Key Scientists
He boiled broth... but not for long enough, mistakenly “supporting” spontaneous generation.
John Needham
What energy source did the Urey–Miller experiment use to simulate lightning?
An electrical spark
The scientist who named “cells” after observing cork.
Robert Hooke
This 1665 book by Robert Hooke described the first observations of “cells” in cork.
Micrographia
The smallest unit of life.
A cell
Used sealed broth experiments to show microbes came from the air, not broth.
Lazzaro Spallanzani
Meat left uncovered attracted maggots, but covered meat did not. What idea did this challenge?
Spontaneous generation
Proposed all plants and animals are made of cells.
Matthias Schleiden and Theodor Schwann
What gases were included in the Urey–Miller setup to simulate early Earth?
Methane (CH₄), ammonia (NH₃), hydrogen (H₂), and water vapor (H₂O)
All living things maintain a stable internal environment, a process called ____.
Homeostasis
Used curved-neck flasks to disprove spontaneous generation.
Louis Pasteur
In the Urey–Miller experiment, gases like methane, hydrogen, ammonia, and water were used. What important molecules formed as a result?
Amino acids (organic molecules)
Scientist who discovered that all cells come from pre-existing cells.
Rudolf Virchow
What feature of mitochondria and chloroplasts provides strong evidence for endosymbiosis?
They contain their own DNA and ribosomes.
Living things use energy to build and break down molecules. This set of processes is called ____.
Metabolism
He showed that maggots on meat came from flies, not the meat itself.
Francesco Redi
Curved-neck flasks showed that no life appeared unless dust and microbes reached the broth. What principle did this prove?
Biogenesis (life comes from life)
The three main points of classical cell theory include: (1) All organisms are made of cells, (2) Cells are the basic unit of life, and (3) ____.
“All cells come from pre-existing cells”
Which gas was absent from Earth’s early atmosphere (and Urey-Miller's Experiment) but is abundant today?
Oxygen (O₂)
When a seed grows into a plant or a tadpole becomes a frog, this life characteristic is being demonstrated.
Grow and change
These two scientists simulated early Earth conditions to create amino acids.
Stanley Miller and Harold Urey
Margulis proposed that mitochondria and chloroplasts were once free-living bacteria that formed a partnership inside cells. What theory is this?
Endosymbiotic theory
He observed blood cells, sperm cells, and bacteria, opening up a new world of microscopic life.
Anton van Leeuwenhoek
Mitochondria and chloroplasts likely originated from these.
Free-living bacteria
Populations of living things change over time, passing traits to offspring. This long-term change is called ____.
Evolution