Download 12.3 Notes on Amphibians

CHAPTER 12.3 NOTES: AMPHIBIANS
What is an Amphibian?
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


An amphibian is a vertebrate that is ectothermic and spends its early life in __________________.
Spend most of their adulthood on land, returning to the water to reproduce.
Amphibian means double life.
i.e. frogs, toads, salamanders
Reproduction and Development
 __________________________ = internal fertilization
o Larvae look like adult salamanders
o Metamorphosis to lose gills
 _________________________ = external fertilization
o Fertilized eggs covered in jelly are laid in the water to develop
o Stages of frog/toad lifecycle: egg => tadpole => tadpole with legs => froglet => frog
o Tadpoles have gills and live in water
 Metamorphosis to grow lungs/lose gills and add to circulatory system
Diversity of Amphibians
 2 majors groups:
o salamanders- have a tail
o frogs/toads- no tail
 difference is the ______________________________________________________________________
Living on Land

Respiratory and circulatory systems of adult amphibians are adapted for life on land, i.e.
movement, breathing.
Obtaining Oxygen
 Lose ______________________ and grow _________________________ during metamorphosis
 Lungs are sac-like organs of air breathing vertebrates which transfer oxygen from the air
into the blood and CO2 from the blood into the air.
 _________________________ also used in O2 and CO2 exchange
Circulatory System
 Tadpoles:
o Single loop heart with 2 chambers (like fish)
 Adult: 2 loops and a heart with 3 chambers
o Atria: Upper chambers of heart, receive blood from lungs/body
o Ventricle: lower chamber of heart, pumps blood to lungs/body
Movement
 Strong skeleton to _________________________________
 Muscular limbs for __________________ (salamanders), walking and _______________ (frogs/toads)
o Hopping = strong hind legs and shock absorbing skeleton
Amphibians in Danger!
 Habitat destruction is causing a major decline in amphibian species.
 Mostly deforestation and pollution
 Frogs are very sensitive to environmental change and are therefore used frequently as an
________________________________________ to determine the health of the entire ecosystem
o Environmental changes due to: pesticides, water pollution, etc.
EXTERNAL ANATOMY
INTERNAL ANATOMY
·http://www.aa.psu.edu/biology/frog/femaleanat.htm
·http://dissect.froguts.com/
·http://frog.edschool.virginia.edu/Frog2/Dissection/Incisions/skin1_first.html
CHAPTER 12.3 NOTES: AMPHIBIANS: TEACHER
What is an Amphibian?




An amphibian is a vertebrate that is ectothermic and spends its early life in water.
Spend most of their adulthood on land, returning to the water to reproduce.
Amphibian means double life.
i.e. frogs, toads, salamanders
Reproduction and Development
 Salamanders = internal fertilization
o Larvae look like adult salamanders
o Metamorphosis to lose gills
 Frogs = external fertilization
o Fertilized eggs covered in jelly are laid in the water to develop
o Stages of frog/toad lifecycle: egg => tadpole => tadpole with legs => froglet => frog
o Tadpoles have gills and live in water
 Metamorphosis to grow lungs/lose gills and add to circulatory system
Diversity of Amphibians
 2 majors groups:
o salamanders- have a tail
o frogs/toads- no tail
 difference is the presence of a tail as an adult
Living on Land

Respiratory and circulatory systems of adult amphibians are adapted for life on land, i.e.
movement, breathing.
Obtaining Oxygen
 Lose gills and grow lungs during metamorphosis
 Lungs are sac-like organs of air breathing vertebrates which transfer oxygen from the air
into the blood and CO2 from the blood into the air.
 Skin also used in O2 and CO2 exchange
Circulatory System
 Tadpoles:
o Single loop heart with 2 chambers (like fish)
 Adult: 2 loops and a heart with 3 chambers
o Atria: Upper chambers of heart, receive blood from lungs/body
o Ventricle: lower chamber of heart, pumps blood to lungs/body
Movement
 Strong skeleton to support body
 Muscular limbs for crawling (salamanders), walking and hopping (frogs/toads)
o Hopping = strong hind legs and shock absorbing skeleton
Amphibians in Danger
 Habitat destruction is causing a major decline in amphibian species.
 Mostly deforestation and pollution
 Frogs are very sensitive to environmental change and are therefore used frequently as an
indicator species to determine the health of the entire ecosystem
o Environmental changes due to: pesticides, water pollution, etc.