Amphibians

General Information

• Amphibians are tetrapods
• Tetrapods: (amphibians, reptiles), have 4 limbs (or ancestors had 4 limbs)
• Grouping of tetrapods vast, since they consist of many different animals such as birds, frogs, turtles, lions, etc.
• Since the amphibians descended from tetrapod ancestors, they themselves are tetrapods

Where are amphibians found?

• Niche: environment and its factors that best suit a specific group of organisms

• Case of amphibians: they adapted to be able to survive in places like forests, streams, rivers, lakes, ponds, swamps, etc.
• Characteristic of amphibians:

• Have thin skin (lose lots of water in their body easily, which is why they live near humid/moist areas w/ lots of water to replenish fluids)
• Other amphibians such as specific toads/frogs are able to live in the desert by burrowing underground, because of this it shows that amphibian regions are versatile, meaning they can be found all over the world

Key adaptations of amphibians

• have/are:

• Thin-skinned: skin of amphibians permeable, meaning that it allows liquids and gases to pass thru easily, causing oxygen to pass thru easily, makes it easier for them to breathe
• Colorful skin: amphibians that have bright, colorful skin to indicate that they are toxic to keep harmful predators away
• Ectotherms: trait they share w invertebrates, fish, and reptiles (indicates why they all have common ancestry)

• Them being ectotherms, they rely on surrounding temperature to determine their body temperature, they cannot make internal head on their own
• Causes amphibians to seek sunlight if they are too cold or to burrow underground if it is too hot on the surface

• Special skin glands: mucous glands have the role of producing useful proteins and transport water, oxygen, and CO2 inside/outside

Body systems of amphibians

• Have digestive, excretory, and reproductive systems
• Common ground w these systems is that they share a cloaca, which is a body cavity
• Waste is produced from both the digestive/excretory system/gametes from the reproductive system, enter the cloaca
• Cloaca has opened as well that allows the gametes/wastes to be released from the body
• Circulatory system:

• Three chambered hearts w/ lungs that allow them to breathe
• Skin absorbs oxygen to let them breathe more

Key Orders/family of amphibians

• Some kinds of amphibians are frogs, toads, salamanders, newts, and caecilians
• Species make up the three types of amphibia which are Anura (tailless), urodele (tailed), and apoda (legless)
• Amphibians extremely important to ecosystems (specifical crops) because their main source of food is insects 
• Since they eat insects, they prevent insects from harming crops, which helps humans have a consistent food source, making them umbrella or keystone  species

Phylum of Amphibians

• Amphibian phylum belong to chordates
• Amphibians have bilateral symmetry
• Eats food through the mouth rather than absorption (digestive system)
• Segmented muscle bands and brain
• Notochord that helps maintain structure in the body
• These factors classify them as members of phylum chordates