Foundations of General Biology: Scientific Method, Ecology, and Evolution

Scientific Method and Biological Inquiry

Overview of the Scientific Method

The scientific method is a systematic approach used in biology to investigate natural phenomena. It involves making observations, forming hypotheses, conducting experiments, and drawing conclusions.

• Steps of the Scientific Method:

  1. Observation

  2. Question

  3. Hypothesis (testable explanation)

  4. Experimentation

  5. Data Collection and Analysis

  6. Conclusion

  7. Communication of Results

• Scientific Theories: Broad explanations supported by extensive evidence; differ from casual use of the word "theory" (which may mean a guess or assumption).

• Scientific Method Styles: Both stepwise and cyclic, allowing for repeated testing and refinement.

Scientific Communication

• Peer-Reviewed Journal Article: A scholarly article evaluated by experts before publication. Typical parts include:

  • Abstract

  • Introduction

  • Materials and Methods

  • Results

  • Discussion

  • Works Cited

Types of Observations and Measurements

• Subjective Observation: Based on personal feelings or opinions.

• Objective Observation: Based on measurable facts and evidence.

• Precision vs. Accuracy:

  • Precision: Consistency of repeated measurements.

  • Accuracy: How close a measurement is to the true value.

Biology: The Study of Life

Defining Biology

Biology is the scientific study of living organisms and their interactions with the environment.

• Hierarchy of Organization: Atoms → Molecules → Cells → Tissues → Organs → Organ Systems → Organism

• Levels of Organization (smallest to largest): Organism, Population, Community, Landscape/Ecosystem, Biome

Major Theories in Biology

• Cell Theory: All living things are composed of cells; the cell is the basic unit of life.

• Evolution: Populations of organisms change over time through processes such as natural selection.

Characteristics of Living Things

• Use energy

• Maintain homeostasis

• Adapt to environments

• Grow and develop

• Reproduce

Experimental Design and Data Analysis

Key Terms and Variables

• Sample: Subset of a population used for study.

• Population: Group of individuals of the same species in a given area.

• Mean (average): Sum of all values divided by the number of values.

• Dependent Variable: The variable measured in an experiment.

• Independent Variable: The variable that is changed or controlled.

• Control: Standard for comparison in an experiment.

• Null Hypothesis: Assumes no difference between groups.

• Alternative Hypothesis: Assumes a specific effect or relationship will occur.

Thermodynamics in Biology

• First Law (Conservation of Mass & Energy): Energy cannot be created or destroyed, only transformed.

• Second Law (Entropy): Entropy (randomness/disorder) increases in a closed system.

• Application: These laws explain energy flow and nutrient cycling in ecosystems.

Types of Energy

• Kinetic Energy: Energy of a moving object; energy that is released.

• Potential Energy: Stored energy due to position or structure.

Ecology: Interactions and Organization

Ecological Terms and Trophic Levels

• Primary Producer: Autotroph; produces own food (e.g., plants, algae).

• Primary Consumer: Herbivore; eats primary producers.

• Secondary Consumer: Carnivore; eats primary consumers.

• Tertiary Consumer: Eats secondary consumers.

• Autotroph: Organism that produces its own food (usually via photosynthesis or chemosynthesis).

• Heterotroph: Organism that obtains food from other organisms.

Ecological Concepts

• Biological Hotspots: Regions with high species diversity and endemism.

• Endemic Species: Species native to a specific region.

• Dominant Species: Most abundant species in an ecosystem.

• Keystone Species: Species with a disproportionately large effect on its ecosystem.

• Ecosystem Resistance: Ability to withstand disturbance.

• Ecosystem Resilience: Ability to recover after disturbance.

• Ecosystem Services: Benefits provided by biodiversity (e.g., medicines, carbon storage, food).

• Overpopulation: When population consumes more resources than sustainable.

• Niche: Specific role or function of an organism in its ecosystem.

Biomes and Environmental Factors

• Biomes: Large geographic areas with similar climate, plants, and animals (e.g., Arctic, tundra, boreal/taiga).

• Eutrophication: Water becomes enriched with nutrients, leading to excessive growth of algae.

• Species-Area Curve: Shows relationship between area surveyed and number of species found; more area usually means more species.

Taxonomy and Classification

• Taxonomic Order (largest to smallest): Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species

• Three Domains of Life: Bacteria, Archaea, Eukarya

Evolutionary Biology

• Ancestral Traits: Traits shared with a common ancestor.

• Derived Traits: Traits that have evolved from ancestral traits.

• Homologous Traits: Similar structure, different function; share ancestry.

• Analogous Traits: Similar function, different ancestry and structure.

• Paedomorphism: Retention of juvenile traits into adulthood.

Sample Table: Trophic Levels and Examples

Trophic Level	Definition	Example
Primary Producer	Autotroph; produces own food	Grass, algae
Primary Consumer	Eats primary producers (herbivore)	Cow, caterpillar
Secondary Consumer	Eats primary consumers (carnivore)	Frog, small bird
Tertiary Consumer	Eats secondary consumers	Hawk, snake

Key Equations

• Mean (Average): $\text{Mean} = \frac{\sum x_i}{n}$

• Species-Area Relationship: $S = cA^z$ Where $S$ = number of species, $A$ = area, $c$ and $z$ are constants.

Additional info: Some explanations and examples have been expanded for clarity and completeness.