Cell Types - Prokaryotic vs. Eukaryotic
Cell Types
You know that the cell is the basic unit of structure and function in all living organisms. In your body, cells are the units that build the tissues of your organs – your heart, lungs and skin, for example. Other, simpler organisms exist as a single cell. However, the cells of all living organisms have the same basic structure. In this interactivity, learn about the two basic types of cells and how their names originated. Click the player button to begin.
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The Search for the Origin of Life
When life first began on Earth, the atmosphere of the planet was very different. Earth’s early atmosphere did not have oxygen and was rich in poisonous gases, like carbon dioxide and carbon monoxide. Scientists still study how life originated on Earth today. They search for areas where conditions like those that produced Earth’s first life forms are present. One example is the deep hydrothermal vents in the oceans. However, studying these vents is dangerous and expensive. To help, scientists study structures similar to hydrothermal vents that are available on the surface of Earth, like Yellowstone National Park. View The Search for the Origin of Life: Early Earth from eMediaVASM to learn how two scientists are exploring Yellowstone National Park to observe the chemical reactions that could provide clues for how life originated on Earth.
Origins of Life
If you traveled back to the formation of Earth, you would find that the recently-formed planet was much different than it is today. Scientists believe that cells began as simple prokaryotic cells and evolved into more advanced eukaryotic cells. In this interactivity, learn about the early Earth and the origins of life. Click the player button to begin.
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Experiments and Theories Explaining the Origins of Life
Fossil evidence suggests that Earth’s first life forms were primitive prokaryotic cells. Early ideas about the origins of life included the idea of spontaneous generation, or that that living things come from non-living things. Once, people believed that mice came from a pile of dirty laundry, or that maggots came from rotting meat. Scientists who performed experiments to test the idea of spontaneous generation found that life could not come from non-life. In this interactivity, learn about the different experiments and theories that attempted to explain how life originated on Earth. Click the player button to begin.
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Revealing the Origins of Life
In 1953, Stanley Miller's experiments showed how amino acids could be created in conditions similar to those present on the early Earth. These experiments discredited the ideas of spontaneous generation. However, they did not show how DNA and RNA could be created from the primordial soup of early Earth. DNA and RNA are complete molecules. They make possible the inheritance of genetic information, which is essential to life. View Revealing the Origins of Life from eMediaVASM to learn how new experiments, similar to the experiments by Miller, were successful in producing RNA.
Cell Types Review
Now that you have learned the different cell types, complete this activity to check your knowledge. In this non-graded interactivity, drag the words or phrases and drop them into the correct location on the Venn Diagram. Click the player button to get started.