8. Fig 1.15
C. When does a supported hypothesis become a theory?
1. EVERY FINDING IS GIVNG PROVISIONAL ASSENT
a) It is believed to be true for now pending new evidence
2. EVERY ASSERTATION IS SUBJECT TO CHANGE AND REASON
3. Results obtained in experiments must be reproducible
4. Theories only become widely accepted in science if they are supported by an accumulation of
extensive and varied evidence
5. EXAMPLE OF SCIENTIFIC THEORIES
a) Cell Theory
b) Theory of Evolution
c) Gene Theory
d) Homeostasis Theory