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97 Cards in this Set

  • Front
  • Back
Why did limbs evolve?
Fishes evolved in times of drought, had to move between ponds
They needed to walk around on the bottom of lakes and ponds
Crawled on shores to escap predators
Many underutilized ecological niches
How did limbs evolve?
ugh...
Why did these animals leave the comforts of the aquatic environment
A likely explanation is that these animals were forced to crawl across land to escape ponds that were drying out and shrinking
Competeing theory- early vertebrates ventured increasingly onto land in pursuit of insect prey
Early tetrapod changes
Loss of several cranial bones, the skull was rigidly linked to shoulder girdle by several bones that disappeared early in the evolution of terrestrial vertebrates
This allowed for a mobile neck
Allowing the head to remain relatively stable while walking
How do early tetrapods adapt to gravity without water
Sacral rib connecting the axial skeleton (the spine) the the pelvic girdle (the hip)
Lepospondyli
Early in amphibian evolution
"spool-shaped" vertebral centra
forms from direct ossification of the notocord
Labyrinthodontia
"Labyrinth-teeth"
Vertebral central formed from leurocentra and intercentra - cartilaginous precursors
Ichthyostegida- "first" amphibians
Notocord amphiban changes
REduction of notochord and a rigid spine
Vertebral centra of osteolepiforms are thin and surround the notochord (persists in most tetra pods as the intervertebral disks) without constricting it greatly
A shorter notochord that does not exten into the braincase
Presacral vs postsacral
vertebrae before vs vertebrae after the pelvis
Tetrapod soft parts vocab
Parathyroid glands
controls level of blood calcium
Tetrapod soft parts vocab
Harderian gland
Located anterior to the eye
secrets oily liquid that lubricates the eye
Vomeronasal organ
Olfactory organ located in the palate
Used to smell food in the mouth
Tetrapod soft parts
Layer of dead cells that reduces water loss- present in amniotes and in most lissamphibians
Well0developed muscular tongue with glands
Loss of internal gills
Problems of life on land
Gravity
Locomotion
Different modes of senses
dryness
Respiring
Temperature
Solutions to life on lands
Gravity- Stronger skeletal system, development of more complex muscular arrangment
Locomation- shifting from swimming to crawling
Dryness- mucous glands to moisten skin, then water proof barriers, i.e. keratinized tissues, scales
Respiring- refinement of lung as a respiratory structure
Temp- ability to maintain higher , constant body temperature
Lissamphibian synapomorphies
Moist, permeable skin that allows for cutaneous (of or relating to the skin) gas exchange

Papilla amphibiorum- a sensory area in the wall of the sacculus of the inner ear, sensitive to sound frequencies below 1000Hz
Papilla amphibiorum
A sensory area in the wall of the sacculus of the inner ear, sensitive to sound frequencies below 1000hz

Lissamphibian synamorphies
Operculum-plectrum complex
Bones involved in the transmitting of sounds to the inner ear
Pectrum columella is derived from the hyoid arch
Columella and plectrum are fused in anurans, caecilians and in some salamanders

Lissamphibian synapomorphies
Green rods
retinal cells unique to amphibians
seen in caudates and anurans, but not caecilians (may be related to reduced eyes)
Pedicellate teeth
Crown and base or pedicel of teeth composed of dentine, seperated by a zone of uncalcified dentine made of fibrous connective tissue

Lissamphibian synampomorphies
Levator bulbi
thin muscle in the floor of the orbit
Innervated by the 5th cranial nerve, that causes the eye to bulge outward and to enlarge the buccal cavity
Present in anurans and urodeles and in a modified form in caecilians

Lissamphibian synapomorphies
Orders within Lissamphibia
Proanura- ancestral frog-like group
Anura- Frogs and toads
Caudata- Salamanders
Gymnophiona - caecilians (legless, wormlike amphibians)
Amphibian skin Epidermis
Keratinzed specialization
Amphibian Aquatic Adult skin
Thin layer, 1-2 cell layers only, low in waxes
Amphibian Terrestrial Adult skin
Thickness increases relative to adaptation to terrestrial/dry environment
Some have more waxes/phospholipids and produce less mucus making dry skin (toads)
Osmoregulation of Amphibia
Epidermal glands
Epidermal glands Functions
Aestivation (hibernation)- some drought adapted frogs build mucous cocoons
Protect skin from bacteria and parasites
Aids cutaneous (through the skin) respiration (it requires a moist skin, though)
Epidermal glands functions continued
Phermonal- attract mates in some salamander
Poisonous or sticky - deter predators, often buy not always widespread over body
Keratinised caps
Amphibian skin specialization
On fingertips, may be sharp
used by frogs and slamanders in fast fresh water streams to grasp ground
Tubercles
Amphibian skin specialization
Thick keratinized pads on front thumbs
Used by males for holding females during mating
common in frogs and salamanders
Spade
Amphibian skin specialization
Blade-like structure on rear feet for digging
Salamander reproduction
Return to water (some breed on land i.e. plethodon)
Usually ponds without fish (toxic species can breed with fishes)
Courtship and sperm transfer - spermatophore, spermatheca
Lay eggs in gelatinous masses, possibly a symbiotic algae relationship
spermatophore
a capsule or mass created by males of various animal species, containing spermatozoa and transferred in entirety to the female's ovipore during copulation.

used by salamanders
Spermatheca
receives and stores sperm from the male or, in the case of hermaphrodites, the male component of the body, and can sometimes be the site of fertilization when the oocytes are sufficiently developed.

