Animals: Spoges - Annelids

Anterior

Refers to the front or head end of an organism.

Ventral

Relating to or situated on the belly side of an organism.

Spicule

A hard structure found in sponges that is used for defense or providing structural support.

Choanocyte

The most interior cell of a sponge that has a flagellum and plays a role in water circulation and feeding.

Amoebocyte

A type of cell in sponges that can form spicules and perform various functions like transporting nutrients and waste.

Osculum

The main opening of a sponge through which water exits.

Morula

A solid mass of cells that forms after a series of cleavage divisions in the early stages of embryo development.

Radial cleavage

A pattern of cell division in deuterostomes where cells divide along the vertical axis, resulting in cells stacked on top of each other.

Spiral cleavage

A pattern of cell division in protostomes where cells divide diagonally and obliquely, resulting in a spiral arrangement of cells.

Cleavage

The early cell divisions of an embryo.

Diploblastic

Having two germ layers, namely the endoderm and ectoderm.

Triploblastic

Having three germ layers, namely the endoderm, ectoderm, and mesoderm.

Protostomes

mouth develops before the anus during embryonic development.

Deuterostomes

anus develops before the mouth during embryonic development.

Blastula

A hollow ball of cells formed during early embryonic development.

Mesoderm

The middle germ layer of an embryo that gives rise to muscles, bones, and other internal structures.

Ectoderm

The outer germ layer of an embryo that gives rise to the skin and nervous system.

Endoderm

The inner germ layer of an embryo that gives rise to the gut and other internal organs.

Gastrulation

The process in which a hollow embryo invaginates, forming the archenteron (primitive gut) and blastopore (opening to the archenteron).

Archenteron

The cavity inside a gastrula that develops into the digestive tract.

Blastopore

The opening to the archenteron in a gastrula.

Cephalization

The concentration of sensory organs and nerve tissues at the anterior (head) end of an organism.

Acoelomate

An organism that lacks a fluid-filled body cavity.

Pseudocoelomate

An organism that has a fluid-filled body cavity, called a pseudocoelom, in which internal organs are suspended. It lacks a true mesoderm.

Coelomate

An organism that has a true body cavity, called a coelom, that develops within the mesoderm.

Hydrostatic skeleton

A type of skeleton found in animals where muscles contract and push against a fluid-filled cavity, allowing for movement.

Nerve nets

Diffuse nervous systems found in organisms like jellyfish, where neurons are spread throughout the body.

Hydra

A sessile polyp phase of a cnidarian, characterized by a tubular body with tentacles surrounding the mouth.

Medusa

The motile jellyfish phase of a cnidarian, characterized by a bell-shaped body and tentacles hanging down.

Nematocyst

A fluid-filled capsule found in cnidarians that holds a stinging cell called a cnidocyte.

Cnidocyte

A specialized stinging cell found in cnidarians.

Corona

A structure found in rotifers that sweeps food into the mouth.

Mastax

A grinding organ in rotifers that breaks down food.

Lophophore

A structure consisting of tentacles arranged around the mouth of certain aquatic invertebrates, used for food collection and gas exchange.

Trochophore

A larval stage found in some marine invertebrates, characterized by a band of cilia used for movement.

Dorsal

the upper side or back of an animal.

zygote-morula-blastula-gastrula

body plan elements

symmetry, body cavity structure, segmentation, appendages, nervous system

sensory informatin is processed in the

brain

muscle action is coordinated to

allow movement of appendages and body parts

general characteristics of animals

multicellularity, heterotrophic metabolism, internal digestion, movement and nervous system

bilateral symmetry allows for

More developed and well-coordinated nervous systems with brain and nerves

list cnidaraians

jellyfish, sea anemones, corals

protostomes

bilaterally symmetrical, triploblastic , anterior brain, ventral nervous system

list plenaria

flatworms, tapeworms, flukes

list annelids

fan worms, tube worms, earthworms, leeches

nephridia

• Function: Excretory organs in invertebrates.

• Role: Remove waste, regulate osmotic balance.

• Structure: Tubular structures with ciliated funnels.