Exploratour - Life on Earth

Short-eared owl
Click on image for full size
Corel Photography

This tour is a detailed look at life on Earth, and what we know about how it came to be. To proceed with the tour, just click on the forward indicator in the "football" at the top right portion of this page.

If you had to explain to someone what "life" is, what would you tell them? Do all living things move? Do they eat and breathe? Even though we all seem to know what is meant by saying something is "alive", it's not very easy to describe what "life" is.

The study of life is called "biology" and the people who study it are "biologists". They even have a tough time describing what life is! But after many years of studying living things, from the mold on your old tuna sandwich to monkeys in the rainforest, biologists have determined that all living things, do share some things in common:

1) Living things need energy
2) Living things grow and develop
3) Living things respond to their surroundings
4) Living things reproduce

We will discuss some of these things in the pages that follow.

This is page 1 of 20

You might also be interested in:

Science, Evolution, and Creationism

How did life evolve on Earth? The answer to this question can help us understand our past and prepare for our future. Although evolution provides credible and reliable answers, polls show that many people turn away from science, seeking other explanations with which they are more comfortable....more

Exploratour - Life in the Solar System

Life as we know it on earth requires a certain environment to survive. Life on Earth can survive in temperatures of -130 degrees to +130 degrees. Even so, there are creatures on earth which seem to be...more

Exploratour - Life in the Solar System

Believe it or not, many scientists believe that life may have begun on these distant, solar system traveling objects. Out in their distant home, the Oort Cloud, comets are exposed to the kind of cosmic...more

Exploratour - Life in the Solar System

In spite of the fact that Mars has an atmosphere, the environment of Mars seems unfriendly toward life as we know it on earth. Mars is small, so there is not much gravity. For this reason, much of the...more

Exploratour: NASA's Exploration for Life

Believe it or not, many scientists believe that life may have begun on these distant, solar system traveling objects. Out in their distant home, the Oort Cloud, comets are exposed to the energy needed...more

Exploratour - Life in the Solar System

Earth is teeming with life. The table below gives a brief overview of life on Earth, in catagories. The Animal Kingdom mammals elephants, rodents, etc arthropods insects, crabs reptiles is multi-cellular...more

Exploratour - The Archean Age

In the 1950's, Stanley Miller and Harold Urey, conducted an experiment which demonstrated that some of the basic elements of life could be formed by simulating the conditions of Earth's early atmosphere....more

Exploratour - Life on Mars?

Mars is about the same size as Earth. And it is fairly close to the Sun. But Mars is cold. Mars also doesn't have a very big atmosphere to protect life from ultraviolet rays which can destroy life. So,...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