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NATURE OF SCIENCE NAME
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CHAPTER 1 - Biology: Exploring Life
Biology: The Scientific Study of Life
1.1 What is life?
1. Biology is the scientific study of life.
2. But what is life? Properties of life include order, reproduction, growth and development, energy pro-
cessing, regulation, response to the environment, and evolutionary adaptation.
3. The cell is the structural and functional unit of life.
1.2 Biologist arrange the diversity of life into three domains
1. We can think of biology’s enormous scope as having two dimensions.
a. The “vertical” dimension is the size scale that stretches from molecules to the
biosphere.
b. The “horizontal” dimension spans across the great diversity of organisms existing now and over
the long history of life on Earth.
2. Diversity is the hallmark of life.
a. Biologists have identified about 1.8 million species.
b. Estimates of the actual number of species ranges from 10–100 million.
3. Taxonomy names species and classifies them into a system of broader groups.
4. The diversity of life can be arranged into three categories called domains
a. Domain- Bacteria are the most diverse and widespread prokaryotes (without a nucleus).
b. Domain- Archaea are prokaryotes that live in Earth’s extreme environments (extremophiles)
c. Domain- Eukarya have eukaryotic cells (have a nucleus) and include
i. single-celled protists (amoeba, paramecium) and
ii. multicellular fungi, animals, and plants.
5. Below the domain system, living things are classified into subcategories by morphological
(physical) characteristics
a. Kingdom (largest)→ Phylum → Class→ Order→ Family → Genus → Species (smallest)
b. Binomial nomenclature- two part naming system by Carl Linnaeus of all living things using
Latin (Homo sapiens or Rosa chinensis)
Domain Eukarya Eukarya
Kingdom Animalia Plantae
Phylum Chordata Angiosperma
Class Mammalia Eudicot
Order Primata Rosales
Family Hominidae Rosaceae
Genus Homo Rosa
Species H. sapiens R. chinensis
6. Dichotomous Key-a tool that allows the user to determine the identity of items in the natural world-
meaning “divided into two parts.”
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Vertebrate Dichotomous Key
1.3 In life’s hierarchy of organization, new properties emerge at each level
1. Biological organization unfolds as follows:
a. Biosphere—all of the environments on Earth that support life,
b. Ecosystem—all the organisms living in a particular area and the physical components (abiotic)
with which the organisms interact
c. Community—the entire array of organisms living in a particular ecosystem,
d. Population—all the individuals of a species living in a specific area,
e. Organism—an individual living thing,
f. Organ system—several organs that cooperate in a specific function,
g. Organ—a structure that is composed of tissues and that provides a specific function for the or-
ganism,
h. Tissues—a group of similar cells that perform a specific function,
i. Cells—the fundamental unit of life,
j. Organelle—a membrane-bound structure that performs a specific function in a
cell, and
k. Molecule—a cluster of small chemical units called atoms held together by chemical bonds.
2. Emergent properties are
a. new properties that arise in each step upward in the hierarchy of life,
b. from the arrangement and interactions among component parts.
The Process of Science
1.4 What is science?
1. Science is a way of knowing—an approach to understanding the natural world.
a. Science uses an evidence-based process of inquiry to investigate the natural world.
b. The scientific approach involves observations, hypotheses, predictions, tests of hypotheses via
experiments or additional observations, and analysis of data.
c. A scientific theory is broad in scope and supported by a large body of evidence.
2. Question types
a. Closed- specific facts, requires one word or short response- for example “Yes or No?”
1) Specific information, clarify and gather information quickly
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b. Open- meant to develop ideas and elaborate further- for example “Describe its appearance?”
1) Problem solving, emotions, attitudes, and details
1.5 Hypotheses can be tested using controlled experiments
1. In an experimental test of a hypothesis, researchers often manipulate one component in a system and
observes the effects of this change.
2. Three types of variables
a. Independent variable is the variable that is being manipulated / changed; goes on x-axis
b. Dependent variable is the variable being measured to judge the outcome of the experiment. This
variable depends on the independent (manipulated) variable; goes on y-axis
c. Controlled variable is the one which could be changed but for the purpose of the
experiment is being kept at a constant value to the best of the experimenter’s ability
1) Any change in a controlled variable in an experiment would invalidate the correlation of
dependent variable (DV) to the independent variable (IV), thus skewing the results.
d. Constant- a value that does not change either during or between experiments
Handwashing and Bacteria Growth
3. Data types
a. Qualitative- based on descriptions using senses
b. Quantitative- based on numbers and formulas
4. An experiment compares an experimental group with a control group.
a. Experimental group (treatment group) -the group that receives the variable being tested
b. Control group- the group that does not receive the tested variable
5. Hypotheses can be tested in humans with clinical trials, as well as retrospective or prospective obser-
vational studies.
