Biology as a Science: Origin of Life & Unifying Themes

Thirty vocabulary flashcards summarizing key terms from the lecture on biology as a science, origin-of-life experiments, and the unifying characteristics of living organisms.

Biology

The scientific study of life and living organisms.

Hypothesis-Based Science

An approach that tests specific, explanatory statements through controlled experiments.

Discovery-Based Science

Observation-driven inquiry that collects data without a predefined hypothesis.

Scientific Method

A logical process involving problem identification, data collection, hypothesis formation, experimentation, and conclusion.

Identify the Problem

The first step of the scientific method that frames a clear research question.

Gather Data

Collecting background information and observations to inform a hypothesis.

Hypothesis

A tentative, testable explanation for an observed phenomenon.

Experiment

A controlled procedure designed to test a hypothesis.

Abiogenesis

The idea that life can arise from nonliving matter; also called spontaneous generation.

Spontaneous Generation

Historic belief, championed by Aristotle, that living things originate from inanimate material.

Biogenesis

The principle that life arises only from pre-existing life.

Aristotle (Origin of Life)

Ancient philosopher who proposed that life could spontaneously emerge from nonliving matter.

Francesco Redi

Italian physician (1668) whose meat-and-maggot experiment challenged spontaneous generation.

Redi’s Experiment

Showed that maggots come from fly eggs, not from meat itself, supporting biogenesis.

John Needham

English priest (1745) who boiled broth briefly and claimed microbial life appeared spontaneously.

Needham’s Experiment

An attempt to support spontaneous generation; lacked adequate sterilization controls.

Lazzaro Spallanzani

Italian scientist (1767) who fully boiled and sealed broth, preventing microbial growth.

Spallanzani’s Experiment

Demonstrated that microorganisms enter from the air, disputing spontaneous generation claims.

Louis Pasteur

French chemist (1861) whose swan-neck flask experiment definitively supported biogenesis.

Pasteur’s Experiment

Used S-shaped flasks to show sterile broth remained microbe-free until exposed to airborne particles.

S-Shaped Neck Flask

Curved glassware that traps dust and microbes, allowing air in but preventing contamination.

Metabolism

The chemical processes that convert energy to power cellular activities.

Evolutionary Adaptation

The capacity of populations to change genetically over generations to fit their environment.

Heredity

Transmission of genetic information guiding growth and development.

Cellular Organization

Highly ordered structure in which the cell is the basic unit of life.

Homeostasis

Regulation of internal conditions to maintain a stable, balanced state.

Interdependence (Responsiveness)

The ability of organisms to detect and respond to environmental stimuli.

Reproduction

The biological process by which organisms produce offspring of their own kind.

Unifying Themes of Life

Common characteristics—metabolism, evolution, heredity, cellular organization, homeostasis, interdependence, and reproduction—shared by all living things.

Origin of Life Question

The scientific inquiry into how life first emerged on Earth.