Invertebrates: Anatomy of Hydra, Earthworm, and Sea Star

A set of vocabulary flashcards covering key concepts related to the anatomy of invertebrates, including Hydra, Earthworm, and Sea Star.

Invertebrate

An animal without a backbone.

Symmetry

The balanced distribution of duplicate body parts or shapes within the body of an organism.

Coelomate

An animal that possesses a true coelomic cavity, lined with mesoderm.

Diploblastic

Organisms having two germ layers: ectoderm and endoderm.

Triploblastic

Organisms having three germ layers: ectoderm, mesoderm, and endoderm.

Gastrulation

The phase of embryonic development where cells move inward to form a tube, leading to tissue differentiation.

Metamerism

The segmentation or division of an organism's body into repetitive segments, seen in annelids.

Nephridia

Excretory organs in annelids that filter waste from the coelomic fluid.

Hydrostatic skeleton

A skeletal structure made of fluid-filled coelom and surrounded by muscle, allowing movement.

Monoecious

Organisms that have both male and female reproductive organs.

Detritivore

An organism that feeds on decomposing organic matter.

Hemoglobin

An iron-containing protein in blood that binds oxygen for transport.

Cephalization

The concentration of sensory organs and nervous tissues at the anterior end of an organism.

Blastula

An early stage of embryonic development characterized by a hollow ball of cells.

Archenteron

The primitive gut formed during gastrulation in the embryo.

Mesoderm

The middle germ layer in triploblastic organisms that forms muscles, the circulatory system, and other structures.

Clitellum

A thickened segment of an earthworm involved in reproduction.

Invertebrate

An animal without a backbone.

Symmetry

The balanced distribution of duplicate body parts or shapes within the body of an organism.

Coelomate

An animal that possesses a true coelomic cavity, lined with mesoderm.

Diploblastic

Organisms having two germ layers: ectoderm and endoderm.

Triploblastic

Organisms having three germ layers: ectoderm, mesoderm, and endoderm.

Gastrulation

The phase of embryonic development where cells move inward to form a tube, leading to tissue differentiation.

Metamerism

The segmentation or division of an organism's body into repetitive segments, seen in annelids.

Nephridia

Excretory organs in annelids that filter waste from the coelomic fluid.

Hydrostatic skeleton

A skeletal structure made of fluid-filled coelom and surrounded by muscle, allowing movement.

Monoecious

Organisms that have both male and female reproductive organs.

Detritivore

An organism that feeds on decomposing organic matter.

Hemoglobin

An iron-containing protein in blood that binds oxygen for transport.

Cephalization

The concentration of sensory organs and nervous tissues at the anterior end of an organism.

Blastula

An early stage of embryonic development characterized by a hollow ball of cells.

Archenteron

The primitive gut formed during gastrulation in the embryo.

Mesoderm

The middle germ layer in triploblastic organisms that forms muscles, the circulatory system, and other structures.

Clitellum

A thickened segment of an earthworm involved in reproduction.

Acoelomate

An animal without a body cavity between the digestive tract and outer body wall.

Pseudocoelomate

An animal possessing a body cavity that is not completely lined with mesoderm.

Ectoderm

The outermost germ layer of an embryo, which gives rise to the epidermis and nervous system.

Endoderm

The innermost germ layer of an embryo, which gives rise to the lining of the digestive tract and associated organs.

Protostome

An animal in which the mouth develops from the blastopore during embryonic development.

Deuterostome

An animal in which the anus develops from the blastopore during embryonic development, and the mouth forms secondarily.