1. FISHES AND AMPHIBIANS
CHAPTER 28
MRS. BENDER

2. AMPHIBIANS Begin life as aquatic and live on land as adults
Modern amphibians are descendants of tetrapods

3. Adaptions to Land
Air less buoyant than water, so move against gravity causing limbs to develop along with skeletal and muscular systems
Cant remove dissolved Oxygen from water developed lungs, which are more efficient
Water retains heat, on land temperature change more easily so need to develop behavioral and physical adaptations for protection
Development of ears to sense sound
Live in variety of biomes

4. Characteristics of Amphibians
Begin life as aquatic larvae then metamorphosis for land
Cold blooded, ectotherms, obtain their body heat from the external environment
As adults: four legs
Moist skin with no scales
Gas exchange through skin
Lungs
Double loop circulatory system

5. Feeding and Digestion Frog larvae are herbivores
Salamander larvae are carnivores
Adults are both predators and feed on invertebrates and small vertebrates
Mouth…esophagus….stomach (digestion begins)…small intestine (receives enzymes from pancreas, food is absorbed into blood stream)….large intestine…cloaca…(chamber at the end on intestine that receives digestive wastes, urinary wastes, and egg and sperm before they leave body)

6. Excretion Filter wastes from blood through their kidneys
Excrete either ammonia or urea as waste products of cellular metabolism
Ammonia is the end product of protein metabolism and is excreted by amphibians that live in water
Urea is produced by land amphibians, made from ammonia in the liver and is stored in the urinary bladder until eliminated through the cloaca

7. Respiration As larvae exchange gases through gills and skin
As adults, most use lungs and through their thin moist skin, and through the lining of their mouth cavity

8. Circulatory System Double loop system Three chambered heart
First loop moves oxygen-poor blood from the heart to pick up oxygen in the lungs and skin, and moves the oxygen-filled blood back to the heart
Second loop blood filled with oxygen from the heart through the vessel to the body
Three chambered heart
Atrium
Right receives deoxygenated blood from the body
Left receives oxygenated blood from lungs
Ventricle
One chamber blood mixes before sent out to body

9. Reproduction Lay eggs in water to be fertilized by males (frogs)
Eggs do not have shells or protective covering
Sticky substance covers to adhere
Tadpoles use gills and only have two chambered heart

10. Amphibian diversity Order Anura Order Caudata Order Gymnophiona
Frogs and toads
Frogs powerful legs, moist smooth skin
Toads small hops, dry bumpy skin, have gland which produce foul taste
Order Caudata
Salamanders and newts
Salamanders, four legs
Newts are generally aquatic
Order Gymnophiona
Caecilians
Legless and worm like
Burrow in soil and feed on worms and invertebrate
Internal fertilization

11. Characteristics of Vertebrates
Have a backbone
Specialized cells that develop into a nerve cord
Neural crest forms – a group of cells that develop form the nerve cord, which portion of the brain, skull and sense organs develop
Vertebral Column
Spinal cord
Surrounds and protects the dorsal nerve cord
Replaces the notochord with cartilage (tough flexible material) or bone
Strong flexible rod for muscles to attach to
Allows for increase in speed and strength
Closed circulatory system

12. Characteristics of Fish
Most have a vertebral column
Jaws
Allows to prey on larger animals
Defense against predators
Paired fins,
Used for balance and steering and propulsion

13. Characteristics of Fish
Scales
Ctenoid scales and Cycloid scales are made of bone and skin and are thin and flexible
Placoid scales are made of toothlike materials and are rough and heavy
Ganoid scales are diamond shaped and made of both enamel and bone
Gills
Covered with lamellae- folded structures of the gills containing many vessels to diffuse oxygen and carbon dioxide from the blood
About 85% of oxyen is removed
Operculum is a movable flap that covers the gills protecting them and it also aids in pumping water

14. Characteristics of Fish
Single looped circulatory system
Heart pumps blood in vessels
Blood passes heart one direction then to gills, then through the body delivering oxygenated blood
Hearts have two main chambers
Atrium which receives blood from the body
Ventricle which pumps blood from the heart to the gills

15. Feeding and digestion
Fish swallow food passes through the esophagus to the stomach where digestion begins
Pyloric ceca a small pouch at the junction of the stomach and the intestine that secretes enzymes for digestion and absorption into the blood stream

16. Excretion
The main functional unit of the kidney is the nephron, which is a filtering unit that helps maintain the salt and water balance of the body
Some cellular wastes excreted by the gills
Cellular wastes are filtered by kidneys

17. Brain and senses Nervous system consists of a brain and spinal cord
Cerebellum is involved in coordinating movement and controlling balance
Receptors that sense smell and detect chemicals in the environment
Olfactory bulbs record and respond to incoming chemical input
Color vision, optic lobes responsible for visual input
Cerebrum coordinates input from other parts of the brain
Medulla oblongata controls the internal organs
Lateral line system are special receptors that enable fish to detect movement and it keeps them upright and balanced

18. Reproduction External fertilization
Spawning in when females and males release gametes near each other in the water
Sharks reproduce internally

19. Movement Streamlined bodies
Mucus that lubricates surface to reduce friction
Swim bladder is a gas-filled space that allows fish to control their depth

20. Classes of Fish Jawless fish Class Myxini is the hagfish
No scales, eel like shape, no fins, no bony skeleton
Have a notocord
Live on sea floor and feed on dead fish or invertebrate
Produce slime to prevent from being caught by predators
Class Cephalaspidomorphi
Lampreys
Have a notochord
parasitic

21. CLASSES OF FISH Cartilaginous fish Body made of cartilage
Class Chonodrichthyes
Sharks, skates, rays
Several rows of teeth
Streamlined bodies
Sense chemicals in water
Lateral lines
Whale sharks are filter feeders

22. CLASSES OF FISH Bony fish Class Osteichthyes
Rayed fish : most fish today
Lobed fish have muscular joints like land vertebrate
Use lungs to exchange air like the lung fish