Introduction to Biology: Life, Diversity, and Scientific Method

CH.1: Introduction: Biology Today

Defining Life: The Seven Characteristics

Biology is the study of living organisms, which are defined by seven key characteristics. Understanding these traits helps distinguish living things from non-living matter.

• Order: Living things have a complex, organized structure.

• Regulation: Organisms regulate their internal environment to maintain homeostasis (a steady state).

• Growth and Development: Living things grow and develop according to specific instructions coded in their DNA.

• Energy Processing: Organisms obtain and use energy to power their activities.

• Response to Environment: Living things respond to environmental stimuli.

• Reproduction: Organisms reproduce, passing their genetic material to offspring.

• Evolutionary Adaptation: Populations evolve over generations through adaptation.

Theme 1: The Scope of Life and Emergent Properties

Life is organized into levels, from molecules to the biosphere. Emergent properties arise at each level due to the arrangement and interactions of parts.

• Emergent Properties: New properties that arise at each level of biological organization.

Theme 2: Organisms Exchange Matter and Energy Within Ecosystems

All organisms interact with their environment, exchanging matter and energy. This is essential for maintaining life and ecosystem stability.

• Energy Flow: Energy enters ecosystems as sunlight and exits as heat.

• Chemical Cycling: Chemicals cycle between organisms and the environment.

Theme 3: Cells are an Organism's Basic Unit

The cell is the fundamental unit of life. All living things are composed of cells, which carry out essential functions.

• Cell Theory: All living organisms are made of cells; cells are the basic unit of structure and function.

Theme 4: The Continuity of Life is Based on Information in DNA

Genetic information is stored in DNA, which is passed from one generation to the next, ensuring continuity of life.

• DNA: Deoxyribonucleic acid, the molecule that carries genetic instructions.

Theme 5: Diversity is the Hallmark of Life and the Diverse Forms of Life Fit Their Functions

Life is incredibly diverse, and each organism's structure is adapted to its function in the environment.

• Adaptation: Traits that improve an organism's ability to survive and reproduce.

Classification of Life

The Three Domains

All life is classified into three domains, which represent the broadest categories of living organisms.

• Bacteria: Prokaryotic, unicellular organisms.

• Archaea: Prokaryotic, often found in extreme environments.

• Eukarya: Eukaryotic organisms, including plants, animals, fungi, and protists.

Taxonomy: Classifying the Diversity of Life

Taxonomy is the science of naming, describing, and classifying organisms. It organizes life into hierarchical categories.

• Domain

• Kingdom

• Phylum

• Class

• Order

• Family

• Genus

• Species

Mnemonic: Dear King Philip Came Over From Great Spain

Level	Example (Human)
Domain	Eukarya
Kingdom	Animalia
Phylum	Chordata
Class	Mammalia
Order	Primates
Family	Hominidae
Genus	Homo
Species	Homo sapiens

Theme 6: Evolution

Heritable Changes in Populations Over Generations

Evolution explains the unity and diversity of life. It is the process by which populations change over time due to genetic variation and natural selection.

• Unity of Life: All organisms share common features due to shared ancestry.

• Diversity of Life: Differences arise due to evolutionary changes.

The Scientific Method

Steps in Scientific Investigation

The scientific method is a systematic approach to understanding the natural world through observation and experimentation.

1. Observe and Question: Make observations and ask questions about phenomena.

2. Formulate a Hypothesis: Propose a testable explanation.

3. Make a Testable Prediction: Design an experiment to test the hypothesis.

4. Experiment: Collect data and analyze results.

5. Modify Hypothesis: Revise the hypothesis if necessary based on results.

6. Decision: Increase confidence in the hypothesis or reject it.

Example: Testing whether light affects plant growth by growing plants under different light conditions and measuring their growth.

Additional info: The notes provide a foundational overview of biology, including the characteristics of life, classification systems, and the scientific method, which are essential for understanding subsequent chapters in General Biology.