Invertebrates Flashcards
Phylum : Porifera (Sponges)
The Simplest of all living animals and lack true tissues or organs.
They live attached to solid surfaces, and feed on nutrients that they filter from the water using specialized cells and a system of canals and pores.
The soft parts are supported by a skeleton of spicules (slivers of carbon carbonate or silica).
Phylum: Platuhelminthes (Flatworms)
These worms are simple, bilaterally symmetrical animals with distinct heads and flattened, elongate, unsegmented bodies.
They contain no respiratory system and no circulatory system.
Most species, such as tapeworms, are parasitic, but some are free-living predators in freshwater and marine habitats, and others rely on symbiotic algae.
Phylum: Nematoda (Roundworms)
These small, free-living or parasitic, wormlike animals are amount the most abundant creatures in the planet
Their unsegmented, cuticle-covered bodies are round in cross section and taper toward both ends. They have no circular muscles and maintain their shape by high internal pressure. They move by thrashing their bodies around in characteristic C- and S- shapes using longitudinal muscle bands.
Phylum: Cnidaria (Jellyfish, corals, and sea anemones)
Members of this group of aquatic animals have radially symmetrical bodies that are essentially tubes, open at one end. The tube is either flattened into a bell shape (medusa) or elongated with the closed end attached to a hard surface (a polyp).
All cnidarians have tentacles around their mouths that contain stinging cells for prey capture and defense.
Most species reproduce asexually by budding. In some species, such as corals, the new creatures remain joined to form a colony.
Phylum: Annelida (Segmented Worms)
The bodies of annelids differ from other worms in being divided into a series of linked, but partly independent, functional sections. Each section contains a set of some of the same organs.
The head is often well delevoped, with sense organs, a brain, and a mouth.
Locomotion by expansion and contraction of the body is made possible by circular and longitudinal muscles.
Phylum: Echinodermata (Starfish, sea urchins, sea cucumbers)
The bodies of these marine invertebrates are typically spiny, and usually divided into 5 equal parts arranged symmetrically around a central point. Their bodies may be drawn out into arms (as in starfish), feathery (as in sea lilies) or spherical to cylindrical (as in sea urchins).
A unique internal network, called the water-vascular system, helps them move, feed, and exchange gases.
Phylum: Mollusca (Mollusks)
Mollusks have one of the widest ranges of body form of all invertebrates, but most species have a head, a soft “body” mass, and a muscular foot, which is used for location.
In the most advanced mollusks, the cephalopods, which includes the octopus, the head is well developed and has sophisticated sense organs, and parts of the head and foot are modified to form prey-capturing arms.
All mollusks have 1 or all of the following features:
• a horny, toothed ribbon (the radula) used for rasping food
• a calcium carbonate shell or other structure covering the upper surface of the body
• a mantle, which is an outer fold of skin covering the mantle cavity.
Mollusks are adapted to life on land, and in fresh or sea water.
Phylum: Arthropods
Panarthropods with a rigid outer layer and joined limbs.
Segmented animals with pairs of joined limbs and a rigid exoskeleton.
Body segments are aggregated or fused into functional units, the most universal being a head.
