disection lab

Phylum Arthropoda

A diverse group of invertebrates characterized by jointed limbs and a segmented body, including insects, spiders, and crustaceans.

Exoskeleton

A rigid outer covering or integument that provides support and protection to animals like arthropods.

Chitin

A polysaccharide that forms the main component of the exoskeleton in arthropods.

Cephalothorax

The fused head and thorax region in some crustaceans, such as crayfish and lobsters.

Hemocoel

The blood-filled space in arthropods that functions as a body cavity.

Open circulatory system

A system in which blood (hemolymph) is not always contained within vessels and bathes organs directly.

Carapace

A hard protective shell covering the dorsal part of the cephalothorax in crustaceans.

Telson

The last segment of the crayfish's abdomen, forming a tail fan with the uropods.

Swimmerets

Paired appendages on the abdomen of crayfish used for swimming and in reproductive processes.

Mandibles

The mouthparts of crustaceans used to crush food.

Copulation

The process of mating in crayfish, where sperm is transferred from male to female.

Gastric mill

A structure in the stomach of crustaceans that grinds food, consisting of calcareous plates.

Osmoregulation

The process by which organisms regulate water and electrolyte balance; managed by green glands in crayfish.

Hemolymph

The fluid that circulates within the hemocoel of arthropods, equivalent to blood in vertebrates.

Radical symmetry

A form of symmetry where body parts are arranged around a central axis, common in adult echinoderms.

Echinodermata

A phylum of marine invertebrates characterized by spiny skin and include starfish and sea cucumbers.

Gonopores

External openings in crayfish through which sperm or eggs are released for reproduction.

Maxillipeds

Appendages in crayfish located behind the mandibles, primarily used for feeding.

Cheliped

The clawed appendage in crayfish used for defense and grasping food.

Nephridia

Excretory organs in crustaceans for filtering and excreting waste products; located in green glands.

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.