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Class Amphibia Shared Characteristics (4)

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Class Amphibia Shared Characteristics (4)

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Major characteristics shared between Amphibians, including external, internal, behavioral and habitat information

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Amphibians all have backbones which are considered vertebrates.  They are all cold-blooded, meaning they cannot regulate their own body temperature.  They spend parts of their lives on both water and land.  They have gills for either part or all of their lives.  Amphibians have permeable skin, meaning molecules and gases can pass through it.  Their skin is moist and scaleless, except for caecilians which have scales, which makes it thin and fragile so that it can soak up water.  Amphibians skin also has glands to create mucus.  Their eggs will lack a calcified shell, making it mostly of a jelly material.
https://study.com/academy/lesson/amphibians-traits-types-roles.html
https://animalcorner.co.uk/amphibian/

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The taxonomic Class Amphibia reproduces by or in the water and also lay their eggs by or in the water. All amphibians reproduce in the moonlight, using the lunar cycle to base their times to mate. Their eggs develop into larvae, usually underwater, and the parents can either lay them and not protect them at all, or only protect a select few of the offspring. The gestation period it about 33 days at the most. When climate is against what they prefer, which is low humidity and high temperatures, they will become inactive until the weather is favorable, which is also known as estivation.  In cold regions, some amphibians will go into hibernation in mud, trees, or caverns.  They are also known to communicate by croaks or calls as a sign of distress, mating, or territorial concerns.  Amphibians can eat a large range of foods, including earthworms or insects.  Some will find food in water, using their mouths to suck in their prey, while others find their prey on land.
http://animals.mom.me/courtship-behaviors-amphibians-10388.html
https://www.britannica.com/animal/amphibian#ref40624

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Amphibians are found in tropical climates, to go along with their moist skin to prevent dehydration.  They are exothermic, meaning they cannot regulate their core body temperature, therefore they cannot be in cold or temperate climates.  When they are adults, the mainly live near a freshwater source, not a dry area, as their skin needs to moisture. They also must live near large bodies of water for egg delivery and development of larvae.
https://www.pecva.org/our-mission/wildlife-habitat/675-the-history-a-habitat-of-amphibians

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Examples of organisms who show the wide variety of characteristics within the Class Amphibia.

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Kingdom | Animalia
Phylum | Chordata
Class | Amphibia
Order | Anura
Family | Hylidae
Genus | Agalychnis
Species | callidryas
http://tolweb.org/treehouses/?treehouse_id=4841

Location & Habitat ~
They are found in tropical lowlands, including southern Mexico, throughout Central America, and in northern South America.  They live in humid lowland rain forest areas, and are “tree dwelling” frogs (arboreal).  As tadpoles, they live in the water, and as they grow older, they move to the trees.  They survive in a leafy environment, as they are nocturnal and their belly color helps to camouflage them during the day when they sleep.  Adults live in the canopy layer of the rain forest and sometimes hide in the bromeliads.
https://www.nationalgeographic.com/animals/amphibians/r/red-eyed-tree-frog/
http://tolweb.org/treehouses/?treehouse_id=4841

Physical Characteristics ~
They have red eyes to scare their predators, giving them time to get away.  The bright red makes their predator second-guess their prey.  They have bright lime green bodies, and according to their mood, they can change it to dark green or reddish-brown.  They have white bellies and throats, with blue sides with white vertical bars.  Their feet are bright red or orange with cup-like footpads to allow them to cling to leaves in the rain forest canopy.  Males can be up to 2 inches in length and females can grow to be about 3 inches.  It can keep its limbs close to its body, helping to prevent dehydration.  Their bellies are soft and fragile, while their backs are thicker and rougher.  Red-Eyed Tree Frogs also have bilateral symmetry.
https://www.rainforest-alliance.org/species/tree-frog

