Lucy was found by Donald Johanson and Tom Gray on November 24, 1974, at the site of Hadar in Ethiopia. They had taken a Land Rover out that day to map in another locality. After a long, hot morning of mapping and surveying for fossils, they decided to head back to the vehicle.
Alkanes are an example of saturated compounds. An unsaturated compound is a chemical compound that contains carbon-carbon double bonds or triple bonds, such as those found in alkenes or alkynes, respectively. Saturated and unsaturated compounds need not consist only of a carbon atom chain.
Alkenes have the general formula C n H 2n, and are examples of unsaturated hydrocarbons. The presence of a double bond compound's structure causes there to be two fewer hydrogen atoms in the molecule than there are in an alkane with the same number of carbon atoms.