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Themes in the Study of Biology
Properties of life include
1. Order—the highly ordered structure that typifies life,
2. Reproduction—the ability of organisms to reproduce their own kind,
3. Growth and development—consistent growth and development controlled by
inherited DNA,
4. Energy processing—the use of chemical energy to power an organism’s activities and chemi-
cal reactions,
5. Response to the environment—an ability to respond to environmental stimuli,
6. Flow of information- inheritance passes genetic information on to each generation
7. Regulation—an ability to control an organism’s internal environment within limits that sustain
life, and
8. Evolutionary adaptation—adaptations evolve over many generations as individuals with traits
best suited to their environments have greater reproductive success and pass their traits to off-
spring.
Some Majors Themes in Biology
1.9 Theme: Evolution is the core theme of biology
1. Life is distinguished by its unity and its diversity.
2. The scientific explanation for this unity and diversity is evolution, the process of change that has
transformed life on Earth from its earliest forms to the vast array of organisms living today.
1.11 Theme: Life depends on the flow of information
1. The processes of life all depend on the transmission and use of information.
a. DNA is responsible for heredity and for programming the activities of a cell by providing the
blueprint for proteins.
b. Information from the external and internal environment includes the stimuli, signals, and pathways
that regulate body processes and gene expression.
1.12 Theme: Structure and function are related
1. The relationship between structure and function can be observed at every level of life.
2. On the cellular level, the long extensions of nerve cells enable them to transmit impulses from your
spinal cord to your toes.
1.13 Theme: Life depends on the transfer of energy and the transformation of matter
1. Energy is one way flow in an ecosystem
2. Matter is recycled in an ecosytem
1.14 Theme: Life depends on interactions within and between systems
1. The study of life extends from the microscopic scale of the molecules and cells that make up an or-
ganism to the global scale of the living planet.
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Chapter 1 – Biology: Exploring Life
Word Parts
Word part Meaning Word part Meaning
a without, not, together graph, -graphy writing, write
archaea-, arch ancient, old karyo- nucleus
bi- two kilo- a thousand
bio- life logo, logous, logy word, study of
di- two -meter distance
eco- house, abode nomen, nom- name
-ell small pro- before
eu- true sphere ball, sphere
Vocabulary
1. biosphere- The entire portion of Earth inhabited by life; the sum of all the planet's ecosystems.
2. ecosystem- All the organisms in a given area, along with the nonliving (abiotic) factors with which
they interact; a biological community and its physical environment.
3. community- An assemblage of all the organisms living together and potentially interacting in a particular
area.
4. population- A group of individuals belonging to one species and living in the same geographic area.
5. organism- An individual living thing, such as a bacterium, fungus, protist, plant, or animal.
6. organ- A structure consisting of several tissues adapted as a group to perform specific functions.
7. organ system- A group of organs that work together in performing vital body functions.
8. tissue- An integrated group of cells with a common function, structure, or both.
9. cell- A basic unit of living matter separated from its environment by a plasma membrane; the
fundamental structural unit of life.
10. organelle- A membrane-enclosed structure with a specialized function within a cell.
11. molecule- A group of two or more atoms held together by covalent bonds.
12. emergent properties- New properties that emerge with each step upward in the hierarchy of
life, owing to the arrangement and interactions of parts as complexity increases.
13. prokaryotic cell- A type of cell lacking a membrane-enclosed nucleus and other membrane-
enclosed organelles; found only in the domains Bacteria and Archaea. Has circular
DNA and ribosomes.
14. eukaryotic cell- A type of cell that has a membrane-enclosed nucleus and other membrane-
enclosed organelles (e.g. vacuole, mitochondria). All organisms except bacteria and
archaea are composed of eukaryotic cells.
15. domain- A taxonomic category above the kingdom level. The three domains of life are Archaea,
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Bacteria, and Eukarya.
16. Archaea- One of two prokaryotic domains of life; extremophiles
17. Bacteria- One of two prokaryotic domains of life (e.g. E.coli)
18. Eukarya- The domain that includes all eukaryotic organisms.
19. Kingdom- In classification, the broad taxonomic category above phylum.
20. Species- The lowest taxonomic rank, and the most basic unit or category of biological classification
21. hypothesis- (plural, hypotheses) A tentative explanation a scientist proposes for a specific phenomenon
that has been observed. Written in “If…then…because” format.
21. theory- A widely accepted explanatory idea that is broad in scope and supported by a large body of
evidence. (e.g Big bang, evolution)
23. independent variable- a variable that is intentionally changed to observe its effect on the
dependent variable
24. dependent variable- the event studied and expected to change when the independent variable is changed
25. controlled variable- what is kept the same throughout the experiment, and it is not of primary concern
in the experimental outcome.
26. constant- something invariable or unchanging; a number that has a fixed value in a given situation or
universally
27. controlled experiment- A component of the process of science whereby a scientist carries out two
parallel tests, an experimental test and a control test. The experimental test
differs from the control by one factor, the independent variable which is being
changed.