Transcript Chordata: Amphibians, Reptiles and Birds

Chordata: Amphibians,
Reptiles and Birds
By: Nikita Mathew, Noor Al-Alusi, Sara Shu
Period 3
http://www.animalpicturegallery.net/animal-picture-peacock-Laurence-Shan.jpg
Amniotes
 An amniote is a member
of a clade of tetrapods that
have an amniotic egg
containing specialized
membranes that protect
the embryo (i.e. mammals,
birds and other reptiles).
 Embryonic membranes
distinguish amniotes from
tetrapod amphibians.
http://kentsimmons.uwinnipeg.ca/16cm05/1116/34-19-AmnioticEgg-L.gif
2
AMPHIBIANS
http://www.sheppardsoftware.com/content/animals/kidscorner/classification/kc_class
ification_appearance.htm
Phylum: Chordata
 Class: Amphibia
 Salamanders
-Order: Urodela “tailed ones”
 Frogs

-Order: Anura “tail-less ones”
 Caecilians

-Order: Apoda “legless ones”

Sample Animals
http://www.sciencedaily.com/images/2009/04/
090401101745-large.jpg
http://static.howstuffworks.com/gif/salamander-regrowbody-parts-1.jpg
http://www.nhm.ac.uk/resourcesrx/images/caecilian_30881_1.jpg
Body Cavity
 Has Coelom
Body Symmetry
 Bilateral symmetry
http://z.about.com/d/animals/1/0/W/5/s
hutterstock_716539.jpg
Nervous System
 Present
 Brain has medulla, cerebellum, a small cerebrum
 Has spinal cord and nerves
 Two eyes with third eyelid/protective membrane
Circulatory System
 Are cold blooded (body temperature same as
surrounding environment)
 Three chambered-heart with two atria and one
ventricle
Digestive System
 All amphibians
use mouth,
stomach, and
small intestine for
digestion
 Frogs have a long
sticky tongue that
is usually folded
backwards in
their mouth
http://www.pollsb.com/photos/o/26648frog_tongue.jpg
Excretory System
 Two kidneys are the main excretory organs
 Filter waste that leaves the body as urine
 Liquid and solid wastes leave through cloaca
Locomotion/Musculature
 Frogs and
salamanders are
tetrapods (“four feet”)
 Most frogs and
salamanders use
strong hind legs to
move
 Caecilians burrow in
moist soil because
they are legless
http://animals.timduru.org/dirlist/frog/frog993
8-LeopardFrog-Jumping.jpg
Skeletal Type
 Endoskeleton—consists of hard supporting elements
(cartilage and/or bone)
 Has axial skeleton (skull, backbone, and ribcage) and
appendicular skeleton (limbs)
 Skeleton provides support and enables movement
Sensory Structures/Features
 Frogs and
salamanders have
eyes while caecilians
are nearly blind
 Can sense vibrations
on the ground
 Frogs have external
eardrums that sit
behind the eyes
http://departments.juniata.edu/biology/vertzoo/Fro
g_morphology.jpg
Reproduction: Frogs and
Salamanders
 Sexual reproduction
 Eggs laid and fertilized outside of mother’s body in
water/moist environment
 Eggs lack shell so are prone to dehydration so
amphibians lay them in moist environments with a
jelly-like layer for protection
Reproduction: Caecilians
 Only amphibians to use internal insemination
 Fertilized eggs are laid outside and guarded by
female
 When hatched, caecilians are already metamorphed
Gas Exchange
 Mostly rely on moist skin for gas exchange
 Breathe using positive pressure
 Lowers roof of mouth and take in air through nostrils.
Nostrils then close and roof of mouth is raised, pushing
air into lungs.
Other features
 Amphibian means “two lives” (many live in aquatic
and terrestrial environments)
 Have complex social behaviors, including certain
vocal communication during breeding
http://www.amphibian.com.au/amphibian_frog.jpg
Reptiles
Phylum:
Chordata
http://www.sheppardsoftware.com/content/animals/kidscorner/classification/kc_clas
sification_appearance.htm
http://derek4messiah.wordpress.com/2009/10/07/eat
ing-lizards-acts-10-11/
http://www.marathonbooks.com/Alligator.html
http://www.w
orldlatestnew
s.com/worldnews/t-rexwas-acowardlybully-whopicked-onrunts-60933
http://naturescrusaders.wordpress.com/2009/02/19/sea-turtles-aredrowning-save-them-from-bottom-longline-fishing-nets/
Body Cavity
Body Symmetry
 present
 bilateral
http://en.academic.ru/pictures/enwiki/70/Flo
rida_Alligator.jpg
http://fireflyforest.net/images/firefly/200
5/June/gopher-snake-head.jpg
http://i.dailymail.co.uk/i/pix/2008/12/03/article-109165402ACEF34000005DC-483_468x463.jpg
Nervous System
 Nervous system consists of a brain, spinal
cord, and sense organs.
 More advanced nervous system than
amphibians
 Reptiles have much smaller brains
compared with mammals
 Olfactory bulb
http://www.britannica.com/EBchecked/topic-art/409665/70848/In-the-brain-of-reptilessuch-as-the-caiman-the
•Snake’s tongue have
highly sensitive smell
sensors.
•Alligators have sensory
nodules on jaws, connect
to nerve fibers
responding to vibrations
and small pressure
changes in the water.
•Crocodiles have similar
organs on almost every
scale on their body
Circulatory System
 Cold blooded- do not use metabolism to control body
temperature
 Behavioral adaptations to regulate body temperature
 Ectothermic-absorption of external heat as main
source of body heat
Digestive System
 Present [mouth, teeth,
esophagus, stomach,
rectum]
 Snakes: loosed
articulated jaws and
elastic skin to swallow
prey larger than itself
http://news.nationalgeographic.com/news/2006/09/060915
-python-ewe.html
Excretory System
 Cold blooded
 Covered with scales
 Kidneys and ureters to get rid of liquid wastes
 Molt/shed their skin
Locomotion/Musculature
 Snakes use waves of lateral




