Supplementary File	Title
Supplementary Note	Glossary
Supplementary Figures	Supplementary figures 1-3
Software	Zip file of code written in IDL for calculating strain rates in a domain of tissue
Supplementary Video 1	Tracked cell trajectories and membrane shapes in Drosophila amnioserosa. Video to accompany Figure 4a. Video duration is 50 mins, with frames at 2 min intervals. Details are as in Figure 4.
Supplementary Video 2	Tracked cell trajectories and membrane shapes in Drosophila germband. Video to accompany Figure 4d. Video duration is 15 mins, with frames at 30s intervals. Details are as in Figure 4.
Supplementary Video 3	Tracked cell trajectories and membrane shapes in zebrafish trunk ectoderm. Video to accompany Figure 4g. Video duration is 50 mins, with frames at 2 min intervals. Details are as in Figure 4.
Supplementary Video 4	Cellular simulation of a domain dominated by cell shape change. Video to accompany Figure 2a simulation. Video duration is 50 mins, with frames every minute.
Supplementary Video 5	Cellular simulation of a domain dominated by cell intercalation. Video to accompany Figure 2b simulation. Video duration is 50 mins, with frames every minute.
Supplementary Video 6	Tissue deformations and rotations in Drosophila amnioserosa. Video to accompany Figure 4b. Video duration is 50 mins, with frames at 2 min intervals. Details are as in Figure 4.
Supplementary Video 7	Cell shape deformations in Drosophila amnioserosa. Video to accompany Figure 5a. Video duration is 50 mins, with frames at 2 min intervals. Details are as in Figure 5.
Supplementary Video 8	Cell intercalation deformations in Drosophila amnioserosa. Video to accompany Figure 5b. Video duration is 50 mins, with frames at 2 min intervals. Details are as in Figure 5.
Supplementary Video 9	Tissue deformations and rotations in Drosophila germband. Video to accompany Figure 4e. Video duration is 15 mins, with frames at 30s intervals. Details are as in Figure 4.
Supplementary Video 10	Cell shape deformations in Drosophila germband. Video to accompany Figure 5d. Video duration is 15 mins, with frames at 30s intervals. Details are as in Figure 5.
Supplementary Video 11	Cell intercalation deformations in Drosophila germband. Video to accompany Figure 5e. Video duration is 15 mins, with frames at 30s intervals. Details are as in Figure 5.
Supplementary Video 12	Tissue deformations and rotations in zebrafish trunk ectoderm. Video to accompany Figure 4h. Video duration is 50 mins, with frames at 2 min intervals. Details are as in Figure 4.
Supplementary Video 13	Cell shape deformations in zebrafish trunk ectoderm. Video to accompany Figure 5g. Video duration is 50 mins, with frames at 2 min intervals. Details are as in Figure 5.
Supplementary Video 14	Cell intercalation deformations in zebrafish trunk ectoderm. Video to accompany Figure 5h. Video duration is 50 mins, with frames at 2 min intervals. Details are as in Figure 5.