Amphibian Reproduction Notes

Amphibian Amphibian ReproductionReproduction

By Mr. “Where does a tadpole come from” ChapmanBy Mr. “Where does a tadpole come from” Chapman

ReproductionReproduction What is 1 difference between male What is 1 difference between male

frogs/toads and newts/salamanders on frogs/toads and newts/salamanders on how they attract females?how they attract females?

Male frogs/toads have vocal sacs to call Male frogs/toads have vocal sacs to call and attract females and other males and attract females and other males during mating season.during mating season.

ReproductionReproduction Frogs – males arrive first at the breeding

sites and they emit a call (advertisement call) to attract other males and females. Males form a chorus (lots calling together).

Females are attracted to their species adv. call. The biggest male attracts the most females.

ReproductionReproduction Once the female Once the female

finds a suitable mate, finds a suitable mate, the male climbs on the male climbs on the back of the the back of the female and grabs the female and grabs the female from behind.female from behind.

ReproductionReproduction This formation is This formation is

called called Amplexus.Amplexus.

Anuran ReproductionAnuran Reproduction To help maintain their

grip on the female, males develop rough skin patches, called nuptial pads, on the inside of the forearms.

In some species males’ forearms and thumbs become swollen and muscular during mating season.

ReproductionReproduction While in the water the female releases While in the water the female releases

the eggs and the male covers them with the eggs and the male covers them with sperm to fertilize them.sperm to fertilize them.

What type of fertilization is this?What type of fertilization is this?

External Fertilization-External Fertilization- fertilization is done fertilization is done outside of the body.outside of the body.

ReproductionReproduction

The eggs usually The eggs usually attach to plants, attach to plants, rocks, and some time rocks, and some time float on the surface.float on the surface.

ReproductionReproduction If you see an egg If you see an egg

mass in a pond how mass in a pond how do you tell if it is toad do you tell if it is toad eggs or frog eggs?eggs or frog eggs?

Frog eggs are in Frog eggs are in clumps and toad clumps and toad eggs are in strands.eggs are in strands.

ReproductionReproduction Eggs (anurans) hatch into larvae called

tadpoles. Tadpoles are tiny and easy prey. Females may lay up to 50,000 eggs.

ReproductionReproduction Tadpoles have....... 1. gills 2. dorsal and ventral

(anal) fin 3. lateral line system 4. Anurans have Jaws

for scraping algae. - herbivores

ReproductionReproduction What is the difference between frog/toad What is the difference between frog/toad

tadpoles and salamander tadpoles?tadpoles and salamander tadpoles?

Salamander tadpoles are carnivorous Salamander tadpoles are carnivorous and frogs/toads are herbivores.and frogs/toads are herbivores.

MetamorphosisMetamorphosis – the change from a – the change from a tadpole to a frogtadpole to a frog

Steps in GrowthSteps in Growth:: 1. Develop rear legs1. Develop rear legs 2. 2. Mouth begins to change from algae

scraper to the wide mouth of a frog - can’t eat.

Energy is stored in the fat of their tail. If there was plenty of fat, then some of

the tail will remain after metamorphosis. If the tadpole didn’t make enough fat, it

will die during metamorphosis.

3. Front limbs appear. 4. Lungs begin to form. 5. Gills are absorbed.... skull widens &

eyes to top of the head.

Anuran ReproductionAnuran Reproduction 6. Mandible and Maxilla is completed 7. Digestive system and enzymes must

change from plant digestion to animal digestion.

This process can take from 3 weeks to 3 This process can take from 3 weeks to 3 years depending on species.years depending on species.

ReproductionReproduction Metamorphosis ends > froglet/toadlet

can move to land. Adults - carnivores.

Salamander ReproductionSalamander Reproduction Salamanders – most

species breed in late winter (Feb to mid March).

They approach their pond, both males and females), on the first warm (55 degrees), rainy night of the late winter.

Sal ReproSal Repro Salamanders do not make noises, but find Salamanders do not make noises, but find

each other by smell.each other by smell.

In the water, males release pheromones (external hormones).

F’s smell and approach the pheromones. Males fan the pheromones towards the F with their tail.

Sal. ReproductionSal. Reproduction M does a courtship dance.

Sal. Repro.Sal. Repro. F lays her chin on male’s pelvis

ReproductionReproduction M deposits a sac of M deposits a sac of

sperm on the bottom sperm on the bottom of the pond.of the pond.

The sac of sperm The sac of sperm that the male lays on that the male lays on the bottoms is called the bottoms is called a a SpermatophoreSpermatophore..

F picks off the sperm packet with her cloaca- packet of sperm opens and fertilizes her eggs. Fertil. is internal.

Next night F climbs onto a submerged twig and lays her eggs on it.

Salamander TadpolesSalamander Tadpoles Larvae hatch >

external gills, 4 legs.

Diet - zooplankton (tiny animals) carnivores as larvae.

Metam. > lungs develop > gills absorb and they leave the water.

Adults carnivores.

ReproductionReproduction In aquatic species In aquatic species

they keep these they keep these external gills and are external gills and are considered to be considered to be Neotinic (incomplete Neotinic (incomplete metamorphosis) metamorphosis)

FeedingFeeding Feeding as LarvaFeeding as Larva:: Frog/Toad tadpoles are herbivores.Frog/Toad tadpoles are herbivores. Salamander tadpoles are carnivores.Salamander tadpoles are carnivores.

Feeding as AdultFeeding as Adult:: Anurans are carnivoresAnurans are carnivores Caudatans are carnivoresCaudatans are carnivores

FeedingFeeding Tadpoles in captivity Tadpoles in captivity

can be fed rabbit can be fed rabbit pellets or fish flake pellets or fish flake food.food.