Bio 111 – General Biology I: Chapter 1 – The Science of Biology, Scientific Method, Characteristics of Life, Unity and Diversity of Life

What is biology? the study of life (bio = life, -logy = to study)
How do scientists study life? (refer to the overview of methods and inquiry that follow in the Scientific Method section)

A set of guidelines to use when investigating an unknown
7 main steps to the scientific method
Step 1: Observation
- Definition: to notice and register as significant
Step 2: Question
- The scientific mind asks “why”
- Start to explore, do research, ask around
Step 3: Hypothesis
- An educated guess as to what could be going on
- Can have more than one guess/idea
- Must be testable
- Science cannot answer questions about God, ethics, etc
Step 4: Prediction
- “Formal hypothesis”
- Written in an If… then… format
- Has to be testable
Step 5: Experiment
- Controlled experiment with 2 groups:
- Control group: designed to mimic the “normal” state of things
- Experimental group: identical to control except for one variable
- Data collection
Step 6: Results (data)
- Numbers, graphs, tables
- Data analysis
Step 7: Conclusion/Discussion
- Do the data support the hypothesis?
- Report results/peer review
- Repeat, revise, repeat, revise, repeat…
The ultimate goal of science is to understand the natural world in terms of a theory
A theory is a related set of hypotheses that explain a natural phenomenon
Examples: The theory of gravity, the cell theory of life, the germ theory of disease, the theory of evolution
A theory is accepted as true but is always open for improvement, refinement, additions

Basic science: goal is to expand knowledge regardless of short-term public or commercial value
Applied science: goal is to solve real-world problems (e.g., improve crop yield, find a cure, protect species from extinction)

Order of organization begins with chemistry: atoms → molecules; example: Glucose (C6H12O6) with composition 6 carbons, 12 oxygens, 6 hydrogens
Organelles as the nucleus example:
- The nucleus, dyed blue in these onion cells, is an example of an organelle
In a forest, each pine tree is an organism
Populations: Together, all the pine trees make up a population
Communities: All plant and animal species in the forest comprise a community
Cells: Human blood cells
Tissues: Human skin tissue
Organs and Organ Systems: Organs, such as the stomach and intestine, make up the human digestive system
Ecosystems: This coastal ecosystem in the southeastern United States includes living organisms and the environment in which they live
The Biosphere: Encompasses all the ecosystems on Earth
Choices (for matching levels to terms): organs, biosphere, tissue, ecosystem, organism, cell, organelle, population, community

Organelles: The nucleus (in onion cells) is an organelle
Organisms, Populations, and Communities:
- Forest example: pine trees as organisms; all trees as a population; forest as a community
Cells: examples include human blood cells
Tissues: human skin tissue
Organs and Organ Systems: stomach and intestine → digestive system
Ecosystems: coastal ecosystem example
The Biosphere: all ecosystems on Earth

Taxonomy: the science of identifying, classifying, and naming living organisms
Carl Linnaeus (1707–1778), “father” of taxonomy
Binomial nomenclature:
- First name = Genus
- Second name = species
- Example: Ursus maritimus, Ursus arctos, Ursus americanus
Unity and Diversity of Life
- Phylogenetic Tree concept (evolutionary relationships using genetic information)
- Dr. Carl Woese (UIUC) used genetic information to determine evolutionary relationships

Cell Type:
- Prokaryotic Cell: very simple in structure
- Eukaryotic Cell: complex in design; contain nuclei and other membrane-bound organelles
Number of Cells:
- Unicellular or multicellular
Mode of Nutrition:
- Autotroph – self-feeder
- Heterotroph – relies on other food

Unity – shared characteristics, including DNA
Ancestry traced to a common ancestor
Diversity – evolution and adaptation have occurred, leading to a large variety of life
Estimated number of species: more than $8.7 \times 10^6$ (≈ $8.7\times 10^6$ )

The theory is not “proved true” in an absolute sense but is supported by a large body of evidence
Scientific inquiry recognizes limits where questions of ethics, meaning, and values fall outside the scope of empirical investigation

Biology: $\text{the study of life}$
The Scientific Method: $7$ steps with structured flow from Observation to Conclusion
If… then… format for predictions: $\text{If } P, \text{ then } Q$
Autotroph: $\text{self-feeder}$ ; Heterotroph: $\text{relies on other food}$
Levels of Organization: organelle, cell, tissue, organ, organ system, organism, population, community, ecosystem, biosphere
Binomial nomenclature: Genus + species (e.g., $\textit{Ursus maritimus}$ )
3 Domains: $3$ domains: $Eukarya,\; Bacteria,\; Archaea$
Phylogenetic Tree: represents evolutionary relationships using genetic information
Common ancestor: unity across diverse forms of life via shared ancestry
Theories mentioned: gravity, cell theory, germ theory, theory of evolution