Amphibian Activities from Hands-On Education
Amphibians are a cold-blooded species of animal representing a crucial evolutionary step between water-dwelling fish and land-dwelling mammals and reptiles. They are among the most fascinating and critically endangered animals on earth.
Unlike most animal groups, cold blooded amphibians such as toads, frogs, newts, and salamanders change from marine-based to land-based early in their life cycle. Scientists divide living amphibians into three main animal groups. Frogs and toads; salamanders and newts; and the strange, worm-like, limbless vertebrates called caecilians. As of 2023 there are about 6,000 species of frogs and toads around the world with only one-tenth as many newts and salamanders and even fewer caecilians.
Existing in an evolutionary position halfway between fish and fully terrestrial vertebrates, many amphibians release eggs in water. Their young briefly pursue a fully marine lifestyle, complete with external gills. These larvae then undergo a metamorphosis where they lose their tails, shed their gills, grow sturdy hind legs, and develop primitive lungs. Many amphibians then spend their remaining life on or around dry land.
Another curious amphibian characteristic: unlike reptiles and mammals, amphibians don't have the ability to chew their food. They possess only a few primitive "vomerine teeth". These allow them to hold onto wriggling prey but not much else. Thankfully, many amphibians possess long sticky tongues, which they flick out at lightning speeds to snag their meals.
Teaching Animal Science with Hands-On Education
All of our activities are based off the National Curriculum in England. This presents a programme of study for primary and secondary school aged children that ensures pupils build solid foundations in their subject of choice. At Hands-on Education we closely follow the national curriculum for science throughout our class amphibia activities, worksheets and numerous videos. By following practical scientific methods and taking into account the skills and areas of scientific knowledge needed for young learners, our programmes focus on designing suitable, challenging and engaging activities.
There are five different types of commonly recognized animals currently in existence. These are amphibians, reptiles, fish, birds and mammals. While all of these animals possess their own characteristics and traits there are many elements that are not easily distinguishable.
Hands-On Education have created over one hundred animal related activities for key stage one and lower key stage two children. One of our goals it to use everyday materials commonly found in homes and classrooms. Our aim is to support primary school teachers as well as home educating parents and families. Children will develop their animal knowledge and skills through the use of simple scientific language, presenting data, and using proper vocabulary to develop methods processes and skills.
Our many animal activities cover the entire English national curriculum for science within key stage one and lower key stage two. All of our amphibian activities within the national curriculum for science focus on encouraging children to participate in simple practical lessons involving investigation and experimentation. In using the science and art curriculum as a primary guide, Hands-On Education are able to introduce scientific vocabulary and ideas without the need for expensive scientific equipment. School aged pupils are provided with opportunities to develop their knowledge of amphibians though engaging activities, worksheets and down to earth videos.
In this comprehensive article on amphibian characteristics, we will look at the ways in which our exclusive hands-on activities support children in developing their animal knowledge and conceptual understanding throughout a range of key stage one and lower key stage two topics.
Hands-On Animal Activities
If you are simply looking for our animal subject activities then here is a quick list to our current class amphibia and other animal’s activities:
An In-depth Look At Animal Groups
There are five different types of commonly recognized animals currently in existence. These are amphibians, reptiles, fish, birds and mammals. While all of these animals possess their own characteristics and traits there are many elements that are not easily distinguishable. For example, most species have hind legs, however birds and fish do not. Not all reptiles have hind legs, however all amphibians do. So, let’s start by looking at what the different types of animals not including humans, there are and what differentiates them all from one another.
What are amphibians?
Adult amphibians release eggs into water and are cold blooded. When the eggs hatch their young have gills for breathing, later in life they develop primitive lungs which enable them to live on dry land. Overall, many amphibians are quite happy living on land but must be near water or in very moist conditions due to their thin skin which they can breathe through.
Most amphibians lay eggs in water and these released eggs are often translucent and soft. Other animals, such as reptiles lay very solid eggs on dry land. Amphibians are born with gills, which means they can breathe under water. Quick fact: amphibians are cold blooded vertebrates.
