Khan Academy

Energy flow & primary productivity (K-A)

Flow of energy and matter through ecosystems (K-A)

Food chains & food webs (K-A)

What is an ecosystem? (K-A)

The nitrogen cycle+A212-video (K-A)

Climate (K-A)

How biodiversity is distributed globally (K-A)

New localities lead to new biodiversity (K-A)

Tolerance ranges of species (K-A)

Tropical rainforest biomes (K-A)

Why biodiversity is distributed unevenly (K-A)

Introduction to metabolism: Anabolism and catabolism (K-A)

Overview of metabolism (K-A)

First Law of Thermodynamics introduction (K-A)

Introduction to energy (K-A)

Introduction to entropy (K-A)

Second Law of Thermodynamics (K-A)

Second Law of Thermodynamics and entropy (K-A)

The laws of thermodynamics (K-A)

Types of energy (K-A)

Why heat increases entropy (K-A)

Endergonic, exergonic, exothermic, and endothermic (K-A)

Free energy-link (K-A)

Gibbs free energy and spontaneous reactions (K-A)

ATP and reaction coupling-link (K-A)