Download phylum chordata a survey of its diversity - Newberry

PHYLUM CHORDATA
SUBPHYLUM VERTEBRATA
A SURVEY OF DIVERSITY
BIO 122: Zoology
Part 2
Amphibians, Reptiles & Birds
CLASS AMPHIBIA
Amphibians:
include frogs, toads, salamanders & others
 Tetrapods (4 legs)
 Have a gelatinous egg covering
 Have a 3-chambered heart
2 atria, 1 ventricle
CLASS AMPHIBIA
Amphibian 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
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Variations in developmental pattern seen:
some remain in water w/ gills:
mud puppy, & few salamanders (newts)
CLASS AMPHIBIA
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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 AMPHIBIA
Variation in respiration mechanisms:
 gills for aquatic forms
 lungs on terrestrial forms
 through skin (diffusion) on all forms
CLASS AMPHIBIA
Breathing in frogs: have lung and mouth pouch
1.
suck air into mouth through nostrils
2.
close nostrils and force air into lungs
3.
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 AMPHIBIA
Caecilians - 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 AMPHIBIA
Salamanders - have similar front & back legs, a
tail
 are carnivorous: eat worms, small arthropods
 greatest diversity is in North America
CLASS AMPHIBIA
Frogs and toads - have longer back legs, no tail
 tadpoles are herbivorous, adults carnivorous,
largest can eat rats!
 found throughout world
 frogs & toads are not easily
separated - typical:
frog in water, toad terrestrial
CLASS AMPHIBIA

South Carolina state amphibian – spotted
salamander
CLASS REPTILIA
Reptiles:
include snakes, lizards, turtles, crocodiles
 Tetrapods (4 legs)
 leathery egg covering
 3-chambered heart
CLASS REPTILIA

Characteristics to separate reptiles from
amphibians include …
CLASS REPTILIA
1.
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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
CLASS REPTILIA
2.
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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
3.
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egg shell with food and protective membrane
allows for protective development on land
CLASS REPTILIA
4.
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jaw better able to grip and/or crush
designed for quick
closure - larger & longer
amphibian only
good to grab
CLASS REPTILIA
5.
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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 REPTILIA
6.
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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 REPTILIA
7.
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nervous system more complex
even with small brain, cerebrum is relatively
large
CLASS REPTILIA
Turtles
 bony case of dorsal carapace + ventral plastron
(shell)
 beak rather than teeth
 tongue not extensible
CLASS REPTILIA
Snakes & lizards
 skin of scales or plates
 teeth present, jaw with diapsid anatomy
(allows to open wide)
 tongue extensible
CLASS REPTILIA
Separation 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
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Dinosaurs are considered
large lizards
Recent studies suggest
birds are descendants
of dinosaurs
CLASS REPTILIA
Crocodiles (and others)
 skin of scales or plates
 teeth present, jaw without diapsid anatomy
 tongue not extensible
 also: 4-chambered heart
CLASS REPTILIA
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South Carolina state reptile –
Loggerhead Sea Turtle
CLASS AVES
birds
 2 legs + 2 wings
 calcareous egg covering
 4-chambered heart
CLASS AVES
Other 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 AVES
Flight 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 AVES
air 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
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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 AVES
Types 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 AVES
Small species use songs for two reasons
1) warns other males to stay away
2) attracts prospective females
Once female attracted male will display
additionally to keep female
1) songs
2) plumage displays
3) dances &
acrobatic flights
CLASS AVES
Superorders:
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flightless birds with vestigial
wings & stiff palate
(ostrich, emu, kiwi)
birds with well developed wings
(including penguins) and flexible palate
CLASS AVES
Orders:
 over 20 Orders in eastern North America
 Orders are separated by
+ bill shape (feeding)
+ foot shape
+ size
+ other characteristics
CLASS AVES
CLASS AVES
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South Carolina state bird -