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which of the following is a shared characteristic of all chordates
dorsal, hollow nerve chord
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what is one characteristic that separates chordates from all other animals
post-anal tail
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which of these are characteristics of all chordates during at least a portion of their development
a dorsal, hollow nerve chord, pharyngeal clefts, post-anal tail, *e
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which extant chordates are postulated to be msot like the earliest chordates in appearance
lancelets
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external armor of bony plates, no paired lateral fins, and a suspension-feeding mode of nutrition. in addition it will have
no jaws
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what do craniates have that earlier chordates did not have
partial or complete skull
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which feature excludes it from being a leech?
its lack of external segmentation
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the brain had lian in a sort of panlike structure that only partially surrounded the brain structure is:
cranium, cartilage
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if a hagfish you should see
a notochord, located underneath a spinal chord
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tooth-like object same protein found in
scales
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lampreys differ from hagfishes in
having a notochord that is surrounded bya tube of cartilage
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the feeding mode of the extinct conodonts was
predation
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hagfishes and lampreys have what in common with extinct conodonts?
the jawless condition
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the earliest known mineralized structures in vertebrates are associated with which function?
feeding
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the endoskeletons of most vertebrates are composed of calcified
cartilage
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why is this concern misplaced?
lancelets live only in saltwater environments
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lamprey species whose larvae live in freshwater streams, but whose adults live most of their lives in seawater, are similar in this respect to certain species of
actinopterygians
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which extant classes did jaws occur earliest?
chondrichthyes
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according to one hypothesis, the jaws of vertebrates were derived by the modification of
skeletal rods that had supported pharyngeal (gill) slits
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what wouldn't have been observed in the common ancestor of chondrichthyans and osteichthyans?
swim bladder
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distinctive feature of the chondrichthyans
mostly cartilaginous endoskeleton
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which of these are the scales of chondrichthyans most closely related in a structural sense?
chondrichthyan teeth
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similarity between sharks and ray-finned fishes?
they have a lateral line that is sensitive to changes in water pressure
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which groups members have (had) both lungs and gills during their adult lives?
lungfishes
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theres evidence that ray-finned fishes originally evolved in
freshwater environments
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the ray-finned fishes are characterized by
a bony endoskeleton, operculum, and usually a swim bladder
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the swim bladder of ray-finned fishes
was probably modified from simply lungs of freshwater fishes
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dont belong in lobe-fin clade
chondrichthyans
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trend first observed in teh evolution of the earliest tetrapods
feet with digits
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true of fossils of the earliest tetrapods?
should indicate limited adaptation to life on land
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permits reptiles to thrive in arid environments
scales contain the protein keratin, helps prevent dehydration
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not considered an amniote
amphibians
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amniotic egg considered an important evolutionary breakthrough because
allows incubation of eggs in a terrestrial environment
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added most to vertebrate success in relativel dry environments
amniotic egg
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snakes most likely descended from
lizards
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characteristic of most extant reptiles and most extant mamals
keratinized skin
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most dinosaurs and pterosaurs became extinct at the close of the
cretaceous era
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only extant animals that descended directly from dinosaurs
birds
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examination of the fossils of archaeopteryx reveals that in common with extant birds it had
feathers
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significance of fossil archaeopteryx
phylogenetic relatedness of birds and reptiles
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structure possesesed only by birds
feathers and keeled sternum
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-
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pair of numbers represents extinct reptiles that had returned to an aquatic life
1 and 2
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extent nonbird reptiles
3 and 4
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during chordate evolution sequence from earliest to most recent
A 2,3,4,1,5
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sheet f muscle called the diaphragn found in
mammals
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differentiation of teeth is observed in
mammals
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characteristic of all mammals, only mammals
giving birth to live young
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determine whether a fossil represents a reptile or a mammal
examine the teeth
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trend in hominin evolution
increased brain to body ratio
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primates differ from all mammals
opposable thumbs in many species
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vertebrates that fertilization is exclusively internal
reptiles and mammals
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scales closely resmble teeth in both structure and origin
chondrichthyans
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internal fertilization, amniotic egg, skin that resists drying, heavy bones
nonbird reptiles
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egg-laying, pouched, placental
mammals
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lungs, gillsa nd use skin as respiratoy surface
amphibians
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no urinary bladder, females with one ovary, no teeth
birds
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most abundant and diverse of the extant vertebrates
feathers
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hominin traits occured before the others
bipedalism
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trait associated with adoption of bipedalism
repositioning of foramen magnum
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human evolution
fossil evidence indicates that early anthropoids were arboreal, cat-sized
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humans and apes are classified in same category except
genus
-
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most primitive hominin discovered to date
walked on two legs
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first to have adapted for long-distance bipedalism
h. ergaster
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first to craft stone tools
h. habilis.
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first members migrate out of africa
h. erectus
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direct ancestory of h. neanderthalensis
h. heidelbergensis
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symbolic thought, art, full-blown language
h. sapiens
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biologist agreee
humans and apes represent divergent lines of evolution from a common ancestor
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human evolution
different species of the genus homo have coexsisted at various times
-
oldest fossil remains of homo sapiens found
195,000
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homo erectus
fossils not limited to africa
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most inclusive group of all whose members have foramina magna centrally positioned in the base of the cranium
anthropoids
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-
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most inclusive group whose members have fingernails instead of claws
primates
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most inclusive groupp whose members have fully opposable thumbs
anthropoids
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