In most species of frogs, fertilization is external. The male frog grabs the female’s back and fertilizes the eggs as the female frog releases them (Figure 2.2B). The egg pronucleus and the sperm pronucleus will meet in the egg cytoplasm to form the diploid zygotic nucleus.

Chordate

Rana is the genus and tigrina is the species. Hence the correct answer is B) Chordata, Craniata, Gnathostomata, Amphibia, Rana.

Bull Frog (Rana Tigrina Daud.)

Indian bull frog

Answer: Estrogen is highest in females captured in amplexus when presumably they are closest to laying their eggs. At this point, receptivity is highest and choosiness lowest. Estrogen, along with both behaviors, falls after eggs are released.

Usually male and female frogs are roughly the same colour. But not always. In a handful of species, males are vastly different than females all the time. In others, males match the females most of the time, but get more colourful in the breeding season.

When strolling by a pond, river or large puddle at night, you may see two frogs clinging onto each other. This is a behavior called amplexus: it allows the male frog to place his cloaca near the female’s in order to fertilize her eggs.

Scientists have long recognized that vocal calls are frogs’ chief means of communication, but recent studies detail a growing body of evidence for visual cues used in communication among several frog species, said the study authors. …

Amplexus (Latin “embrace”) is a type of mating behavior exhibited by some externally fertilizing species (chiefly amphibians and horseshoe crabs) in which a male grasps a female with his front legs as part of the mating process, and at the same time or with some time delay, he fertilizes the eggs, as they are released …

Specific positions may serve to ensure that species of frogs only mate with their own kind. Such a prolonged process makes life difficult for frogs, especially females, who must go about their day literally carrying around a male frog. To find out how difficult this is, researchers tied amplexing cane toads together.

When reptiles, birds, and mammals mate, the male fertilizes the eggs inside the female’s body. Like fish, almost all frogs fertilize the eggs on the outside. The male holds the female around the waist in a mating hug called amplexus.

Frogs scream when you touch them out of fright. Frogs scream when they perceive danger and are not trying to attract a mate, as some believe. When you touch a frog, it no longer feels safe. Thus, it emits a high pitched screech that sounds like the high scream of a very small child.

Frogs don’t stay together to raise their babies and usually split up right after breeding. If any care is given, it’s normally the female frog that does it. She may attach her eggs to underwater plants or other items to protect them until they hatch.

Usually when frogs breed, the parents part ways and the eggs are left to fend for themselves but some species of frogs and toads provide care for the eggs and younglings. There are many different ways that the frogs provide care for their offspring. Some frogs brood their eggs by sitting on them like birds do.

Among frogs, about 10 percent of known species take care of their young. Of that group, half to two-thirds of species rely on males to do the job. For instance, male parental care is common among the brightly colored Neotropical poison frogs of Central and South America.

The tadpoles remain in her stomach for up to 8 weeks, until finally hopping out of her mouth as little frogs. During the brooding period, gastric secretions cease–otherwise she would digest her own offspring.

In such species, male frogs often produce a release call when clasped by another male. During mating season, researchers can use release calls to tell which frogs are male and which are female. All frogs’ eggs require moisture to develop, and most frogs abandon their eggs once they’re fertilized.

When tadpoles have fully absorbed their tails, they leave the water as tiny froglets. Adult frogs may be seen around ponds or in damp areas of the garden as they attempt to cool off in the hot weather.

Rana is a genus of frogs commonly known as the Holarctic true frogs, pond frogs or brown frogs. These true frogs are usually largish species characterized by their slim waists and wrinkled skin; many have thin ridges running along their backs, but they generally lack “warts” as in typical toads.

Frog spawn normally appears in ponds and slow-moving streams in March. If you’re too late to see frog spawn never fear – tadpoles will appear around April and are even more fun to find.