Learning Objectives: CH.18 Amphibians

Amphibians 

Phylum Chordata

Subphylum Vertebrata     

Superphylum Tetrapoda

Class  Amphibia

Know The Taxa

Class Amphibia

Order Gymnophiona(naked snake)

Order Urodela( w/tail)

Order Anura (w/o tail)

-Family Ranidae-true frogs

-Family Hylidae- tree frogs

-Family Bufonidae-toads

Animal Richness

Areas of the world that consist of a lot of animals.

Concertina

Similar to the accordion; scrunched up

Internal Concertina

Being able to scrunch up the back half of the spine and anchor to the soil, then charge the front half of the body forward

Jacobson’s Organs

Sensory tentacles on the snout used in olfaction

Viviparous

Where the young develop inside the body of the parent

Oviparous

Producing young by laying eggs that hatch after they have been laid by the parent

Urodela

With tail

Cutaneous Respiration

Process where gas exchange through the skin

Paedomorphosis 

The evolution of an adult form that resembles the juvenile form.

Eft

The immature, terrestial juvenile stage of newt.

Speciose

Have the most species

Ambush Predators

An animal that hunts by using stealth and surpise rather than speed

Anura

Without tails

Parotid

The largest major salivary glands located in the front of the slightly below each ear.

Granular Poison Glands

Specialized secretory glands in amphibians which contain poison, like toads, that secrete when stressed, to protect against predators

What are the three orders of amphibians?

Gymnophiona (caecilians), Urodela (salamanders/newts), Anura (frogs/toads)

Body characteristics of caecilians

Long, limbless, smooth or slimy skin, no post-anal tail, some with small dermal scales.

Habitat and distribution of caecilians

Tropical forests of South America, Africa, and Southeast Asia; mostly underground, some aquatic.

Locomotion of caecilians

Internal concertina movement—anchor the back half, push forward through soil.

Sensory structures of caecilians

Small eyes (often covered by skin/bone); tentacles on snout connected to Jacobson’s organ for detecting chemicals.

Feeding behavior of caecilians

Carnivorous; eat worms, arthropods, small fish; use “death roll” for powerful bite.

Respiration in caecilians

Lungs, mouth, and skin; some species lack lungs and rely on cutaneous respiration

Reproduction and development in caecilians

Internal fertilization; mostly viviparous, some oviparous; maternal care; young may feed on maternal skin or oviduct lining.

Body and habitat of salamanders

Elongated body with equal limbs and tail; live in cool, moist habitats near water; nocturnal.

Distribution of salamanders

Found worldwide except Australia and Antarctica; most diverse in North America.

Locomotion of salamanders

S”-shaped trunk movement; limbs move alternately.

Feeding in salamanders

Carnivorous; eat worms, arthropods, and molluscs; some have long projectile tongues.

Respiration in salamanders

Internal fertilization; males deposit spermatophore; pheromones attract females; some parental care.

Development in salamanders

Aquatic eggs or terrestrial eggs; some direct development or live birth; paedomorphosis in some species.

Body characteristics of anurans

Fused head and trunk, no tail, long hindlimbs, short forelimbs, compact upright body.

Habitats of anurans

Extremely diverse—tropical, temperate, desert, and subarctic biomes.

Feeding in anurans

Carnivorous; sticky projectile tongue; swallow using eye retraction.

Defenses of anurans

Camouflage, lung inflation, poison glands, aggressive behavior, or toxin secretion.

Hibernation in anurans

Temperate frogs hibernate; wood frog survives freezing using urea and glucose as antifreeze.

Reproduction in anurans

External fertilization via amplexus; males call to attract females; eggs laid in water; some parental care.

Development in anurans

Tadpole larvae metamorphose into adults; hindlegs appear first; tail reabsorbed; some have direct development (no tadpole stage).

Center of diversity for Gymnophiona

Tropical South America, Africa, and Southeast Asia—tropical rainforests.

Center of diversity for Urodela

North America—cool, moist forests and streams.

Center of diversity for Anura

Global, especially in the tropics—forests, swamps, deserts, and subarctic zones.

Which amphibian order has the most species?

Order Anura (frogs and toads).

How do caecilians move?

Internal concertina motion—scrunch and push through soil.

How do salamanders move?

“S”-shaped walking motion with limbs of equal size.

How do frogs and toads move?

Jump using powerful hindlimbs and shock-absorbing forelimbs.

What adaptations allow frogs to jump many times their body length?

Long, muscular hindlimbs, stiff pelvis, fused radius/ulna, elongated pelvic girdle, and elastic connective tissues.

Family Ranidae – Key traits

Long legs, webbed hind feet, aquatic or semi-aquatic habitats; found worldwide except Antarctica.

Family Hylidae – Key traits

Adhesive toe pads, forward-facing eyes, less webbing; adapted for arboreal or semi-aquatic life.

Family Bufonidae – Key traits

Dry, warty skin, no teeth, parotid poison glands; mostly terrestrial; widespread except Australia & Antarctica.

What is the largest amphibian in the world?

The giant salamanders ( Chinese Giant Salamander)