Amphibians PART II VERTEBRATE ZOOLOGY (VZ Lecture13 – Fall 2012 Althoff - reference PJH Chapter...
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Transcript of Amphibians PART II VERTEBRATE ZOOLOGY (VZ Lecture13 – Fall 2012 Althoff - reference PJH Chapter...
Amphibians
PART II
VERTEBRATE ZOOLOGY (VZ Lecture13 – Fall 2012 Althoff - reference PJH Chapter 10)
Classification of Amphibia
CLASS Amphibia
SUBCLASS Labryinthodonotia*
Leposondyl*
Lissamphibia
ORDER Urodela
Anura
Gymnophiona
* = extinct
(salamanders)
(frogs)
(caecilians)
Focus on Frogs• ORDER: ________ (Greek: “an” = without, “uro”= tail)
• 29 familes, ~4,800 species(compare to 10 families, ~515 species for salamanders)
• Found on all continents except Antarctica
• Body form is more compact, clearly specialized for jumping. Jumping aided by hind limb-muscle arrangement form lever-like action that can catapult them into the air a) powerful pelvis b) pelvis strongly fastened to vertebral column
c) posterior vertebrate fused into solid rod forming ___________d) hind legs elongate, tibia and
fibula fused
Primitive vs. Derived Skeletal Characters
Reduction number of toes on front feet
Reduction in presacral vertebrae
Pelvic girdle changes
Hind limbs & toes
5
14
short ilium,no urostyle
short
Closer look at “rear” end “adjustments”
• Hind legs elongate, ____________________ = 1 bone
• Stronger attachment of a stronger, __________ ________ to the vertebral column
• _________ (part of pelvis) is elongate and reaches far anteriorly.
• Urostyle (part of pelvis) is what was vertebrae—now all fused into a solid rod
Closer look at “midway” adjustments
• Reduction in number of ____________ vertebrae
• Presacral vertebrae are strongly braced by _________________ that restrict lateral bending
Specialization of Locomotor Systems
Fig. 10-8 p231 PJH
HINDLIMBLENGTH(longer)
FORELIMB LENGTH(longer)
walker-hopperwalker-jumper
jumperhopper-burrower
walker-hopper-burrower
hopper
swimmer
Frog Natural History & Locomotion
• ________-legged species that move by hopping frequently are wide-ranging predators
a) more vulnerable to predatorsb) shorter legs prevent rapid escapec) result most have potent defensive
chemical released from glands in skin when attacked
• ________-legged species that move by jumping usually are sedentary predators (“ambush” predators) a) cryptically colored b) usually lack chemical defenses c) result escape w/ rapid series of leaps
Webbing & Toe Specializations
• _______________ species have webbed feet vs.
• Most _____________ based frogs (including those referred to as toads) usually have little webbing between the toes
• Spadefoot toads (NA) have keratinized structure on hindfoot that aids digging backward into the soil
Tree Frog Toe Surfaces• Many tree frogs have enlarged toe disks a)
epidermal layer has peg-like projectionswhich has mucus gland that secretes a viscous solution b) canals in between c) result ____________ & __________ hold toe pad and surface together
Fig. 10-10 p233 PJH
Toe Disks – Found in Several Lineages• Toe disks are not a “tree frog” exclusive…some
terrestrial species (vs. the “arboreal” tree frog species) also have expanded toe disks
• Toe disks have evolved independently in several lineages….a specific example of convergence in structure. This, in a more general sense, is known as _____________________ which….
• Bottomline: diversity in structure and form among anurans is considerable if one looks at the finer points!
…… is the process whereby organisms notclosely related (not monophyletic), independently evolvesimilar traits as a result of having to adapt to similarenvironments or ecological niches
Ohio – 4 families represented
• Family Pelobatidae - ___________________
• 1 species – southeast Ohio…____________ _____________________
eastern spadefoot
Ohio – 4 families represented
• Family Bufonidae - ___________________
• 2 species in Ohio eastern American toad
Ohio – 4 families represented
• Family Hylidae - ___________________
• 6 species in Ohiogray tree frog