Why are sponges considered to be primitive animals?

Answer 1

Sponges were first though to be plants because, at first glance, they appear to be so. They are immobile, have no appendages to speak of, and lack a nervous and circulatory system. What sets them apart from plants, however, are two main things. The first being that they are filter feeders; they siphon water through their bodies and specialized cells with cillia catch the food and transport it to speceialized cells to be digested, whereas the vast majority of plants make their own food. The second is that most sponges start out as free-swimming larvae that eventually settle down onto a solid surface and transform into the sessile soft-bodied creatures we know as sponges.

Answer 2

Sponges are considered primitive animals because they lack true tissues and organs, have a simple body plan, and rely on a filtering system to feed. They represent one of the earliest branches in the evolutionary tree of animals, dating back to over 500 million years ago.

Answer 3

because they lack a nervous system and differentiated tissues and organs.

Answer 4

Sponges are the most basic form of animal lacking true tissues. They fall into phylum Porifera.

Answer 5

Sponges are considered animals because they have the same cell stucture and type of metabolism as animals and reproduce in a similar fashion to many animals as well.

Answer 6

because it breathes and eats