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Transcript
Reptiles
Scientists believe
other land
vertebrates
evolved from BONY
LOBE-FINNED fish
310 million
years ago…
reptiles were the
first
vertebrates to
make the
complete
transition to
life on land
• an increase in competition
for food and space among all
the life-forms in aquatic
environments
•
limited competition for the
insects and plants that
could be used as food on
the land
Adaptations to Land
•
Waterproof Skin
dry body covering of horny
scales or plates
– develops as surface cells fill
w/ keratin
- same stuff as bird
feathers and fingernails
– prevent water loss (lipids
and proteins)
– protect from wear and tear
associated w/ living in
rugged terrestrial
environments, keeps out
germs
– unlike amphibians who can’t
be far from water or they’ll
dry out
External Structural Adaptations
(for land)• some limbs have toes
•
•
w/ claws
– permit to climb,
dig, and move in
various terrains
others have toes
modified into
suctions cups
– aid in climbing
absence of limbs
– snakes use scaly
skin and highly
developed skeletal
and muscular
systems
TURTLE
EXTERNAL
ANATOMY
Nictitating membrane
Tympanic membrane
External nares
Only reptiles with NO TEETH
NAME THE MEMBRANES
Red arrow = ? Nictitating membrane
Function= ? Protect eyes; “Swim
goggles”
Green arrow = ?
Tympanic membrane
Function =?
eardrum
Limbs at right
angles to body
Location of
Pelvic and
Pectoral girdles
allow turtle to
pull limbs into
shell
http://www.biosci.ohio-state.edu/~eeob/anatomy/eeob512/miscellaneous/turtleskeleton.jpg
Claws on feet
SHELL IS LIVING PART OF BODY
Expanded ribs form shell
Can regenerate damaged scutes
Growth rings tell age
The small segments on a turtle’s
shell are called ______________
scutes
This part of the shell that covers the
Dorsal surface is the _____________
carapace
This part of the shell on the
ventral surface is the
plastron
_______________
This side part that connects the upper
and lower shells is the
Bridge
_________________
CURVE OF PLASTRON
MALE PLASTRON
slightly CONCAVE
to fit on top of female
FEMALE PLASTRON
slightly CONVEX
to make more room for eggs
Image by Riedell/Vanderwal©2005
This part of
the shell is
the
bridge
________
plastron
It connects the ___________
carapace
and ________________
TURTLE
INTERNAL
ANATOMY
TURTLE
LATIN meaning
ANIMALIA
KINGDOM _____________
PHYLUM ____________________________
CHORDATA
“backbone”
SUBPHYLUM VERTEBRATA
___________________________
REPTILIA
“to
creep
or
crawl”
CLASS _______________________________
CHELONIA “tortoise”
ORDER _____________________________
NERVOUS
• COMPLEX BRAIN
• DORSAL SPINAL CORD
(Spine is fused to shell)
• Cranium (skull bone)
• Nerves connecting to spinal
cord and brain
Nervous Cont.
• Cerebellum
–Controls balance & motor
coordination
• Medulla oblongata
• Controls involuntary organs
• Cerebrum
• Controls higher thinking and learning
Nervous Cont.
• Tympanic membrane
– Eardrum
• Bone connecting eardrum to inner ear:
columella
• Olfactory lobe
– Smell
• Optic lobes
– Processes info about vision
• Jacobson’s organ
– Sense organ for smell in roof of
mouth of snakes & lizards
TURTLE BRAIN
BIGGER CEREBRUM than same sized amphibian
Image modified from:
http://theturtlepages.crosswinds.net/anatomy/reprodexc.html
ENDOCRINE
Glands that make
hormones that
control other body
organs
PANCREAS controls
blood sugar levels
THYROID: located above heart
Makes hormones that control heart rate,
blood pressure; cell development and
growth
Respiration
• Well developed
lungs (not gills)
– tissues
involved in gas
exchange area
located inside
body
- kept moist
in even
driest
environmen
ts
INTERNAL NARES
(connects to External
nares “nostrils”)
PHARYNX
GULLET
GLOTTIS
(Opening to lungs )
Tell one thing you could
look for to tell which of
these tubes is the
trachea and which is the
esophagus?
