Transcript Those Scaly Reptiles

Those Scaly Reptiles
Mrs. Redinger
Plant & Animal Bio
Best Class Ever!!!!!
Classification
• Kingdom: Animalia
• Phylum: Chordata
– Subphylum : Vertebrates
• Class: Reptilia
4 Orders
1) Chelonia – 250 species of turtles &
tortoises
2) Crocodilia – 21 species of crocs &
gators
3) Squamata – 5,500 species of snakes &
lizards
4) Rhynchocephalia – 2 species of
tuaturas
Evolutionary History
• Evolved ~ 300 mya
- from amphibians
- had sharp teeth, claws, &
strong jaws for hunting insects
• 300 different genuses of dinosaurs
- adapted to wide range of environmental
conditions
- 65 mya = EXTINCT = MASS EXTINCTION
- # 1 hypothesis = ASTEROID
- Only the 4 modern
Orders of reptiles SURVIVED
Reptilian Traits
Reptilian Traits
1) Dry, scaly, waterproof skin
Reptilian Traits
• 2) Amniotic egg = shell & yolk
Reptilian Traits
• 3) Lungs
Reptilian Traits
4) Ecto/Exotherms
Reptilian Traits
• 5) Molt/Shed their skin
Amniotic Egg
~ this is strong evidence that 3 groups
(Reptiles, Birds, & Some Mammals)
come from the same ancestor
Purpose: nutrients, protection,
support, prevents H2O loss,takes in
O2 / rids CO2
Amniotic Egg
Amnion: thin
membrane which
encloses embryo
& contains
floating liquid
Amnion
Amniotic Egg
Yolk sac: nutrients & fats
Amniotic Egg
Allantois: store N2 waste &
exchanges O2 & CO2
Amniotic Egg
Chorion: protects
embryo & its
vital parts
Amniotic Egg
Albumen: white – stores protein &
H2O for the embryo
Amniotic Egg
Egg Shell: protection, prevents H2O
loss, & is tough & leathery
Amniotic Egg
Air Sac/Space: breathe when
hatching
Water Tight Skin
Purpose:- decreases H2O loss
- protection against wear,tear,
& infections
Made up of: keratin – thick protein with
lipids to help repel
- same as
hair & nails
H2O
Respiration
Purpose: exchange O2 & CO2
with animal & environment
Made up of:
- Lungs ~ increased surface area
-Alveoli ~ air sacs that make up lungs for
increased surface area
Respiration
Mechanics: Diaphragm
- rib cage expands when
inhale & contracts when exhale
Respiration
Variation in snakes: larger right lung
(½ length of body)
~ small, non-functioning left lung
Excretory
Purpose: to remove nitrogenous waste
Nitrogenous waste:
- reptile’s urine is very concentrated
with ammonia
Digestive
Purpose: Break down
food into useable
molecules
1-way system
composed of:
- mouth & anus
Circulatory
~ more advanced & efficient than amphibians
2 loop system:
Systemic loop:
- heart to
body to heart
Pulmonary loop:
- heart to
lungs to heart
Number of heart chambers:
Lizards, snakes, turtles: 3
2 A
1 V
Crocs, gators: 4
2 A
2 V
partial or full septum
Nervous
Sight: larger eyes
better sight
Hearing: all reptiles except *SNAKES!*
- tympanic membrane
(inner ear)
Variation in snakes: use lower jaw to
detect vibrations
Smell:
Jacobson’s organ:
~ located on roof of mouth
- brings in scents by using
tongue
Pits: small openings under
eyes that detect heat
given off by prey
~ brain = same size as amphibians brain
but larger cerebrum & optic lobe
~ all have nares except crocs & gators
Nervous System
Thermoregulation:
Two Types:
Ecto/exotherms: cold blooded – use sun to
regulate body temperature
Examples: reptiles & amphibians
Thermoregulation:
• Advantages
– Require less energy
– 1/10 food
Thermoregulation:
• Limitations
– Can’t live in cold environment unless they
hibernate
– Not very active
Endotherms
- warm blooded
- regulate own body temp.
thru metabolism
Examples: mammals & birds
Endotherms
• Advantages
– Can live anywhere
– Lots of energy
– Very mobile
Endotherms
• Limitations
– Need large quantities of food
Reproduction
3 patterns of reproduction:
Oviparity: most reptiles, all birds, & 3
species of mammals
~ shell formed in reproductive tract
~ laid outside the body
Reproduction
Ovoviviparity: some reptiles
~ shell is retained in female
~ young hatch while inside cloaca
Reproduction
Viviparity: most mammals
~ female releases egg, internal
fertilization
~ mom houses, protects, & feeds young
via placenta
Modern Reptiles:
4 orders and they all share the following
traits:
1. Dry, scaly, water tight skin
2. Ecto/exothermic ~ low metabolisms
3. Amniotic egg with internal fertilization
4. Respire through lungs
Order Chelonia:
Traits of the order:
1. Beak *NO TEETH*
2. Oviparity: lay eggs in sand/soil
3. Body covered with 2 shells,
pieces called SCUTES
Order Chelonia:
Carapace:
- top, dome-like shell
- vertebrae of turtle is fused
into shell
- ribs form off vertebrae
Plastron:
- lower, ventral shell
- protect internal organs
Turtle Skeleton
4. Body Shapes & Adaptions
Aquatic turtles:
~ flat disc-like shaped shell: easier
to move in H2O
~ webbed feet for
swimming
4. Body Shapes & Adaptions
Terrestrial turtles:
~ dome-shaped shell
~ feet are scaled & clawed
More on Turtles…
Order Crocodililia:
Traits of order:
1. Large, heavy armored
2. Carnivorous
3. Oviparity
- lay eggs in nest
- mom cares for
young for 1-3 yrs.
Order Squamata:
Traits of order:
Lizards:
1. Carnivorous (insects & small mammals)
2. Lower jaw attached loosely to skull
3. Agility, speed, & camo to elude predators
4. Actually detach & regrow tail in order to
escape
Snakes:
1. No legs
2. Very long backbone
with a pair of ribs
off each vertebrae
3. 100-400 vertebrae
4. Can pop lower jaw
in or out to eat
prey whole
5. 1000’s of muscles
for movement
Snakes:
Constriction:
~ coil around prey
~ each time prey breathes,
snake increases its tension
~ suffocates to death
Injection of venom:
2 Types:
hemotoxins = affects blood
neurotoxins = affects nerves
Snakes:
Fangs:
~ back of throat
Elapids:
~ 2 small fixed fangs
in front of mouth
Vipers:
~ 2 retractable fangs
on roof of mouth
Ex: copperheads &
rattle snakes
Order Rhynchocephalia:
Order traits:
1. New Zealand
2. Third eye
- sun detector
- on crest of head
~ burrow during the day
~ hunt insects at night