As amphibians get older, they develop primitive lungs, allowing them to breathe air. Most amphibians also have four legs, however there are a few species without any legs at all. They also generally have smooth skin. Amphibians are cold blooded; this means they adapt to the temperature around them. For example, when it’s cold outside, they are cold and tend to hibernate. Amphibians generally prefer a warm climate and can often be seen basking in the sun much like their reptilian cousins.
What are reptiles?
The most famous reptiles ever were the dinosaurs. This does not mean that reptiles are extinct, in fact there are many different types of thriving reptiles, both with and without legs. There are more than 10,700 extant species of reptiles recorded to date, making reptiles one of the most diverse types of vertebrates in the world. Compared to other species, only birds and fish have more types of species than reptiles. There have been approximately 3,750 species of lizards recorded while scientists have recorded a mere 5,000 mammals!
Certain species of reptile lay eggs but not all. Reptiles are as varied as their neighbouring species in that some give birth to live young, some lay eggs, some are slimy, some are smooth and others are scaly.
Much like the over 7,000 recorded types of amphibians, reptiles are cold blooded vertebrate, meaning they get hot if it’s hot outside and cold if it’s cold. Certain reptiles, like crocodiles, spend most of their time in water to cool down. However, like all reptiles they have fully developed lungs and breathe air, therefore they cannot spend their life underwater like fish.
What Are Fish?
The easiest way to spot a fish is that it lives full time in and primarily under the water. Fish are unable to breathe fresh air and have gills instead of lungs. These gills allow them to breathe underwater. Fish skin contains numerous mucous glands which aid in maintaining the water balance and offer them protection from bacteria. Fish come in lots of different sizes from a giant shark to a tiny anchovy. Not all animals that live only in water however are fish. Animals such as whales and dolphins are actually mammals that give birth to live young as opposed to hatching eggs.
Unlike reptiles, fish don’t have legs. Most fish lay lots of release eggs. These soft eggs are often in clusters and translucent. Fish have adapted many different techniques to keep their young from being eaten by prey such as hatching them among coral. While humans do not know much about the ocean what we do know is it’s a dangerous environment full of many wonderful creatures that we can’t even begin to understand.
What are mammals?
Every human is also a certain species of mammal. In this article we are looking at animals not including humans so we will not dive further into this subject. We know mammals have lungs and breathe air, they cannot survive underwater for very long. Whales are able to stay underwater for roughly half an hour, that is holding their breathe a lot longer than you or I will ever be able to do. Like most reptiles, fish and class amphibia, mammals come in lots of different varieties. Some common features include that mammals give birth to live babies and do not hatch eggs.
Did you know that all mammals have either no legs or four legs? Wait, if that’s true, then how can humans be considered a mammal? Humans and some mammals have special front legs called arms and feet called hands. All adult stage mammals are hairy, even dolphins and whales. All mammals are also warm blooded, which means their body temperature does not change with the external weather conditions.
What are birds?
Do humans including mammals share any common traits with birds? Humans including many other mammals are unable to fly, no matter how many attempts are made. Humans are hairy but do not have feathers. Humans including mammals give birth to live young, whereby birds always lay eggs. Therefore, is there anything we share with a common pigeon or the great American bald eagle?
Birds need to breathe fresh air, so while penguins spend a lot of time in the water, or seagulls will dive into the freezing oceans to get food, they must come up for air or will die. Another common feature is that birds are warm blooded, meaning they can keep warm and adapt to nearly all-weather conditions. While a reptile would struggle to survive in the arctic circle a penguin and other birds will get cold but can survive and even thrive. Lastly, birds are an ancient species that scientists commonly agree evolved from that ever so famous reptile group: dinosaurs.
Semi-Aquatic Amphibians of South America
A few species and their amphibian characteristics
Thanks to the temperate regions of the Amazon rainforest covering vast amounts of South America there are many species of modern amphibians living in the region. We will look at a few species right now that thrive in this wet and humid environment.
- Argentine Horned Frog – during its adult stage this frog is a striking-looking amphibian, with brightly-coloured skin and horn-like projections above its eyes and a huge mouth. This South American amphibian is a voracious predator, eating almost anything that it can fit into that enormous mouth; including mammals and other frogs. There is no messing with this cold-blooded killer frog species.
