Cells are the basic structural and functional unit of all life on Earth.
This lecture reviews the basic building blocks of cells, the main
chemical components, the two basic types of cells (Prokaryotes and
Eukaryotes), and introduces the Phylogenetic Tree of Life, the way
biologists order life by their biochemical and genetic relationships.
Understanding li ... Show More
Oct 2009
Lecture 13: What is Life?
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 admit ... Show More
46m 16s
Mar 2022
Comment calculer l'âge d'une étoile ?
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.
L'importance de la masse
En évaluant, grâce à la radioactivité, l'âge d ... Show More
1m 58s