Terms in this set (76)
How long have amphibians survived for?
hundreds of millions of years
Where do they live?
in places where fresh water is plentiful
How many species are there?
Amphibians are the only modern descendants of an ancient group that did what?
gave rise to all other land vertebrates
How long ago did the 1st amphibians evolve from lobe-finned fish and became the 1st vertebrates to live on land?
370 million years ago
What is the age of the amphibians called?
the Carboniferous Period
How many orders of small amphibians survive today?
3 orders - frogs and toads, salamanders, and caecilians
Where do amphibians live?
in water as a larva and on land as an adult
What do they breath with as adults?
What does their moist skin contain?
What do they lack?
scales and claws
Characteristics of Early Amphibians
1. Evolved from lobe-finned fish
3. Features of the skull
4. vertebral column
5. bones in the fin of love-finned fish are similar in shape and position in the limbs
6. Forelimbs of amphibians are homologous to pectoral fins and hind limbs to pelvic fins
7. Breathe air with lings
8. They have specialized sense organs to detect scent and sound
Why would the Early amphibians have spent some time in water?
They had a large tail fin and lateral line canals and teeth were large and sharp indicating a diet of fish. Some even had gills
Whats the difference between the number of toes Early Amphibians had and how many today's Amphibians have?
Early Amphibians had 7-8 on each hind foot
Today's Amphibians have 5 on each foot
What were the 2 evolutionary lines amphibians split into during the Carboniferous Period?
One line included the ancestors of modern day amphibians and the other reptiles
Characteristics of Modern Amphibians?
1. Most change from an aquatic larval stage to a terrestrial form, called metamorphosis
2. Most have moist, thin skin with no scales
3. Feet, if present, lack claws and are often webbed
4. Most use gills, lungs and skin in respiration
5. Amphibian eggs lack multicellular membranes or shells, and are usually laid in water or moist places and fertilized externally
How many species are divided into 3 orders?
What are the 3 orders?
1. Order Urodela - salamanders
2. Order Anura - frogs and toads
3. Order Apoda - caecilians (leg-less, wormlike, tropical amphibians)
What are the 2 important functions of the skin of amphibians?
1. Respiration - skn is moist and permeable to gases and water, allowing diffusion
2. protection - skin provides foul-tasting or poisonous substances
supply a lubricant that keeps the skin moist in air
What are Amphibians vulnerable to?
What does the vertebrae of the skin interlock and form?
a rigid structure that can support body weight
What do Forelimbs attach to?
the pectoral girdle (the shoulder and supporting bones)
What do hind limbs attach to?
the pelvic girdle (the hips)
What 2 structures transfer the body's weight to the limbs?
pectoral and pelvic girdle
allow for neck movement
What are the bones that absorb the forces of jumping and landing ?
radio-ulna and the tibio-fibula
Frogs have few vertebrae and they are fused at the posterior end
What are the 2 separate loops called?
Pulmonary circulation and Systemic circulation
carries deoxygenated blood from the heart to the lungs and returns oxygenated blood (first loop)
carries oxygenated blood from the heart to the muscles and organs of the body and brings deoxygenated blood back to the heart (second loop)
What do all terrestrial vertebrates have that provides a faster blood flow to the body?
How many chambers does an Amphibians heart have?
Where does deoxygenated blood travel to?
Where does oxygenated blood travel to?
What do larval amphibians respire through?
their gills and skins
What do adults respire through
most adults lose their gills but respire through lungs and skin
respiration through the lungs, they show positive breathing, pumping air into the lungs
How does a frog control the direction of air flow?
by opening or closing his nostrils
What do inhalation and exhalation involve?
a 2-step process during which the floor of the frog's mouth is raised or lowered
respiration through the skin, important because the lungs have a small surface area for gas exchange
What kind of eaters are adult amphibians?
carnivores, the most common foods are insects and arthropods, but some larger amphibians will eat mice, snakes, fish and other amphibians
What do amphibian larvae eat?
algae or bacteria
What do salamander larvae eat?
larvae of other species
a muscle at the lower end of the stomach relaxes and allows food to move into the small intestine
upper portion of the small intestine
coiled middle portion
membrane resembling plastic wrap that holds the small intestine in place
What collects indigestible wastes and muscles push them into the cloaca?
the large intestine
What are passed into the cloaca?
waste from kidneys and urinary bladders as well as sperm or eggs
waste materials exit the body
What produces bile?
what stores bile?
What does bile break help do?
break down fats (emulsifies fates)
a gland located near the stomach, secretes enzymes that enter the small intestines and help break down food into products that can be absorbed by the blood
What are the primary excretory organ?
Where are the kidneys?
lie on either side of the spine against the dorsal body wall, they filter nitrogen containing wastes from the blood
nitrogen containing wastes combines with water; moves into the urinary ducts them to the cloaca and finally into the urinary bladder
serves as a water storage organ, during dry periods water can be reabsorbed from the urine in the bladder
What do Amphibian larvae excrete?
nitrogen containing wastes as ammonia, and is very toxic and must be moved quickly or diluted with large amounts of water
How do adult Amphibians conserve water?
by converting ammonia into urea which is less toxic and saves water
What are larger in amphibians than in fish?
behind the olfactory bulbs and is responsible for learning
processes info from the eyes and lies behind the cerebrum
Can frogs see color?
a small band of tissue and the center of muscular coordination
at the back of the brain and controls some organ functions
How many pairs of cranial nerves do Amphibians have?
conducts signals from the body and is responsible for reflex actions
Larval amphibians have a lateral line system, but when is it lost?
What senses are well developed?
smell, sight and hearing
What do all amphibians have that help with hunting and avoiding predators?
transparent, moveable membrane that covers the eyes that helps them see underwater without damaging their eye
external eardrum that transmits sound
a small bone that extends between the tympanic membrane and inner ear
vibrations - tympanic membrane - columella - fluid filled ear - converted to nerve impulses by sensitive hair cells - to brain