Week 10: Evolution of Animals I

These flashcards cover key vocabulary related to animal evolution discussed in the lecture.

Porifera

Phylum containing sponges; characterized by lacking true tissues and organs.

Cnidaria

Phylum including corals, jellyfishes, and anemones; possesses specialized cells for hunting.

Rotifera

Phylum of microscopic aquatic animals known as rotifers, which are pseudocoelomates.

Platyhelminthes

Phylum of flatworms; includes parasitic and free-living species, lacks a coelom.

Annelida

Phylum of segmented worms, including earthworms and leeches, characterized by a true coelom.

Mollusca

Phylum that includes snails and squids; features a muscular foot and visceral mass.

Nematoda

Phylum of roundworms, which are characterized by a complete digestive system and pseudocoelom.

Arthropoda

Phylum with the highest number of species; includes insects and crustaceans with segmented bodies.

Echinodermata

Phylum encompassing sea stars and urchins; notable for bilateral symmetry in juveniles and pentaradial symmetry in adults.

Chordata

Phylum defined by the presence of notochord, nerve chord, post-anal tail, and pharyngeal slits.

Mesoderm

The embryonic layer that develops into muscles, circulatory systems, and other internal organs.

Coelom

A fluid-filled body cavity that allows for greater complexity in body structure and organ function.

Ecdysis

The process of shedding the exoskeleton in certain invertebrates for growth.

True Tissues

Groups of cells that work together to perform specific functions in an organism.

Symmetry

The arrangement of body structures in space; can be radial, bilateral, or asymmetrical.

Segmentation

The division of an organism's body into repetitive segments, which can allow for greater complexity in structure.