Look for the cartilage
rings. That’s the trachea,
air tube that connects the
larynx to the lungs.
BRONCHI
• Two tubes that
connect the lungs
with the trachea
• Carry air.
This is the _____g_
lun
gg
Image by Riedell/Vanderwal©2005
Its function is
Gas exchange
• Fills lungs by
expanding rib cage.
• Pressure reduced
within thorax draws
in air.
LUNGS HAVE ALVEOLI
TURTLE LUNG
Increase surface area for more gas
exchange
Images modified from:
http://www.stclement.pvt.k12.il.us/studentWeb/science98/GarrittPatM/alveoli.gif
Circulation
• like amphibians have double
circulation
• most have 3 chambered
heart
• partial division of ventricle
separates oxygen-poor blood
flowing from the body from
the oxygen-rich blood
returning from the lungs
• alligators and crocodiles
have 4 chambered hearts
– separation of oxygenated
and deoxygenated blood
TURTLE HEART
3 CHAMBERS
2 atria; 1
ventricle
Image from: BIODIDAC
PARTIAL SEPTUM:
begins to divide
ventricle into two
sides
Sinus Venosus &
Conus
Arteriosus are
smaller
Circulation
• Right atrium: Receives blood
from sinus venosus
• carries only LOW oxygen blood
• Left atrium: Receives blood
#1
#2
from lungs
• carries only HIGH oxygen blood
• Sinus venosus: Receives
#3
deoxygenated blood from body
(smaller)
• Conus arteriosus:sends
oxygenated blood to organs and
deoxygenated blood to lungs.
(smaller)
• Ventricle: pumps blood out of
the heart
• Carries both high and low oxygen
blood
Circulation
• Veins carry deoxygenated blood to the
heart.
• Arteries carry away oxygenated blood
from the heart.
– Pulmonary artery can be constricted so blood
bypasses lungs to warm body quickly!
• Capillaries carry oxygenated blood that will
diffuse into organs.
Single Loop: Fish
Double Loop: Amphibians & Reptiles
Sinus
venosus

 

 Lungs
RIGHT LEFT

Atrium Atrium


Ventricle



 Body
organs


Conus
arteriosus
FROG/TURTLE CIRCULATION
SPLEEN
Make, store, recycle RBC’s
Digestive System
Vent
Image from:
http://theturtlepages.crosswinds.net/anatomy/index.html
Image from:
http://www.spc.cc.tx.us/biology/jmckinney/Studyimages/turtle/turtledissectlist.html
This tube is the
_______________
esophagus
It carries __________
food
stomach
to the ___________
STOMACH
Add ACID; Start DIGESTION;
Grind & mash food
SMALL INTESTINE
Duodenum
Ileum
LARGE INTESTINE
(Also called
COLON)
Name this part
of the tube
duodenum
Give a function
Add trypsin,bile
Finish digestion
Absorb nutrients
Image by Riedell/Vanderwal©2005
Pink arrow = ?
____________
Ileum (SI)
Function = ?
______________
Finish
digestion
Absorb nutrients
Image by Riedell/Vanderwal©2005
Red arrow = ?
Large intestine
____________
Give a function
Collect/
concentrate
digestive waste
Also called
the COLON
Image by Riedell/Vanderwal©2005
LIVER
Makes BILE
Stores
GLYCOGEN
Stores VITAMINS
Processes TOXINS
including nitrogen
waste for
kidneys
GALL
BLADDER
Stores BILE
PANCREAS
In mesentery near first loop of small intestine
Makes TRYPSIN, INSULIN, GLUCAGON
Image by Riedell/Vanderwal©2005
cloaca
Red arrow = ?
Name the body systems that empty here
Excretory, digestive, reproductive
MESENTERY
This
membrane
that holds
the
digestive
organs in
place
This exit opening
is the
vent
__________
Name the body systems that use
this exit
Digestive, excretory, & reproductive
__________________
WHAT SEX IS IT?
