Term
| Chordata: General characteristics |
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Definition
Phylum, has:
(1) Notochord
(2) Dorsal Tubular Nerve Cord
(3) Pharyngeal gill slits
(4) Post-anal Tail
(5) Endostyle/thyroid gland |
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Term
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Definition
- A flexible, rod-like structure that extends the length of the body
- Function: serves as an axis for muscle for muscle attachment
- The first part of the skeletal system to develop
- In vertebrates, vertebrae develop from blocks of cells (“somites”) lateral to the notochord; vertebrae either surround or replace the notochord as development proceeds |
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Term
| Dorsal Tubular Nerve Cord |
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Definition
- A hollow tube (at least in early development) that is dorsal to the gut (alimentary canal)
- Anterior end becomes enlarged to form the brain |
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Term
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Definition
- Usually, perforated slit-like openings that lead from the pharynx to the outside
- In some vertebrates (mostly terrestrial), grooves form instead of slits
- Original function: filter feeding; later used in respiration
- In terrestrial vertebrates, as embryological development proceeds, the grooves develop into other structures (eustachian tube, tonsils) |
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Term
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Definition
- Original function: increases propulsion ability for locomotion in water
- Most terrestrial vertebrates retain the tail (use for balance)
- In humans, it is present only as the coccyx, a series of vertebrae at the base of the spinal column |
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Term
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Definition
-functions in Iodine metabolism
-Endostyles are present in all nonvertebrate chordates
-Vertebrates have thyroid glands
-Hypothesis: endostyles developed into thyroid glands |
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Term
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Definition
Phylum includes Starfishes, brittle stars, etc.
-Possesses none of the chordate characteristics
-Share some characteristics of embryological development with chordates and protochordates (animals with these characteristics are called deuterostomes)
-Radial cleavage of the zygote (protostomes have spiral cleavage)
-Coelom develops from outpockets of the gut (in protostomes, coelom develops from splitting of tissue around the gut)
-The anus develops before the mouth (in protostomes, the mouth develops before the anus); The “hole” that the mouth and anus develop from is called the blastopore) |
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Term
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Definition
Phylum includes:
Acorn Worms [pp. 55-57]
- Marine intertidal zone inhabitants
- Distinctive body with a proboscis, a collar and a trunk (see Fig. 2.10)
The Perobranchs [pp. 57-58]
- All marine and sessile
- All possess a ciliary feeding device called a lophophore (see Fig. 2.14)
- The alimentary canal is U-shaped so that the mouth is near the anus
- They have a short proboscis and a small collar
Similarities with other groups:
-With Echinoderms: Both have a ciliated larvae; share some molecular features
-With Chordates: Both have pharyngeal slits and a dorsal nerve cord |
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Term
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Definition
| Urochordata, Cephalochordata, and Vertebrata |
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Term
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Definition
Chordata subphylum:(e.g. Tunicates/Sea Squirts)
-All marine; either sessile or pelagic “drifters”
-Characterized by a tough nonliving tunic (or test) made of the carbohydrate cellulose
-Use pharyngeal slits for filter feeding (See fig. 2.17).