Behavioral Characteristics ~
They are nocturnal (sleep during day), and their eyes will open when a predator is near to scare off with their red eyes.  Loud croaking to attract mate,  jumping from leaf to leaf to establish territory between other males, “quiver” at one another (violently shaking and croaking).  The frogs then wrestle other males, while females come down from trees.  This occurs during the rainy season (May through November), and one to two days after they reproduce, the female lays eggs in the water, about 20-40 eggs, and they reproduce almost once a year.  They tend to live alone, but their habitat keeps them close, during mating season they come closer.
http://animaldiversity.org/accounts/Agalychnis_callidryas/

https://www.mnn.com/earth-matters/animals/blogs/todays-frogs-owe-debt-ancient-asteroid

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Kingdom | Animalia
Phylum | Chordata
Class | Amphibia
Order | Urodela
Family | Salamandridae
Genus | Cynops
Species | pyrrhogaster
https://en.wikipedia.org/wiki/Fire_belly_newts

Location & Habitat ~
Found in grasslands or forests, in paddy fields, ponds, brooks, and streams which is where they breed and larvae will develop.  Found in clear water, on Japanese islands of Atsumi, Hiroshima, Kanto, Sasayama, and Touhoku.

http://www.iucnredlist.org/details/59444/0

Physical Characteristics ~
3.5-5.5 inches in length at average, rough pebbly skin, an arched back, brown or black with black or red spots on its above side, orange to red with a darker pattern on its bottom side (wavy lines, spots, blotches).  Males have a blue iridescent sheen and smoother skin during mating season.  In the wild they are poisonous, as there skin contains tetrodotoxin, a non-peptide toxin.  They have distinct parotoid glands.

https://www.caudata.org/cc/species/Cynops/C_pyrrhogaster.shtml

Behavioral Characteristics ~
Males ram into the females, block their paths, and fan their tails at them (wafting pheromones at female).  Females can lay up to 200 eggs in a breeding season.  Eggs are folded between leaves, hatch about 20 days after laid, metamorphosis occurs 3-5 months later.  Juveniles turn a yellowish reddish color.  1-3 years of age they return to the water as sexually mature adults.  Live alone and come together during mating season.

https://www.caudata.org/cc/species/Cynops/C_pyrrhogaster.shtml

https://www.thesprucepets.com/fire-bellied-newts-as-pets-1237297

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Kingdom | Animalia
Phylum | Chordata
Class | Amphibia
Order | Caudata
Family | Plethodontidae
Genus | Pseudotriton
Species | ruber
http://www.iucnredlist.org/details/59404/0

Location & Habitat ~
They are found in the Eastern Area of the US, living in moist habitats including meadows, mountains, and forests.  Adults usually live burrows near streams or under rocks or logs.  In the summer they prefer to be on land and can be found very far away from water.  They like to remain in deep springs where temperatures remain constant throughout fall and winter.  They migrate to more terrestrial regions in the spring and summer to be under logs or leaves.

https://www.ducksters.com/animals/red_salamader.php

Physical Characteristics ~
They lack lungs (plethodontid) and breath through gills, when they are fully developed they can be between 11-18 cm long, their dorsum can be bright orange-red or red with scattered black spots.  Their chin area is black.  They have short tails and have about 16 grooves around their body.  Females are slightly bigger than males.  When they are older, they can be more purplish-brown and their spots grow larger.  They are ectothermic.

http://animaldiversity.org/accounts/Pseudotriton_ruber/

Behavioral Characteristics ~
Lays eggs in autumn, 2-3 months for incubation before hatched, larval period 18-33 months, do not reach adulthood for about 3.5 years.  They perform metamorphosis between April and November.  During breeding season they can be polygynandrous (multiple mates), male rubs chin against female to attract.  They are oviparous (sexually mature 43 to 48 months after hatching), breed year round except cold months (December to February).  The female holds fertilized eggs until autumn, lays around 29-130 eggs which are found on undersides of rocks in or near water.  Incubated for about 2-3 months and hatch in mid-December to mid-February.  Once hatched they are independent.

