Download Why amphibians breathe through their skin

Amphibians
Animals with a double life
Primary Characteristic
Amphibians have
a completely
aquatic larvae
which transforms
into an air
breathing, semiterrestrial adult.
Three orders of
Amphibians
• Caudata: salamanders &
newts
• Anura: frogs and toads
• Apoda: caecilians
Characteristics of Amphibians
•
•
•
•
•
•
•
Undergo metamorphosis (change)
Thin, moist skin
Four legs
No claws on toes
Three chambered heart
Rely on water for reproduction
Ectothermic
Thin, Moist Skin
• Many amphibians
breathe some
through their skin
• Some
salamanders
ONLY breathe
through their skin
• Reptiles have dry,
scaly skin
Four legs
with no claws
on toes
Reptiles have claws
and sometimes
no legs
Three-chambered
Heart
•
•
The amphibian
heart is
inefficient
Oxygenated and
deoxygenated
blood gets
mixed together
in the 3rd
chamber
Why amphibians
breathe through
their skin
• Because the heart mixes blood, they
must take in extra oxygen through their
skin
• The skin must remain moist for gas
exchange
Water needed for reproduction
•
•
Fertilization usually
external
Water needed as
medium for
transporting sperm
Ectotherms
•
Body temp
changes with
the temp of
environment
• Regulates body temp through behavior
• Become dormant in extreme heat or cold
Metamorphosis: Frogs
•
Frog eggs hatch into tadpoles with:
–
–
–
•
Fins
Gills
two-chambered heart
Tadpoles grow into adults with:
–
–
–
Legs
Lungs
three-chambered heart
Metamorphosis: Salamanders
• Larvae have:
– Gills
– tail fin
• Adults:
– Have no gills
– Have no tail fin
– Breath through moist skin or lungs.
Larvae vs. Adult
Spotted Salamander
Caudata: Salamanders
•
•
•
•
Long, slender body with a neck and tail.
Look like lizards, but have smooth, moist skin
and lack claws.
One fourth breathe through skin and have no
lungs.
Most have four legs, but some have only 2 front
legs.
Newts vs. Salamanders
• Newts are salamanders that live
entirely in water.
Local Salamander Species
Eastern Red Spotted
Newt , Slimy
salamander, Blue Ridge
two-lined salamander
The Hellbender
• Largest salamander in
North America, and one
of the largest in the
world.
• Up to 29 in. long
• Live in rivers and large,
swift streams
Anurans:
Frogs
•
•
•
•
•
No tails
Jaws and teeth
Vocal cords capable of producing a
range of sound
Use sound to find a mate
Breathe through lungs or skin
Frog Songs
•
Vocal cords capable of producing a
range of sound
– Vocal cords = band of tissues in the
throat
– Use sound to find a mate
– Frogs can be identified by their
songs
Dart Frogs
•
•
•
Secrete toxic chemicals through skin as
a defense against predators.
Some have enough toxins to kill 10
people
Bright colors act as warning coloration
• Imported to
Australia to
eat beetles
• Toxic to fish
and
animals
• Secretes
toxin from
glands
• Causing
reduction in
wildlife
Cane Toads
The Beauty of Frogs
Frog Leaping
• Frogs can jump over 20
times their own length
• That is like a person
jumping 100 feet!
Frog Respiration
Breathe through lungs or skin
Sensitive to Environmental Changes
1. Are indicator species for pollution in
land, air, or water.
2. Declining numbers or deformities
indicate an unhealthy environment.
Frogs vs. Toads
Frogs:
•
Long, hind legs
•
Smooth, moist skin
Toads
• Bumpy, dry skin
• Short legs
Local Species:
American Toad
• Poison glands in
paratoid gland behind
ears
• Squirts milky poison at
predators (like dogs)
Local Species: Fowler’s Toad
• Common in U.S.
• Call sounds like the
bleat of a sheep
Southern Cricket Frog
• Dark triangle between the eyes
• Call sounds like a series of cricket-like clicks
• Tiny – less than 1-1/4 inches long
• One of the first songs of the spring
• Call is a high-pitched whistle with a trill
Common Local Frogs
Spring Peeper
Eastern Narrowmouth Toad
• Sounds like a bleating sheep
• Good at burrowing in soil or leaf litter
Bullfrog
• Largest frog in North America
• Eat crayfish, insects, birds, fish
• Harvested for legs, which are eaten
Green Frog
• Sounds like the twang of a loose banjo string
• Can be green, bronze, or brown
Southern Leopard Frog
• Has a light spot in the center of the eardrum
• To escape predators, dives in water, makes a
sharp turn, and returns to original shore to hide
Apoda: Caecilians
•
•
•
•
•
No limbs, short or no tail
Tropical
Look like worms
Small eyes and often blind when eyes are
covered by skin
Eat earthworms and other invertebrates in soil
What is this?
1
3
2
4
5. Which is a newt?
A
B
Quiz
6. What does the word, “amphibian” mean?
7. What are the three classes of amphibians?
8. How are amphibians different from
reptiles?
9. How are amphibian frog larvae different
from the adult frogs?
10. Where do caelilians live?
11. Why do many amphibians need to have
moist skin?
Quiz
12. What is an ectotherm?
13. What kind of salamander
is pictured to the right?
14. What is the largest salamander in North
America?
15. How are frogs different from toads?
16. Why are frogs such good indicator
species, and what does this mean?
Quiz
17. What kind of amphibian has no legs, often
has no eyes, and can be found in tropical
environments only?
18. What is the purpose of the bright skin in a
dart frog?
19. What is the main purpose for a frog song?
20. What are 3 functions for a cloaca?
21. What is the function of the tympanic
membrane and where is it on the frog?
22. Where would you find the nictitating
membrane?
Label the parts
25. Which of the following are
amphibians, and how do you know?
A
C
B
D
Name the species:
A B
C
D