PHYLUM CHORDATASUBPHYLUM VERTEBRATAA SURVEY OF DIVERSITY

BIO 122: ZoologyPart 2

Amphibians, Reptiles & Birds

CLASS AMPHIBIAAmphibians:

include frogs, toads, salamanders & others

Tetrapods (4 legs) Have a gelatinous egg covering Have a 3-chambered heart

2 atria, 1 ventricle

CLASS AMPHIBIAAmphibian development is well known egg laid in water hatch into larval forms or tadpoles with

gills lungs and leg develop, tail stops growing

with time adults come out of water

CLASS AMPHIBIA

CLASS AMPHIBIA Variations in developmental pattern seen:

some remain in water w/ gills: mud puppy, & few salamanders (newts)

CLASS AMPHIBIA Heart is 3-chambered: atrium is separated into two distinct

chambers blood circulation: body right atrium &

ventricle lungs left atrium & ventricle oxygen rich blood goes out

to body, oxygen-poor blood goes to lungs

CLASS AMPHIBIAVariation in respiration mechanisms: gills for aquatic forms lungs on terrestrial forms through skin (diffusion) on all forms

CLASS AMPHIBIABreathing in frogs: have lung and mouth pouch1. suck air into mouth through nostrils2. close nostrils and force air into lungs3. pull air into & out of mouth several times

(an alternate mechanism to get oxygen)4. contracting of body wall to expel air from

lungs (this is method to obtain most oxygen)

most carbon dioxide lost through diffusion out skin

CLASS AMPHIBIACaecilians - snake-like with no visible

appendages most species lack eyes food of small animals most are tropical; are either aquatic or live

in burrows

CLASS AMPHIBIASalamanders - have similar front & back

legs, a tail are carnivorous: eat worms, small

arthropods greatest diversity is in North America

CLASS AMPHIBIACLASS AMPHIBIAFrogs and toadsFrogs and toads - have longer back legs, - have longer back legs,

no tailno tail tadpoles are herbivorous, adults tadpoles are herbivorous, adults

carnivorous, largest can eat rats!carnivorous, largest can eat rats! found throughout worldfound throughout world frogs & toads are not easily frogs & toads are not easily

separated - typical: separated - typical: frog in water, toad terrestrialfrog in water, toad terrestrial

CLASS AMPHIBIACLASS AMPHIBIA South Carolina state amphibian – South Carolina state amphibian –

spotted salamanderspotted salamander

CLASS REPTILIAReptiles:

include snakes, lizards, turtles, crocodiles

Tetrapods (4 legs) leathery egg covering 3-chambered heart

CLASS REPTILIA Characteristics to separate reptiles

from amphibians include …

CLASS REPTILIA1. lungs more efficient as only mechanism

for breathing reptile suck air into lungs, not force as in

amphibians do so by enlarging pleural cavity or

expanding rib cage (no diaphragm present)

no larval stages with gills

2. tough, dry, scaly skin offers protection against desiccation &

physical injury thin epidermis which is shed regularly well developed dermis with pigmented

cells (chromatophores) scales are of keratin (derived from

epidermis)

CLASS REPTILIA

CLASS REPTILIA3. egg shell with food and protective

membrane allows for protective development on

land

CLASS REPTILIA4. jaw better able to grip and/or crush designed for quick

closure - larger & longer amphibian only

good to grab

CLASS REPTILIA5. reptiles have a more efficient circulatory

system and higher blood pressure left & right atrium completely separated left & right ventricles incompletely

separated, but mixing minimal

CLASS REPTILIA6. reptiles have efficient strategies for

water conservation presence of metanephric kidney

(w/ own drainage - ureter) nitrogenous wastes are uric acid (highly

concentrated) salt glands near nose or eyes

CLASS REPTILIA7. nervous system more complex even with small brain, cerebrum is

relatively large

CLASS REPTILIATurtles bony case of dorsal carapace + ventral

plastron (shell) beak rather than teeth tongue not extensible

CLASS REPTILIASnakes & lizards skin of scales or plates teeth present, jaw with diapsid

anatomy (allows to open wide) tongue extensible

CLASS REPTILIASeparation of lizards & snakes: snakes generally lack pectoral and pelvic

girdles snake vertebrae shorter & wider

(undulations) snakes lack a movable eyelid

(but have a permanent transparent eyelids)

CLASS REPTILIA Dinosaurs are considered

large lizards Recent studies suggest

birds are descendantsof dinosaurs

CLASS REPTILIACrocodiles (and others) skin of scales or plates teeth present, jaw without diapsid

anatomy tongue not extensible also: 4-chambered heart

CLASS REPTILIA South Carolina state reptile –

Loggerhead Sea Turtle

CLASS AVESbirds 2 legs + 2 wings calcareous egg covering 4-chambered heart

CLASS AVESOther important characteristics body covering: body of feathers;

legs of scales forelimbs modified to wings (or fins?) beak with no teeth endothermic (body temperature by

metabolism) - previous groups exothermic females with only left ovary developing eggs with much yolk and hard calcareous

shell

CLASS AVESFlight made possible by: wings - flattened structures

to catch air movement sternum with keel

for attachment of flight muscles

bones pneumatized (full of air cavities)

presence of air sacs, extensions of lung into abdomen

CLASS AVESair sacs - extensions of lung into abdomen up to 75% of air bypasses the lungs as

breathing in flows through lungs on way out (more

efficient)

CLASS AVES Migration common among

many species Summer nesting grounds,

take advantage of abundant food in summer

Winter feeding - migrate to other suitable site

Arctic tern with pole to pole migration!

CLASS AVESTypes of annual migration patterns: permanent resident - here year round summer resident - migrate here to breed during

warm months winter resident - summer breeding somewhere else,

typically further north summer or winter visitor - present during only part

of year, eg. ocean birds spring / fall transient - moving through during

migration accidental - strange presence on a very erratic basis

CLASS AVESSmall species use songs for two reasons

1) warns other males to stay away2) attracts prospective females

Once female attracted male will display additionally to keep female1) songs2) plumage displays3) dances & acrobatic flights

CLASS AVESSuperorders:

flightless birds with vestigial wings & stiff palate (ostrich, emu, kiwi)

birds with well developed wings (including penguins) and flexible palate

CLASS AVESOrders: over 20 Orders in eastern North America Orders are separated by

+ bill shape (feeding)+ foot shape+ size + other characteristics

CLASS AVES

CLASS AVES South Carolina state bird -