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Read this to better understand how fish move!

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Simple Facts about the 5 Classes of Vertebrates

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Simple Facts about the 5 Classes of Vertebrates

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The Difference between Endotherms and Ectotherms

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The Difference between Endotherms and Ectotherms

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This video won't help you describe each class of vertebrate in detail, but it will help you understand cold blooded and warm blooded vertebrates.

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Rob & Jonny Show Episode 2: Endotherms & Ectotherms

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Rob and Jonny are back with another mildly educational and highly humorous episode - Ectotherms vs. Endotherms! Stay tuned for new episodes.

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Class Reptilia is the group of animals known as the reptiles. These are a diverse group of animals that are "cold-blooded" and have (or had) scales. They are vertebrates, which puts them in the same phylum as humans, dogs, cats, fish and many other animals. There are over 6,000 species of reptiles. They are also found in the sea, and referred to as marine reptiles.

The Class Reptilia, or reptiles, traditionally included a diverse group of animals: turtles, snakes, lizards and crocodiles, alligators, and caimans.

Many scientists believe that birds also belong in this class.

Characteristics of Reptiles

Animals in the Class Reptilia:

Are ectotherms (commonly called "cold-blooded"). These animals need to warm themselves up using external heat (e.g., the sun).

Mostly bear their young in eggs, which are protected by an amniotic membrane (so reptiles are referred to as "amniotes").

Have scales, or did have at some point in their evolutionary history.

Breathe using lungs rather than gills. Thus, reptiles in the ocean may be able to hold their breath to go underwater, but eventually need to go to the surface to breathe.

Have a three- or four-chambered heart.

Classifying Reptiles and Marine Reptiles

Marine reptiles are divided into several orders:

1. Testudines: Turtles. Sea turtles are an example of turtles that live in the marine environment.

2. Squamata: Snakes. Marine examples are sea snakes.

1. Sauria: Lizards. An example is the marine iguana. In some classification systems. lizards are included in the Order Squamata.

2. Crocodylia: C rocodiles. A marine example is the saltwater crocodile.

The above list is from the World Register of Marine Species (WoRMS).

Habitat and Distribution

Reptiles live in a wide range of habitats.

Although they can thrive in harsh habitats like the desert, they are not found in cooler areas like Antarctica, because they need to rely on external heat to keep warm.

Sea Turtles

Sea turtles are found in oceans worldwide. They nest on subtropical and tropical beaches. The leatherback turtle is the species that can go in cold waters, such as off Canada. These amazing reptiles have adaptations that allow them to live in colder water than other turtles, including the ability to shunt blood away from their flippers to keep their core body temperature warmer. However, if sea turtles are in cold waters too long (such as when juveniles don't migrate south quickly enough in the winter), they might become cold-stunned.

Sea Snakes

Sea snakes include two groups: laticaudid sea snakes, which spend some time on land, and hydrophiid snakes, which live wholly at sea. Sea snakes are all venomous, but they rarely bite humans. They all live in the Pacific Ocean (Indo-Pacific and eastern tropical Pacific regions).

Marine Iguanas

The marine iguana, which lives in the Galapagos Islands, is the only marine lizard. These animals live on the shore and feed by diving in the water to eat algae.

Crocodiles

In the U.S., the American crocodile often enters saltwater.

These animals are found from southern Florida to northern South America and can be found on islands, where they swim or are pushed by hurricane activity. One crocodile, nicknamed Cletus, swam out to the Dry Tortugas (70 miles off Key West) in 2003. American crocodiles tend to be more timid than American alligators and the saltwater crocodiles, which are found in the Indo-Australian region from Asia to Australia.

Most reptiles give birth by laying eggs. Some snakes and lizards can give birth to live young. In the world of marine reptiles, sea turtles, iguanas and crocodiles lay eggs while most sea snakes give birth to live young, who are born underwater and must swim immediately to the surface to breathe.

Marine Reptiles

Reptiles that can live at least part of their lives in the marine environment include sea turtles, crocodiles and some lizards.

References and Further Information

Galapagos Conservancy. Iguanas and Lizards. Accessed October 30, 2015.

IUCN. 2010. Sea Snakes Fact Sheet. Accessed October 30, 2015.

Morrissey, J.F. and J.L. Sumich. 2012. Introduction to the Biology of Marine Life. Jones & Bartlett Learning. 466pp.

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Class Reptilia is the group of animals known as the reptiles. These are a diverse group of animals that are "cold-blooded" and have (or had) scales. They are vertebrates, which puts them in the same phylum as humans, dogs, cats, fish and many other animals. There are over 6,000 species of reptiles.

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Here are the main reptile characteristics, ranging from their vertebrate anatomies to their habit of laying hard-shelled eggs.

