Key Terms – Animal Diversity
- acoelomate
- without a body cavity
- Actinopterygii
- ray-finned fishes
- amniote
- a clade of animals that possesses an amniotic egg; includes reptiles (including birds) and mammals
- amoebocyte
- an amoeba-like cell of sponges whose functions include distribution of nutrients to other cells in the sponge
- amoeboid cell
- An amoeboid cell is a cell that has a flexible shape and moves by extending and retracting pseudopods, which are temporary protrusions of the cell’s surface
- Amphibia
- frogs, salamanders, and caecilians
- ampulla of Lorenzini
- a sensory organ that allows sharks to detect electromagnetic fields produced by living things
- Annelida
- a phylum of worm-like animals with metamerism
- anthropoids
- a clade consisting of monkeys, apes, and humans
- Anura
- frogs
- Apoda
- caecilians
- Arthropoda
- a phylum of Ecdysozoa with jointed appendages and segmented bodies
- asymmetrical
- having no plane of symmetry
- bilateral symmetry
- a type of symmetry in which there is only one plane of symmetry that creates two mirror-image sides
- body plan
- the shape and symmetry of an organism
- brachiation
- swinging through trees
- budding
- a form of asexual reproduction that occurs through the growth of a new organism as a branch on an adult organism that breaks off and becomes independent; found in plants, sponges, cnidarians, and some other invertebrates
- caecilian
- a legless amphibian that belongs to clade Apoda
- Cephalochordata
- a chordate clade whose members possess a notochord, dorsal hollow nerve cord, pharyngeal slits, and a post-anal tail in the adult stage
- cephalothorax
- a fused head and thorax
- chaeta
- a chitinous projection from the cuticle found in annelids
- chelicerae
- a modified first pair of appendages in subphylum Chelicerata
- chitin
- a tough nitrogen-containing polysaccharide found in the cuticles of arthropods and the cell walls of fungi
- choanocyte
- a cell type unique to sponges with a flagellum surrounded by a collar used to maintain water flow through the sponge, and capture and digest food particles
- Chondrichthyes
- jawed fishes with paired fins and a skeleton made of cartilage
- Chordata
- a phylum of animals distinguished by their possession of a notochord, a dorsal hollow nerve cord, pharyngeal slits, and a post-anal tail at some point during their development
- clitellum
- a specialized band of fused segments in some annelids, which aids in reproduction
- Cnidaria
- a phylum of animals that are diploblastic and have radial symmetry and stinging cells
- cnidocyte
- a specialized stinging cell found in Cnidaria
- coelom
- a lined body cavity derived from mesodermal embryonic tissue
- complete digestive system
- a digestive system that opens at one end, the mouth, and exits at the other end, the anus, and through which food normally moves in one direction
- craniate
- a proposed clade of chordates that includes all groups except the tunicates and lancelets
- Crocodilia
- crocodiles and alligators
- ctenidia
- specialized gills in mollusks
- cutaneous respiration
- gas exchange through the skin
- deuterostome
- describing an animal in which the blastopore develops into the anus, with the second opening developing into the mouth
- dioecious
- having separate male and female sexes
- diphyodont
- refers to the possession of two sets of teeth in a lifetime
- diploblast
- an animal that develops from two embryonic germ layers
- diploid
- describes a cell that has two complete sets of chromosomes, one from each parent
- dorsal hollow nerve cord
- a hollow, tubular structure derived from ectoderm, which is located dorsal to the notochord in chordates
- down feather
- feather specialized for insulation
- Echinodermata
- a phylum of deuterostomes with spiny skin; exclusively marine organisms
- ectoderm
- in diploblasts, the ectoderm is the outer germ layer that typically gives rise to the outer covering and sometimes nervous tissues. In triploblasts, the ectoderm is the outermost germ layer that gives rise to the skin and nervous system.
- endoderm
- in diploblasts, the endoderm is the inner germ layer that typically forms the gut. In triploblasts, the endoderm is the innermost layer that forms the digestive tract and associated organs.
- epidermis
- the layer of cells that lines the outer surface of an animal
- eucoelomate
- describing animals with a body cavity completely lined with mesodermal tissue
- eutherian mammal
- a mammal with a complex placenta, which connects a fetus to the mother; sometimes called placental mammals
- extracellular digestion
- a form of digestion, the breakdown of food, which occurs outside of cells with the aid of enzymes released by cells
- flagella
- a form of asexual reproduction in which a portion of the body of an organism breaks off and develops into a living independent organism; found in plants, sponges, and some other invertebrates
- fragmentation
- A flagellum is a whip-like appendage that extends from the cell body and is used for locomotion, typically by undulating back and forth.
