How do we define life? This lecture reviews the six basic criteria
for living systems described by biologists: order, reproduction, growth and
development, energy utilization, reaction to environment, and evolution
that characterize life. The last third of the lecture is an admittedly
whirlwind review of natural selection (I got off my stride and got a
lit ... Show More
Oct 2009
Lecture 15: The Chemistry of Life
What is the basic chemistry of living organisms? We introduce the requirements for metabolism (raw materials and energy), the ATP/ADP energy cycle in cells, auto- and heterotrophs, photosynthesis and chemosynthesis, and the role played by liquid water. The goal of today's lecture ... Show More
45m 4s
<p>La durée de vie d'une étoile peut nous renseigner sur sa composition et sur l'existence éventuelle de la vie dans le cosmos. mais, en dehors du Soleil, il est assez difficile de déterminer l'âge d'une étoile.</p><br><p>L'importance de la masse</p><br><p>En évaluant, grâce à la ... Show More