bending to propel themselves
forward
They also grip ground with belly
scales at several points, pulling
its other parts forward.
Other Reptiles:
-stomachs close to ground
- low center of gravity forces
body to work more
http://www.rubberbug.com/reptiles.htm
Skeletal Type
 endoskeleton
 Breast bone protects lungs and heart
 Turtles have a hard shell that are fused to the
vertebrae and ribs; defense against predators.
http://static.howstuffworks.com/gif/turtle-shell-1.jpg
Sensory Structures/Features
 Scales that contain keratin—provides waterproof
barrier that helps prevent dehydration in dry air
 Snakes:

-acute chemical sensors and lack eardrums—
their sensitivity to ground vibrations help them detect
movement
 -flicking tongue helps to fan odors toward olfactory
organs on roof of mouth
Reproduction
 Sexual
 Female’s eggs fertilized internally
 Eggs, with a leathery and flexible shell, are then
deposited
The Amniotic Egg
•extraembryonic
membranes protect
the embryo.
•gas exchange,
waste storage,
transfer of stored
nutrients to embryo
•Amnion: a fluid filled
cavity that cushions
against shock
•Is not found in
amphibians
Gas Exchange
 Watertight skin (due to scales) not used as respiratory
surface.
 Most rely solely on lungs for gas exchange
 Turtles also use moist surfaces of cloaca.
Unique Features
 Some lizards can lift their front
legs off the ground while
running
http://forums.xkcd.com/viewtopic.php?f=2&t=24742&start
=200
http://www.duiops.net/seresvivos/galeria/lagartos/Ani
mals%20Funny_Lounge%20Lizard.jpg
http://images.google.com/imgres?imgurl=http://www.duiops.net/seresvivos/galeria/lagartos/Animals%
2520Funny_Lounge%2520Lizard.jpg&imgrefurl=http://www.duiops.net/seresvivos/gallery_lizards.htm
l&usg=__CtYkVu8qt4gCQjHxAPznnjygUeQ=&h=1200&w=1600&sz=263&hl=en&start=2&sig2=uKXN
wOkb_vXSt0JdEuzWWg&um=1&itbs=1&tbnid=vX9baTQziSNaBM:&tbnh=113&tbnw=150&prev=/ima
ges%3Fq%3Dfunny%2Breptiles%26um%3D1%26hl%3Den%26sa%3DN%26rlz%3D1T4SNNT_enU
S353US353%26ndsp%3D21%26tbs%3Disch:1&ei=DaOdS6OoF4bmtgPl5t2dAg
Birds
Phylum: Chordata
http://www.sheppardsoftware.com/content/animals/kidscorner/classification/kc_clas
sification_appearance.htm
Sample Animals
Ostrich
Finch
http://www.icis.com/blogs/asian-chemicalconnections/035ostrich_468x538.jpg
http://www.steveklotz.com/blog/wpcontent/uploads/2007/05/finch.jpg
Ducks
Toucan
http://www.wildernessclassroom.com/www/sc
hoolhouse/rainforest_library/animal_images/to
ucan.jpg
http://kecute.files.wordpress.com/2008/03
/ducks-cute.jpg
Body Cavity
Body Symmetry
 Present (has coelom)
 Bilateral symmetry
http://www.birdsafaris-uganda.com/images/bird%20watching.jpg
Nervous System
 Present
http://www.uoguelph.ca/zoology/devobio/miller/brainfig7-11.gif
 The central nervous system is composed of a brain, a
spinal chord, and nerves.
 The autonomic nervous system controls heartbeat,
breathing, and digestion.
Circulatory System
 Present
 Warm-blooded
 Heart pumps blood through
body to give energy to all
parts of the bird
 Birds have a four-chambered
heart to keep tissues well
supplied with oxygen and
nutrients, supporting a high
rate of metabolism.
http://chickscope.beckman.uiuc.edu/explore/embryolo
gy/day02/graphics/bird_heart.jpg
