bio 120 chapter 35

postnatal tail

chordates have a postnatal tail that extends beyond the anus, at least during their embryonic development

amniotes

classes of membranes within the reptiles eggs

pharyngeal slits

connect the pharynx, a muscular tube that links the mouth cavity and esophagus with the external environment -in terrestrial vertebrates, the slits to not connect to the outside and are better termed pharyngeal puches

ossicles

echinoderms endoskeleton is composed of calcium carbonate (calcite) plates called ossicles

amnion

encases the developing embryo within a fluid filled cavity

Echinoderms

ex. sea star -ancient and unmistakable -characterized by deuterostome development, pentameral symmetry, an endoskeleton covered by a delicate epidermis, and a water vascular system

radial canals

extend from central ring canal

water vascular system

fluid filled system that aids in movement or feeding - a modification of one of several coelomic spaces and is composed of a central ring canal

notochord

forms on the dorsal side of the primitive gut in the early embryo and is present at some developmental stage in all chordates -located just below the nerve chord

monotremes

the duck billed platypus and two species of the echidna are the only living monotremes. -mammals that lay shelled eggs

difference marsupials and mammals

their embryonic development. in marsupials are fertilized egg is surrounded by a chorion and amniotic membranes, but no shell forms around the egg as it does in montotremes

madreporite

water enters the water vascular system through the madreporite -a sievelike plate that is on echinoderm's surface and flows to the ring canal through a stone canal

Vertebrate timeline

-evolved half a billion years ago: an overview - in fishes, evolution of a hinge jaw was a major advance -other changes allowed a move into the terrestrial environment giving rise to amphibians, reptiles, birds, and mammals.

echinodermata contains five extant classes

1. Asteroidea (sea stars) 2. Crinoidea (sea lilies) 3. Echinodea (sea urchins and sand dollars) 4. Holothuroidea (sea cucumbers) 5. Ophiuroidea (brittle stars)

Key Characteristics of Mammals

1. Hair: all mammals have hair even whales and dolphins have bristles on their snouts, endothermic 2. mammary glands: all possess mammary glands that secrete milk 3. endothermy: this way mammals can be active at anytime of the day and colonize in extreme environments 4. placenta: females carry their developing young internally in a uterus, nourishing them through the placenta

reptiles exhibit 3 characterisitcs

1. amniotic eggs: must be laid in water or a moist setting to avoid drying out. eggs contain a food sourceL the yolk sac, the amnion, the allots and chorion 2. dry skin: dry watertight skin. a layer of scales covers there bodies to reduce water loss 3. thoracic breathing: pulmonary breathing, expanding and contracting the rib cage and diaphragm to suck air into the lungs and then force it out.

Key characteristics of birds

1. feathers: modified reptilian scales made of keratin, just like hair and scales. serve two functions: providing lift for flight and conserving heat 2. flight skeleton: bones of birds are thin and hollow. many of the bones are fused, making the bird skeleton more rigid than a reptilian skeleton arose from 150MYA

Key features of primates

1. grasping fingers and toes 2. binocular vision: eyes are shifted forward to the front of their face

amphibian key characteristics

1. legs: 4 legged 2. lungs 3. cutaneous respiration: respire through their skin, which is kept moist and provides an extensive surface area 4. pulmonary veins: after blood is pumped through the lungs two large veins called pulmonary veins return the aerated blood to the heart for rep umping 5. partially divided heart: a dividing wall helps prevent aerated blood from the lungs mixing with nonaerted blood being returned to the heart from the rest of the body -the blood circulation is divided into 2 separate paths: pulmonary and systemic

