Note: This article is illustrated by many images and videos taken in the MBL Embryology Course and features the research of Nicole King of University of California, Berkeley, who will become co-director of the MBL Physiology Course in 2019.

Juvenile of the Longfin inshore squid, Doryteuthis pealei. The F-actin staining (red) reveals the musculature of the mantle; and the acetylated-tubulin staining (green) reveals the tufts of cilia on the surface of the mantle and rest of the body. Nuclei stained blue. Credit: Wang Chi Lau, MBL Embryology Course
Juvenile of the Longfin inshore squid, Doryteuthis pealei. The F-actin staining (red) reveals the musculature of the mantle; and the acetylated-tubulin staining (green) reveals the tufts of cilia on the surface of the mantle and rest of the body. Nuclei stained blue. Credit: Wang Chi Lau, MBL Embryology Course

Billions of years ago, life crossed a threshold. Single cells started to band together, and a world of formless, unicellular life was on course to evolve into the riot of shapes and functions of multicellular life today, from ants to pear trees to people. It's a transition as momentous as any in the history of life, and until recently we had no idea how it happened. Read more of the article here.

Source: The momentous transition to multicellular life may not have been so hard after all | Science | AAAS