The earliest sponges were soft-bodied creatures without the mineral skeletons seen in their modern relatives, which explains their missing early fossils. Credit: Shutterstock Sponges rank among the oldest known animals on Earth, yet scientists have struggled to pinpoint exactly when they first appeared. DNA from living sponges and chemical traces preserved in ancient rocks indicate they emerged at least 650 million years ago. The findings are reported in Science Advances . That early date has

Tag-uri: DNA