Invertebrates

What determines an animal's complexity?

• Its feeding habits

• Its size

• The number of specialized cells it has

• Its ability to move

Why are sponges considered simple?

• They lack specialized tissues and organs

• They are not multicellular

• They have specialized tissues and organs

• They can move freely

How do sponges feed?

• Grazing on algae

• Through photosynthesis

• Filtering water for food

• By preying on smaller animals

What significant evolutionary feature do Cnidaria have?

• Three germ layers

• Bilateral symmetry

• Two germ layers

• A coelom

What are cnidocysts?

• Stinging cells in Cnidaria

• Cells that produce light

• A type of digestive enzyme

• Sensory cells

What is the significance of the mesoderm in animal evolution?

• It is responsible for the development of the exoskeleton

• It provides better mobility for the animal

• It enables the formation of true organ systems

• It allows for the development of specialized cells

What defines a coelomate?

• Having a body cavity within the mesoderm

• Lacking a body cavity

• Having multiple body cavities

• Having a body cavity outside the mesoderm

What was the Cambrian Explosion?

• The appearance of the first multicellular organisms

• A period of rapid evolutionary innovation

• A meteor impact that changed the course of evolution

• A volcanic event that caused mass extinctions

What adaptation do most gastropods have?

• A coelom

• Tentacles for capturing prey

• A radula for feeding

• Cnidocysts

Which phylum includes organisms with a true coelom?

• Mollusca

• Platyhelminthes

• Cnidaria

• Porifera