Subphylum Amphibia Flashcards
(11 cards)
What were the problems faced by amphibians in moving from water to land?
- Access to oxygen
- Difference in densities
- Temperature regulation (it is more regulated in water than on land)
- Habitat diversity
General characteristics of class Amphibia
- Bony skeleton with varying no of vertebrae
- Absence of exoskeleton
- Notochord not persistent
- Varying body forms
- Usually tetrapods but some have no legs
- Smooth, moist skin with many glands
- Presence of chromatophores
- Respiration by lungs, gills, skin
- 3-chambered heart, double circulation
- Separate sexes, internal or external fertilization
Orders under class Amphibia
Order Gymnophiona (Apoda) Order Caudata (Urodela) Order Anura (Salientia)
Gymnophiona
- Elongated, burrowing, resembling snakes, mostly hidden in the ground
- Long, slender body, small scales, terminal anus
- Food is worms and small underground vertebrates
- Internal fertilization
Caudata
- Possesion of long tails
- Lizard-like apperance
- Limbs at right angle to the body, equal sizes
- Moist skin, swampy habitat
- Regeneration
- Salamanders are carnivorous
- Ectotherms with low metabolic rate, relying on environment for body temperature
Anura
- Some types spend their entire life in or near water, but others live mainly on land and come to the water only to mate
- Some frogs and toads are climbers that dwell in trees or burrowers that live underground.
- Some basic differences between them are: toads have dry, warty skin, while frogs have smooth, wet skin.
- External fertilization
Blood circulation in Anurans
A B F C S
All Boy Friends Can See
A - 2 separate ATRIA, a single ventricle
B - BLOOD from the body enters a receiving chamber called the sinus venosus which forces blood into the right atrium.
F - The left atrium receives FRESHLY oxygenated blood from the lungs
C - Both atria CONTRACT almost simultaneously, driving blood from them to the ventricle.
S - Although the ventricle is undivided, blood remains mostly SEPARATED so that when the ventricle contracts, pulmonary blood enters the systemic circuit and deoxygenated blood enters the pulmonary circuit
What do burrowing caecilians eat?
Earthworms
Anurans food
Insects, other vertebrates and arthropods
What kind of hunters are salamanders and diurnal anurans?
Active foragers, using the sit-and-wait technique
Adaptation for terrestrial existence for amphibians
- Tough, dry, scaly skin for protection
- Shelled amniotic eggs which support embryonic development on land
- Jaws designed for carnivorous life
- Copulatory organs for internal fertilization
- More efficient respiration and circulation
- Better-developed lungs
- Stronger limbs with claws
- Strategies for water conservation
- Better body support