Digestive System
 Present
 Beaks evolutionarily modified
http://www.ericsons.net/images/129.jpg
according to diet/environment
 The crop organ is unique to birds,
stores food, continuously supplies
small amounts of food to the
stomach
 Stomach has two parts:
Proventriculus (secretes digestive
juices) & Gizzard (gravel and
muscles grind up food)
 Extremely high metabolism
Excretory System
 Two kidneys are the
main excretory organs
 Birds lack a urinary
bladder
 Both liquid and solid
wastes are excreted
through cloaca
http://4.bp.blogspot.com/_6PVnFGph9uU/Ss0uSC
4yUI/AAAAAAAABTs/Y6wXEuD_TlU/s400/seagull
+pic.JPG
Locomotion/Musculature
 Wings (made of B-keratin)
http://raptorrehab.files.wordpress.com/2009/04/bird_wing_by_lily.jpg
adapted for flight
 Power for flapping comes from
contractions of the large
pectoral attached to sternal
keel
 Some birds have wings
adapted to soar on air currents
and flap their wings only
occasionally
 Ratites = flightless birds (lack
sternal keel and enlarged
pectoral muscles)
Skeletal Type
 Internal skeleton
 Two legs and two wings
 Reduction in weight
facilitates flight (no teeth,
no jaw bones, reduced
skull)
 Hollow bones make bones
stronger, not lighter
 Sternal keel allows for flight
(not present in ratites)
http://www.emperor-penguin.com/penguin-chick.jpg
Sensory Structures/Features
http://www.markhazeldesign.com/images/owl-eyes.jpg
 Well developed mid brain -> acute vision
 Excellent sense of hearing
 Reduced olfactory lobes -> poor sense of smell
 Large Corpora Striata -> instinctive behavior (i.e.
feeding, flying, reproduction, etc.)
Reproduction
 Sexual reproduction
 Eggs fertilized internally
 Eggs have protective shell
http://www.klamathbirdingtrails.com/images/ed-eggs.jpg
Reproduction (cont’d.)
 Birds engage in
elaborate
courtship rituals
during breeding
season
http://www.cs.stir.ac.uk/~iag/peacock3b.jpg
Gas Exchange
 Complex respiratory system
 Air goes into nostrils -> trachea
-> syrinx -> bronchi -> lungs ->
abdominal air sacs ->lungs ->
other air sacs -> up the bronchi
http://www.earthlife.net/birds/breath.html
Other Unique Features
 Wide range of feet and beaks,
adapted to the environment
and food
 A bird’s brain is actually 10x
http://static.lulu.com/items/volume_63/4086000/4086238/1/preview/32
0_4086238.jpg
larger than a non-bird reptile’s,
and only slightly smaller than a
mammal’s
QUIZ!
Of the amphibians (frogs, salamanders,
caecilians), which organisms use external
fertilization?
Frogs
Salamanders
Caecilians
Both A and B
 ANSWER: D
 (eggs of frogs and salamanders are fertilized outside
the body while caecilians’ eggs are fertilized
internally)
2. Platyhelminthes, birds, amphibians, and reptiles all
possess:
a. A true circulatory system
b. A true respiratory system
c. Bilateral Symmetry
d. Coelom
e. A vertebrae
 ANSWER: C
 (amphibians, birds, reptiles, and Platyhelminthes all
have bilateral symmetry)
3. Which of the following are cold-blooded?
A. Amphibians
B. Birds
C. Reptiles
D. Both A and C
 ANSWER: D
 (amphibians and reptiles are cold blooded)
4. True or false: Amphibians use amniotic eggs
in their reproductive process
 ANSWER: False
 (reptiles and birds use amniotic eggs)