Chapter 27 Flashcards: Animal Diversity

This set of flashcards covers key terms and definitions related to animal classification and development.

Choanoflagellates

Unicellular organisms that have no tissues.

Metazoa

Multicellular organisms that have various forms. Not all have true tissues.

Porifera (parazoa)

A group of animals, known as sponges, that lack true tissues and organs.

Ctenophora

Aquatic invertebrates also known as comb jellies, characterized by their gelatinous bodies.

Cnidaria

A phylum including jellyfish and corals, known for their stinging cells and radial symmetry.

Eumetazoa

Animals that have true tissues and a nervous system.

Diploblastic

Organisms with two germ layers: ectoderm and endoderm.

Bilateria

Organisms characterized by bilateral symmetry and three germ layers.

Triploblastic

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

Coelom

A fluid-filled body cavity lined by mesoderm, allowing space for internal organs.

Acoelomate

Organisms that do not possess a coelom.

Pseudocoelomate

Organisms with a body cavity partially lined by mesoderm.

Coelomate

Organisms that possess a true coelom completely lined by mesoderm.

Placozoa

A simple phylum of marine animals that are often flat and tissue-like.

Choanocytes

Flagellated cells in sponges that create water currents for feeding.

Amoebocytes

Cells in sponges responsible for nutrient transport and digestion.

Porocytes

Cells in sponges that form pores to allow water flow.

Colloblasts

Sticky cells used by ctenophores for capturing prey.

Echinodermata

A phylum of marine animals known for their radial symmetry and water vascular system.

Protostomes

Organisms in which the mouth forms before the anus in embryonic development.

Lophotrochozoa

A major grouping of protostomes including mollusks and annelids.

Ecdysozoa

A clade of protostomes that undergo ecdysis or molting.

Trochophore

A free-swimming larval stage of some invertebrates, characterized by a ciliated band.

Lophophore

A feeding structure with ciliated tentacles around the mouth.

Annelids

Segmented worms belonging to the phylum Annelida.

Mollusks

Soft-bodied invertebrates that often have a shell, such as snails and octopuses.

Arthropods

Invertebrates with jointed appendages and an exoskeleton.

Ecdysis

The process of molting exoskeleton in arthropods.

Gastropods

A class of mollusks that includes snails and slugs.

Cephalopods

A class of mollusks that includes squids and octopuses.

Bivalves

Mollusks with two shells, such as clams and oysters.

Tagmata

The main divisions of an arthropod's body, such as cephalothorax and abdomen.

Chelicerata

Subphylum of arthropods that includes spiders and scorpions.

Crustacea

A class of arthropods that includes crabs, lobsters, and shrimp.

Hexapoda

A class of arthropods that includes insects, characterized by six legs.

Myriapoda

A class of arthropods that includes centipedes and millipedes.

Deuterostomes

Organisms in which the anus forms before the mouth during embryonic development.

Echinoderms

Marine animals with spiny skin, such as sea stars and sea urchins.

Chordates

Animals that possess a notochord at some stage in their development.

Endoderm

The innermost germ layer that forms the lining of the digestive system.

Mesoderm

The middle germ layer that forms muscles, circulatory system, and more.

Ectoderm

The outermost germ layer that forms skin and the nervous system.

Notochord

A flexible rod that provides support in chordate embryos.

Dorsal hollow nerve cord

A characteristic feature of chordates that becomes the spinal cord.

Pharyngeal slits

Openings that develop in the pharynx, seen in various stages in chordates.

Post anal tail

A tail extending beyond the anus, characteristic of many chordates.

Lancelets

Small, fish-like chordates that retain all four chordate characteristics.

Vertebrates

Animals with a backbone or vertebral column.