Lesson 13.3 AMPHIBIANS: True or False
Name_________________________ Date______________ Period________
Write true if the statement is true or false if the statement is false.
1. _______ Amphibians are thought to have evolved from cartilaginous fish.
2. _______ The mucous glands of some species of amphibians secrete toxins.
3. _______ The respiratory and reproductive systems of amphibians share a single body
cavity.
4. _______ Frogs have a larynx that allows them to make sounds.
5. _______ Amphibians are oviparous.
6. _______ Amphibian parents typically guard their eggs and defend their larvae from
predators.
7. _______ All known species of amphibians are placed in one of three orders.
Lesson 13.3: Critical Reading
Read this passage based on the text and answer the questions that follow.
There are only about 6,200 known living species of amphibians. They are placed in three
orders: frogs, salamanders, and caecilians.
The frog order includes toads as well as frogs. Unlike other amphibians, frogs and toads lack a
tail by adulthood. Their back legs are also longer because they are specialized for jumping.
Frogs can jump as far as 20 times their body length. That’s like you jumping more than the
length of a basketball court!
The salamander order includes both salamanders and newts. Salamanders and newts keep
their tails as adults. They have a long body with short legs. They are adapted for walking and
swimming rather than jumping. Unlike other vertebrates, salamanders can regrow legs or
other body parts if they are bitten off by a predator.
The caecilian order is the amphibian order with the fewest species. Caecilians are closely
related to salamanders. They have a long, worm-like body. They are the only amphibians
without legs. Caecilians evolved from a four-legged ancestor but lost their legs later in their
evolution. As adults, they often burrow into the soil. That’s one reason why Caecilians tend
to be less well known than other amphibians.
Questions
1. Summarize how amphibians are classified.
2. Explain how frogs are adapted for jumping whereas salamanders are adapted for
walking and swimming.
3. What are two reasons that caecilians are not familiar to most people?
Lesson 13.3: Multiple Choice
Circle the letter of the correct choice.
1. Amphibians have all of the following except
a. sensory organs
b. a digestive system
c. an excretory system
d. scales
2. Which statement about amphibian reproduction is true?
a. Most amphibians reproduce asexually as well as sexually
b. Fertilization may take place inside or outside the body
c. Amphibian embryos develop inside the mother’s body
d. Amphibians produce amniotic eggs that do not dry out
3. Frog larvae
a. live in water
b. resemble fish
c. lack legs
d. all of the above
4. When a frog larva goes through metamorphosis it
a. develops lungs
b. grows a tail
c. loses its swim bladder d. all of the above
5. The only continent where amphibians do not live is
a. Australia
b. Antarctica
c. Africa
d. South America
6. Animals that prey on amphibians include
a. Birds
b. snakes
c. fish
d. all of the above
7. Amphibians live in all of the following habitats except
a. saltwater lakes b. freshwater lakes. c. freshwater ponds d. moist soil
Lesson 13.3: Matching
Match each definition with the correct term.
Definitions
1. _______ amphibian order that includes newts
2. _______ substance that keeps amphibian skin moist
3. _______ organs that amphibian adults use to breathe
4. _______ amphibian order that has the fewest species
5. _______ protein in amphibian skin
6. _______ multi-purpose body cavity in amphibians
7. _______ organs that amphibian larvae use to breathe
Terms
a. Lungs
b. mucus c. cloaca d. gills. e. salamander f. caecilian g. keratin
Lesson 13.3: Fill in the Blank
Fill in the blank with the appropriate term.
1. _________________ were the first vertebrates to evolve four legs and colonize the
land.
2. Amphibians become sluggish in cool weather because they are _________________.
3. Amphibians breathe with gills or lungs and absorb extra oxygen through their
_________________.
4. An opening in the _________________ allows wastes and gametes to exit an
amphibian’s body.
5. The early larval stage of a frog is called a(n) _________________.
6. Toads are placed in the _________________ order of amphibians.
7. The only amphibians without legs are placed in the _________________ order.
Lesson 13.3: Critical Writing
Name___________________ Class______________ Date________
Thoroughly answer the question below. Use appropriate academic vocabulary and clear and
complete sentences.
Explain why amphibians are at high risk of extinction.