-In sea squirts, larvae posses the four chordate characteristics, but in adults, the notochord and tail disappear and the dorsal nerve cord becomes very reduced (see Fig. 2.16). |
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Term
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Definition
Chordata subphylum:(Lancelets/Amphioxus; genus Branchiostoma)
-Marine, bottom-dwellers ("benthic")
-Posterior end is burrowed into the sand;
-Anterior end is free for filter feeding
-Poorly-developed brain and sense organs
-All four chordate characteristics present in the adult
-See fig. 2.22/2.23 (lateral and cross sections) |
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Term
| Garstang’s hypothesis of the evolution of chordates |
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Definition
Suggests that evolution occurred through the larval stages (see fig. 2.30)
-The echinoderms were an early stage (no major chordate characteristics)
-Hemichordates added gill-based filter-feeding and dorsal nerve cord
-Urochordates added the notochord and post-anal tail, but only in the larval stage
-Cephalochordates had all 4 characters in the adult
-The last step was to abandon filter-feeding for the life of an active predator (pharyngeal gills began to function in respiration), leading to the vertebrates |
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Term
| Dipleuruloid hypothesis of the evolution of chordates |
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Definition
similar to Garstang’s, but downplays the importance of larvae
(1) echinoderms and hemichordates were early sessile side branches:
(2) a “prechordate” (with the 4 chordate characteristics) was an active predator
(3) then there were three main lines:
- Uro- and cephalochordates reverted to filter feeding
- Vertebrates exaggerated the traits associated with an active life-style. |
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Term
| St. Hillaire’s hypothesis of the evolution of chordates |
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Definition
suggests evolution of chordates directly from annelids or arthropods
- Pro: similar body plan (if inverted); all are segmented
- Con: different embryology (protostome vs. deuterostome) |
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Term
| Hypotheses on the evolution of chordates |
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Definition
| Garstang, Dipleuruloid, and St. Hillaire |
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Term
| Life-style change associated with the evolution of vertebrates |
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Definition
-Filter-feeding active predator
-Selection for larger size
-Selection for larger muscles and faster swimming
-Selection for better respiration/circulation
-Selection for better developed sense organs
-Selection for larger brain |
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Term
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Definition
Jawless Fishes ("A" = without;"Gnath" = jaw)
Cyclostomes (Classes Myxini and Petromyzoniformes)
Class Conodonta
Ostracoderms (Classes Pteraspidomorpha and Cephalaspidomorpha) |
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Term
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Definition
(“cyclo” = round; “stome” = mouth);
includes all living (“extant”) agnathans
- Lack both bone and scales; endoskeleton is cartilage
- No paired fins
Classes Myxini and Petromyzoniformes |
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Term
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Definition
Cyclostome Class - hagfishes
- Slimy ("Myx" = slime), eel-like scavengers
- Considered to be the more primitive group; their physiology is more similar to that of invertebrates that of other vertebrates (e.g., they are the only vertebrate that is iso-osmotic) |
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Term
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Definition
Cyclostome Class
- Includes the living Lampreys; most are eel-like parasites (“myz” = suck) as adults. All spawn in fresh water, producing a suspension-feeding larval form called an ammocoete |
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Term
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Definition
Extinct Agnathan class
(from “cone-shaped teeth”)
- Main characteristic: comb-like “teeth”
- Fossils are poorly preserved (except for the teeth); no bone |
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Term
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Definition
(from “shell” + “skin”) [p. 89-90]
- Heavily armored with bony plates forming a head shield and smaller scales over the rest of the body; the endoskeleton was cartilage
- Some had paired anterior appendages
- Ancestor of jawed fishes
- Two classes:
-Class Pteraspidomorpha (Fig. 3.10): two nasal openings
-Class Cephalaspidomorpha (Fig. 3.11): one nasal opening |
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Term
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Definition
Jawed Fishes
("gnath" = jaw; "stome" = mouth)
- Jaws
- Paired pectoral (anterior) and pelvic (posterior) fins
Classes Placodermi, Chondrichthyes, and Osteichthyes |
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Term
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Definition
Gnathostome class: ("Plate" + "skin")
- Heavy body armor with bone; some bone in the endoskeleton
- Among the earliest jawed fishes
- All extinct with no direct living descendants |
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Definition
Gnathostome class: ("cartilage" + "fishes")
- Cartilaginous skeletons: absence of bone is the modified condition; their ancestors had bone and there are traces of bone on the placoid scales and teeth
- Lack a swim bladder: buoyancy is maintained by large livers that produce buoyancy-promoting oils, pectoral fins that act as hydrofoils, and caudal fins that provide lift
