Transcript Amphibians - T. Schor Middle School

Chordate Classes
The Amphibians
Pgs. 382-386
Amphibian Body Characteristics
• Body Symmetry: Bilateral
• Cell Organization: Cells to tissues to organs
to organ systems
• Reproduction: Sexual
• Body Development: “Double Life”
Metamorphosize to adult
Three Orders of Amphibians
Frogs, Salamanders and Newts, and Toads
Just the facts…
– Name means “double
life”
• Begin life in water,
live on land, return
to water to
reproduce.
– Are ECTOTHERMIC
VERTEBRATES
Newt
Caecilians – a rare legless amphibian
Just the Facts…
• Skin lack scales,
feathers, and hair
• Must remain
moist
• Feet have no claws
• 3-chambered heart
The endangered Asian Giant salamander
can grow up to 5 feet long!
Amphibian Metamorphosis –
“Double Life”
• Fertilization in
frogs and toads is
EXTERNAL
• Fertilization is
INTERNAL in most
salamanders
Salamander Life Cycle
Frog Life Cycle
Life isn’t easy for a tadpole!
• Eggs are laid on or
in water
• Tadpoles live in
fresh water and
breathe with gills
• Grows legs, loses
its tail
• Adapts to land by
breathing with
lungs
Life on Land
• How do amphibians breathe?
• How do amphibians get food?
• How do amphibians move?
How do Amphibians Breathe?
• Most amphibians
lose their gills
and develop
lungs.
• O2 and CO2 is
also exchanged
through their
skin.
The Axolotl is the larva form
of a salamander. It is at
this stage that it breathes
through gills; a mature adult
breathes through lungs and
its skin.
Moving Oxygen Through the Body
• Three chambered
heart
• Path of Blood
– Heart
– Lungs
– Heart
– Body
• Called a “double loop”
– Happens in most
vertebrates
How do Amphibians Eat?
• Tadpoles are
HERBIVORES
• Adult Amphibians are
CARNIVORES
– Insects, worms, slugs, etc.
Goliath frog eating another frog.
How do Amphibians Move?
• Salamanders
crawl
• Frogs and Toads
have adaptations
for jumping and
swimming
– Shock absorbing
skeleton
– Powerful hind legs
– Webbed hind feet
for swimming
Frog Facts!
Comparison of a Frog and a Toad
Frog Mouth
Frog Digestive System
Mouth
Esophagus
Stomach
Small Intestine
Large Intestine
Anus
Amphibian Systems - Circulatory
• 3–
chambered
heart
• 2 lungs
Amphibian Systems - Nervous
Brain and Spinal
Cord
Optic (eye)
nerve
Why Study the Frog?
Many systems of the frog are similar to
ours. So by studying the frog, we in
turn, learn more about ourselves and the
anatomy of the human species.
Remember, biology is the study of life.
The frog dissection is just one step of
many steps that takes us closer to
learning about the details of human life.