Download Amphibians (1)

Phylum Chordata
Superclass Vertebrata
Class Amphibia
(salamanders, newts, frogs and toads)
Class Amphibia
Boophis viridis
Amphibia means “double life”
• Endoskeleton (the rest being made of cartilage), complete gut, closed circulatory
system.
• The skin is almost always moist and is water permeable. It lacks scales, and can be
smooth (frogs) or bumpy (toads).
• Most have 4 legs
• Ectothermic - body temperature controlled by environment
• Metamorphosis
• Wide variety of shapes, sizes and colors,
– some of the most poisonous vertebrates are amphibians (arrow-point frogs).
Amphibian Orders
There are approximately 3000 species in 3 orders:
Apoda (caecilians - legless amphibians) 160 species
Caudata (salamanders, newts) 300 species
Anura (frogs, toads) 2500 species
Metamorphosis
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Frogs and Toads - fertilized eggs hatch into tadpoles.
Tadpoles have tails, gills, and a 2 chambered heart.
Adults develop legs, lungs, and a 3 chambered heart.
Young Salamanders resemble adults but have a tail fin
and gills, while most adults lack gills and fins.
Life cycle
Metamorphosis!!!
• They all have three-chambered hearts
• Viviparous – some give birth to live young
• Most have external fertilization
• Oviparous (egg-laying) – some lay eggs
– will lay several hundred small, round eggs covered in a gelatinous
mass.
• Eggs laid in water, either a pond or puddle or pool of water in a leaf.
• Some species carry the eggs in their belly, and hatch inside of the
mother.
Respiratory System
Juvenile forms - gills, either
internal or external, (for
breathing underwater).
• Adult form - lungs.
• + Water-permeable skin
which allows oxygen to
diffuse through it, so they
can "breathe" through
their skin. “Lungless” species found in a clear,
cold-water stream on the island of
Borneo in Indonesia
• There are separate sexes
• Some species can change
gender depending on the
circumstances.
– Due to over farming and
pesticides, researchers
are finding fewer males.
• Amphibians are the most
vulnerable vertebrates due
to reliance on the
environment.
Caecilians
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•
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Inhabit the wet tropical regions of
south America, Africa and south
east Asia.
Lack limbs but possess a
retractable sensory tentacle.
Have a burrowing lifestyle.
The skin of one African species is
fat and nutrient-rich, so the larvae
peel this skin off the parent and
eat it.
Oviviparous
Salamanders
• Capable of regenerating lost limbs,
as well as other body parts.
• Sticky tongue which adheres to the
prey
• Defense
– Tail autotomy to escape predators. The
tail will drop off and wriggle around for a
little while.
– They can also produce a white milky
substance that is poisonous
https://www.haikudeck.
com/copy-of-amphibian-limbregeneration-science-andtechnology-presentationc598c828d5# slides on
regeneration in salamanders
Salamanders/Newts and
Disease
Texas Blind Salamander
Vestigial Eyes –
Left over, non-functional eyes
Axolotl
Mexican Walking Fish
Newts
• Produce toxins in their skin as a
defense mechanism against
predators.
• Taricha granulosa, “rough-skinned”
newts of western North America
are particularly toxic producing
more than enough tetrodotoxin to
kill an adult human.
• Some Native Americans of the
Pacific Northwest used the toxin to
poison their enemies.
However, the toxins are only
dangerous if ingested.
Frogs
Poison dart frogs
Toads
Bufo Bufo –
the common toad
Frog documentary, dissection
Quiz Questions
What does “amphibia” mean?
Describe ectothermic.
Describe metamorphosis.
List the orders and organisms in each order.
Define vivparous.
Define oviparous.
How many chambers do the hearts of amphibians have?
Describe amphibian respiration.
Which amphibian is limbless?
Which amphibian can regenerate lost parts?
What is the scientific name for the common toad?
Describe amphibian skin.