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PART ONE OF THE VIDEO

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Cuckoo Hijacks Warbler Nest | Natural World | BBC Earth

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PART TWO OF THE VIDEO

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Big Brother Eviction Cuckoo Style | Natural World | BBC Earth

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Strauss, Bob. "10 Facts About Birds." ThoughtCo, Oct. 12, 2017, thoughtco.com/facts-about-birds-4069408. Strauss, Bob. (2017, October 12). 10 Facts About Birds. Retrieved from https://www.thoughtco.com/facts-about-birds-4069408 Strauss, Bob. "10 Facts About Birds." ThoughtCo. https://www.thoughtco.com/facts-about-birds-4069408 (accessed October 15, 2017).

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Do You Know These 10 Essential Bird Facts?

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Strauss, Bob. "10 Facts About Birds." ThoughtCo, Oct. 12, 2017, thoughtco.com/facts-about-birds-4069408. Strauss, Bob. (2017, October 12). 10 Facts About Birds. Retrieved from https://www.thoughtco.com/facts-about-birds-4069408 Strauss, Bob. "10 Facts About Birds." ThoughtCo. https://www.thoughtco.com/facts-about-birds-4069408 (accessed October 15, 2017).

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Watch the video to learn about the world's largest fish.

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Watch the incredible moment when Sir David Attenborough and BBC filmmakers filmed a huge whale shark opening its mouth to feed.

Even better, you can watch a further 1000 more memorable moments, for free, anytime, on your smartphone or tablet, via Attenborough's Story of Life app, which is now available to download via Google Play, or Apple's app store.
Find out more at http://www.bbc.com/earth/storyoflife. The Story of Life has been produced in collaboration with Sir David Attenborough, BBC Earth and ideas and innovation company AKQA.

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Watch the incredible moment when Sir David Attenborough and BBC filmmakers filmed a huge whale shark opening its mouth to feed. Even better, you can watch a further 1000 more memorable moments, for free, anytime, on your smartphone or tablet, via Attenborough's Story of Life app, which is now available to download via Google Play, or Apple's app store.

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Amphibians are a class of animal that represents a crucial evolutionary step between water-dwelling fish and land-dwelling mammals and reptiles. They are among the most fascinating (and rapidly dwindling) animals on earth.

Unlike most animals, amphibians such as toads, frogs, newts, and salamanders finish up much of their final development as an organism after they are born, changing from marine-based to land-based lifestyles in the first few days of life. What else makes this group of creatures so fascinating?

They Are Descended From Lobe-Finned Fish

At some time during the Devonian period, about 400 million years ago, a brave lobe-finned fish ventured onto dry land-not a one-time event, as is often depicted in cartoons, but numerous individuals on numerous occasions, only one of which went on to produce descendants that are still alive today.​

With their four limbs and five-toed feet, these ancestral tetrapods set the template for later vertebrate evolution, and various populations went on over the ensuing few million years to spawn the first primitive amphibians like Eucritta and Crassigyrinus.

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Amphibians are a class of animal that represents a crucial evolutionary step between water-dwelling fish and land-dwelling mammals and reptiles. They are among the most fascinating (and rapidly dwindling) animals on earth.

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What Makes Mammals different than other Vertebrates?

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What Makes Mammals different than other Vertebrates?

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Mammals are amazingly diverse animals. They live in nearly every available habitat on Earth-including deep seas, tropical rainforests, and deserts-and they range in size from one-ounce shrews to 200-ton whales. What exactly is it that makes a mammal a mammal, and not a reptile, a bird or a fish? There are eight main mammal characteristics, ranging from having hair to four-chambered hearts, that set mammals apart from all other vertebrates.

As with some of the other traits on this list, mammals aren't the only vertebrates to possess a diaphragm, a muscle in the chest that expands and contracts the lungs. However, the diaphragms of mammals are arguably more advanced than those of birds, and definitely more advanced than those of reptiles. What this means is that mammals can breathe and utilize oxygen more efficiently than other vertebrate orders, which, combined with their warm-blooded metabolisms allows for a wider range of activity and the fuller exploitation of available ecosystems.

Four-Chambered Hearts

Like all vertebrates, mammals have muscular hearts that contract repeatedly to pump blood, which in turn, delivers oxygen and nutrients throughout the body while removing waste products such as carbon dioxide. However, only mammals and birds possess four-chambered hearts, which are more efficient than the two-chambered hearts of fish or the three-chambered hearts of amphibians and reptiles.

A four-chambered heart separates oxygenated blood coming from the lungs from the partially deoxygenated blood that heading back to the lungs to be re-oxygenated. This ensures that mammalian tissues only receive oxygen-rich blood, allowing for more sustained physical activity with fewer intervals of rest.

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These Eight Traits Separate Mammals From Other Vertebrates

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Mammals are amazingly diverse animals. They live in nearly every available habitat on Earth-including deep seas, tropical rainforests, and deserts-and they range in size from one-ounce shrews to 200-ton whales. What exactly is it that makes a mammal a mammal, and not a reptile, a bird or a fish?

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Do You Know These 10 Essential Fish Facts?

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The world's oceans, lakes, and rivers harbor tens of thousands of fish species. Here are 10 essential facts about fish that everyone should know.