Lecture Test One

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What are the five chordate characteristics?
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Terms in this set (184)
What are the five chordate characteristics?
a notochord, a dorsal hollow nerve cord, pharyngeal slits, endostyle, and a post-anal tail
Name bones that are homologous to each other
The Humerus in a human is homologous to the humerus in a cat. The quadrate is homologous to the incus. The articular is homologous to the malleus.
Notochord
A long axial rod composed of a fibrous connective tissue wall around cells and/or a fluid-filled space
Vertebral Column
It encloses the spinal cord and the fluid surrounding the spinal cord. The bones, muscles, tendons, and other tissues that reach from the base of the skull to the tailbone.
Dorsal arches
an anatomical term for the combination (anastomosis) of dorsal carpal branch of the radial artery and the dorsal carpal branch of the ulnar artery near the back of the wrist.
ventral arches
is a bony arch on the ventral side of a tail vertebra of a vertebrate.
intercentrum
an element of the vertebral column alternating with the true centra of the vertebrae in several different classes of vertebrates.
pleurocentrum
one of a pair of dorsal and lateral elements of the centrum of the vertebra of the fish and of an extinct amphibian representing or formed from dorsal arcualia.
Vertebral segments
the basic constituent part into which the spine may be divided. It represents a single complete vertebral bone with its associated articular processes and laminae
aspidospondyly
The condition of having the centra of the vertebra arranged in separate ossifications.
monospondylyThe condition in which a vertebral segment is composed of one centrum.diplospondylyThe condition in which a vertebral segment is composed of two centra.polyspondylyThe condition in which a vertebral segment is composed of two or more centra.Apophysesa natural protuberance from a bone, or inside the shell or exoskeleton of a sea urchin or insect, for the attachment of musclesDiapophysesa transverse process of a vertebra that is an outgrowth of the neural arch on the dorsal sideparapophysesone of the transverse processes that project from the centrum of each vertebra of many lower vertebratesBasapophysesAre paired ventrolateral processes, remnants of the hemal arch bases that may receive the articulation with ventral ribs.ZygapophysesThe projection of a neural arch that articular with the adjacent neural arch.Ribseach of a series of slender curved bones articulated in pairs to the spine (twelve pairs in humans), protecting the thoracic cavity and its organs.EmbryollogicalyThe branch of biology that deals with the formation, early growth, and development of living organismsAppendicular Skeletonis one of two major bone groups in the body, the other being the axial skeleton. Is comprised of the upper and lower extremities, which include the shoulder girdle and pelvis.Anteriorfront of the bodyPosteriorfurther back in position; of or nearer the rear or hind end, especially of the body or a part of it.Yawmovement on vertical axis swing side to sideRollrock about on its long axisPitchbuck forward or backArchipterygial finBasic fin-type in which the axis runs down the middle of the fin.Metapterygial finBasic fin type in which the axis is located posteriorly in the fin.Gill-arch theoryproposed by Gegenbauer, Archipterygial fin is most primitive, evolved from posterior gill archFin-Fold theoryby Balfour and Thatcher, •Paired fins arose within a continuous series of ventrolateral folds along the body that was stiffened internally by transverse endoskeletal pterygiophoresPectoral- scapulocoracoid barIn marsupials and eutherian mammals, only clavicle and scapula are left, Coracoid is reduced to the coracoid process on the scapula, Procoracoid is lost completelyPelvic- puboischiac bareither a curved cartilaginous structure called the puboischial bar or a pair of bars lying transversely in the ventral part of the body anterior to the cloaca; projecting dorsally on each side is a so-called iliac process.cleithruma bone external to and beside the clavicle in the pectoral arch of some fishes, stegocephalians, and primitive reptiles.Pectoral Girdle Evolutionevolved in primitive fish as a support for the pectoral fins, and was juxtaposed to the base of the skull.Pentadactyloushaving five digits on each limb.Mesotarsal jointa roller-type hinge develops between the astragalus plus the calcaneum and the distal tarsals or metatarsalsIntratarsal jointare the joints of the tarsal bones in the foot.Crurotarsal jointone that's situated between the bones of crus, i.e. shin (tibia and fibula) and the proximal tarsal bones, i.e. astragalus and calcaneum.Devonian periodwas time of droughts and floods - lobed fins may have helped to get from one shallow pool to another. Was also known as the "Age of fishes"; lobe-fins may have enabled exploitation of shallow water to escape predators and/or exploitation of new food resources (insects on land)Unguligradewalking on hoovesDigitigradewalking on its toes and not touching the ground with its heels, as a dog, cat, or rodent.Plantigradewalking on the soles of the feet, like a human or a bear.What are the different modes of terrestrial locomotion?Cursorial (running) Fossorial (digging or burrowing) Saltatorial (hopping) Aerial or volant (flying) Scansorial (climbing in trees with the aid of claws) Brachiation (climbing in trees by grasping with hands)SplanchnocraniumThat part of the skull arising first to support the pharyngeal slits and later contributes to the jaws and other structures of the head; branchial arches and derivates; visceral cranium.ChondrocraniumThat part of the skull is formed by endochondral bone or cartilage that underlies and supports the brain; also includes the fused or associated nasal capsules.DermatocraniumThat part of the skull formed from dermal bonesBraincasefused cranial components immediately surrounding the brain; parts may be derived from chondrocranium, splanchnocranium and dermatocraniumNeurocraniumossified chondrocranium + associated sensory capsulesThe Origin of JawsWithout jaws, vertebrates are limited to feeding upon small particulate matter (ostracoderms) or fluids (lampreys). Jaws appear first in placoderms and acanthodians. Jaws are derived from neural crest cellsEvolution of JawsJaws are derived from Mandibular arch, with dorsal component contributing to the neurocranium and the ventral component becoming the mandible properTable 7.2Table 7.3Figure 7.53Figure 7.66Paleostylyno arches attach to the skull - agnathan conditionEuautostylymandibular arch suspended from skull without the support of the hyoid arch - placoderms and acanthodiansAmphistylyjaw are attached by two articulations - early sharks, some bony fishes and rhipidistiansHyostylymodern bony fishes, mandibular arch attached to skull via hyomandibulaModified hyostylynew bone aids in jaw suspension, the symplectic boneMetautostylyjaws attach to braincase directly through the quadrate (articulates with articular bone in lower jaw); hyomandibula becomes the stapesCraniostylyentire upper jaw becomes incorporated into skull, jaw joint is between squamosal and dentary bones; quadrate becomes incus and articular becomes the malleusCranial KinesisRefers to movement within the skull; often between braincase and upper jaw, but not exclusively. Absent in mammals, crocodilians, turtles, and modern amphibians. Provides a mechanism to change the size and configuration of the mouth, i.e., suction feeding. Also enables tooth-bearing bones to move quickly into strategic positions (fishes and venomous snakes).Describe Ostracoderm SkullPaleostyly suspensorium. Head shield of bone, cartilaginous chondrocranium and splanchnocraniumDescribe Living AgnathansCartilaginous braincase with an unjointed branchial basket. Paleostyly suspensorium. Specialized feeding adaptationsDescribe Placoderm SkullEuautostyly suspensorium. Cranial shield (externally), cartilaginous chondrocranium, and splanchnocranium. PredatorsDescribe Acanthodian SkullEuautostyly suspensorium. Had operculum bone to cover gills. Dermal bone (the mandibular) reinforced Meckel's cartilage of the lower jaw; 3 ossification centers in palatoquadrate. Splanchnocranium composed of mandibular arch, hyoid arch, and five branchial archesDescribe Skulls of ChondrichthyesLacks bone, no dermatocranial elements. Amphistyly suspensorium. Chondrocranium expanded to form roof of the braincase. Jaws used to crush or capture prey; suction feeding may also be used; also capable of jaw protrusion. PredatorsDescribe Actinopterygian SkullsWell-developed dermatocranium. Hyostyly or modified hyostyly suspensorium. Well-developed opercular and extrascapular bones. Highly kinetic skulls; a diverse array of feeding strategies, predators, suction feeders, crushingWhat are some changes in the skulls of tetrapods?1. Loss of posterior dermatocranial elements (cleithrum, extrascapular and opercular bones); pectoral girdle no longer attached to the skull 2. Change in nasal sac structure (internal nares appear) 3. Suspensorium is metautostyly 4. Reduction in bones of the snout 5. Hyomandibula no longer involved in jaw suspension, become stapes for sound conduction 6. Splanchnocranium is reduced; some elements become important in lingual feedingDescribe Amniote SkullsDevelopment of robust attachment sites for jaw closing muscles. In some lineages, fenestrae developed in outer dermatocranium (anapsid skulls may feature emarginations)Describe Mammal SkullsCraniostyly suspensorium. One large temporal fenestra (evolved from the synapsid condition); loss of postorbital, postfrontal and prefrontal bones. Heterodont, diphyodont. 