Echinoderms and Arthropods Quiz

Animals are multicellular, eukaryotic organisms that lack cell walls. They are heterotrophic, meaning they get their nutrients from other organisms.

Invertebrates are animals without a backbone. They make up the majority of the animal kingdom.

Invertebrates have a wide variety of body plans, including those with radial symmetry, bilateral symmetry, and no symmetry, all of which evolved independently.

Internal parasites lacking a digestive tract. Their body is composed of repeating segments called proglottids, containing eggs. They attach to the host's intestines using a scolex (head).

The tapeworm infection occurs by ingesting infected meat containing larval cysts.

Roundworms are unsegmented worms with a three-layered body plan and bilateral symmetry. They have a pseudocoelom and a two-opening digestive system, consisting of a mouth, pharynx, intestine and anus.

The ascarid infection occurs through ingesting food or water containing ascarid eggs.

They are segmented worms with a coelom and a closed circulatory system. They have a two-opening digestive system, a hydrostatic skeleton, bilateral symmetry, and cephalization.

Polychaetes, mainly found in saltwater environments, have bristly, fleshy appendages on each segment. Examples include sandworms and fanworms.

Oligochaetes lack appendages and have few bristles. They are found in terrestrial or freshwater environments. Examples include Tubifex (sludge worm) and earthworms.

A group of arthropods that includes centipedes, millipedes, and insects. They are characterized by having one pair of antennae, mandibles, and a body that is divided into segments.

Centipedes are carnivorous arthropods with a long body consisting of many segments, each with one pair of legs. They have poison claws that they use to subdue their prey.

Millipedes are herbivorous arthropods with a long body consisting of many segments, each with two pairs of legs. They are known for their slow, crawling movement.

Insects have a body divided into three parts (head, thorax, abdomen), three pairs of legs, and one or two pairs of wings. Some insects undergo metamorphosis, a process of transformation from larval to adult stage.

Symbiosis is a close relationship between two species. There are three types of symbiosis: mutualism (both organisms benefit), commensalism (one benefits, the other is unaffected), and parasitism (one benefits, the other is harmed).

A false body cavity, partially lined by mesoderm, found in organisms like roundworms.

A true body cavity, completely lined by mesoderm, found in organisms like annelids.

The phylum that includes sponges, characterized by filter feeding, a lack of true tissues, and an endoskeleton made of spongin and spicules.

The basic body plan of sponges, characterized by the absence of germ layers, body cavity, and a lack of symmetry.

The movement of water through a sponge: from the pores (ostia) to the central cavity and out the osculum.

The phylum that includes cnidarians, characterized by stinging cells (nematocysts), radial symmetry, and alternation between polyp and medusa forms.

The two basic body forms of cnidarians: polyps are sessile, flower-like forms, while medusas are free-swimming, bell-shaped forms.

Specialized stinging cells found on cnidarian tentacles, used to immobilize prey.

A class within Phylum Cnidaria, characterized by freshwater and marine members, including Hydra and the Portuguese Man-of-War, and exhibiting the polyp body form predominantly.

A class within Phylum Cnidaria, characterized by predominantly medusa forms, including jellyfish like the Lion's Mane Jellyfish and Moon Jelly.

Kidney-like structures that remove nitrogenous waste products from the body.

A tube that connects the mouth to the anus in earthworms, responsible for digestion.

Worms that lack appendages, are carnivores or blood-sucking parasites, and often live in freshwater.

A phylum of invertebrates that includes mollusks, such as clams, snails, and octopus.

The basic body structure of a mollusk, consisting of a foot, shell, mantle, and visceral mass.

A class of mollusks characterized by their two-part hinged shell, wedge-shaped foot, and often sessile lifestyle.

A broad, muscular foot used for movement, often with a spiral shell, and a distinct head. Includes snails, slugs, and nudibranchs.

A class of mollusks with a well-developed head and tentacles, a closed circulatory system, and examples such as octopus, squid, and nautilus.

A large phylum of invertebrates with jointed appendages, an exoskeleton made of chitin, and a segmented body. Includes insects, crustaceans, and spiders.

An extinct subphylum of arthropods with a distinctive three-lobed body plan.

Phylum Echinodermata includes marine invertebrates like sea stars, sea urchins, and sea cucumbers. They have a unique radial symmetry (body parts arranged around a central axis) and a water vascular system used for locomotion and feeding.

The water vascular system is a network of canals filled with fluid that connects to tube feet. These tube feet help in movement, feeding, and gas exchange.

Sea stars are carnivorous bottom-dwellers with a central body and radiating arms. They have a mouth on their underside and an anus on the top.

Brittle stars are small, delicate echinoderms with a central body disk and long, flexible arms. They are often filter feeders or detritus feeders.

Sea urchins and sand dollars are round echinoderms covered with spines. They lack arms and have a rigid, box-like body.

Sea cucumbers are soft-bodied echinoderms with a leathery, cylindrical body. They have feeding tentacles on one end and are important detritus feeders.

An exoskeleton is a hard, external covering that provides support and protection. An endoskeleton is an internal support structure, like the bones in vertebrates.

A hydrostatic skeleton is a fluid-filled cavity that provides support and allows for movement. It's common in invertebrates like worms and jellyfish.