Chapter 1: Introduction to Biology – Study Guide

Chapter 1: Introduction to Biology

Vocabulary

This section introduces key terms essential for understanding the foundations of biology. Mastery of these terms is crucial for success in the course.

• Artificial selection: The process by which humans breed plants and animals for particular genetic traits.

• Biology: The scientific study of life and living organisms.

• Biosphere: All regions on Earth where life exists, including land, water, and the atmosphere.

• Cell: The basic structural and functional unit of all living organisms.

• Community: All the different populations that live together in a defined area.

• Controlled experiment: An experiment in which only one variable is changed at a time.

• Data: Recorded observations or measurements collected during scientific investigation.

• Dependent variable: The variable being tested and measured in an experiment.

• Domain: The highest taxonomic rank in the classification of organisms, above kingdom.

• Ecosystem: A community of living organisms and their physical environment interacting as a system.

• Emergent properties: New properties that arise with each step upward in the hierarchy of life, due to the arrangement and interactions of parts as complexity increases.

• Evolution: The process by which different kinds of living organisms develop and diversify from earlier forms.

• Experiment: A scientific procedure undertaken to test a hypothesis.

• Gene: A segment of DNA that codes for a specific protein or function.

• Gene expression: The process by which information from a gene is used to synthesize a functional gene product, often a protein.

• Hypothesis: A testable explanation for an observation or scientific problem.

• Independent variable: The variable that is changed or controlled in a scientific experiment.

• Molecule: Two or more atoms held together by covalent bonds.

• Natural selection: The process by which organisms better adapted to their environment tend to survive and produce more offspring.

• Organ: A group of tissues that work together to perform a specific function.

• Organ system: A group of organs that work together to perform complex body functions.

• Organelle: Specialized structure within a cell that performs a specific function.

• Population: A group of individuals of the same species living in a particular area.

• Science: The systematic study of the structure and behavior of the physical and natural world through observation and experiment.

• Systems biology: The computational and mathematical analysis and modeling of complex biological systems.

• Technology: The application of scientific knowledge for practical purposes.

• Theory: A well-substantiated explanation of some aspect of the natural world that is based on a body of evidence.

• Tissue: A group of similar cells that perform a specific function.

Key Concepts

Properties and Organization of Life

Biology seeks to understand the characteristics and organization of living things. The following concepts are foundational:

• 7 Properties Common to All Life: Order, evolutionary adaptation, response to the environment, regulation, energy processing, growth and development, and reproduction.

• Levels of Biological Organization: Life is organized in a hierarchy from molecules to the biosphere. The main levels are: molecule → organelle → cell → tissue → organ → organ system → organism → population → community → ecosystem → biosphere.

• Emergent Properties: New properties that arise at each level of organization, not present at the preceding level.

• Example: A single neuron cannot think, but a network of neurons (the brain) can produce thought.

Classification and Domains of Life

Organisms are classified into three domains based on genetic and cellular differences:

• Three Domains: Bacteria, Archaea, and Eukarya.

• Subgroups in Domain Eukarya: Includes kingdoms such as Plantae, Fungi, Animalia, and various protists.

• Taxonomic Hierarchy: Domain → Kingdom → Phylum → Class → Order → Family → Genus → Species.

• Example: Homo sapiens (humans) belong to Domain Eukarya, Kingdom Animalia.

Scientific Inquiry and Experimental Design

Science relies on systematic investigation and experimentation to answer questions about the natural world.

• Qualitative vs. Quantitative Data: Qualitative data describes qualities or characteristics; quantitative data involves numerical measurements.

• Hypothesis vs. Scientific Theory: A hypothesis is a testable statement; a theory is a broad explanation supported by extensive evidence.

• Controlled Experiment: An experiment in which only one variable (the independent variable) is changed, while all others are kept constant.

• Variables: Independent variable is manipulated; dependent variable is measured.

• Example: Testing the effect of sunlight on plant growth by varying light exposure (independent variable) and measuring plant height (dependent variable).

Evolution and Natural Selection

Evolution is the central theme of biology, explaining the diversity and unity of life.

• Natural Selection: The process by which individuals with advantageous traits survive and reproduce more successfully.

• Artificial Selection: Humans select for desirable traits in organisms.

• Comparison Table:

Feature	Natural Selection	Artificial Selection
Agent of Selection	Environment	Humans
Purpose	Adaptation to environment	Desired traits for human use
Example	Darwin's finches	Dog breeds

Unifying Themes of Biology

Several core themes connect all areas of biology:

• Evolution

• Information flow (genetics and gene expression)

• Structure and function

• Energy and matter pathways

• Interactions within systems

Science, Technology, and Society

Science and technology are interconnected, with discoveries in one often leading to advances in the other.

• Science: Seeks to understand natural phenomena.

• Technology: Applies scientific knowledge for practical purposes.

• Example: Discovery of DNA structure (science) led to genetic engineering (technology).

Energy Flow and Nutrient Cycling in Ecosystems

All living organisms require energy and nutrients, which flow and cycle through ecosystems.

• Producers: Organisms (like plants) that convert solar energy into chemical energy.

• Consumers: Organisms that obtain energy by eating other organisms.

• Decomposers: Break down dead matter, returning nutrients to the environment.

• Energy Flow: Energy flows one-way through ecosystems, while nutrients cycle.

Types of Science

Biology uses various scientific approaches to understand life:

• Discovery Science: Describes nature through observation and analysis of data.

• Hypothesis-Driven Science: Uses the scientific method to test specific hypotheses.

Summary Table: Levels of Biological Organization

Level	Description
Molecule	Group of atoms bonded together
Organelle	Specialized structure within a cell
Cell	Basic unit of life
Tissue	Group of similar cells performing a function
Organ	Group of tissues working together
Organ System	Group of organs performing complex functions
Organism	Individual living thing
Population	Group of individuals of the same species
Community	All populations in a given area
Ecosystem	Community plus physical environment
Biosphere	All ecosystems on Earth

Formulas and Equations

• Scientific Method (General Steps):

$\text{Observation} \rightarrow \text{Question} \rightarrow \text{Hypothesis} \rightarrow \text{Prediction} \rightarrow \text{Experiment} \rightarrow \text{Analysis} \rightarrow \text{Conclusion}$

• Energy Flow in Ecosystems:

$\text{Sunlight} \rightarrow \text{Producers} \rightarrow \text{Consumers} \rightarrow \text{Decomposers}$

Additional info:

• Some explanations and examples have been expanded for clarity and completeness.

• Tables have been recreated to summarize comparisons and hierarchies.