Eugene Odum explains the key concepts of "ecosystem ecology"
Part 2: https://www.youtube.com/watch?v=6P9V6h2z79w
Part 3: https://www.youtube.com/watch?v=b6NmohVKEfg
Part 4: https://www.youtube.com/watch?v=zA65QA29bXM
Part 5: https://www.youtube.com/watch?v=f5EhdXpDO3o
Part 6: https://www.youtube.com/watch?v=_N6NbK5Bw_g