- Cane Toad - frogs and toads are not to be mistaken for each other. The video below will help you to distinguish between the two species. As the world’s largest ‘true’ toad, the cane toads’ body reaches lengths of up to 24 cm. or 9.4 in., and that’s not including its limbs! The cane toad is native to Central and South America where it is considered a common species.
- Cayenne Caecilian - this third type of amphibian isn’t as widely known as toads, frogs, newts or salamanders. Caecilians are mostly blind worm-like animals living underground. A few South American caecilians species however live in water. The Cayenne caecilian is an aquatic caecilian found in the Amazon rainforest. This eel-like predator emerges from a burrow at night to feed on small fish, insect larvae and crustaceans.
- Nauta Salamander – Salamanders are a far more common species in North and Central America, with comparatively few being found outside the Northern Hemisphere. However, the Nauta salamander likes being different. They lack lungs and are able to ‘breathe’ via their skin and tissue in their mouths. This salamander considers the lowland rainforests of Central and South America home.
- Smoky Jungle Frog / South American Bullfrog - is a large frog found in Bolivia, Brazil, Colombia, Ecuador, French Guiana, and Peru. Their newly hatched larvae are aquatic and free swimming. The tadpoles in this frog species are large, reaching lengths of up to 83 mm or 3.27 in. Adult stage females are larger than males typically, and the males can be distinguished due to a spine found on each of their thumbs and two further spines on their chests. This unusual feature is used as a defence mechanism against predators. The smoky jungle frog is also able to secrete a large amount of toxic slime if feeling under threat.
Frogs and Toads of South and Central America
This animal group can be found almost anywhere on the planet
Now hopefully you’ve just finished watching our video on the life cycle of frogs and toads. But if not, then here’s loads of information on one of the largest amphibian groups out there: frogs and toads. Let’s learn all about those long hind limbs and start with the first question:
Are frogs and toads the same species?
Yes and no! All toads are frogs, but not all frogs are toads. Frog species include toads as all toads are terrestrial frogs classified as amphibians. Scientifically speaking, there is no distinction between toads and frogs. To put it simply, toads are terrestrial frogs and are classified among a number frog species. Our next natural question then becomes:
What is the difference between a frog and a toad?
Looking at these two largely common modern amphibians the most obvious place to start is their skin. A toad skin is bumpy and always looks dry. A frog’s smooth skin by contrast is always moist looking and it’s this glandular moist skin that most species are identified by. Earlier I mentioned long hind limbs in a general way, however, frog legs tend to be very long while toads tend to hop or crawl on their short back legs.
Class amphibia have evolved to include multiple ways of breathing. The larvae are aquatic and free-swimming—frogs and toads at this stage are called tadpoles. Young amphibious frogs, as tadpoles, use gills to breathe, and never leave the water they were hatched into. At a certain size, the young develop limbs and primitive lungs. Some also lose their tails. Eventually, they hop or climb out of the water as adults, and spend the rest of their lives on land. This process is known as metamorphosis. As the tadpole grows, its gills disappear and lungs grow, although some living amphibians retain gills for life. These primitive lungs are not as evolved as mammalian lungs. Adult amphibians completely lack or have a reduced diaphragm, this makes amphibians breath difficult.
Breathing for aquatic adults is a diffusion across the skin. To aid this diffusion, amphibian skin must remain moist and contains vascular tissues to make this gaseous exchange possible. With their unique lungs these cold-blooded animals must keep their skin moist or die.
Are frog species habitats currently under threat?
Far too many species of cold-blooded vertebrates such as frogs and toads are on critically endangered lists. While there certainly are extinct groups of frogs, most frog species are surviving. A decline in this wonderful glandular moist skinned amphibian is however an early warning sign of a decline of their aquatic habitat. If your local pond or lake suddenly seems void of frog spawn or tadpoles in spring this could be cause for concern.
Nearly 900 species of frogs, are listed as “Endangered” by IUCN’s Red List. Over 500 species of frogs are listed as “Critically Endangered.” Overall, the northern hemisphere and southern hemisphere are facing an amphibian extinction crisis. According to IUCN in 2021, 41% of the world’s amphibians are threatened with extinction.
