Lecture 2 Flashcards
What are characteristics of the unisexual ambystoma
all female, possess DNA from multiple species, range in ploidy from 2-5, reproduce by stealing sperm
Why are unisexual ambystoma assigned the same threat level as their host species?
They are reproductively dependent on them and they look very similar
Where is the central newt found in ontario?
West of lake superior
Where is the red spotted newt found in ontario?
South and east of lake superior in ontario
What is one feature of a red spotted newt that stands out
spots are encircle with black
Where was the single accepted specimen of an eastern tiger salamander collected?
Point pelee
What is a feature of the 5 lined skink and why do they lose it as adults?
they have a blue tail so that birds go for the tail and not the body, they are less vulnerable as adults
What is the closest relative to tetrapods?
Lungfish
What are phylogenetic trees?
A hypothesis about the evolutionary relationships within a group
What kind of group are reptiles and what do they exclude?
Paraphyletic, aves
What are some synapomorphies of Lissamphibia?
Cutaneuous respiration, two sound transmission channels in inner ear, two types of skin glands (mucous and granual(poison)), pedicellate teeth
what is a synapomorphy?
a characteristic present in an ancestral species and shared exclusively by its evolutionary descendants
What is a crown group?
The smallest clade that includes all living members of a group and anyfossils nested within it
What is a stem group?
set of extinct taxa not in the crown group but are more closely related to the crown group than any other
What are gymnophiona?
Caecilians
What are some features of gymnophiona ?
limbless and no pelvic girdle, vesitigial eyes, retractable sensory tentacles
what are some characteristics of lissamphibia gerobatrachus?
fused ankle bone, wide froglike skull, presacral vertebral number was reduced to 17, dorsal ribs not present on 3 lumbar vertebrae
what is gerobatrachus the best candidate for?
a common ancestor to all living frogs and salamanders
What is within caudata?
salamanders
what are major synapomorphies of caudata?
ossification sequence of the skull, absence of a middle ear, origin of jaw abductor muscle, gill slits and external gills in larvae
What is within anurans?
frogs and toads
What are some major families of anurans?
Craugastoridae, hylidae, micohylidae, bufonidae
what are some synapomorphies of anurans?
No true tails in adults, reduction in presacral vertebrae (9 or less), dorsal ribs absent/reduced
What are the two superfamilies in anura?
Hyloida and ranoidea
What kinds of anurans are in hyloida?
True toads, poison dart frogs, treefrogs, glass frogs, leaf frogs
What kinds of anurans are in Ranoidea?
True frogs, malagasy poison frogs, rain frogs, narrow mouthed frogs, giant frogs, afroasian tree frog
What are features of an amniotic egg?
dessication resistant shell, four membranes that permit gas exchange and management of waste products produced by the embryo
Sperm cannot penetrate shell so amniotic eggs must be ___________ before eggshell is produced?
fertilized internally
Egg was a key adaptation that led to what?
enabled amniotes to inhabit dry habitats that amphibians couldnt tolerate
What is included in sauropsida?
Birds and other dinosaurs
what is included in lepidosauria?
Spehnodontida (tuatara), squamates (lizards and snakes)
What are features of lepidosauria?
hemipenis, can automize tails
What is rhynchocephalia?
group containing sphenodontida
What are features of Rhynchocephalia?
Acrodont dentition, diapsid, enlarged premaxillary teeth fused to upper jaw, parietal eye
what is within testudines?
Turtles, tortoises and terrapins
What are features of testudines?
Keratinous beak, carapace, plastron, scutes
What is within squamates?
Lizards and snakes
What are the two major groups within testudines? What feature identifies them?
Pleurodira (side necked turtle), Cryptodira (hidden necked turtle)
What is within archosauria?
Crocodiles, dinosaurs and pterosaurs
what features do archosauria have?
Teeth set in sockets in jaw bone (thecodont), forelimbs with sharp claws
What is not found in archosauria?
viviparity, limblessness, elongate snake like body, highly kinetic skull, venom
What is within crocodilia?
alligators & caimans, crocodiles, gharials
Patterns of relatedness among ________ determined by __________
extinct amniotes, skeletal anatomy
What features are found in early reptiles (reptilia)
well ossified skeletons, anapsid, heterogenous teeth, lost palatine fangs
What skull type do todays reptiles include?
dispsids
What are osteoderms?
Dermal bone structures that support the upper layer of skin and serve as protection against the elements
What features do archosaurs have in common?
mandibular fenestrae, high narrow skulls, modified ankle joint, thecodont
What are the two large groups of archosaurs and what type of ankle joint do they have?
Crurotarsi (rotational joint), Ornithodira (hinge joint)
What are the two groups of dinosaurs?
Saurischia & ornithischia
What is saurischia?
lizard hipped, theropods and sauropods
What is ornithischia
bird hipped, stegosaurs etc
Turtles are more closely related to:
Archosaurs more than lizards and snakes