http://animaldiversity.org/accounts/Pseudotriton_ruber/

http://georgiainfo.galileo.usg.edu/topics/history/article/the-leo-frank-case/red-salamander-pseudotriton-ruber

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Kingdom | Animalia
Phylum | Chordata
Class | Amphibia
Order | 
Family |
Genus | 
Species | 

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1. Red-Eyed Tree Frog (Agalychnis callidryas)
2. Red Salamander (Pseudotriton ruber)
3. Japanese Fire Belly Newt (Cynops pyrrhogaster)
4. Strawberry Poison Dart Frog (Oophaga pumilio)
5. Barred Tiger Salamander (Ambystoma mavortium)
6. Long-Headed Caecilian (Ichthyophis longicephalus)

7. Red Caecilian (Uraeotyphlus oxyurus)
8. European Hyla (Hyla arborea)
9. Spring Peeper (Pseudacris crucifer)
10. American Toad (Anaxyrus americanus).

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Taxonomy classification is a great way to show the relatedness of organisms, as it shows their relationship throughout broad and specific characteristics.  It provides grouping from the kingdom of an organism, all the way through to its species.  When comparing species, such as the three exemplary examples provided, you can look to see if these species where once the same and diversified due to factors of evolution, or they were two different species who interbred to become more similar.

The three exemplary species are all very similar, as you can see based on their taxonomy.  They all belong to the Animalia Kingdom, the Chordata Phylum, and the Amphibia Class.  They all share characteristics of living in and out of water throughout their lives.  They all live in temperate climates and near a freshwater source.

There are also difference among these species. They all belong to different Orders, Families, Genus, and Species. Specific examples of differences includes skin, although they all require moisture, their skin has different textures and chemical makeups because their climate and temperature in their habitat directly impacts how they function.

Overall, when looking at taxonomy of different species to compare them, you can see their relatedness as you look down through the KPCOFGS classifications, becoming more specific as you go lower.

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In Amphibian Embryology, they have a specific similarity.  In the development of Amphibians, they have radial cleavage. This is different from other types of cleave, such as spiral cleave, where the deuterostomes bend around the embryo, whereas in radial, they line up symmetrically with the embryo.
http://www.animalsmix.com/animals/biradial-cleavage-animals-bdc012.html

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http://www.onlinebiologynotes.com/development-of-frog-embryonic-development/

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Frogs and salamanders also have many similarities with how they develop as embryos.  After about 12 hours, the cleavage furrows and the cells begin to split to allow it to grow.  For the frog, a tail bud begins to develop after 3.5 days, while the salamander develops one after 11 days.  The salamander has a visible heartbeat after 14 days, while the frog does after 5 days.  This is also the same with gill development.  Both the frog and salamander develop the same, yet the time it takes is different.  This shows how they all develop very similar, yet later on in the development they receive individual characteristics.  But these characteristics provide similarities with how they live in water and on land.

https://embryology.med.unsw.edu.au/embryology/index.php/Frog_Development https://www.sciencedirect.com/science/article/pii/S0925477315000179

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https://www.sciencedirect.com/science/article/pii/S0925477315000179

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When evaluating fossils, scientists are able to make conclusions based on the changes in  amphibians throughout the many years.  When looking at the 6 fossils provided, you can see how certain fossils are related to those of the exemplary species. Such as fossil #2, which has a very similar bone structure to the Red-Eyed Tree Frog. Also, Fossil #1 is very similar to that of the Red Salamander, as it has a long body with shorter arms.

