Chapter 1: Introduction to Biology – The Nature of Science & the Characteristics of Life

Vocabulary flashcards covering key terms from the lecture notes on science, biology, the scientific method, viruses, and the properties of life.

Science

A systematic process of understanding the natural world based on evidence and observation.

Biology

The scientific study of life and its diverse forms and processes.

Observation

Noticing and describing phenomena using the senses; the starting point of scientific inquiry.

Hypothesis

An educated, testable explanation that identifies a natural cause for an observation.

Prediction

A testable forecast derived from a hypothesis, often written as an if…then statement.

Experimentation

Testing predictions by manipulating variables under controlled conditions.

Descriptive science

Science that describes natural phenomena through observation and data without manipulation.

Theory

A broad, well-supported explanation that unifies many related phenomena.

Cell theory

All living things are composed of cells; the cell is the basic unit of life; new cells arise from existing cells.

Theory of evolution

A broad explanation for the diversity of life through natural selection.

Preformation Theory

An obsolete idea that a miniature human (homunculus) is contained in the sperm or egg.

Homunculus

A supposed miniature human believed to reside in sperm (as per Preformation Theory).

Semen

Male reproductive fluid; discussed in historical contexts of development theories.

Phlogiston Theory

An obsolete theory proposing a fire-like element released during combustion.

Spontaneous Generation

The obsolete belief that life arises from nonliving matter; disproven by experiments in the 17th–19th centuries.

Redi

Italian physician who challenged spontaneous generation with experiments on meat and maggots.

Louis Pasteur

Scientist whose experiments helped disprove spontaneous generation and supported germ theory.

Germ theory

The idea that many diseases are caused by microorganisms.

Falsifiability

A criterion that a scientific hypothesis must be testable and potentially disprovable.

Emergent properties

New characteristics that arise at higher levels of organization and are not present at lower levels.

Biological hierarchy

Organization of life from molecules to the biosphere, with new properties at each level.

Biosphere

The global sum of all ecosystems where life exists on Earth.

Molecule

Two or more atoms bonded together; the basic unit of chemical compounds.

Cell

The basic unit of life; the smallest unit that can carry out all life processes.

Nucleus

The organelle in eukaryotic cells that houses DNA and controls cellular activities.

DNA

Deoxyribonucleic acid; the genetic material that encodes hereditary information.

Virus

A non-cellular infectious agent that requires a host cell; can have DNA or RNA and evolves; not alive by strict definitions.

Obligate intracellular parasite

A parasite that must live inside a host cell to reproduce.

Not alive by strict biological definitions

Viruses lack cellular structure and independent metabolism, challenging strict life criteria.

Autotroph

Organisms that capture energy from sunlight or chemical sources to make their own food.

Heterotroph

Organisms that obtain energy by consuming organic matter made by others.

Photosynthesis

Process by which autotrophs convert light energy into chemical energy (sugars).

Cellular respiration

Metabolic process by which cells convert sugars into ATP energy.

Energy Processing/Metabolism

All organisms obtain and use energy for maintenance, growth, and reproduction. Ex. ATP

Order (Property of Life)

Living systems are highly organized; cells are the basic units of organization. Ex. Cells

Sensitivity/Response to Stimuli

Organisms detect and respond to environmental changes or signals. Ex. Pain

Reproduction

The process by which living things propagate their genetic material to offspring. Ex. Replication

Growth and Development

Directed increase in size and complexity over an organism’s life cycle. Ex. Cycle of life

Adaptation

Evolutionary changes in populations that enhance survival and reproduction in an environment. Ex. Evolution , not acclimation

Regulation

Active management of cellular processes and internal functions. Ex. Action for management

Homeostasis

Maintenance of a constant internal environment in the face of external change.