Description
Transcript: Simple organisms such as bacteria reproduce by making copies of themselves. Once cells had developed the capability of having nuclei, sexual reproduction became possible, and this is very important for genetic diversification. In sexual reproduction, the offspring get half their genetic material from each of the parent organisms. Genes can combine in different ways from generation to generation which facilitates experimentation and adaptation to a changing environment.
Transcript: The history of life on Earth is not a simple linear progression from simple to more complex, from bacteria to us. There have been many twists and turns in this tale, many evolutionary dead ends. Chance effects are important on the history of life, for example, the role of giant...
Published 07/29/11
Transcript: If planetary scientists are asked to speculate on the most possible sites for life within the solar system, they will generally give five places: Mars, Venus, Europa, Titan, and Io. These five places are significant. Mars is a traditional place where we might imagine life could have...
Published 07/28/11
Transcript: It’s particularly important to consider the possibility of life on or in the gas giant planets of the solar system because these are the type of planets that have been found around nearby stars. Over a hundred extrasolar planets are now known, and most of them are Jupiter-like or...
Published 07/28/11