3 middle ear ossicles. Secondary palate; turbinate bones. Jaw joint between the dentary and squamosal (temporal bones); one bone in the lower jawWhat are some functions of the integument?•Provides shape and support to the organism •Barrier to pathogens •Osmotic regulation •Gas exchange surface •Thermoregulation •Blocks UV radiation •CommunicationWhat are the structures of the skin and where are they located?•Epidermis (superficial, epithelial tissue) •Dermis (deep, connective tissue) •Hypodermis (not part of the skin, separates the skin from underlying muscle; AKA subcutaneous layer AKA superficial fascia)What are the specializations of skin?•Epidermis: hair, feathers, baleen, claws, horns, beaks, and some types of scales •Dermis: osteoderms and dermal bones •Together: teeth, denticles, and scales of fishWhat is the structure of the dermis?•Distinct layers of collagen known as plies, bundles lie at angles to each other •When present, dermal bones form directly through intramembranous bone formationName some examples of the structure of the epidermis?•Epidermis of fishes and amphibians produces mucus to moisten the surface •In reptiles and mammals, the epidermis is covered in a keratinized layer (stratum corneum)Scalesare folds of the integumentdermal scale (most fishes)If dermal elements predominateepidermal scale (most amniotes)If the fold is largely epidermalOntogenyis the origination and development of an organism (both physical and psychological, e.g., moral development), usually from the time of fertilization of the egg to adult.Life historyAre how organisms grow, survive, and reproduce over time. Organisms face many trade-offs between growing, surviving, and reproducing. These trade-offs are key to understanding the diversity of life histories in the world. Growing for a longer time requires later reproduction.Senescence (aging)is a process by which a cell ages and permanently stops dividing but does not die.Viviparity - Parturitionretention and growth of the fertilized egg within the maternal body until the young animal, as a larva or newborn, is capable of independent existence.Oviparity - Ovipositionfemale animals that lay their eggs, with little or no other embryonic development within the mother.Primary egg envelopeAn extracellular coat that surrounds the egg in invertebrates and most nonmammalian vertebrates. is produced from ovarian cytoplasmSecondary egg envelopeis the product of the ovarian follicleTertiary egg envelopemembrane is secreted by the lining of the uterine tubeMatrotrophyPertaining to the nutrition the embryo receives through the placenta or from uterine secretions.LecithotrophyPertaining to the nutrition that the embryo receives from the yolk of the ovum.MicrolecithalIs isolecithal, Pertaining to eggs that contain small quantities of stored yolk.Mesolecithalis either isolecithal or telolecithal, Pertaining to eggs with moderate amounts of stored yolk.Macrolecithaltelolecithal, Pertaining to eggs with large quantities of stored yolk.isolecithalPertaining to an egg in which the yolk is evenly distributed throughout the cytoplasm.telolecithalPertaining to eggs in which yolk stores are concentrated.Name and define the types of cleavage1. Holoblastic-Early mitotic planes pass entirely through the cleaving embryo. 2. Meroblastic-Early mitotic planes that do not complete their passage through the embryo before subsequent division planes form. 3. Discoidal-Early mitotic divisions restricted to the animal pole; extreme case of meroblastic cleavage.Name and define the variation in blastulationBlastulation-the layer of embryonic tissue that forms prior to the development of the embryonic axis. 1. Blastoderm-fishes and amphibians 2. Blastodisc-reptiles and birds 3. Blastocyst-The mammalian blastulaGastrulationis the process of forming the gut and embryonic tissue types (endoderm, ectoderm and mesoderm)Neurulationis the process of forming the neural tube from ectodermWhat are the patterns of gastrulation?Epiboly, Involution, Invagination, Delamination, IngressionWhat are the four major types of tissues in vertebrates?1. Epithelium (endoderm, ectoderm, mesoderm) 2. Nervous (ectoderm) 3. Muscular (primarily mesoderm) 4. Connective (mesoderm)Endochondral (indirect)relating to, formed by, or being ossification that takes place from centers arising in cartilage and involves deposition of lime salts in the cartilage matrix followed by secondary absorption and replacement by true bony tissueIntramembranous (direct)relating to, formed by, or being ossification of a membrane intramembranous bone developmentList the neural crest cell derivatives•Peripheral nervous system •Hormone producing cells •Schwann cells •Parts of meninges •Branchial cartilage cells •Chromatophore cells •Odontoblasts •Dermis of facial region •Vasoreceptors •Sensory capsules and parts of neurocranium •Cephalic armor and derivatives •Heart (connective tissue and outflow septa)Extraembryonic MembranesArise from embryonic germ layers and grow to surround the embryo. Amniotes have just one - yolk sac. Amniotes have four: yolk sac, allantois, chorion and amnionWhat are the sources of extraembryonic membranes?