chapter 44 Flashcards
Poriferans
an aquatic invertebrate animal of the phylum Porifera; a sponge.
Cnidarians
a phylum characterized by radial symmetry, two germ tissues in the embryo, a closed internal gastric cavity, and well-developed tissues but not organs
radial symmetry
symmetry around a central axis, as in a starfish or a tulip flower
bilateral symmetry
symmetry on both sides of a midline, animals with bilateral symmetry have a distinct head and tail, marking front and back, with a single plane of symmetry running between them at the midline
Bilateria
the monophyletic group of animals with bilateral symmetry
acoelomates
a bilaterian without a body cavity
coelomates
a body cavity surrounding the gut
pseudocoelomates
an invertebrate that has a fluid-filled body cavity not lined with mesoderm tissue
protostomes
a bilaterians in which the blastopore, the first opening to the internal cavity of the developing embryo, becomes the mouth
deuterostomes
a bilaterian in which the blastopore, the first opening to the internal cavity of the developing embryo, becomes the anus
lophotrochozoans
are a taxon of protostome animals
ecdysozoans
a group of protostome animals
choanocytes
a type of cell that lines the interior surface of a sponge
Eumetazoa
the monophyletic group of all animals other than sponges
gastric cavity
in cnidarians, a closed internal sit where extracellular digestion and excretion take place
epidermis
in mammals, the outer layer of skin, which serves as a water-resistant, protective barrier
endodermis
the inner lining of the cnidarian body
mesoglea
in cnidarians, a gelatinous mass enclosed in by the epidermis and endodermis
ctenophores
comb-jellies; species in this phylum have a radial body plan but a flow-through gut
Annelida
a phylum of worms that have a cylindrical body with distinct segments and a bilaterian body plan
Cambrian explosion
a transition period in geologic time during which the body pans characteristic of most bilaterina phyla developed
Mollusca
a monophyletic group distinguished by a mantle, which plays a major role in movement, skeleton-building, breathing, and excretion
gastropods
a group of mollusks consisting of snails and slugs
cephalopods
a monophyletic group of mollusks, including squid, cuttlefish, octopus, and chambered nautilus, with distinctive adaptations such as well-developed eyes and muscular tentacles that capture prey and sense the environment
bivalves
mollusks that includes clams, oysters, and mussels; they have an enclosing skeleton in which two hard shells are connected by a flexible hinge
Arthropoda
a monophyletic group of animals that included insects and contains more than half of all known animal species, distinguished by their segmented bodies and jointed legs
chelicerates
one of the four main groups of arthropods, including spiders and scorpions, chelicerates have pincer-like claws and are the only arthropods that lack antennae
myriapods
one of the four main groups of arthropods, including centipedes and millipedes; distinguished by their many pairs of legs
crustaceans
one of the four main groups of arthropods; including lobsters, shrimp, and crabs; distinguished by two pairs of antennae and their branched legs or other appendages
metamorphosis
the process in some animals in which the body changes dramatically at key stages in development
spiracles
an opening in the exoskeleton on either side of an insect’s abdomen through which gases are exchanged
tracheae
an internal system of tubes in insects that branch from openings along the abdominal surface into smaller airways, directing oxygen to and removing carbon dioxide form respiring tissues
Chordata
one of the three major phyla of deuterostomes, this group included vertebrates and closely related invertebrate animals such as sea squirts
Echinodermata
one of the three major phyla of deuterosomes, defined by five-part symmetry; this group includes sea urchins and sea stars
pharynx
the region of the throat that connects the nasal and mouth cavities; in hemichordates, a tube that connects the mouth and the digestive tract
pharyngeal slits
a vertical opening separated form other slits by stiff rods of protein in the pharynx of hemichordates
dorsal nerve cord
a nerve cord that develops in a location dorsal to the notochord, this embryonic feature is unique to chordates
water vascular system
a series of fluid-filled canals that permit bulk transport of oxygen and nutrients in echinoderms
tube feet
small projections of water vascular system that extend outward from the body surface and facilitate locomotion, sensory perception, food capture, and gas exchange in echinoderms
vertebrates
a subphylum of Chordata, distinguished by a bony cranium that protects the grain and (unless lost through evolution), a vertebral column
craniates
a subphylum of Chordata, distinguished by a bone cranium that protects the brains
notochord
in chordates, a stiff rod of collagen and other proteins that runs along the back and provides support for the axis of the body
vertebral column
a skeletal structure in vertebrates that functionally replaces the embryonic notochord that supports the body
vertebrae
the series of hard bony segments making up the jointed skeleton that runs along the main axis of the body in vertebrates
neural tube
in chordates, a cylinder of embryological tissue that develops into a dorsal nerve cord
myotomes
in chordates, any one of a series of segments that organizes the body musculature
hagfish
one of the earliest-branching craniates, with a cranium built of cartilage but no jaws; hagfish feed on marine worms and dead and dying sea animals
lampreys
one of the earliest-branching craniates, with a cranium and vertebral column built of cartilage but no jaws; many lampreys live parasitically, sucking body fluids from fish prey
Chondrichthyes
cartilaginous fish, a monophyletic group that includes about 800 species of sharks, rays and chimaeras
Osteichthyes
bony fish that have a cranium, jaws, and mineralized bones, there are about 20,000-25,000 species
fleshy-finned fishes
have muscles and Class Sarcopterygii
coelacanth
a genus of two species of lobe-finned fish found off the coast of Africa and thought to have been extinct for 80 million years but which is still living today; along with lungfish, he nearest relative of tetrapod
lungfish
several species of lobe-finned fish that use a simple lung to survive periods when their watery habitat dries by burying themselves in moist med and breathing air; along with coelacanths, the nearest relative of tetrapods
Tetrapoda
a monophyletic group of animals whose last common ancestor had four limbs; this group includes amphibians, lizards, turtles, crocodilians, birds and mammals
Amphibians
a monophyletic group of vertebrates, including frogs and salamanders, with an aquatic larval form with gills and an adult terrestrial form that usually has lungs
amniotic egg
an egg that can exchange gases while retaining water, permitting amniotes to reproduce in dry terrestrial habitats that amphibian eggs cannot tolerate
amniotes
the group of vertebrate animals that produce amniotic eggs, this group includes lizards, snakes, turtles, and crocodilians
Mammalia
a class of vertebrates distinguished by body hair and mammary glands from which they feed their young
monotremes
are basal mammals that lay eggs instead of giving birth to live young like marsupials and placental mammals
marsupials
a group of mammals that includes kangaroos, koalas, and opossums; their young are born at an early stage of development and must crawl to a pouch where mammary glands equipped with nipples provide them with milk
placental mammals
a mammal that provides nutrition to the embryo through the placenta, a temporary organ that develops in the uterus; placental mammals include carnivores, primates, hooved mammals, and whales
