Amphibians: Different Types, Definition, Photos, and More

There are about 4,000 kinds of amphibians, including anurans, anurans, and anurans. Characteristics: 1. Need to spend its childhood in water. 2. It has a bone structure adapted to living on land, has limbs, moist skin, and many glands. 3. The body has no scales or body hair. 4. The tongue is bifurcated, inverted, and can extend outward. 5. Mating and fertilization occur in water. 6. Larvae breathe through gills, while adults breathe through skin, oral lining and lungs.

Amphibia is a type of vertebrate that can live both in water and on land, and is an important transitional group in the evolution from aquatic animals to terrestrial animals. Their life cycle usually includes two stages: aquatic larvae and terrestrial adults, so they are called "amphibians".

• Scientific name: Amphibia

• Main features:

1. Moist skin: The skin is exposed and moist, which helps breathing.

2. Amphibious: The larvae are mostly aquatic and breathe with gills; the adults are mostly terrestrial and breathe with lungs and skin.

3. Oviparous: Most of them lay eggs in water, and the larvae develop in water.

4. Poikilotherms: Body temperature changes with the environment.

5. Inner ear and vocal organs: Amphibians can usually hear sounds, especially frogs can make sounds.

• Ecological role:

• Pest control: Prey on small invertebrates such as mosquitoes.

• Important link in the food chain: Both predator and prey.

• Evolutionary history:

• Originated in the Devonian period about 350 million years ago, it is the earliest vertebrate adapted to terrestrial life.

• Amphibians are the ancestors of reptiles and are also important links between aquatic and terrestrial environments.

Classification table of amphibians

Amphibians are mainly divided into three orders: Anura (frogs), Caudata (salamanders), and Apoda (caecilians).

Main characteristics and adaptations of amphibians

1. Body structure

• Moist skin: The skin helps with water balance and gas exchange.

• Differentiated limbs: Most amphibians have four limbs, which are suitable for swimming and jumping.

• Evolution of the tail: Anura adults have no tail, Caudata adults retain their tail, and Apoda adults are worm-like.

2. Breathing method

• Gill breathing: Larvae absorb oxygen through gills.

• Lung and skin breathing: Adults mainly rely on lungs and skin for breathing.

3. Reproduction and development

• Egg laying in water: eggs are mostly colloid and absorb water easily.

• Metamorphosis: larvae undergo metamorphosis (such as tadpoles turning into frogs).

4. Environmental adaptation

Most amphibians live in humid environments, but a few species are adapted to dry areas or completely aquatic environments.

Evolutionary History of Amphibians

1. Early Amphibians:

• Amphibians originated in the Devonian period, and the earliest fossil records show that they evolved from lobe-finned fish.

• With strong flippers and lungs, these early amphibians entered land life for the first time.

2. Development and Diversification:

• During the Carboniferous and Permian periods, amphibians rapidly diversified and occupied a variety of ecological niches.

• The emergence of reptiles gradually replaced the dominance of amphibians.

3. Modern amphibians:

• Existing amphibians are descendants of ancient amphibian groups, including Anura, Caudata and Apoda.

Ecological Roles of Amphibians

1. Pest Control:

• Prey on insects and small invertebrates, controlling pest populations.

2. Key Link in the Food Chain:

• Provide food for birds, mammals and snakes.

3. Ecological Health Indicators:

• Highly sensitive to habitat changes and environmental pollution, it is an important indicator species of ecosystem health.

Amphibians are one of the oldest and most important vertebrates on Earth. Whether it is beautiful frogs, rare giant salamanders, or mysterious caecilians, they all show the diversity of life.