Are frogs only in the Northern Hemisphere?
Frogs and toads can be found in a variety of habitats on every continent except Antarctica. As of today, there are over 5,000 species of known frogs and toads, and scientists continue to discover new species. Frog species come in a variety of sizes and colours and are cold-blooded vertebrates, meaning they have backbones, and don’t have scales. Most frogs and toads live both on land and in water. A few species of other amphibians include salamanders, newts, and caecilian.
The smallest amphibian
The world's smallest frog, and the smallest amphibian, is Paedophryne amauensis of Papua New Guinea, which is on average between 7 mm (0.27 in.) and 7.7 mm (0.3 in.) in length when fully grown. When discovered in 2012, it stood as the smallest amphibian of the world’s 60,000 vertebrates. Vertebrates are creatures with a backbone while invertebrate such as snakes do not have a backbone.
Salamander Species of Asia and Central America
Central and South America are home to more than 500 amphibian species.
Let’s have a quick look at the salamanders of Central America. The largest of this group is called Plethodontidae, they inhabit large parts of Central and South America. There are two main types of salamander species: true salamanders and newts. Newts commonly have rough skin, whereas a true salamander has smooth skin that is wet and shiny. Many species of salamander resemble lizards to the untrained eye. In fact, salamanders are a group of tailed amphibians closely related to frogs and toads.
It has recently been discovered that there are up to three different types of one very special salamander that lives very far away from its American cousins, the Chinese giant salamander. This amazing amphibian can grow to be over five feet long! Of the 6,500 known amphibian species living salamanders and newts total more than 400. Thankfully this wonderful animal is one of the few species currently not under threat by human land development. There are of course extinct groups of salamanders, newts and caecilians, but overall, their population is healthy.
Salamanders represent some of the most fantastic and diverse modern amphibian life forms on Earth. While they resemble lizards, salamanders are amphibians and lizards are reptiles. Other differentiations include that salamanders do not have scales and their feet lack claws; they also do not have webbed toes. Typical of most amphibians, salamanders have very glandular moist skin that has the ability to absorb oxygen in water.
Salamanders also have very thin skin and some salamander species don’t have lungs at all, they are able to breathe exclusively through their skin, a process known as cutaneous respiration. While all salamanders have front and hind legs a few species of aquatic salamanders have very short hind legs that are barely visible.
The Largest Amphibian
There are at least three species living of this amazing amphibian the: Chinese giant salamander. New research analysis of museum specimens shows that the species of Chinese giant salamanders are not one, but rather that there are at least three different varieties. It is likely that the largest of the three has been given the name of: Andrias sligoi, or the South China giant salamander, according to a study published September 17 in the journal Ecology and Evolution.
“It’s amazing in this day and age that it took until now to work out what the world’s largest amphibian is,” says study lead author Samuel Turvey, a conservation scientist with the Zoological Society of London.
The news comes at an urgent time for the animals. Andrias davidianus is already considered critically endangered, and the creatures are perilously close to going extinct in the wild, Turvey says. The two new species are almost certainly in even worse shape, he adds. Turvey believes that properly identifying the creatures at this stage could lead to better conservation efforts and help to highlight their plight.
A plethodontidae salamander is an amphibian, and all amphibians are cold blooded vertebrates. This salamander species is unable to use their body to control its body temperature. Instead, like all adult amphibians including salamanders they rely on environmental factors, like the sun, to keep their bodies at the right temperature.
Primitive Cryptobranchoidea Salamanders
The Cryptobranchoidea are a sub-order of salamanders found in Asia, European Russia, and the United States. They are known as primitive salamanders, in contrast to Salamandroidea, the advanced salamanders. Primitive salamanders have two living subdivisions, Cryptobranchidae, which includes the largest amphibian, the Chinese giant salamander and Hynobiidae, commonly known as Asian salamanders. Many species of the fully aquatic salamander family Cryptobranchidae are known as giant salamanders due to their large size which can be up to five meters long.
