Introduction to Biology

Definition and Scope of Biology

Biology is the scientific study of life and living organisms. The term comes from the Greek words bios (life) and logos (study). Biology seeks to answer fundamental questions about the nature of life through observation, experimentation, and analysis.

• Biology is an ongoing inquiry into the nature of life.

• It encompasses a wide range of subfields and applications.

Subdivisions of Biology

Biology is divided into several specialized fields, each focusing on different aspects of living organisms:

• Botany: Study of plants

• Zoology: Study of animals

• Microbiology: Study of microorganisms

• Immunology: Study of the immune system

• Pathology: Study of diseases

• Histology: Study of tissues

• Ornithology: Study of birds

• Entomology: Study of insects

• Herpetology: Study of reptiles and amphibians

Terminology in Biology

Many biological terms are derived from Greek and Latin roots. Understanding these roots can help decipher the meaning of complex scientific vocabulary.

• Examples: cyto- (cell), derm- (skin), hemo- (blood)

Interdisciplinary Nature of Biology

Modern biology is built upon principles from other sciences:

• Chemistry: Understanding molecular and cellular processes

• Physics: Explaining energy and physical laws in biological systems

• Mathematics: Analyzing data and modeling biological phenomena

Why Study Biology?

• To improve the human condition (e.g., crop improvements, antibiotics, disease control)

• To make intelligent and ethical decisions (e.g., genetic engineering, environmental policy)

• To understand the natural world and our place in it

Properties of Living Organisms

Common Characteristics

All living organisms share several fundamental properties:

• Complex organization (based on DNA/RNA)

• Growth and development (can change organization over time)

• Use of energy (intake, transformation, and utilization)

• Reproduction (produce offspring similar to parents)

• Response to stimuli (external and internal)

• Adaptation (to their environment)

• Intraspecific variation (variation within a species)

• Homeostasis (maintenance of stable internal conditions)

Organization of Living Things

Levels of Biological Organization

Biological systems are organized in a hierarchy from smallest to largest:

• Atoms → Molecules → Organelles → Cells → Tissues → Organs → Organ Systems → Organisms → Populations → Communities → Ecosystems → Biosphere

Classification of Organisms

Organisms are classified based on evolutionary relationships and shared characteristics.

• Estimated number of named species: 2.3 million

• Estimated total species: 10–20 million

Taxonomic Hierarchy (from most inclusive to least inclusive):

• Domain

• Kingdom

• Phylum (plural: phyla)

• Class

• Order

• Family

• Genus

• Species

The Three Domains of Life

• Bacteria: Unicellular prokaryotes, lack a nucleus, "before nucleus"

• Archaea: Unicellular prokaryotes, often extremophiles (e.g., thermophiles, halophiles, acidophiles)

• Eukarya: Unicellular and multicellular eukaryotes, have a nucleus; includes Kingdoms Animalia, Plantae, Fungi, and several other kingdoms

The Process of Science

Definition and Nature of Science

Science (from Latin "to know") is a way of knowing about the natural world. It is characterized by:

• Curiosity and asking questions (why, how)

• Attempting to answer questions through experimentation

• Focus on natural phenomena (that can be studied by people)

• Skepticism until claims are supported by rigorous evidence

Inductive vs. Deductive Reasoning

• Inductive reasoning: Deriving generalizations from many observations (looking for patterns)

• Deductive reasoning: Using general principles to make specific, testable predictions

Both types of reasoning are used in scientific investigations.

The Scientific Method

The scientific method is a systematic approach to inquiry:

1. Make observations

2. Formulate a hypothesis (an educated scientific prediction)

3. Design and conduct an experiment (collect data)

4. Analyze results (using statistics)

5. Determine if results support the hypothesis

6. Communicate findings with the wider scientific community

Latin and Greek Roots in Biology

Importance of Roots

Understanding Latin and Greek roots helps decipher the meaning of many biological terms without memorizing each word individually.

Example: The word erythrocyte can be broken down into erythro- (red) and -cyte (cell), meaning "red cell" (a red blood cell).

Study Tips for Biology

• Take good notes that include key concepts and terminology.

• Review notes after each class to ensure understanding.

• Use concept checks and chapter reviews in the textbook.

• Form study groups to discuss and quiz each other.

• Analyze mistakes on quizzes and tests to understand why answers are right or wrong.

Additional info:

• Some content was inferred and expanded for clarity and completeness, such as the explanation of the scientific method and the importance of Latin/Greek roots.

• Tables were recreated and condensed for readability; refer to the original for a more comprehensive list of roots.