invertebrates evolution and diversity

What was the Cambrian Explosion?

• An event during which a meteorite collision initiated a mass extinction

• A time when living organisms first arose from inorganic molecules

• A period when many modern multicellular phyla first appeared

• A time during which humans evolved quickly from a single ancestor

When does fossil evidence indicate that the first animals evolved?

• About 600,000 years ago

• About 6 million years ago

• About 60 million years ago

• About 600 million years ago

Which characteristic of early animals explains the scarcity of animal fossils older than the Cambrian Period?

• They were carnivorous.

• They were large.

• They were soft-bodied.

• hey were fast-moving.

A cladogram is a type of diagram. What does it show?

• Migratory paths of similar organisms

• Evolutionary relationships among groups of organisms

• Homologous structures among organisms

• Continental drift since Earth's origin

What does the cladogram of invertebrates show?

• The sequence in which some important invertebrate features evolved

• The number of invertebrates currently thought to exist on Earth

• The basic functions of the major types of invertebrates

• The groups into which current invertebrates are evolving

Cambrian fossils show that animals evolved structures protruding from the body, such as legs or antennae, called

• segmentation.

• appendages.

• body symmetry.

• skeletons

The most abundant animals on Earth today are

• invertebrates.

• mammals.

• reptiles.

• birds.

The most ancient members of kingdom Animalia are

• worms

• reptiles

• insects

• sponges

Animals in the phylum Cnidaria include

• jellyfish.

• sponges

• roundworms

• insects

Worms with segmented bodies and a true coelom lined with tissue derived from mesoderm belong in phylum

• Nematoda.

• Chordata

• Mollusca

• Annelida