Phylum Chordata - Class Amphibia

1. Objective: Phylum Chordata: Amphibians
Homework: CC 25.2-25.4

2. Animals that live on land are faced with different
environmental challenges than those that live in the water
Adaptations for life on land:
Tetrapods – “four-footed”; two sets of paired appendages that
are modified as legs that can support the
animal
Lungs to avoid dessication (drying out)
The Transition from Water to Land

3. What are Lungs?
Gas exchange (inhaling oxygen
and exhaling carbon dioxide)
requires a moist environment
But air is a dry environment, so
lungs are folded inside the
animal's body
To limit the loss of water, lungs
open to the outside by narrow
passages.

4. Amphibian Characteristics
Permeable skin
–Permeable: allows the
transfer of oxygen and
carbon dioxide to allow
respiration
–Can allow the uptake of
chemicals in the
environment
Green Frog
Spring Salamander

5. Amphibians were the first
vertebrates to live on land
Amphibians live part of their life
cycle in water and part on land
Do NOT make amniotic eggs
Larval stage – in water
METAMORPHOSIS
Adult – on land
As larvae, use gills to breathe
As adults, most use lungs,
however, skin may stay moist and
also serves in gas exchange

6. Amphibians are Ectothermic
–Regulate temperature from outside sources
•Water temperature
•Basking

7. Amphibians are Cryptic
–Very abundant but their presence is largely
unknown by the average person

8. Amphibians are Important to the
Ecosystem
–An important prey item for:
•Raccoons, opossums, birds
–An important predator of:
•Mice, rats, insects
Spring Peeper
Spring Salamander
Green Salamander

9. Amphibians include frogs, toads, caecilians,
and salamanders/newts

10. The Difference Between Frogs and Toads
Frogs – smooth, moist skin; stick to mostly
aquatic environments
Toad – rough skin and live in terrestrial
environments

11. Caecilians
•Live in the tropics
•Leg-less and blind
•Look very similar to a worm
CaecilianCaecilian

12. Salamanders
•Either don’t have lungs and
must breathe entirely through
their skin
•Or have lungs, but can also
breathe through their skin
•Salamanders can lay eggs in:
–Streams
–Wetlands
–Soil
Marbled Salamander
Two-lined Salamander
Spring
Salamander

13. Amphibian Defense Mechanisms
•Poison in skin
–Toads and Newts
•Producing large numbers
of offspring
•Producing noisy squawks
when attacked
Green Frog Tadpole
American Toad
Red-Spotted Newt

14. 1/3 1/2 !
to of All Amphibians are Facing Extinction
•Climate change
•Habitat loss
•Pollution
•Disease (fungus)
due to stress