Advanced Salamandroidea Salamanders
In the above paragraph I mentioned primitive and advanced salamanders. Both of these salamander species are in existence today. The primary difference of this thin skinned, cold blooded vertebrate amphibian is in mating rituals and their bone structure. These are simply the two largest species with the previously mentioned Plethodontidae salamander being the biggest group of all the species.
Over time, salamanders have adapted to thrive in wet, cool habitats. While there are some species that can thrive in warmer climates, salamanders usually use water to keep their bodies cool. Salamanders can also seek shade by hiding under rocks.
Salamanders and newts are most common in the cool cooler mountain woodlands regions of the Northern Hemisphere, such as North, Central and South America. Other species can be found in tropical Asia. Aquatic salamanders inhabit freshwater ponds, cool mountain streams, marshes, swamps, rivers, and underground caves. Land-dwelling species inhabit damp forests and may be found under moss, rocks, piles of leaves, fallen logs, in trees, or buried beneath the soil.
Undergoing Metamorphosis and the Life Cycle of a Salamander
After birth, almost all species of salamanders undergo metamorphosis and a larval stage of development before reaching adulthood. Undergoing metamorphosis for a salamander is similar to a frog’s transformation as a tadpole. It may last from a few days to many years. Typical larval stage features include external gills, teeth in both jaws, and no eyelids. Some aquatic salamanders such as mud puppies and sirens, retain some of their larval stage features throughout their life cycle.
Scientists refer to this condition as paedomorphosis, or neoteny whereby they undergo metamorphosis unlike other species. One example is the lungless woodland salamander who does not undergo metamorphosis at all and is born as miniature replicas of the adults. Because salamanders and newts include many diverse species, they do not all fit neatly into one particular life cycle and therefore undergoing metamorphosis can vary greatly. Experts tend to classify salamander life cycles as either completely aquatic adults, terrestrial adults, or amphibious semi-aquatic.
Regrowth of limbs in Salamanders
Salamanders are the only living amphibian tetrapod’s able to regenerate limbs, as well as other body parts in a process known as controlled cell death or programmed cell death. In extraordinary fashion Salamanders can lose a tail or any limb to a predator without causing it any serious damage. This is partly thanks to a process known as controlled cell death. Within a week the limb or tail will begin to regrow and often within a fortnight will be fully reformed.
A Little Look at Fish
Are fish amphibians?
Fish are not an amphibian species, as most amphibians spend a portion of their life underwater and a portion of their lives on land. Some of the most popular amphibians include toads, frogs, and salamanders. These species often have to keep their thin skin wet, which is why they periodically return to the water.
Other amphibians are also able to breathe through their skin, known as cutaneous respiration, and don’t have lungs at all. Only amphibians are known to lay their eggs in water to keep them moist until they hatch. While fish obviously do this as well, fish do not have a metamorphosis that turns them into terrestrial adults. Amphibians typically start their lives with gills, very similar to fish, then develop primitive lungs and spend their adult lives on or near land.
Are fish reptiles?
Fish are not reptiles. Common reptiles include snakes, turtles, alligators, and lizards. All adult reptiles have fully developed lungs that they use to live and breathe on land. Unlike adult amphibians and fish, reptiles do not need to keep their skin wet. Reptiles also produce solid amniote eggs, which are rich in calcium carbonate and do not dry out, therefore reptiles have a big advantage over amphibians and fish in that they can lay their eggs in relative safety on land.
So, what are fish?
Firstly, there are seven classes of living species that are vertebrates, fish make up three of these. Invertebrates do not have a backbone, such as snails.
Vertebrate animals are distinguished from the rest of the animal kingdom in that they have a specific skeletal system, reproductive system, and general environmental adaptation. Fish make up three classes of vertebrate animals.
- Osteichthyes – Of all the species of fish this is the largest species. Osteichthyes is composed of more than 20,000 bony fish making it exceed all other kinds of vertebrates combined! Bony fish have stiff skeletons, unlike cartilaginous fish, and very acute eyesight. One amazing fish fact is that by simply moving its operculum, a fish can breathe without swimming. There are a few lobe-finned fish species which have ultra-muscular fins supported by their bones. Sadly, all of these species are on extinct bar one. The lobe-finned fish: coelacanth. Many scientists believe these are the ancestors of tetrapod’s, otherwise known as four-legged land animals.