•Amnion - ectoderm, somatic mesoderm •Chorion - ectoderm, somatic mesoderm •Allantois - endoderm, splanchnic mesoderm •Yolk sac - endoderm, splanchnic mesodermHeterochronyAn ontogenetic shift in the onset or timing of a feature's appearance in a descendent species compared to its ancestor.Paedomorphosislarval or embryonic traits of ancestors appear in adults of descendantsPeramorphosisadult characters of ancestors become exaggerated in adults of descendantsProgenesisearly cessation of somatic developmentNeotenyfeature grow slower so that normal sexual maturation overtakes somatic developmentPostdisplacementthe feature appears later in the development of descendant as compared to the ancestorHypermorphosisontogeny is longer in descendant, allometric growth occursAccelerationcharacter grows faster during ontogeny in descendantPredisplacementonset is earlier and the characters starts to grow earlier in descendantHomeotic genesmaster regulatory genes that command many secondary genes that are responsible for the formation of body partsbody polaritythe quality or condition inherent in a body that exhibits contrasting properties or powers in contrasting parts or directions.Give an example how body size effects organisms•Ant: surface tension of water is a life-threatening force; but falling off a building is no big deal •Elephant: surface tension of water can be ignored, but falling off a building means broken bones and probable deathScalingStudy of size and its consequencesExplain how metabolism is affected by sizeLarge endotherms consume less energy per unit mass than do smaller endotherms. Lower surface area to volume ratio means greater heat conservation. Elephants still need to eat more than shrews, but not per unit mass (they eat less)What is the importance of volume and mass?When a solid object increases in volume, its mass increases proportionately. In terrestrial vertebrates, the mass of the body is borne by the limbs. The strength of the limbs is proportional to their cross-sectional areaWhat is the importance of Shape?As an animal grows, its design can be altered as its length and area and mass grow at different rates. Animals must have different shapes at different ages. Change in shape in correlation with a change in size is known as Allometry (positive or negative). Growth in which the proportions remain constant (no allometry) is known as IsometryBiomechanicsPhysical forces are a part of life. The study of how biological design reflects the impact of physical forces upon animals is known as Biomechanics or bioengineeringVelocityrate of change in an object's positionForceeffects of one body acting on another through their respective mass and accelerationWorkis force applied to an object multiplied by the distance the object moves in the direction of the forcePoweris the rate at which work gets doneExplain the concept of Life on Land vs. WaterTerrestrial vertebrates experience the effects of gravity and so exhibit forms that address these challenges. Skeletal system and changes in the cross-sectional area of long bones as mass increases. Aquatic vertebrates move through a fluid, and the fluid exerts a resisting force in the opposite direction known as DRAG. Aquatic animals must also deal with buoyancy (tendency of submerged objects to float or sink)What are the tissue responses to mechanical stress?If living tissue is unstressed, it tends to decrease in prominence or ATROPHY. If living tissue experiences stress, it tend to increase in prominence or HYPERTROPHY. Cell division under stress is termed HYPERPLASIA. Changes in tissue (from one type to another) under stress is known as METAPLASIABiophysicsConcerned with principles of energy exchange such as use of light, exchange of heat, and diffusion of moleculesFunctional Morphologyinvolves the study of relationships between the structure of an organism and the function of the various parts of an organism.Evolutionary Morphologyembraces the "how" of morphology, such as the mechanics of how an animal can bite into a hard object with extraordinary force without knocking out its own teeth or shattering them.What are the similarities in anatomy?•Common ancestry •Selective pressures produce similar solutions (no common ancestry) •Selective pressures produce similar solutions and common ancestryWho is Carl von Linne?He lived between 1707-1778. (aka Carolus Linneaus) - species concept, binomial nomenclature, and taxonomic hierarchyWho is J-B. de Lamarck?