Animal Evolution Bio 2

Dr. Mino’s general biology 2

eukaryotes

life domain that animals belong to

550-575 million years ago

when did animals first arise/evolve?

choanoflagellate

What did animals first evolve from?

Cambrian explosion

when most of the animal groups started to appear in the fossil record, a time of rapid expansion of different forms of life on Earth

burgess shale fossils

first evidence we have of internal organs

trilobites

considered the first animals to appear

arthropods

fossils (from the early cambrian period) that supports the theory of continental drift

porifera

an animal with no tissues, symmetry, digestive system, body cavity, segmentation, or circulatory system

cnidaria