The document discusses the class Amphibia, which includes frogs, salamanders, and caecilians. Amphibians were the first vertebrates to live on land but still require water to breed and for their larvae to develop. They have moist skin to aid respiration and undergo metamorphosis from an aquatic larval stage to a terrestrial adult stage through a process of physiological changes.

1. Phylum Chordata!
Class amphibia

2. Class amphibia!
The amphibians
– First vertebrates to inhabit
land
Still live part of life in water
– Metamorphosis
Aprx. 5,000 species!
Characteristics
– Moist skin for gas exchange
– Ectothermic
– Larval stage
• metamorphosis

3. Movement from water to land
What does it take to move
from water to land?
What has to change?

4. Small adaptations through
Evolution

5. Transition from water to land
Living on land brings different challenges
– Example: movement.
Amphibians are tetrapods:
– “four footed: two sets of paired appendages that
are modified as legs that can support the animal.
Lungs to avoid drying out.

6. Adaptations = land living
New adaptations for
living on land
– Lungs
– Ears
– Four limbs with feet
and digits

7. CHARACTERISTICS
Ectothermic
– Regulate
temperature from
outside sources.
• Basking in the sun
• Water temperature
Vs. Endothermic
What would be the
advantages of both?

8. Ectothermic: Advantages
Slow Metabolism
– Eat less
Must self warm
blood enough to be
active
Not enough energy
for continued hard
work

9. CHARACTERISTICS
Respiration: Porous skin
– Allow for gas exchange
(breathing)
– Must live in moist
environments to avoid drying
out
Sensitive to chemicals in
the environment
Salamanders do not have lungs and
must breath through skin

10. REPRODUCTION
Internal sexual reproduction
Lay 100s of eggs
– Advantage of over population of offspring?

11. METAMORPHOSIS
Amphibian = double life

12. DIGESTION
Adults: carnivores
– Use sticky tongue to
trap and suck in prey
– Eat anything that is
small enough to
swallow whole.
Does that make them active
predators or scavengers?
Larva: herbivores

13. SENSES
Great hearing and eye
sight
– Hearing is Important for
terrestrial living
Frogs can see color!
Other senses…
– Chemical receptors on
skin
– Taste buds on tongue
– Nasal senses

14. ECOLOGICAL ROLE
Important prey for:
– Racoons, opossums,
birds
Important predator
of
– Mice, rats, insects

15. CFU
How do amphibians regulate their body
temperature?
What is this process called?
How do amphibians exchange gasses?
What does the word “amphibian” mean?
What does it mean to be a vertebrate?
What does it mean to be a tetrapod?
What are some adaptations necessary for
living on land?