(1744-1829) evolution through the inheritance of acquired traitsWho is Charles Darwin?(1809-1882) evolution by natural selectionWho is Alfred Russel Wallace?(1823-1913) co-author of theory of natural selection, father of biogeographyWho is Louis Agassiz?(1807-1873) recognized evidence of world wide ice ages, founded Museum of Comparative ZoologyWho is Thomas Huxley?(1825-1895) "Darwin's Bulldog" - wrote treatise of the evolution of the vertebrate skullWho is Richard Owen?(1804-1892) concept of homology (archetype); coined term "dinosaur"Who is Georges Cuvier?(1769-1832) functional anatomy studied bones, form follows functionWhat were the pushbacks against Evolution by Natural Selection?•Scientific •Popular Press •CreationismHomologyThe state of having the same or similar relation, relative position, or structure.AnalogyA comparison between two things, typically for the purpose of explanation or clarification.PlesiomorphyAn original character state for the taxa under consideration. Also known as symplesiomorphy.What is an Apomorphy?Is a derived character state. The trait in the descendent has been modified in comparison to the ancestor.AutopomorphyA specialized character or trait that is unique to a monophyletic taxonomic group.synapomorphyA characteristic present in an ancestral species and shared exclusively by its evolutionary descendents.homoplasycorrespondence or similarity in form or function between parts of different species or lineages that is not attributable to common ancestry but is the result especially of parallel or convergent evolution in similar environments or ecological niches.serial homologyThe resemblance between different members of single series of structures in an organism.What the types of the symmetry?Bilateral, radial and noneWhat are the anatomical terms of direction?Dorsal (posterior), caudal, ventral (anterior), transverse, frontal, and sagittalName and Define the types of skeletons1. Hydrostatic skeleton-use a cavity filled with water; the water is incompressible, so the organism can use it to apply force or change shape. 2. Exoskeleton is the rigid covering found on the exterior of many animals, particularly invertebrates such as arthropods and mollusks. 3. Endoskeleton-An internal skeleton or supporting framework in an animalDefine and give an example functionthe action or property of a part as it works in an organism, the quadrate bone attaches the lower jaw to the skull in reptiles; also transmits sound to the earDefine and give an example of biological rolehow a part is used in the environment during life history, the quadrate bone is used in feeding and hearingPreadaptationpossessing the necessary form and function before the biological role arisesMonophyletic groupcontains ancestor and all of descendantsPolyphyletic groupcontains descendants of more than one common ancestorParaphyletic groupcontains ancestor and some, but not all, descendant taxaList the eras in chronological order1. Cenozoic (65 mya - present) 2. Mesozoic (252 mya - 65 mya) 3. Paleozoic (542 - 252 mya)List the periods in chronological order1. Cretaceous Period (145-65 mya) 2. Jurassic Period (199-145 mya) 3. Triassic Period (252-199 mya) 4. Permian Period (299-252 mya) 5. Silurian Period (359-318 mya) 6. Devonian Period (416-359 mya) 7. Cambrian Period (542-488 mya)What are some shared traits of the deuterostomes?•Endoskeleton derived from mesoderm •Radial cleavage during development •Enterocoelic coelom formation •Blastopore becomes the anusList some examples of protochordates and list some characteristics of protochordate.Some examples are 1. Hemichordates (pterobranchs and acorn worms: only pharyngeal slits present), 2. Cephalochordates (all 5 traits as adults) 3. Urochordates-Tunicates and thaliacea (2-5 traits as adults, all 5 as larvae) Some characteristics are 1. Morphological grade, not a clade, 2. Benthic, marine, and have planktonic larvae 3. Suspension feeders, food trapped on sheets of mucus, and filtered water circulated by ciliaProtostomeany of a major group of bilateral metazoan animals characterized in typical forms by determinate and spiral cleavage, formation of a mouth and anus directly from the blastopore, and formation of the coelom by splitting of the embryonic mesoderm.DeuterostomesAny of a major division of the animal kingdom that includes the bilaterally symmetrical animals with indeterminate cleavage and a mouth that doesn't arise from the blastopore.What are the major differences between protostomes and deuterostomes?