Frog

Frogs are amazing animals.

They live in many places. Some live in wet forests. Others live on dry land.

Most frogs have no tail. They have big eyes and strong legs.

They use their long tongues to catch bugs.

Frogs start as tiny eggs in the water. The eggs hatch into tadpoles.

Tadpoles have tails to swim.

As they grow, they change. They lose their tails. They grow lungs to breathe air.

Frogs are very important. They are a snack for other animals. They help keep nature in balance.

Frogs are a large group of animals. They belong to the order Anura. This name means "without tail."

Most adult frogs have stout bodies and big eyes. They have strong back legs for jumping. They also have long tongues to catch food.

Frogs live in many places. You can find them in warm rainforests or cold areas. Some frogs live in water. Others live on dry land or in trees. Their skin is very special. It lets them breathe, but it must stay moist.

Some frogs have skin that is bright to warn predators. Other frogs use colors to hide in plants.

Most frogs start life in the water. They lay eggs that hatch into tadpoles.

Tadpoles have tails and gills to breathe underwater. Later, they go through metamorphosis. This is a way of changing shape. They grow lungs and lose their tails.

Frogs are very important for nature. They eat many small bugs. They are also food for other animals.

Scientists watch frogs closely. If frogs get sick, it can mean the environment is changing.

Frogs are amazing members of a huge group of animals. They belong to the order Anura, which means "without tail."

Most frogs are amphibians, which means they live part of their lives in water and part on land. They are very successful living things. In fact, they make up about 88% of all amphibian species. You can find them in many places, from hot tropical rainforests to cold subarctic regions.

Because they are so diverse, they are one of the five most diverse groups of vertebrates on Earth.

A frog's life involves many changes. Most frogs start as eggs laid in the water.

These eggs hatch into tadpoles, which are small creatures that live entirely underwater. Tadpoles have tails and internal gills to help them breathe. Eventually, they go through metamorphosis, a big change in their body shape.

During this time, they grow lungs and develop legs. Their tails shrink away into a bone called a urostyle. As adults, they use both lungs and their skin to breathe.

Scientists have studied frogs for a very long time. We know that very old "proto-frogs" lived a long time ago. One fossil named Triadobatrachus was found in Madagascar.

This fossil is from the Early Triassic period, about 250 million years ago. Some scientists think frogs might have even appeared 265 million years ago. In 2008, researchers found a fossil called Gerobatrachus hottoni in Texas.

This fossil lived 290 million years ago and looks like both a frog and a salamander.

Adult frogs have many interesting physical traits. They usually have stout bodies and eyes that stick out. Their skin is very special because it is semi-permeable. This means it lets things pass through it. Because of this, frogs must stay in moist places so they do not dry out.

Some frogs have skin that is bright red or yellow. This bright color warns predators that the frog might be toxic. Other frogs have brown or green skin to hide in plants.

Frogs play a vital role in the world's food webs. They are low-level consumers that eat many small things.

Most adults are carnivores that eat insects and other small invertebrates. They catch food by using a long, sticky tongue.

They are also important food for bigger predators. Because of this, scientists call them environmental bellwethers.

This means that if frog populations decline, it is an early warning sign that the environment is in trouble.

Frogs are members of the order Anura, a name derived from Ancient Greek meaning "without tail."

This diverse group of vertebrates includes many species that are semiaquatic, meaning they live both in water and on land. Frogs are incredibly successful, accounting for approximately 88% of all extant amphibian species. This makes them one of the five most diverse vertebrate orders on Earth. While they live in many environments, from subarctic regions to the tropics, the highest concentration of species is found in tropical rainforests and associated wetlands.

The life cycle of a frog involves a complex process called metamorphosis. Most frogs are oviparous anamniotes, which means they lay eggs that do not have a specialized membrane. These eggs are typically spawned in bodies of water.

From these eggs, aquatic larvae called tadpoles hatch. Tadpoles possess tails and internal gills for breathing underwater. They often have specialized mouthparts, such as keratinous beaks, to eat plants or tiny organisms. As they mature, they undergo metamorphosis to become adults. During this change, they develop lungs and legs for life on land. The larval tail eventually regresses into an internal bone called a urostyle.

Adult frogs have several distinct physical characteristics. They generally possess stout bodies, protruding eyes, and limbs that are folded underneath them. Their skin is glandular and semi-permeable, which allows for gas exchange. This means they can use their skin to help them breathe. However, semi-permeable skin also makes them susceptible to dehydration. To survive, they must live in moist niches or develop special adaptations for drier habitats.

Their skin color serves important functions. Some species use dappled brown or green patterns for camouflage. Others use vivid patterns of red, yellow, or black to signal that they are toxic.

There is often confusion regarding the difference between frogs and toads. In scientific taxonomy, the distinction is informal and purely cosmetic. All members of the order Anura are technically frogs. However, only members of the family Bufonidae are considered "true toads."

Generally, people use the word "frog" for aquatic species with smooth, moist skin. The word "toad" is often used for terrestrial species with dry, warty skin. There are exceptions, such as the Panamanian golden frog, which is a toad but has smooth skin.

The evolutionary history of Anura is a subject of intense scientific study. The oldest known fossil "proto-frog" is Triadobatrachus, found in Madagascar.

This fossil dates to the Early Triassic, about 250 million years ago. Molecular clock dating suggests the group may have diverged from other amphibians as far back as the Permian, 265 million years ago. In 2008, the discovery of Gerobatrachus hottoni in Texas provided a potential "missing link." This 290-million-year-old fossil shows characteristics of both frogs and salamanders. This supports the hypothesis that frogs and salamanders belong to a single group called Batrachia.

Frogs play a critical role in global ecosystems as low-level consumers. Most adults are carnivores that eat small invertebrates, particularly insects. They capture prey using an anteriorly-attached, adhesive tongue.

They often use their eyeballs and extraocular muscles to help push food down their throats. Because they are eaten by many larger predators, they are vital to food web dynamics.

This position makes them environmental bellwethers. This means that changes in frog populations can serve as early warning signs of environmental degradation.

Unfortunately, global frog populations and diversity have declined significantly since the 1950s. More than one third of all species are currently considered threatened with extinction. Since the 1980s, over 120 species are believed to have become extinct. One major cause of this decline is a spreading fungal disease called chytridiomycosis. This disease has caused many malformations and population crashes worldwide. Conservation biologists are currently working to study these trends and solve these environmental problems.