Chapter_32_Halo

Heterotrophs

Organisms that obtain energy and nutrients by eating other organisms.

Embryonic tissue layers

The layers formed from embryonic cells that develop into different tissues in animals.

Cleavage

A succession of cell divisions in fertilized eggs, leading to the formation of a blastula.

Blastula

A hollow ball of cells formed during the early development of the embryo.

Gastrulation

The process during which the blastula develops into a gastrula with different layers of embryonic tissues.

Radial symmetry

A body plan where body parts are arranged around a single central axis.

Bilateral symmetry

A body plan where body parts are arranged around two axes of orientation.

Diploblastic animals

Animals that have two germ layers: ectoderm and endoderm.

Triploblastic animals

Animals that have three germ layers: ectoderm, endoderm, and mesoderm.

Coelom

A body cavity surrounded by mesoderm-derived tissues.

Protostome development

A developmental mode where the blastopore becomes the mouth.

Deuterostome development

A developmental mode where the blastopore becomes the anus.

Ectoderm

The outermost layer of the embryo that develops into skin and the nervous system.

Mesoderm

The middle layer of the embryo that develops into muscles, bones, and most organs.

Endoderm

The innermost layer of the embryo that develops into the digestive tract.

Ecdysis

The process by which ecdysozoans shed their exoskeleton to allow for growth.

Lophophore

A crown of ciliated tentacles used for feeding in some invertebrates of the Lophotrochozoa clade.

Trochophore larva

A developmental stage found in some lophotrochozoans.

Phylogeny

The study of evolutionary relationships among various biological species.

Common ancestor

An ancestral species from which multiple species have evolved.

Eumetazoa

A clade of animals characterized by the presence of defined tissues.