Salamanders
Describe the Juvenile stage of salamanders
Small gilled version of adult
Exrternal gills functional early
Swim to surface to gulp air as they near metamorphosis
Carnivorous - feed on aquatic insectrs and macroinvertebrates, some cannibalistic
Describe the pond type salamander larvae
Larger gills
Larger tail fins
Describe the stream type salamander larvae
Smaller gills -reduces drag
Smaller tail fins
Describe mountain brook type salamander larvae
Smallest gills
no tail fins
more muscular appendages
Describe Anuran reproduction ritual
Males vocalize to attract female
Males grab females for breeding (amplexus)
Either Auxillary amplexus (male grabs female around armpits) or Inguinal amplexus (male grabs female around waist)
Most with external fertilization
Lecithotrophy
Reproductive specialization in amphibians
All nutrients for development to hatching contained in yolk of egg
Matrotrophy
Reproductive specialization in amphibians
Some of the nutrients provided by female during gestation
Oophagy- egg feeding, young feed on eggs in oviduct
Adelphophagy - uterine cannibalism, developing young eat on siblings in oviduct
Histophagy- developing embryos feed on maternal secretions
histotrophy- developing embryos absorv maternal secretions
Placentotrophy- developiong embryos receive nutrients from the mother by placental transfer
Oophagy
- egg feeding, young feed on eggs in oviduct

Salamandra atra
Adelphophagy
- uterine cannibalism, developing young eat on siblings in oviduct

salamander altra
Histophagy
- developing embryos feed on maternal secretions

Ceacilians, salamanders and frogs
histotrophy
- developing embryos absorv maternal secretions

Typhlonectes
Placentotrophy
- developiong embryos receive nutrients from the mother by placental transfer

(not found in amphibians but in reptiles.... ooh)
Patrotrophy
Father provides nutrients to developing young
Rhinoderma darwinii - tadpoles in vocal sacs
Important reptilian evolutionary advances
Cleidoic egg
Stored water, food, gas exchange structures, protective function of shell
Keratinised epidermal scales are waterproof
Synapsida
– reptilian skull, inferior temporal fenestra only
Euryapsida
– reptilian skull, superior temporal fenestra only
Anapsida
reptilian skulls, no temporal openings,
found in turtles and related fossil forms
Subclass: Anapsida
orders Cotylosauria (stem reptiles) and Testudinata (turtles) – hard shell (carapace of fused, expanded ribs, ribs positioned outside girdles, horny beak (no teeth)
Subclass: Diapsida
Two temporal openings on each side of skull
Squamata
Crocodilia
Pterosauria - winged reptiles
Ornithischia - dinosaurs with bird-like pelvis
Plesiodaurs
Ithyosaurs


Saurischia - dinosaurs with reptile-like pelvis
Subclass: Synapsida (one temporal opening on each side)
Order: Therapsida - precursor to mammals
Commonalities between reptiles and birds skull
Share common eature of a completely ossified skull and openings (fenestrae) of the outer dermatocranium in the temporal region
Diapsida: superior and inferior temporal fenetrae, above and below the postorpial squamosal bar
Condition in squamate and birds is highly modified
Lower arch is lost in squamates and in snakes the postorbital bar is also lost
Differences in reptile and bird skulls
Reptiles the dermatocranium tends to be haevier than that of birds, which is thinner and has air spaces

