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Announcements
• If caught with food or drinks out, then expect to
throw it in the trash
– All items must be put away in your backpack.
• All Invertebrate RETESTS have been sent to
the learning labs if you are a freshman or
sophomore. Others must retest with me before
or after school.
• Vocab Quiz this FRIDAY
• Project due NEXT Thursday, Jan. 31
Amphibians
Class Amphibia
Characteristics
• Integumentary
– Moist skin with mucus glands
• Skeletal/Muscular
– Endoskeleton
– Adult: legs for walking or jumping; no legs
– Larva: swim
Characteristics
• Circulatory
– Adult: 3 chambered heart, closed-double
loop
– Larva: 2 chambered heart
• Reproductive
– External fertilization; eggs must stay moist
(no shell)
Characteristics
• Nervous
– Brain; eyes w/ nictitating membrane;
tympanic membrane for hearing; lateral lines
• Respiratory
– Adult: through lungs, skin, & lining of the
mouth
– Larva: through skin and gills
Characteristics
• Digestive
– Complete digestive system (mouth --> anus)
– Adult: carnivore
– Larva: herbivore or filter feeder
• Excretory
– Kidneys filter wastes from blood, urine
travels through ureters to urinary bladder and
out through cloaca
Characteristics
• Body Temperature
– Ectothermic
• Habitat
– Adult: live on land near water
– Larva: live in water
Lifecycle of a Frog
Adult
Frog
Young
Frog
Adults are typically ready to
breed in about one to two years.
Frog eggs are laid in water and
undergo external fertilization.
Fertilized Eggs
Tadpoles
Tadpoles gradually grow limbs, lose their tails and gills, and
become meat-eaters as they develop into terrestrial adults.
The eggs hatch
into tadpoles a
few days to
several weeks
later.
Evolution
• The first amphibians looked similar to
lobe-finned fish
Groups of Amphibians
•
Salamanders – have long bodies & tails, most
have 4 legs, usually live in moist woods
Groups of Amphibians
•
Frogs & toads – both jump & lack tails;
frogs more closely tied to water
Groups of Amphibians
•
Caecilians – legless animals; live in
water or burrow in moist soil; many have
fishlike scales
Assignment
•
Frog Paper Dissection
– Color all organs & the frog
– Attach organs correctly & label them
– On the back, answer the following in complete sentences:
1. What adaptations helped amphibians evolve into land
animals? (pg. 783)
2. Why are amphibians restricted to reproducing in moist
environments?
3. What special structure do amphibians have that protects
the eyes while under water?
4. Explain the path of circulation in an amphibian.
(pg. 785)