FEMALES:
Short tail
Vent closer
MALES:
Longer tail
Vent farther from body
Images modified from:
http://theturtlepages.crosswinds.net/anatomy/index.html
REPRODUCTIVE
Vent
Vent
MALE
FEMALE
OVARY• make eggs
OVIDUCT• add shells
• transport to
cloaca
EPIDIDYMIS –sperm mature here;
add tails
TESTES –
make sperm
Image from:
BIODIDAC
INTERNAL FERTILIZATION
Increases chances of
sperm and egg meeting
Image from:
http://www.turtletimes.com/PhotoContest/2001PhotoContests/May2001/Geoemyda%20spengleri%20mating.jpg
SEX is determined by
TEMPERATURE of NEST
Image from:
http://www.parcplace.org/documents/GeneralHerpInfo/learnabout2.htm
Types of Reproduction
Ways offspring enter world
OVIPARITY- Reproductive tract encloses
egg in a protective shell
Eggs deposited outside body to hatch
Nourishment comes from egg
EX:
Most reptiles,birds
& a few mammals
(monotremes)
Ways offspring enter world
VIVIPARITYNo shell around egg
Eggs retained in body
Nourished by mother
through placenta
Offspring are born
alive
Ex: Mammals &
some reptiles
Ways offspring enter world
OVOVIVIPARITYEgg surrounded by protective shell
but kept in body until just before hatching
or can hatch inside female
Nourishment comes from egg not mother
Ex: Some reptiles (snakes)
OVI
PARITY
SHELL?
NO
SHELL?
Embryo
grows?
Food comes
From?
Seen in?
SHELL
OUTSIDE
EGG
Birds,
Reptiles,
Few mammals
OVOVIVI
PARITY
SHELL
INSIDE
VIVI
PARITY
NO SHELL
INSIDE
EGG
MOTHER
Reptiles
Mammals,
few reptiles
Amniote Egg
• an egg with a protective
membrane and a porous
shell enclosing the
developing embryo.
-It forms a “nursery” to
protect the embryo
- The egg derives its
name from the amnion,
the thin membrane
enclosing the salty fluid in
which the embryo floats.
• They yolk sac encloses
the yolk, a protein rich
food supply for the
developing embryo
• The allantois stores the nitrogenous wastes produced by the
embryo until the egg hatches
• The chorion lines the outer
shell and thus encloses the
embryo and all the other
membranes. It regulates the
exchange of oxygen and
carbon dioxide between the
egg and the outside
environment.
• The entire amniote egg is
surrounded by a leathery
shell that may be hard in
some species because of the
presence of calcium
carbonate.
-The egg is water proof,
however it allows gases to
flow between the
environment and the chorion.
• The male places the sperm
inside the female before the
shell is formed. This is called
internal fertilization, makes
water transport of sperm
unnecessary.
DIRECT DEVELOPMENT
Image from:
http://www.neuroscientist.com/animimag/turtles.htm
Excretion
•
conserve water by excreting nitrogenous wastes in
dry or pasty form as crystals of uric acid
Blue arrow = ?
kidney
Function ?
Excrete nitrogen waste
(make urine)
osmoregulation
Image by Riedell/Vanderwal©2005
Image by Riedell/Vanderwal©2005
The red arrow = ?
______________
Urinary bladder
Give a function
Store urine
Name the form of
nitrogen waste
excreted by reptiles
Uric acid
Temperature Regulation
•
•
•
•
metabolism rate controlled in
part by body temperature
Ectothermic (cold-blooded) –
body temp controlled by
environment
not endothermic (warmblooded)
regulate their temp by
behavior
– bask in sun to speed
up metabolism
– hide in shade to
prevent overheating
ECTOTHERMIC
ADVANTAGES:
Slow metabolism means you can survive
on 1/10 the food as a same size endotherm
DISADVANTAGES:
• Can’t to live in extremely cold places
(NO reptiles in Arctic)
• Can’t keep up max activity level for long
Origin and Evolution
• From the studies of fossils and
comparative anatomy, biologists infer
that reptiles arose from a group of
ancestral reptiles called cotylosaurs,
which lived about 310 million years ago.