Birds have more highly developed vision, which results in reinforcement of the eyeball with a ring of bones (sclerotic bones) that ring the orbit but do not articulate with it ( a condition seen in many dinosaurs)
Birds tend to have larger brain-to-body size ratios, requiring increased braincase size
Birds have modification of the jaws into a peak with loss of teeth
Dermatocranium
The skull roof, or the roofing bones of the skull are a set of bones covering the brain, eyes and nostrils in bony fishes and all land living vertebrates.
Sclerotic bones
Ring of bones around the eyeball of birds to provide structural reinforcement
Saurischian vs ornithischian hipbones
Saurischian are more round and detached ischium and pubis bones, while ornithischian are straighter and the ischium and pubis bones run parralel diagonally together
Reptile skin development
Cells more highly keratinzed, create scales
Snakes the scales are modified into scutes used for locomotion
Turtles scales modifided into plates to cover shell
Describe the design of reptilian epidermis
Dermal papilla stimulates localized outgrowth of epidermis into scales
Specialized stratum corneum that is compact, very thin and very hard
Scales clightly lither on exposed surface
Hinge of scale is thinner "ruffled" to allow bending of the body
More heavily keratinized than amphibians
Skin is dry, no mucous glands
Describe the chemical composition of reptilian skin
Typically B keratin and A keratin, in some combination
B keratin is harder that a keratin
Added lipids aid water proofing in some taxa
Turtle skin variation from common reptilian skin
Non-overlapping scales cover bony shells - B keratin
New keratinized scales are added in layers, wear off slowly
Desert tortoise legs
Exposed portion - B kertatin
Hinge region - a keratin
Pattern a and B keratin varies among more aquatic taxa
Archosauria
-are a group of diapsid amniotes whose living representatives consist of birds and crocodilians. This group also includes all extinct dinosaurs, extinct crocodilian relatives, and pterosaurs.
Archosauria skin composition
Exposed portion - B Keratin
Hinge region - a Keratin
New keratinized scles added in layers ( older scales wear off slowly)
Lepidosauria
reptiles with overlapping scales. This subclass includes Squamata and Rhynchocephalia. It is a monophyletic group and therefore contains all descendents of a common ancestor. The squamata includes snakes, lizards, and amphisbaenia
Lepidosauria skin composition
Several unique, derived design features
Keratin pattern unique- exposed portion, 2 layers with top (B keratin) and deep (a keratin), and hinge region, 2 layers with top (B keratin) and deeper (a keratin)
Scales are more highly overlapping and thin than other "reptiles"
Old stratum corneum shed nearly simultaneously (single units in snakes)
A reptilian invention that has to do with the hand?!?!?!?
Claws!
Function of reptilian claws
Aid locomotion on land
Grasp prey
Defense
Chemical composition of claws
Keratinized with calcium salts for added strength
Turtles, crocodiles and lizard respiratory system
Paired lungs
Snakes respiratory system
Most species with single lung -right (limitations of a cylindrical body form
Ancestral groups with two lungs - right is larger (boas and pythons)
Protrusable glottis allows for breathing during swallowing of large prey
glottis
Protrusable glottis allows for breathing during swallowing of large prey
cutaneous
-of, relating to, or affecting the skin.
Mechanoreceptors
Special nerve endings that give information about the body condition (pain, temperature receptors, pressure tension)

Cutaneous receptors. reptilian sensory structures
Labial pits
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A python (top) and rattlesnake illustrating the positions of the pit organs. Arrows pointing to the pit organs are red; a black arrow points to the nostril.

The ability to sense infrared thermal radiation evolved independently in several different families of snakes. Essentially, it allows these animals to "see"[1] radiant heat

Similar in strucutre and funcition
Many pits in seris of labial scales
Boas and pythons - boaidae and pythonidae
Loreal pits
Infrared detection
"pit" vipers - crotalidae , with one pair of pits
Columella
articulates with tympanic membrane in turtles, crocodilians, and lizards.
articulates with quadrate bone in snakes.

the bony or partly cartilaginous rod connecting the tympanic membrane with the internal ear in birds and in many reptiles and amphibians
Quadrate/artocular jaw articulation
vibrations transmitted through jaw elements to quadrate. best at 200-500hz.
These bones shift to become incus and malleus of mammals.
Vision: diurnal species of turtles
good color vision
rods and cones
oil droplets for greater range of wavelength detection.
Vision: good color vision but basically nightblind
diurnal lizards and colubrid snakes with only rods
vision: accomodation
increase in intra-vitreous pressure pushes lens forward.
ciliary muscles contract to flatten lens (not in snakes)
secondary palate
an anatomical structure that divides the nasal cavity from the oral cavity.
partially developed in turtles.
more developed in crocodilians.
vomeronasal organ (VNO)
olfactory epithelium in the roof of the mouth of lizards and especially developed in snakes.
tongue delivers chemical particles to the VNO
tongue flickering indicates chemical sensing
sensory input from this structure leads to olfactory (terminal) nerve and olfactory bulbs.
homodont
(in reptiles) all teeth morphologically similar.
heterodont
differentiation of teeth into morphological types (canines, molars, incisors)
monophyodont
single set of teeth throughout life of animal
polyphyodont
continuous tooth replacement
serpentine undulation
typical slithering.
vertical surface to generate forward thrust
concertina locomotion
movement in burrow or tube
rectilinear locomotion
caterpillar-type motion.
pairs of dermal/costal muscles used to move ventral scutes and ribs
sidewinding locomotion
for movement on loose substrates, sand.
loops of the body lifted and thrown forward.
acrodont
teeth held to leading edge of bone (tuatara)
pleurodont
teeth held on inside edge of bone (some lizards)
thecodont
teeth set into sockets (crocodilians)
Amphibian ventiliation
Glotis
opening to lungs,can be extended by some snakes to go outside of the mouth while eating prey