But complex multicellular organisms have arisen just six times on the tree of life: plants, animals, two groups of fungi, and two groups of algae.

Life and death are traditionally viewed as opposites. But the emergence of new multicellular life-forms from the cells of a ...

Scientists have discovered the fossil of what may be the earliest multicellular animal ever found. Dating back a billion years, the microscopic fossil contains two distinct cell types, potentially ...

Scientists said some single-celled organisms, including fungi and amoebas, have also lost the need to breathe over time, but this is the first time it's been documented in an animal.

For billions of years, single-celled creatures had the planet to themselves, floating through the oceans in solitary bliss. Some microorganisms attempted multicellular arrangements, forming small ...

This most fundamental question was famously posited by none other than Nobel laureate physicist Enrico Fermi (1901–1954).

Researchers find that oxygenation of Earth's surface is key to the evolution of large, complex multicellular organisms. If cells can access oxygen, they get a big metabolic benefit. However, when ...

H. salminicola, a common salmon parasite, is the first animal found in the wild to not have mitochondrial DNA, which is required for respiration.

Indeed, many primitive multicellular organisms probably experienced both unicellular and multicellular states, providing opportunities to forego a group lifestyle.

In just 48 hours, salps can reach maturity, making them the fastest-growing multicellular animals on Earth, with a significant impact on ocean health.

A unique experiment shows how multicellular organisms might have evolved from single-celled ancestors.

Bacteria may have helped single-celled organisms make the leap to multicellular animals. For billions of years, single-celled creatures had the planet to themselves, floating through the oceans in ...