Shop Windows to the Universe

Earth Science Rocks! Select one of our four cool NESTA t-shirts from our online store, and express your love of Earth and space science!
Bacteria
Image courtesy of JPL/NASA

Pre-Cambrian Life

About 2.5 billion years ago (BYA), after the iron in the ocean was gone to form iron ore deposits, oxygen began collecting in the atmosphere. Life took advantage of this change and developed eukaryotic cells. These are cells in which the organelle are outside of the nucleus, and the nucleus has a separate and distinct place within the cell. Both heterotrophs (early animals) and autotrophs (early plants) adapted to the new cells.

In cells with a nucleus respiration and photosynthesis are more efficient, so the production of oxygen in the environment of the early Earth speeded up. That made it possible for respiration (for animals which breathe oxygen) to begin in simple organisms. The new life forms which came to be were single-celled organisms like protozoans, amoeba, etc, animals which we now classify as part of the, Protista Kingdom .

Shop Windows to the Universe Science Store!

"Ready, Set, SCIENCE!: Putting Research to Work in K-8 Science Classrooms", from the National Research Council, provides insight on the types of instructional experiences help K-8 students learn science with understanding. Check our other books in our online store.

Windows to the Universe Community

News

Opportunities

You might also be interested in:

Traveling Nitrogen Classroom Activity Kit

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

Iron Ore Deposits

Eventually, photosynthesis by the earliest forms of plant life (a form of life capable of feeding itself instead of feeding off of others) began to produce significant amounts of oxygen. One important...more

Respiration

Respiration is the name of the general process where organisms convert sugars and oxygen into biochemical energy. The process happens in all organisms, including animals, plants, fungi, and bacteria....more

Photosynthesis

Photosynthesis is the name of the process by which autotrophs (self-feeders) convert water, carbon dioxide, and solar energy into sugars and oxygen. It is a complex chemical process by which plants and...more

Kingdom Protista

Members of the Kingdom Protista are the simplest of the eukaryotes. Protists are an unusual group of organisms that were put together because they don't really seem to belong to any other group. Some protists...more

Can there be Life in the Environment of Jupiter?

Jupiter's atmospheric environment is one of strong gravity, high pressure, strong winds, from 225 miles per hour to 1000 miles per hour, and cold temperatures of -270 degrees to +32 degrees (freezing temperature)....more

The possible discovery of Life on Mars

In July, 1996, it was announced that Dr. David McKay, along with a team of scientists at Johnson Space Center (a division of NASA), had discovered possible fossils of bacteria in a meteorite named ALH84...more

The Environment of Saturn

Saturn's atmospheric environment is one of strong gravity, high pressure, strong winds, from 225 miles per hour to 1000 miles per hour, and cold temperatures of -270 degrees to +80 degrees. With winds...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