Includes subclasses Elasmobranchii and Holocephali |
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Term
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Definition
Subclass of Chondrichthyes
- Have slit-like external gill openings
- A number of extinct forms existed with a variety of body forms
- Living forms are sharks (swim in water column) and skates and rays (bottom dwellers) |
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Term
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Definition
Subclass of Chondrichthyes
- Surviving members are called Chimaeras or ratfishes
- Fleshy operculum covering the gills
- Long tapered caudal (tail) fin
- Teeth are crushing plates |
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Term
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Definition
Gnathostome class: ("bone" + "fishes")
- Most abundant of all vertebrates
- Usually extensive ossification of the internal skeleton
- Small bony scales cover body (no armor)
- Swim bladder present (buoyancy)
- Gills on each side of the body in a common chamber covered by a bony operculum
Subclasses Actinopterygii and Sarcopterygii |
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Term
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Definition
Osteichthyes Subclass: The ray-finned fishes (“Acti” = ray); paired fins supported by bony rays radiating from the fin base
Infraclasses Palaeoniscoformes and Neopterygii |
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Term
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Definition
Actinopterygii Infraclass:
- Scales have a special enamel called ganoine ("ganoid" scales")
- Mouth usually sub-terminal
- Caudal fin shape variable (some symmetrical, some asymmetrical)
- Includes:
- Extinct palaeoniscoid fishes that were the ancestors of other ray-finned fishes
- Extant sturgeons and African birchirs |
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Term
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Definition
Actinopterygii Infraclass:
- Thinner scales without ganoine
- Usually a symmetrical caudal fin
- Usually a terminal mouth
- Includes the following extant fishes:
- gars (relatively primitive)
- bowfins (relatively primitive)
- the modern teleost fishes (abundant: about 20,000 species) |
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Term
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Definition
Osteichthyes subclass: The lobe-finned fishes (“sarco” = flesh): paired fins have fleshy stalks
Superorders Dipnoi and Crossopterygii |
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Term
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Definition
Sarcopterygii Superorder: (lungfish)
- Have functional lungs |
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Term
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Definition
Sarcopterygii Superorder:
- Lungs functional in extinct forms but not in the only living form
- Includes:
- Extinct Rhipidistians which are thought to have given rise to the amphibians
- Extant coelacanth |
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Term
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Definition
- New shapes: stream-lining is not usually as important on land as in the water
- Addition of a neck (movement of head)
- Loss of median fins
- Conversion of paired fins to limbs
- Increased skeletal support due to loss of buoyancy; strengthened limbs, girdles, vertebrae
- Gills replaced by lungs; addition of pulmonary circulation
- Skin becomes cornified (hardened with protein) to resist drying
- Changes in structure of eggs
- Addition of oral glands to keep mouth moist |
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Term
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Definition
| Includes classes Labyrinthodontia, Lepospondyli, and Lissamphibia |
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Term
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Definition
Amphibian Class:
- All extinct
- Ancestors of amphibians and reptiles
- Retained some bony scales (mostly on the abdomen)
- Predominantly aquatic
- Fish-like skulls and vertebrae; 6-8 digits on limbs
- Fin-rays support tail fin (like in fish; different from modern amphibians)
- Each vertebrae contains several separate pieces of bone
- Examples: Icthyostega, Acanthostega |
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Term
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Definition
Amphibian Class:
- All extinct
- Small, mostly aquatic
- Each vertebrae made of a single fused bone |
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Term
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Definition
Amphibian Class:
- Contains all living (extant) amphibians
- Skin can't withstand long exposure to dry air
- Most have lungs; all rely somewhat on cutaneous respiration (through skin)
- No fetal membranes; eggs must be laid in water or in damp places
- Glandular skin, usually lacking scales ("liss" = smooth)
- Simplified skulls and pectoral girdles
Three orders
1.Caudata: salamanders (caud = tail) [aka Urodela; “uro” = tail]
2.Anura: frogs/toads (“an” = without, “uro” = tail) [aka Salientia; “salientia” = jumper)
3.Gymnophiona: caecilians (“gymno” = naked/bare) [aka Apoda; “a” = w/o, “pod” = feet) |
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Term
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Definition
| Cotylosauria, Reptiles, Aves, and Mammalia |
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Term
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Definition
Tetrapod class: transitional between amphibians and reptiles
- Ancestor to reptiles (“stem” reptiles)
- No openings (fenestrae) in the bones that roof over the temporal region of the skull (see fig.3.29a); this type of skull is called an anapsid skull |
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Term