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Apateon pedestris Tetrapod
Lower Permian
http://www.fossilmuseum.net/Fossil-Pictures/Amphibian-Fossils.htm

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Fossil Frog Callobatrachus sanyanensis
Lower Cretaceous
http://www.fossilmuseum.net/Fossil-Pictures/Amphibian-Fossils.htm

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Eryops megacephalus
Lower Permian  http://www.fossilmuseum.net/Fossil-Pictures/Amphibian-Fossils.htm

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Thaumastosaurus gezei

34 million years ago (Cenozoic Era)  http://phenomena.nationalgeographic.com/2013/09/27/fossil-frog-still-looks-gooey-after-over-34-million-years/

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Beiyanerpeton jianpingensis
157 million years ago (Jurassic Period)  http://igorpurlantov.blogspot.com/2012/03/

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Fedexia striegeli
Pennsylvanian Period (300 million years ago) https://www.sciencedaily.com/releases/2010/03/100315144812.htm

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This term or evidence provides examples of similarities in the structures and functions of organisms within the Amphibia Class.  For the Amphibians, they all have permeable skin, as they were born in the water and need water throughout their lives (living in or near it).  Amphibians also have a very common homologous structure of 1 bone, 2 bones, and digits within their limbs. This structure is used for the amphibian to both swim and walk, making them very different from other organisms.

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Has vertebrae, and the homologous limb bone structure in all amphibians.
http://anatomyhumancharts.com/dorsal-muscles-of-a-frog/dorsal-muscles-of-a-frog-dorsal-trunk-muscles-of-the-frog-frog-skeleton-google-search/

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Salamander has a vertebrae and contains the homologous bone structure.
https://animalcorner.co.uk/salamander-skeletal-anatomy/

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Between frogs and salamanders, they have different amounts of chromosomes because they have different amounts of genes to makeup the organisms. Frogs are less complex than salamanders, as their main purpose is to survive and reproduce. While salamanders must move from one area to another and eat a large variety of foods in order to compensate for the activities they perform. They also can be a large variety of sizes, having their chromosome number be larger and more diversified than that of a frog.

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Canebrake Tree Frogs
Even as they are 4 different types of frogs, they have different numbers of chromosomes.
https://bmcgenet.biomedcentral.com/articles/10.1186/1471-2156-13-28

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https://www.semanticscholar.org/paper/Cytogenetic-Studies-of-Hynobiidae-(Urodela)-XVI.-C-Ikebe-Kuro-o/5ce8b543c91fa34016c9a1f4994066a317061871/figure/1

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Has lungs and nostrils, also with permeable skin.
https://www.semanticscholar.org/paper/Cytogenetic-Studies-of-Hynobiidae-(Urodela)-XVI.-C-Ikebe-Kuro-o/5ce8b543c91fa34016c9a1f4994066a317061871/figure/1

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Has lungs and nostrils to breath air on land, also with permeable skin for moisture.
http://www.animalspot.net/salamander

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Amphibians first derived from fish 395 million years ago.  This fish was named sarcopterygians, which has a bony base to their fins, which is where tetrapods got their limbs from.  Tetrapods are four-footed animals with a vertebrate.  These tetrapods then began to evolve, first obtaining lungs which are homologous to the gas bladder in fish to allow buoyancy.  They they had choanaes, which were internal nostrils.  Tetrapods would have one external nostril on each side, connected to  the choanae which acts as a way for the organism to get air through their nose and use lung ventilation, while also smelling out of water.  They then evolved to receive a quiridium-like limb which was stylopodium (one bone, humerus, or femur), the zeugopodium (two bones, radius, tibia,or fibula) and the autopodium (fingers, hands, toes and feet).  The autopodium is a newly evolved characteristic strictly from tetrapods. The first amphibians to leave water were ichthyostegalians (Devonian Period) and would mainly use their muscular tail to move. Also, similar to current amphibians, they had their eggs laid in water, breathed through their skin, and went through metamorphosis.  The main Order to be closely related to modern Amphibians was Order Temnospondyli. These Orders would continue to diversify as they would move from water to land throughout certain periods of their lives and change in shape and size.
https://allyouneedisbiology.wordpress.com/2015/05/07/evolution-amphibians/

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Divergent evolution is when two separate species evolve differently from a common ancestor. The common ancestor in this case would be fish. These certain bony fish had evolved into tetrapods, which is where Amphibians evolved from. These tetrapods had a vertebrae, which is what differentiated Amphibians from fish. Amphibians were then able to evolve and adapt to living on land just as well as they could in water.

