Key Concepts: Scientific Inquiry, Data, and Biology Lab Essentials

Observation and Hypothesis

• Observation identifies a problem or question in the environment.

• Hypothesis: a testable explanation; can be stated as a condition-action form; may be written as $\text{Hypothesis: If } X \text{ then } Y$.

• Inductive reasoning: form explanations from specific observations.

• Example (sheep): observation about Cedars + progesterone; hypothesis: $\text{If Cedars are given and followed by a progesterone shot, then more lambs will be born.}$

Experimental Design: Variables and Groups

• Independent Variable (IV) / Experimental variable: what you intentionally change.

• Dependent Variable (DV) / Data: what you measure (outcome).

• Controlled Variables (CV): factors kept the same.

• Control Group: no treatment or standard condition.

• Experimental Group: receives the treatment.

• Principle: change one thing at a time to isolate effect.

• Outcome: a study tests whether data support or reject the hypothesis; not prove; replication needed.

• Funding and bias: consider who funded the study, as it can influence interpretation.

Data and Reasoning

• Qualitative data: non-numeric (color, smell, etc.).

• Quantitative data: numeric.

• Continuous data: values can vary smoothly (temperature, weight).

• Discrete data: categories (countable, e.g., number of lambs).

• Descriptive analysis: mean, median, range, outliers; statistical significance.

Graphs and Visualization

• Pie chart: parts of a whole; base 100%.

• Bar graph: discrete categories; spaces between bars.

• Histogram: distribution of continuous data; no spaces; shows shape.

• Line graph: changes over time; continuous data.

• Scatter plot: relationships between two variables; look for correlation; trend line; outliers.

Model Systems and Simulations

• Model organisms: mice, pigs; used for ethical/scope reasons.

• Computer modeling: population studies; simulate scenarios.

• Use when real-world studies are impractical or unethical.

Publication, Theories, and Evidence

• Peer-reviewed journals: quality check; not everything is published; subject to bias or funding.

• Theories: highly supported ideas; difficult to overturn; e.g., cell theory.

• Knowledge evolves: examples of shifts over time; viruses living status debated.

• Distinguish evidence from belief: rely on repeatable results.

Basics of Chemistry for Biology

• Matter forms: solid, liquid, gas; plasma (electrically charged gas; common in cosmos, rare on Earth).

• Elements: defined on periodic table; atoms as building blocks.

• Atom structure: nucleus with protons (+1) and neutrons (0); electrons (-1) orbiting.

• Atomic mass units (AMU): proton ≈ 1 AMU; neutron ≈ 1 AMU; electron ≈ 0 AMU.

• Water: $\mathrm{H_2O}$ (two hydrogens, one oxygen).

• Life chemistry: primarily $\text{C}, \text{H}, \text{O}$; water essential.

• Note: bonds and interactions at the atomic level underpin biology.

Quick Reference: Practice Mindset

• One study ≠ proof of a universal conclusion; replication matters.

• Always consider what might be holding variables constant and what could be confounding factors.

• When evaluating information, check funding sources and multiple studies.