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Definition
Tetrapod class:
- Covered with heavy scales made of protein (not bone!); most with claws
- Vertebral column more firmly attached to the pelvis than in amphibians
- Amniotic egg with fetal membranes
Subclasses Parareptilia, Eureptilia, and Synapsida |
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Term
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Definition
Reptilia subclass:
-Some extinct groups
-Includes the living Order Testudinata (“test” = shell):
-Contains the turtles/tortoises
-Retain anapsid skulls
-Skull, limbs and soft parts remain primitive
-Shell, ribs, spine, toothless mouth and pectoral girdle are highly specialized
-Taxonomic status currently in question; Anapsid skull could be the retention of the primitive skull or could be modification of the “diapsid” condition |
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Term
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Definition
Reptilia subclass:
Characterized by having “Diapsid skulls” with either 2 temporal openings ( fig.3.29c) or only 1 because of the loss of 1 ancestral opening
Infraclasses Sauropterygia, Ichthyopterygia, Lepidosauromorpha, and Archosauromorpha |
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Term
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Definition
Eureptilia infraclass:
-A single fenestra, the euryapsid (“eury” = wide) condition, thought to be derived from the diapsid condition through loss of the lower opening
-Includes the extinct Order Plesiosauria (Extinct aquatic reptiles with a long neck and oar-like limbs) |
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Term
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Definition
Eureptilia infraclass:
-Euryapsid skulls
-Includes the Order Ichthyosauria (extinct porpoise-like aquatic reptiles) |
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Term
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Definition
Eureptilia infraclass: (“lepi” = scaly, “saur” = lizard, “morph” = body)
1)Superorder Lepidosauria (p. 111)
-Fenestrae sometimes modified by loss of temporal bars allowing flexible jaws
-Extant forms: Orders Squamata (snakes and lizards) and Rhyncocephalia (the tuatara) |
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Term
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Definition
Eureptilia infraclass: “archae” = ancient
-Two distinct temporal fenestrae
-Extant forms are in the Order Crocodilia (also birds!)
-Extinct orders include:
-Pterosauria: flying reptiles
-Dinosaurs (two taxa differentiated by structure of the pelvis):
-Saurischia includes carnivores and the Theropod dinosaurs that gave rise to birds
-Ornithischia: Exclusively herbivorous |
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Definition
Reptilia subclass:
-A single temporal fenestra, bounded above by the temporal bar (fig. 3.29b)
-Contained two extinct groups:
-Pelycosauria: the sail-backed reptiles
-Therapsida: ancestors of the mammals (architecture of the deep skull, palate, ear and jaw resemble that of mammals) |
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Term
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Definition
Tetrapod class: Diapsid amniotes with feathers
Subclasses Sauriurae and Ornithurae |
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Definition
Aves subclass: “lizard tails”
- All extinct
- Fully feathered but with a number of reptile-like characters including teeth, a long skeletal axis in the tail, and claws on its anterior limb (wings)
- Includes Archaeopteryx |
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Definition
Aves subclass: “bird tails”
- Tail with a short bony axis
- Fusions of many bones
- Air sacs present
- Usually a large keeled breast bone for attachment of flight muscles
- Usually no teeth
- Two extant Superorders
-Paleognathae: ostrich, emu and their relatives; most secondarily flightless
-Neognathae: all other living birds |
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Term
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Definition
Tetrapod class:
- Synapsid skulls
- Hair present
- Mammary glands present
- Unique skeletal features (e.g., three middle ear bones; a single lower jaw bone)
Subclasses Prototheria and Holotheria |
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Definition
Mammalian subclass:
- Extinct; lived at the time of the dinosaurs
- Small omnivores or herbivores
- oviparous (egg laying) |
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Definition
Mammalian subclass:
Infraclasses Monotremata, Metatheria, and Eutheria. |
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Definition
Holotherian Infraclass: “mono” = one, “trema” = hole
-The platypus and the echidna or spiny anteater
-Reptile-like pectoral girdle
-Oviparous (egg-laying)
-Have a cloacal opening rather than separate digestive/urogenial openings |
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Term
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Definition
Holotherian Infraclass: “meta” = change; “therio= beast
→Give birth to tiny embryonic young that are nourished in their mother’s pouch
→Includes Order Marsupialia (opossums, kangaroos, etc.) |
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Term
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Definition
Holotherian Infraclass: “eu” = good/true
-All "placental" mammals
-There are about 17 or more surviving orders and about a dozen extinct orders
-Insectivora: moles and shrews
-Chiroptera: bats
-Cetacea: whales and dolphins
-Sirenia: manatees
-Ungulate (hoofed mammal) orders:
-Perissodactyla (horses)
-Artiodactyla (pigs, camels, cattle, deer, giraffes, antelope)
-Carnivora: cats, dogs, bear, skunks, seals, walruses
-Rodentia: squirrels, mice, porcupines
-Primates: apes, monkeys, humans |
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