1. KEY CONCEPT Amphibians evolved from lobe-finned fish.

2. Q: Why are frogs so good at baseball?
Q: Why are frogs so good at baseball? A: Because they catch a lot of flies...
Amphibian Trivia
Amphibians can breathe with skin, gills, or lungs
All amphibians lay their eggs in water
Salamanders, frogs, toads, and caecilians are all amphibians
Amphibians are herbivores
Frogs are the largest group of amphibians
True
False
Q: Why are frogs so good at baseball?
A: Because they catch a lot of flies...

3. Amphibians were the first animals with four limbs.
Tetrapods are vertebrates that have four limbs.
Includes all vertebrates that live on land and some aquatic animals
The snake is considered a tetrapod!!!
The fossilized remains of Tiktaalik roseae indicate it was a transitional species between fish and tetrapods.

4. How do these adaptations help on land?
Amphibians are animals that can live both on land and in water.
A number of adaptations allow amphibians to live on land.
large shoulder and hip bones
mobile, muscular tongue
middle ear
breathe through skin or with gills or lungs
How do these adaptations help on land?

5. Amphibians return to the water to reproduce. Why?
Amphibians use many strategies to keep their eggs wet.
lay eggs directly in water
lay eggs on moist ground
wrap eggs in leaves
brood eggs in pockets on the female’s back

6. Tadpoles are aquatic larvae of frogs.
Newly hatched: Live off the yolk in their body
Develop gills: 3 pairs
2 chamber heart
Mouth will open and allow it to eat
Can regenerate body parts
During metamorphosis, tadpoles develop into their adult form.
Legs grow, Tail disappears
Mouth broadens: Develops teeth and jaws
Lungs develop from a saclike bladder in the throat
Heart develops a 3rd chamber
Lose the ability to regenerate
Not all amphibians undergo metamorphosis.

7. Tadpoles undergo many changes during metamorphosis
Gills are reabsorbed and lungs develop
Circulatory system sends blood to the lungs
Tail fin/tail is reabsorbed
Grows limbs
Systems reorganize…Nervous, Skeletal, Muscular
Digestive system rebuilt
adult frog
young frog
tadpoles
fertilized eggs

8. Frogs are the largest amphibian group and include toads.
There are over 3000 species of frogs.
Glands in the skin of frogs and toads contain poisons that help to protect them from predators.
Live in all environments except poles and driest deserts
Adult frogs will eat any animal they can catch

9. Cold Blooded/Ectotherm: Body fluctuates up or down depending on the outside temperature
Protects itself by going dormant under unfavorable conditions: torpor
Hibernation is torpor in the winter
Estivation is torpor in the summer

10. Anatomy of a Frog: Circulatory System
1. Right Atrium: Receives deoxygenated blood from the body
2. Left Atrium: Receives oxygenated blood from the lungs
3. Ventricle: Both the Left and Right atrium empty into here
Main pumping chamber of the heart
Oxygenated and Deoxygenated blood mix partially and are pumped to the lungs and the rest of the body.
Using your knowledge of the human heart, name two ways the frog heart is different

11. Left Atrium
Right Atrium
Sinus venosus
Ventricle
Posterior Vena Cava

12. Anatomy of a Frog: Nervous System
Olfactory Lobes: Sense of smell
Optic lobe: Controls vision
Spinal Nerves: Branch off of the Spinal cord to various parts of the body
Spinal Cord: Transmits signals back and forth between the body and brain
Medulla Oblongata: Controls organ functions
Cerebellum: Balance and coordination
Cerebrum: Controls voluntary nervous activity

13. Nervous System

14. Anatomy of a Frog: Digestive System
Tongue-Mouth-Swallows by pressing eyes to the roof of the mouth (Tongue attached in front of mouth: sticky end)
Teeth
Maxillary Teeth: Perimeter of upper jaw
Vomerine Teeth: Roof of Mouth
Alimentary Canal: Digestion occurs here
Includes: esophagus, stomach, small intestine, large intestine and Cloaca
Small Intestine:
Upper Portion: duodenum
Coiled middle: ileum
Mesentery: Fanlike and holds the intestine in place
Large Intestine:
Cavity: Cloaca
Waste exits through the cloacal opening, or anus
Liver: produces Bile, digestive enzyme, stored in the gallbladder
Pancreas: secretes digestive enzymes into the small intestine

15. stomach
duodenum
pancreas
Small intestine
Large intestine
ileum
spleen

16. Mesentery connecting small intestine

17. Fat Bodies
Small intestine
Large intestine

18. Anatomy of a Frog: Excretory System
CO2 mostly excreted through skin
Waste from food:
Kidneys: Primary excretory organ, filter waste from blood
Water and Nitrogenous waste is called urine, excreted through anus

19. Frog Kidney

20. Anatomy of a Frog: Respiratory System
Respiratory System: Tadpoles use gills; Adult: Use lungs
3 ways to respire:
1.Through Lungs: Pulmonary Respiration
2.Through Skin: Cutaneous Respiration
3.Through Mouth: Diffusion through the lining of the mouth.

21. Anatomy of a Frog: Reproductive System
Male: Testes produce sperm
Female: Ovaries produce eggs: Leave body through the cloacal opening
Fertilization: One time per year
Mating call to attract female
When the female releases the eggs the male discharges sperm on them; direct external fertilization
In 12 days the eggs hatch into tadpoles
Frogs produce tons of eggs…Why?

23. Frog Eggs
Ovaries with Frog Eggs

24. Frog Testes
Testes

25. 1 4 2 3 10 9 8 7 6 5

26. Mouth
Tongue attached at front of mouth; 2 sets of teeth to hold prey
2. External Nares (nostrils)
at the top of the frogs head; allows frog to breathe while partially submerged under water
3. Forelimbs
for balance; shorter than hind limbs
4. Digit
grasping
5. Eyes
Nictitating membrane: Third eyelid: Keeps eyeball moist and protects eye under water
6. Tympanic membranes
External eardrums; senses vibrations for hearing; transmits sounds to internal ear
7. Dorsal side
“backside”; darker for camouflage
8. Skin
Respiration and protection (camouflage), Mucus Glands: Secretes lubricant that keeps skin _____, Secretes foul tasting or poisonous substance for protection
9. Hind limbs –
used for jumping and swimming; feet are webbed; up to 6x longer than forelimbs
10. Ventral side
“belly” side of frog; lighter in color for camouflage

27. Mouth
External Nares
Nictitating Membrane
Eye
Tympanic Membrane

28. Internal Mouth

29. Maxillary teeth
Vomerine teeth
Internal Nares
Eustachian tube
esophagus
glottis
tongue

30. Esophagus
Liver
Lung
Gallbladder
Pancreas
Stomach
Small Intestine
Spleen
Large Intestine
Cloacle
Cloacle Opening
Kidneys
Testes
Ovaries/Eggs
Oviducts
Large Intestine
Urinary Bladder
Cloacle Opening

31. Heart
Fat Bodies
Urinary bladder
Liver

32. List two reasons why amphibians must live in moist environments.
Compare and contrast the frog heart to the human heart.
List three changes that occur during metamorphosis.
Amphibians are very sensitive to changes in their environment, which is why they are called Biological Indicators. Why might this be?
Why does amphibian reproduction require a moist environment?
List two adaptations of amphibians abd briefly describe why each is important for life on land.
List the major structures involved in each of the following systems: Respiratory, Digestive, Reproductive and Excretory