When did the first invertebrates appear on earth?

Question

i need help with this i cant find it any where and it is making me mad help plz

Answer 1

Unfortunately, the first invertebrates were likely similar to sponges, small jellyfish, or possibly simple flatworms. These early multicellular organisms didn't possess any hard parts, and thus do not leave much in the way of fossils to be preserved in the fossil record.

The first evidence that indicates that such invertebrates might have existed are about 1 billion years old.

Answer 2

First Invertebrates

Answer 3

Cambrian: Marine Invertebrates
570 to 505 Million Years Ago. Appearance of the first marine invertebrates.

http://www.extinctanimal.com/prehistoric.htm