Fish exhibit 5 key characteristics

1. vertebral column: fish have an internal skeleton with a bony or cartilaginous spin surrounding the dorsal nerve cord, and a body or cartilaginous skull encasing the brain 2 .jaws and paired appendages: fishes other they lampreys and hagfish all have jaws and paired appendages, features also seen in tetrapods. -most fish have two pairs of fins: a pair of pectoral fins at the shoulder, and a pair of pelvic fins at the hip. in the lobe fin fish, these pairs of fins became jointed 3. internal gills: fishes gills are composed of fine filaments of tissue that are rich in blood vessels, extract oxygen dissolved in the water around them 4. single loop blood circulation: blood is pumped from the heart to the gills. from the gills, the oxygenated blood passes to the rest of the body and then returns to the heart. the heart is 2 chambers 5. nutritional deficiencies: fishes are unable to synthesize the aromatic amino acids, (phenylalanine, tryptophan, and tyrosine) so they most consume them in their foods. this inability has been inherited by all of their vertebrate descendent

vertebrates differ from tunicates and lancelets in two important respects

1. vertebral column: in all vertebrates the notochord is replaces during embryonic development by a vertebral column -the column is a series of bony or cartilaginous vertebrae that enclose and protect the dorsal nerve cord like a sleeve 2. head: vertebrates have a distinct and well-differentiated head with three pairs of well-devloped sensory organs, the brain is incased with a protective box, the skill, or cranium, made of bone or cartilage

Nonvertebrate chordates

Tunicates have chordate larval forms -have a swimming larval from exhibiting all the features of a chordate, but their adult form is sessile and baglike Lancelets are small marine chordates -have chordate features throughout life, but as adults they lack back bones and have no distinct head

placenta

a specialized organ that brings the bloodstream of the fetus into close contract with the bloodstream of the mother. food, water, and oxygen can pass across from mother to child and wastes can pass over to the mother's blood and be carried away

deuterostome

an animal whose mouth develops from a second opening in the early embryo, opposite to the initial opening blastopore of the rudimentary gut. Chordates and echinoderms are deuterostomes.

endothermic

animals that are able to generate their heat internally

Vertebrate chordates

have a vertebrae, a distinct head, and other features - a vertebral column encloses and protects the dorsal nerve cord. -the dissect and well-diffrentiated head carries sensory organs. -vertebrates also have specialized internal organs and a bony or cartilaginous endoskeleton

pentaradially symmetrical

have five axes of symmetry

diapsids

have skulls with two pairs of holes on each side of the head, and like amphibians and early reptiles, they were ectotherms

hominoids

includes the apes and the hominids. humans depart from apes in several areas of anatomy related to bipedal locomotion. humans vertebral column is more curved than an apes, and their spinal cord exits from the bottom rather than the back of the skull.

echinoderms symmetry

larvae of echinoderms are bilateral, but adult is pentaradial

chorion

lies beneath the pros shell. allows the exchange or respiratory gases but retains water

anthropoids

monkeys, apes, and humans. -diurnal:active during the day -feeds on mainly fruit and leaves -care for their young for prolonged periods

swim bladder

most bony fishes are heavy from bone but are still buoyant because they have a swim bladder: a gas filled sac that allows them to regulate their buoyant density and so remain suspended at any depth in water effortlessly

operculum

most bony fishes have a hard plate called the operculum -covers the gills on each side of the head -flexing the operculum permits bony fishes to pump water over their gills

vertebrates differ from other chordates in respect to:

neural crest: a unique group of embryonic cells called the neural crest contributes to the development of many vertebrate structures. -cells develop on the crest of the neural tube as it forms by invagination and pinching together of the neural plate -neural crest cells then migrate to various locations in the developing embryo, where they participate in the development of many different structures internal organs: include liver, kidneys, and endocrine glands: secretes hormones that help regulate many of the body's functions endoskeleton: made of cartilage and bone -makes possible great size and extraordinary powers of movement - specialized tissues containing fibers of the protein collagen compacted together

ectothermic

obtaining their heat from external sources

echinoderms water vascular system

one of several coelomic compartments aids in movement, feeding, circulation, respiration, and excretion

yolk sac

provides food from the yolk for the embryo via blood vessels connecting to the embryo's gut

synapsids

reptiles whose skulls had a hole behind the opening for eyes

Chordates

share four features at some time during developmentL a single, hollow nerve chord; a flexible rod, the notochord; pharyngeal slits or pouches and a postnatal tail

nerve chord

single hollow nerve chord runs beneath the surface of the chordate

lepidosauria

snakes and lizzards

allantois

surrounds a cavity into which wastes products from the embryo are excreted