Taxonomy Flashcards
Animals can be categorized according to the absence of different types of tissues (the Parazoa, or * ) and the presence of tissues (Eumetazoa, or all other animals).
sponges
the *, or animals without a backbone, a category that makes up more than 95% of all animal species
invertebrates
The Parazoa consist of one phylum, * (from the Latin, meaning pore bearers), whose members are commonly referred to as sponges.
Porifera
lack true tissues—groups of cells that have a similar structure and function. However, sponges are multicellular and possess several types of cells that perform different functions.
Sponges
members of Porifera are commonly
referred to as
sponges
The Radiata consists of two closely related phyla: the * (from the Greek knide, meaning nettle, and aria, meaning related to; and the * (from the Greek ktenos, meaning comb, and phora, meaning Members of the Radiata phyla, or radiates, are mostly found in marine environments, although a few, such as hydra, are freshwater species .
Cnidaria , Ctenophores
freshwater
species
hydra
hydra, jellyfish, box
jellies, sea anemones, and
corals, and the
Cnidaria
comb jellies
Ctenophora
Nearly all ctenophores exhibit * , a phenomenon that
results from chemical reactions that give off light rather than heat.
bioluminescence
- , or flatworms, were among the first animals to
develop an active predatory lifestyle. *, and indeed
most animals, are bilaterally symmetrical, with a head bearing sensory appendages, a feature called cephalization
Platyhelminthes (from the Greek platy, meaning flat, and helminth,
meaning worm)
Members of the phylum * (from the Latin rota, meaning wheel, and fera, meaning to bear) get their name from their ciliated crown, or corona, which, when beating, looks similar to a rotating wheel . Most rotifers are microscopic animals, usually less than 1 mm long, and some have beautiful colors. There are about 2,000 species of *, most of which inhabit fresh water, with a few marine and terrestrial species. Most often they are bottom-dwelling organisms, living on a pond floor or along lakeside vegetation.
Rotifera
* constitute a very large phylum, with over 100,000 living species, including organisms as diverse as snails, clams, octopuses, and chitons. They are an ancient group, as evidenced by the classification of about 35,000 fossil species. Many serve as sources of food, including scallops, oysters, clams, and squids.
Mollusks (from the Latin mollis,
meaning soft)
snails, clams, octopuses, and
chitons
Mollusks
* are a large phylum with about 15,000 described species. Its members include free-ranging marine worms, tube worms, the familiar earthworm, and leeches. derived from the Latin annulus, meaning little ring. Each ring is a distinct segment of the annelid’s body, and each one is separated from the one in front of it and the one behind it by septa.
Annelida
free-ranging marine worms, tube worms, the familiar
earthworm, and leeches
Annelida
also called roundworms, are small, thin worms that range from less than 1 mm to about 5 cm
nematodes (from the Greek nematos, meaning thread)
About three-quarters of all described living species present on Earth are *
The arthropods (from the Greek arthron, meaning joint, and podos, meaning foot)
The body of a typical * is covered by a hard cuticle, an exoskeleton (external skeleton), made of layers of chitin and protein. * are segmented, and many of the segments bear jointed appendages
arthropod
(class * ) have two pairs of legs per segment, as their class name denotes (from the Latin diplo, meaning two, and podos, meaning feet), not 1,000 legs, as their common name suggests 8toxic
Diplopoda
millipede
Diplopoda
are fast-moving carnivores that have one pair of walking legs per segment
Chilopoda
centipedes
Chilopoda
six-legged arthropods.
Hexapods, insects
crabs, lobsters, crayfish, and shrimp,
crustacea
Body of two to three parts;
three or more pairs of legs;
chewing mouthparts; usually
marine, 10 or more legs
crustacea
- consists of a unique grouping of deuterostomes.
A striking feature of all * is their modified radial symmetry. The body of most species can be divided into five parts pointing out from the center. As a consequence, cephalization is absent in most classes. There is no brain and only a simple nervous system
consisting of a central nerve ring from which arise radial branches to each limb.
The phylum Echinodermata (from the Greek echinos, meaning spiny,
and derma, meaning skin)
starfish, sea urchin, sea cucumber, sea lilies
Echinodermata
Chordates are named for the * , a single
flexible rod that lies between the digestive tract and the nerve cord. Composed of fibrous tissue encasing fluid-filled cells, the notochord is stiff yet flexible and provides skeletal support for all early-diverging chordates. In most chordates, such as vertebrates, a more complex jointed backbone usually replaces
the notochord; its remnants exist only as the soft material within the discs between each vertebrae.
notochord
The Phylum * Includes All the Vertebrates
and Some Invertebrates
Chordata
All vertebrate species that possess jaws are called *
gnathostomes (from
the Greek, meaning jaw mouth)
Jawless fishes, no appendages
Cyclostomata
Fishes with cartilaginous skeleton; teeth not fused to jaw; no swim bladder;
well-developed fins; internal fertilization; single blood circulation
Chondrichthyes
Adults able to live on land; fresh water needed for reproduction;
development usually involving metamorphosis from tadpoles; adults with
lungs and double blood circulation; moist skin; shell-less eggs
live in two worlds
Amphibia
Body encased in hard shell; no teeth; head and neck retractable into shell;
eggs laid on land
Testudines
Lower jaw not attached to skull; skin covered in scales
Squamata
Four-chambered heart; large aquatic predators; parental care of young
Crocodilia
Feathers; hollow bones; air sacs; reduced internal organs; endothermic;
four-chambered heart
Aves
Mammary glands; hair; specialized teeth; enlarged skull; external ears;
endothermic; four-chambered heart; highly developed brains; diversity of
body forms
Mammalia
sharks, skates, and rays
Chondrichthyes
Unlike the cartilaginous fishes, all other gnathostomes have a bony skeleton and belong to the clade known as * . This term means “bony fish”
osteichthyes
Turtles, Lizards, Snakes,
Crocodilians, Dinosaurs, and Birds
Reptiles
- Have Feathers, a Lightweight Skeleton,
Air Sacs, and Reduced Organs
Birds
Plant eating; gnawing habit, with two pairs of continually growing
incisor teeth
Mice, rats, squirrels, beavers,
porcupines (2,277)
Rodentia
Insect or fruit eating; small; have ability to fly; navigate by sonar;
nocturnal
Bats
Chiroptera
Opposable thumb; binocular vision; large brains
Monkeys, apes, humans (404)
Primates
Flesh-eating mammals; canine teeth
Cats, dogs, weasels, bears, seals, sea
lions (286)
Carnivora
Powerful hind legs; rodent-like teeth
Rabbits, hares (92)
Lagomorpha
Marine fishes or plankton feeders; front limbs modified into flippers; no
hind limbs; little hair except on snout
Whales, dolphins (84)
Cetacea
(“Lucy”)
Australopithecus afarensis
