Evidence of Evolution

This illustration of the three domains of life is like a family tree. The branches that are very far apart are not very similar. Branches that are near each other indicate closely related groups.
Click on image for full size
Windows to the Universe original image

Evolution Hits the Beach

How Many Species Have There Been on Earth?

The Mystery of Mass Extinction is No Longer Murky

Early Whales Gave Birth on Land

What Is Evolution?

Evolution is the process of change through time. Many things evolve. Language evolves so that English spoken four hundred years ago during the time of playwright Shakespeare was very different than English spoken today. Technology evolves over time as new things are invented and modified. Scientific theories evolve as more data are collected and analyses are done. Life evolves over very long timescales as species change over many, many generations. This is called biological evolution. Evolution is the foundation for the modern sciences of paleontology (the study of fossils and the history of life), ecology (the study of ecosystems), and biology (the study of life) including medical science.

  • On a small scale, biological evolution is called microevolution and involves changes in the occurance of gene types in a population of the same species over several generations. These changes can lead to changes in the way a species looks over generations.
  • On a large scale, biological evolution is called macroevolution and involves the development of new species through cumulative genetic changes over many, many generations.

This Windows to the Universe Exploratour examines the scientific evidence for biological evolution. Click the “forward” button at the top of this page to continue the tour and learn more about the scientific basis of evolution.

Last modified May 15, 2009 by Jennifer Bergman.

You might also be interested in:

Cool It! Game

Check out our online store - minerals, fossils, books, activities, jewelry, and household items!...more

Evolution Impacts Environment, Study Finds

For a long time, scientists have known that how living things interact with their environment – ecology – has an impact on their evolution. Now, scientists have found that evolution has an impact on ecology...more

Finding the Four-Footed Ancestors of Whales

Scientists have known for a long time that whales, the largest marine mammals, have distant relatives that lived on land millions of years ago. Little was known about whales’ land-loving ancestors until...more

How Many Species Have There Been on Earth?

To predict the future diversity of life on Earth, scientists are turning to the fossil record of marine creatures – the ancestors of snails, clams, sand dollars, and crabs. Diversity is the number of species...more

Newly-Found Rock May Prove Antarctica and North America Were Connected

There are lots of rocks in Antarctica, but the one that scientists just found is special. It may provide evidence that part of Antarctica was connected to North America hundreds of millions of years ago....more

Fish Adapting to a Changing World

Scientists have been studying stickleback fish to learn more about how animals cope when their environment changes. Since the Earth is changing quickly because of global warming and other global changes,...more

Scientists Find Signs of “Snowball Earth” Amidst Early Animal Evolution

There used to be sea ice floating on the tropical ocean, according to new evidence found by geologists. This was quite a long time ago, 716.5 million years ago, during a time known as Snowball Earth. This...more

ExploraTour - Looking at the World in a Different Light

Even though the sleeping man is no longer on the bed, you can still see where he was lying down. The heat from his body warmed up the bed sheets which are now radiating infrared light toward your eyes....more

Windows to the Universe, a project of the National Earth Science Teachers Association, is sponsored in part is sponsored in part through grants from federal agencies (NASA and NOAA), and partnerships with affiliated organizations, including the American Geophysical Union, the Howard Hughes Medical Institute, the Earth System Information Partnership, the American Meteorological Society, the National Center for Science Education, and TERC. The American Geophysical Union and the American Geosciences Institute are Windows to the Universe Founding Partners. NESTA welcomes new Institutional Affiliates in support of our ongoing programs, as well as collaborations on new projects. Contact NESTA for more information. NASA ESIP NCSE HHMI AGU AGI AMS NOAA