- Agnatha Fish - Agnatha is a class consisting of jawless fish and are mostly known to include lampreys and hagfish. This ancient fish species has cyclotomic toothed mouths that they use to bore into the sides of their prey so they can suck out their blood. Agnatha fish are very similar to sharks in that they are primarily made out of cartilage.
- Chondrichthyes - Chondrichthyes are made up of sharks, skates, rays, and other cartilaginous fish. This class of fish dates back more than 450 million years. It is composed of some of the most feared predators such as sharks and some of the most harmless species of mollusc eaters like clams.
Are fish the godfather of all animals?
Scientists believe that of all the species our fish ancestors were established before all other species. Per the evolutionary theory, it is believed that many different species including reptiles, birds, mammals, and amphibians stemmed from fish. Around 400 million years ago, the lobe-finned fish started evolving into aquatic animals that primarily lived on land, but relied on water for reproduction. The few lobe-finned fish still in existence today are the coelacanth and the lung fish.
It is estimated that over 300 million years ago evolution effected a few species and cold-blooded reptiles eventually began to appear. Unlike the amphibius tetrapod’s that came before them, reptiles no longer had to have water available for reproduction and were much better suited for life on land.
Fish versus the rest!
As you now know, fish are considered animals, though they don't belong to the families of reptiles and amphibians. Fish live in water and spend their entire lives there. Dolphins, whales, starfish, and jellyfish spend their lives in the ocean as well, yet they don’t belong to the fish species. Starfish and jellyfish are invertebrates, meaning they do not have backbones. Dolphins and whales, as we discussed earlier, are mammals. Fish are very unique creatures with characteristics that set them apart from other aquatic amphibians and terrestrial adult animals.
What Are Terrestrial Species
Many modern amphibians have biphasic life cycles with aquatic larvae that turn into terrestrial adults. Fossil evidence has accumulated shedding light on the life histories of early amphibians, the origin of metamorphosis, and the transition to a fully terrestrial existence. The majority of early amphibians were aquatic or amphibious and underwent only gradual changes. Terrestrial species are all the animal species that live on land. Therefore, we can exclude all sea creatures and some birds. Most birds and insects, such as terrestrial caecilians, are also considered terrestrial animals even though some species fly.
Caecilians are worm-like amphibians that occur worldwide in the tropics, except for Madagascar and Oceania; only 189 species are known. Most terrestrial caecilians are fossorial, living in moist soils usually adjacent to streams, lakes, and swamps; a few species are aquatic.
These land-dwelling animals have a backbone and spend the majority of their lives on land. While terrestrial vertebrates form a minor proportion of all invasive species, their impacts are often disproportionately high. Terrestrial vertebrates primarily include reptiles, birds, and mammals.
The future of Amphibians
With their small size, permeable skins and dependence on easily accessible bodies of water, amphibians are more vulnerable than most other animals to endangerment and extinction. Amphibians body temperature, breeding season, and overall life cycle can make it difficult to accurately calculate their future. However, it is believed that half of all the world's amphibian species are directly threatened by humans’ insensitive impact upon the Earth. Through air pollution, loss of natural habitat, invasive species, and the thinning of the ozone layer humans are slowly killing off many animal species with as of yet known consequences to our way of life.
Perhaps the greatest threat to frogs, salamanders, newts and caecilians is not actually us humans. Instead, it is in the form of the chytrid fungus, which some scientists believe is linked to global warming and has been decimating amphibian species worldwide.
Not all is lost just yet. Recent studies have shown that not all species of amphibian are susceptible to infection, some species appear to hold a level of immunity against the chytrid fungus. While most species will still carry this disease it does not kill them. Some class amphibia do not even develop disease symptoms. As a result, select non-native species such as the African clawed toads, North American bullfrogs and alpine newts have been named as potentially harmful carriers.
In the UK most native Natterjack toad populations which have been tested have shown positive results, yet seem unaffected. The effects on other UK species are less well understood. Although, in mainland Europe, chytrid fungus has been linked to mass mortalities of species such as the European midwife toad, in the UK no mass mortalities have been linked with chytrid to date.
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