Animal Phylogeny and Development

Flashcards covering animal phylogeny, development, and key evolutionary concepts.

Phylum

A taxonomic level representing major differences in body plans among animals.

Choanoflagellata

Colonial, flagellated protists that are similar to multicellular sponges and considered the unicellular sister group to animals.

Radial Symmetry

Animals with radial symmetry, such as Cnidaria and Ctenophora correlated with cephalization – concentration of sensory organs and nervous tissue at the anterior end or head.

Mesoderm

A germ layer present only in Bilateria that allowed development of diverse, specialized internal structures.

Gastrulation

A key event in embryogenesis where cells migrate through the blastopore into the blastocoel, establishing the three germ layers.

Ectoderm

The germ layer that develops into skin and nervous/sensory system

Mesoderm

The germ layer that develops into muscles, circulatory system, blood and many different organs

Endoderm

The germ layer that develops into digestive system (gut, associated organs)

Larvae

Fully functional animals in a immature stage that often look very different from the reproductive, adult form

Homeobox

Homeobox: 180 bp fragment that encodes the DNA-binding homeodomain

Hox genes

Genes that control positional identity along the body axis

Lophotrochozoa

The process where Trochophore larvae and lophophore spilt into

Deuterostomia

The process where blastopore forms anus

Ecdysozoa

The process where exoskeleton forms moulting