- Fossils indicate that these fourlegged, sprawling vertebrates
resembled small lizards and had teeth
used for eating insects
-The abundance of insects at the
time may have been one reason the
cotylosaurs flourished.
• during the Permian period these
reptiles began to adapt to other
available environments, giving rise to
new forms of reptiles.
- These groups included flying
reptiles called pterosaurs
•
- Two groups of marine reptiles:
the ichthyosaurs and plesiosaurs
•
- And the thecodonts
•
•
•
•
•
The dominant land reptiles came from
the thecodonts.
- The small lizard-like carnivores,
many of which walked on their hind
legs.
The thecodonts were the first
archosaurs ( “ruling reptiles”), a group
that later included the early crocodiles,
the dinosaurs, and the reptiles that
evolved into birds.
The Mesozoic era is known as the Age
of Reptiles.
- During this time reptiles , esp. the
dinosaurs, dominated all other forms of
life.
- Dinosaur means “terrible
lizard” however many of the dinosaurs
were small.
Yet the incredible size of some
dinosaurs distinguish the group from all
other forms of life.
-One of the largest dinosaurs was
the brachiosaurus, 77,00 kg.
It was as long as a tennis court, as tall
as a four-story building, and heavier
than elephants.
•
•
•
•
Over 300 genera of dinosaurs have been identified around the world.
-They were adapted to a wide range of environments.
Brachiosaurus and such related dinosaurs as Diplodocus and
Apatosaurus were herbivores, plant eaters.
- They probably used their long necks to reach the top of trees.
Tyrannosaurus and other carnivores, or meat eaters, walked on their
hind legs and used sharp teeth and huge claws to rip apart prey.
The scientist who studies dinosaurs are known as Paleontologists.
Modern Reptiles
• Reptiles are classified into 16 orders, 12 that are extinct.
- 4 surviving-6, 000 species
• Reptiles occur worldwide except in coldest regions
- Human intervention-major impact
• 4 living orders of Class Reptilia:
- 1. Rhynchocephalia,
- 2. Chelonia,
- 3. Crocodilia,
- 4. Squamata
Rhynochocephalia
• Only living speciesSphenodon punctatus- the
tuatara
- Inhibit islands of coast
of New Zealand
- Resembles a large lizard
about 60 cm long
- Has an inconspicuous
third eye on top of its
head- parietal eyefunctions as a thermostatprotects from overheating
- Active at low
temperatures and feed at
night on insects, worms
and small animals
Chelonia
• Order consists of about 265
species of turtles and tortoises
- Tortoise are terrestrial
Chelonia (Galapagos tortoises)
- Turtles- chelonians that live
in water
- Body covered by a shell
made of hard plates- 2 parts- a
carapace and plastron
- Shape is modified for
variety of ecological demands
- retract heads, swimming
- Forelimbs of a marine turtle
have evolved into flippers and
freshwater turtles have webbed
toes
- Migratory behavior of sea
and river turtles
-return to land to lay eggs
Crocodilia
• Order composed of 20
species of large lizardshaped reptiles- crocodiles,
alligators, caimans and
gavials
- Descendants of
archosaurs
• Crocodilians live in or near
water in tropical/ subtropical
regions of the world
•
- Crocodiles- nocturnal
animals; Africa, Asia and
Americas
•
- Alligators - China and
southern U.S.