- frog
- a tail-less amphibian that belongs to clade Anura
- gamete
- sex cell; sperm in male biological sex, eggs in female biological sex
- gastrodermis
- the layer of cells that lines the gastrovascular cavity of cnidarians
- gastrovascular cavity
- the central cavity bounded by the gastrodermis in cnidarians
- gemmule
- a structure produced by asexual reproduction in freshwater sponges that is able to survive harsh conditions
- germ layer
- a collection of cells formed during embryogenesis that will give rise to future body tissues
- gnathostome
- a jawed fish
- hagfish
- an eel-like jawless fish that lives on the ocean floor and is a scavenger
- haploid
- refers to a cell that contains a single set of unpaired chromosomes
- hemocoel
- the internal body cavity seen in arthropods
- heterodont teeth
- different types of teeth modified by different purposes
- intracellular digestion
- the digestion of matter brought into a cell by phagocytosis
- lamprey
- a jawless fish characterized by a toothed, funnel-like, sucking mouth
- lancelet
- a member of Cephalochordata; named for its blade-like shape
- lateral line
- the sense organ that runs the length of a fish’s body, used to detect vibration in the water
- Lophotrochozoa
- a clade of invertebrate organisms that is a sister group to the Ecdysozoa
- madreporite
- a pore for regulating entry and exit of water into the water vascular system
- mammal
- one of the groups of endothermic vertebrates that possess hair and mammary glands
- mammary gland
- in female mammals, a gland that produces milk for newborns
- mantle
- a specialized epidermis that encloses all visceral organs and secretes shells in mollusks
- marsupial
- one of the groups of mammals that includes the kangaroo, koala, bandicoot, Tasmanian devil, and several other species; young develop within a pouch
- medusa
- a free-floating cnidarian body plan with a mouth on the underside and tentacles hanging down from a bell
- mesoglea
- the non-living, gel-like matrix present in between ectoderm and endoderm in cnidarians
- mesoderm
- in diploblasts, the mesoderm is the middle germ layer that develops into muscles, blood, and various organs.
- mesohyl
- the collagen-like gel containing suspended cells that perform various functions in sponges
- metamerism
- having a series of body structures that are similar internally and externally, such as segments
- Mollusca
- a phylum of protostomes with soft bodies and no segmentation
- monoecious
- having both sexes in one body, hermaphroditic
- monotreme
- an egg-laying mammal
- motile
- ability to move independently, often actively and freely
- Myxini
- hagfishes
- nacre
- a calcareous secretion produced by bivalve mollusks to line the inner side of shells as well as to coat foreign particulate matter
- nematocyst
- the harpoon-like organelle within a cnidocyte with a pointed projectile and poison to stun and entangle prey
- Nematoda
- a phylum of worms in Ecdysozoa commonly called roundworms containing both free-living and parasitic forms
- notochord
- a flexible, rod-shaped structure that is found in the embryonic stage of all chordates and in the adult stage of some chordates
- osculum
- the large opening in a sponge body through which water leaves
- Osteichthyes
- bony fishes
- ostracoderm
- one of the earliest jawless fishes covered in bone
- Petromyzontidae
- the clade of lampreys
- pharyngeal slit
- an opening in the pharynx
- pneumatic bone
- an air-filled bone
- polyp
- the stalk-like, sessile life form of a cnidarians with mouth and tentacles facing upward, usually sessile but may be able to glide along a surface
- Porifera
- a phylum of animals with no true tissues, but a porous body with a rudimentary endoskeleton
- post-anal tail
- a muscular, posterior elongation of the body extending beyond the anus in chordates
- Primates
- includes lemurs, tarsiers, monkeys, apes, and humans
- prosimians
- a group of primates that includes bush babies of Africa, lemurs of Madagascar, and lorises, pottos, and tarsiers of southeast Asia
- protostome
- describing an animal in which the mouth develops first during embryogenesis and a second opening developing into the anus
- pseudocoelomate
- an animal with a coelom that is not completely lined with tissues derived from the mesoderm as in eucoelomate animals
- radial symmetry
- a type of symmetry with multiple planes of symmetry all cross at an axis through the center of the organism
- radula
- a tongue-like scraping organ with chitinous ornamentation found in most mollusks
- salamander
- a tailed amphibian that belongs to the clade Urodela
- Sarcopterygii
- lobe-finned fishes
- sebaceous gland
- in mammals, a skin gland that produce a lipid mixture called sebum
- sessile
- describes organisms that are not capable of independent movement
- Sphenodontia
- the reptilian clade that includes the tuataras
- spicule
- a short sliver or spike-like structure, in sponges, they are formed of silicon dioxide, calcium carbonate, or protein, and are found in the mesohyl
- spiracle
- a respiratory openings in insects that allow air into the tracheae
- spongocoel
- the central cavity within the body of some sponges
- Squamata
- the reptilian clade of lizards and snakes
- stereoscopic vision
- two overlapping fields of vision from the eyes that produces depth perception
- sudoriferous gland
- a gland in mammals that produces sweat and scent molecules
- swim bladder
- in fishes, a gas filled organ that helps to control the buoyancy of the fish
- tadpole
- the larval stage of a frog
- Testudines
- turtles
- tetrapod
- a four-footed animal; includes amphibians, reptiles, birds, and mammals
- trachea
- in some arthropods, such as insects, a respiratory tube that conducts air from the spiracles to the tissues
- triploblast
- an animal that develops from three germ layers
- tunicate
- a sessile chordate that is a member of Urochordata
- Urochordata
- the clade composed of the tunicates
- Urodela
- salamanders
- vertebral column
- a series of separate bones that surround the spinal cord in vertebrates
- water vascular system
- a system in echinoderms in which water is the circulatory fluid