The truth is we really don’t know. Here’s a few relevant currently accepted facts however:

• Animals and Fungi are genetically closer to each other than animals and plants.
• There are several fascinating types of life that carry characteristics of both plants and animals like the Euglena which has chloroplasts for energy, but a flagellum enabling it to move.

• It’s mostly accepted that the Comb Jellyfish was the first animal and many think that it may genetically be the closest animal to vegetative life.