- Caimans- Central
America- some in Florida
- Gavials- eat fish; long and
slender snout- live only in
Burma and India
• Carnivorous- hunt by stealthfeatures adapted for this
behavior
- Eyes on head, nostrils on
top of snout
-see and breathe while
in water
- Valve to prevent water
from entering air passage
- Parental care- both
parents care for young by
carrying in jaws until
development
Squamata
• Order consists of 5,640
species of lizards and snakes
- Loosely jointed upper jaw
and paired reproductive
organs in males
- Structurally diverse
• Lizards- presence of limbs
•
- Common lizards- iguanas,
chameleons, skinks and
geckos
- Live everywhere except
Antarctic
- Special adaptationsagility and camouflage
- 2 species are venomousGila monster (SW U.S.) and
beaded lizard (western
Mexico)
- Most prey on insects or
- Blend with background
- chameleons- remain
inconspicuous and fend off
enemies
- Horned lizards- spiked armor,
when disturbed they inflate
themselves, gape, hiss and squirt
blood from eyes
- Skinks and geckos- lose their
tails and regenerate- autotomyescape from predators
- Most lizards are small- .3m in
length; iguanas- 1m in length
- Largest lizards- monitorsKomodo dragon (Indonesia) 3m
(9.8 ft) in length, 140 kg (308.6
lbs)
- Thought to be related to
snakes
- have a forked tongue for
sense organs
- Consume prey whole and use
tail as defense weapon
Adaptations of Snakes
Snakes probably evolved from lizards that
lived above ground found during the
Cretaceous period.
Movement
• A snake has a backbone
of 100 to 400
vertebrae, each of
which has a pair of ribs
attached.
- Providing the
framework for
thousands of muscles
• The interaction of
bones, muscles, and skin
enables asnake to move
in one of three basic
ways:
1. Lateral undulation
2. rectilinear
movement
3. side winding.
Movement cont.
• Most commonly move by
lateral undulation.
- moving forward in an S
shaped path.
• In rectilinear movement, the
snake applies muscular force
on its belly, not its sides.
- Scutes are scales on its belly
that catch on bark orother
rough surfaces (like a
caterpillar).
• Some desert-dwellers snakes
progress by side-winding.
Feeding
• Snakes eat animals, but lack structural adaptations
common to other carnivores.
• Snakes do not see or hear well, and have no limbs, and
their teeth and small mouth cannot rip and grind
flesh.
Locating Prey
• Snakes evolved a sense
of smell which they use
to locate their prey.
- By flicking its forked
tongue , a snake gathers
chemicals from the
environment.
• The tongue transfers
these chemicals to two
pits in the roof of the
mouth called the
Jacobsons organ where
the nerves are highly
sensitive to the
chemicals.
Locating Prey Cont.
• Some snakes inject their
prey with Toxic venom
• most bite down their fangs
and inject the poison into
their prey.
• Venom is chemically complex.
- The hemotoxins are
proteins that attack the
circulator system, destroy
red blood cells and disrupt
the clotting power of blood.
- The neurotoxins work on
the nervous system, by
disrupting the nerve
pathways which is dangerous
to respiratory and heart
functions.
Swallowing and Digesting Prey
• A snakes upper and
lower jaws are
hinged and move
independently.
• when unhinged, the jaws
stretch to allow the
mouth to open
extremely wide.
• While swallowing it
whole the snake thrusts
its windpipe into the
throat, allowing the
snake to breathe
- the process of can
take several hours.
Defense
• Natural selection resulted in modifications for
defense.
• Camouflage is beneficial for both seeking prey and
hiding from predators.
- many snakes are green and blend with foliage
- others are brown and hide against the bark of trees
Defense Cont.
• Some snakes defend
themselves by signaling
their presence.
• Some ward off danger
by rapidly changing body
shape
- extending a hood like
cobras
• Some hiss
• Others make mechanical
noises
- such as the rattle of
the rattlesnake.
Reproduction
• Most male snakes rely
on the scent of female
snakes of heir own
species.
• Before mating, a male
and female snake may
glide alongside by side,
with the male stroking
the female with his chin
and flicking his tongue
over her body.
• Fertilization is internal.
Reproduction cont.
• Most snakes are oviparous
- female lays eggs that hatch
outside her body.
- To break out a hatchling
uses a special tooth which is
lost soon after.
• Other snakes are
ovoviviparous
- the female carries the
eggs in her body
throughout development
• the young are born live.
- All newborns must fend for
themselves, relying on their
many specialized adaptations
for survival on land.