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Amphibians had lived in mainly water for millions of years as fish, but as they began to evolve, they emigrated to a more suitable habitat on land. This land was near a source of water and in a temperate climate, which helped with how they needed to survive. Amphibians had also immigrated to more warm climates, as their skin needed moisture from the air and water with the new adaptations they obtained. When immigrating, they had to adapt to their new environment, which then led to instances of natural selection where individuals with more suitable characteristics, like moist skin, would more commonly pass down their traits.

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Microevolution had occurred when amphibians evolved into reptiles. Tetrapods were the first vertebrate species that could walk, using all four limbs, which had been the beginning of amphibians when they began to migrate from water to land habitats. However, several species of these evolved amphibians had emigrated to extremely dry and hot areas which had then led to them obtaining scales, which were a naturally selected characteristic. The scale adaptation had then eventually led to other characteristics which would allow the organism to no longer be classified as an amphibian, but now as a reptile because they would mainly live on land and not in the water.  Other adaptations of reptiles was shelled eggs and the ability to breath through their nostrils with their mouths closed.  All amphibians, staying as amphibians or evolving into reptiles, had to adjust their skin type as a way to live and survive within their new environment primarily on land.  Amphibians had evolved to reptiles around 325,000,000 - 250,000,000 years ago.
http://www.michellecaldwell.com/linkfiles/scaredcricket/articles/other/evolution.html

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Descent with Modification & Directional Natural Selection (Conclusion) 

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Descent with Modification & Directional Natural Selection (Conclusion) 

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Amphibians (400 million years ago) had begun to evolve and diversify as they left living primarily in a freshwater source. Scientists do not know the exact reasoning behind this evolution, but they mainly believe it was due to a lack of food in the water food or because the water source they were in dried up as a result of environmental changes. These amphibians are said to have evolved from modern day lungfish, which have a certain bone structure which evolved into limbs. Over a long period of time, these fish grew a pair of lungs as an additional way of receiving air, a pair of nostrils, and bones and tendons in their fins to make them able to reproduce and survive on land areas. Theoretically, if these amphibians were to have remained in the water and not used their adaptations to live on land, the population would have outweighed the amount of resources available in the water, leading to an environmental disaster. With large groups living in the same habitat and periods of starvation and death among the different species, it would lead to negative environmental effects. Although the more suited and adapted would survive more efficiently and be able to overcome their specified area, having only one type of species would create a small gene pool which can lead to extinction, as they wouldn't be very diversified.  These new adaptations were amphibian's process of descent with modification as there grew to be many species of lungfish, each with their own unique traits to later evolve into amphibians. Several of these species had died off very fast as they modified negatively with inconvenient mutations, and went extinct. However, the "fit" species had survived and reproduced more effectively, producing more offspring to ensure the survival of that specific species. The species that had survived were proof that natural selection had taken place and allowed for certain species to evolve into the modern day amphibians. This type of natural selection had been directional selection. Directional selection is where a population's genetic variance will shift to a new phenotype when an environmental change occurs. With amphibians, when they evolved from fish and tetrapods, they experienced environmental changes which resulted in them needing to survive on both land and water. This need would then be the result on natural selection being applied to organisms who had characteristics such as lungs and limbs, to live on land.

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Phylogenetic Tree (Evidence to #2 above)

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Phylogenetic Tree (Evidence to #2 above)

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This Phylogenetic Tree shows how reptiles evolved from Amphibians, and Amphibians evolved from lung fish.
http://www.chegg.com/homework-help/questions-and-answers/statements-phylogenetic-tree-true-select-apply-organism-c-common-ancestor-lampreys-lungfis-q20276279