•Protostomes -Blastopore becomes the mouth -Skeleton derived from ectoderm -Schizocoely Spiral cleavage •Deuterostomes -Blastopore becomes the anus -Skeleton derived from mesoderm -Enterocoely -Radial cleavageWhat is the Aricularian hypothesis?The view that the basic chordate body plan that originated through modification of an echinoderm larva. •Larval echinoderm ancestral to tadpole larva of tunicate •Paedomorphosis in tadpole larva produces Amphioxus-like organism •Development of head and brain and stronger swimming and feeding mechanisms produces pre-vertebrate ancestorWhat are the morphological grades in vertebrata?•Agnathans (cyclostomes) •Gnathostomes •Fishes •Tetrapods •Anamniotes AmniotesDescribe the agnathansThe most primitive, two are two alive and one has gone extinct, they were among the first in the fossil recordDescribe the conodontsThey are placed in their own class, they are jawless and eel-like, they are extinctDescribe the Ostracodermextinct, jawless fishes with cartilaginous endoskeletons, a few species with bony exoskeletons, in rare cases they had one pair of fins, but in most cases, they have the bony exoskeleton asDescribe class petromyzontidaThese are the lampreys, they are suspension feeders as larvae and become parasitic adults, they have no jaws, but circular teethDescribe class myxiniThe hagfish, are not parasites, they are scavengers, so they feed on dead and decaying matter, they don't have large eyes, they have multiple hearts, have kidneys that don't filter and they produce large amounts of slime. They don't have fins, so to anchor onto their food source they will tie themselves into knots and they also do this to escape from predators.Describe the class placodermsExtinct jawed fishes with a boney exoskeleton and cartilaginous endoskeleton. There are small as some large placoderms, these fish have evidence to show that they could grow as large as a human, these fish were the predators of the sea.Describe the class ChondrichthyesThey still exist today, they are jawed, cartilaginous fish; the rays, sharks, and ratfish make up the class, subclass Elasmobranchii (rays) feed on the bottom and are flat, the rays can grow large, sharks can rotate their jaws. Some sharks can live in vary deep water and some can live for hundreds of years, the most massive sharks are basking sharks and whale sharks-these are filter feeders, subclass Holocephali-the ratfish, are deep water fish.veryDescribe the osteichthyesThe boney fish, include three classes the acanthodian, which are extinct, they are the spiny sharks, class Actinopterygii, which are the ray-finned fish, such as marlins and goldfish; and class sarcopterygian-the lobe-finned fish, they are most closely related to tetrapods.Describe class acanthodiiBoney fishes and spiny sharks. They are extinct, they have many pairs of fins, their teeth are usually compared to other vertebrates.Describe class actinoptergyiiRay0finned fishes, the largest class of living vertebrates there are some derived ray fined fish, like the swordfish and some primitive ray-finned fish such as the Gar, they occur in every aquatic habitat.Describe class Sarcoptergyiilobe-finned, bony fishes coelacanths are big, and when they are disturbed they will do headstands. Rhipidistians had existed in the Devonian period, they went extinct, the closest to the amphibians, Tiktaalik is the most famous fish and is similar to a missing linkDescribe class amphibiansthey are fish-like, the ichthyoses has a fish-like tail, but its pelvic is similar to amphibians, the labyrinthodonts are amphibians that have gone extinct, they were a mix between a fish and an amphibian, they always had six or more fingers/toes, they tend to be large. The lissamphibians are the living amphibians such as the frogs, salamanders and caellians are the living amphibianscaecilians.Describe the amniotesHave four layers of membrane surrounding the yolk sac, there are four types of amniote skulls, the anapsid belong to turtles, the synapsid belong to reptiles and diapsid belong to mammalsDescribe class reptiliaturtles-they don't have teeth, some turtles live in oceans and some live in freshwater, like the alligator snapping turtle, their tong looks like a worm, so they are able to lure fish into their mouths, some turtles live on land, their feet are flat. Snakes, lizards, crocodiles, alligators, dinosaurs, and birds also make up the reptiles.Describe the synapsidesContains the mammals and the ancestors of the mammals. having a single pair of lateral temporal skull openingsDescribe the diapsidesreptiles (such as the crocodiles) with two pairs of temporal openings in the skullDescribe class mammaliaThere three major groups of mammals, the monotremes, marsupials, and placental. the mammals are abundant and diverse. Montremes are egg-laying, only two exist, the platyapus and akidna. marsupials have pouchs such as kangaroos and opposiuopossumsms. The placental are live birth such as humans and catsare platypupouches