This animation shows how the proton gradient across the mitochondrial membrane powers the ATP synthase enzyme to make ATP. It is the third of three animations about cellular respiration.

This animation shows how the enzyme complexes of the electron transport chain harvest energy from cofactor molecules to pump protons across the mitochondrial membrane and establish a chemical gradient. It is the second of three animations about cellular respiration.

This animation shows the reactions of the citric acid cycle, which splits off carbon atoms and generates energy-rich reduced forms of cofactor molecules. It is the first of three animations about cellular respiration.

This three-part animation series explores the biology of the virus SARS-CoV-2, which has caused a global pandemic of the disease COVID-19.

This activity explores images of elephants with and without tusks, which serve as phenomena for learning about selection and human impacts on the frequency of traits within populations.

The added information provided at pause points within the animation Coral Bleaching allows for a richer exploration of coral reefs, symbiosis, and other topics in biology.

The world cut its daily carbon dioxide emissions by 17% at the peak of the pandemic shutdown last month, a new study found.

To give rivers more room to sprawl, cities are keeping adjacent lands for limited uses such as parks that can flood when rivers rise.

The world has lost more than one quarter of its land-dwelling insects in the past 30 years, according to researchers whose big picture study of global bug decline paints a disturbing but more nuanced problem than earlier research.

An unplanned grand experiment is changing Earth. As people across the globe stay home to stop the spread of the new coronavirus, the air has cleaned up, albeit temporarily.

Samoa’s population of “little dodos” is dwindling down to nothing, but the appetites of wealthy people keep putting these rare birds at risk.

In this video, ecologist Tony Sinclair takes us through the steps of how he uncovered that the eradication of an infectious disease in cattle led to a boom in the Serengeti’s buffalo and wildebeest numbers.