How are turtles related to tortoises?

Short answer: the tortoises are a subgroup of turtles that have specialized for life on land.

Long answer:

Typical tortoises belong to one family, the Testudinidae, distributed all over the world, but there are tortoise-like species that belong to other families.

Consequently, their similar appearance is the result of (1) shared ancestry (e.g. the members of the same family) and/or (2) similar adaptations for similar habits and habitats.

For instance, the box turtles also have a high-domed shell and are sometimes called tortoises, but they belong to a different family (Emydidae).

For a terrestrial turtle, having a high-domed shell and pillar-like legs is better in terms of resistance to gravity and locomotion on land. Also, the shells of terrestrial tortoises usually have relatively thin bony scutes and thicker corny plates, so they're not too heavy but very resistent. So these characteristics have evolved in different lineages of turtles and may result in superficial similarity.

To answer the last question: yes, all turtles, including tortoises, are related and evolved from a common ancestor. They share characteristics of their skeleton and soft anatomy that are not present in other vertebrates; among these, two of the most remarkable features are (a) their pectoral girdle is located within the ribcage - which in turn, is fused to the carapace, and (b) they have an enlarged otic capsule (the part of the brain that encases the inner ear) and consequently their jaw-closing muscles are "curved" around this capsule.

Modern turtles also lack teeth, but their oldest known common ancestor Proganochelys had them.

There's a better discussion of these characters in the link below.

Whether turtles are Anapsids or actually derived Diapsids is a matter of controversy - perhaps in the near future, new data will settle the matter.

Yes, the numerous species share a common ancestor. For the most part, the terms "turtle" and "tortoise" are used to refer to the differences in where the animals live, and their adaptations to these environments, but the terms do not indicate a strict taxonomic separation. "Turtle" is often used for both turtles and tortoises. Check out the link below.

The first turtles already existed in the era of the dinosaurs, some 300 million years ago. Turtles and tortoises are the only surviving branch of the even more ancient clade Anapsida, which includes groups such as the procolophonoids, millerettids and pareiasaurs. Most of the anapsids became extinct in the late Permian period, with the exception of the procolophonoids and the precursors of the testudines (turtles and tortoises).

Regarding evolution dinosaurs are closely related to birds and some lizards (Birds share over a hundred distinct anatomical features with theropod dinosaurs, which are now generally accepted to have been their closest ancient relatives),......turtles and tortoises did not evolve from any other dinosaur and they didn't evolve into anything else either,.....they pretty much stayed the same like sharks and crocodilians.

Turtles, tortoises and terrapins are all considered a division of reptiles called chelonians. There are differences in their adaptations, but they are all the same species. They all have scales, lay eggs, and are ectothermic. Most people use the words interchangeably, but there are differences in where they live and use their habitat.

Turtles generally live in or near water and have adapted to swim by holding their breath underwater. Sea turtles tend to have webbed feet, flippers and a streamlined body shape. They spend most of their time in the ocean with the females coming ashore to lay their eggs. There are also fresh water turtles which swim but may climb out to bask in the sun. When it gets cold, they may go into torpor, a state much like hibernation. Both are more omnivorous with their diet including plants, insects and fish.

Tortoises are mainly land-dwellers, living in more arid regions, adapted for storing their own water supply and walking on sandy ground. They are mainly herbivorous, eating cactus and plants that have lots of moisture. They have round, stumpy feet adapted for walking on land, and when it's too hot, they dig burrows and go underground. (or in the case of my sister's tortoises, under the house). Their shell is more rounded so they can pull their head and legs inside. The hissing sound they make is just them letting out air so they can fit better in their shell.

"Terrapin" refers to those animals that are somewhere between a turtle and tortoise. They tend to live in swampy areas or begin life underwater and eventually move to dry land.

Hope this was what you were looking for.

tortoises are just another species of turtles and thats all they look like old turtles too thankz bye

tortoises

Usually herbivorous land turtles having clawed elephant-like limbs; worldwide in arid areas except Australia and Antarctica

turtles

Any of various aquatic and land reptiles having a bony shell and flipper-like limbs for swimming

Turtles are reptiles whose soft body is covered by a hard shell. Most turtles can pull their legs, tail, and head into the shell for protection. Different turtles live on land, in water, or both on land and in water. Some turtles that live on land are called tortoises. A terrapin is a turtle that lives in or near freshwater or partly salty, coastal water. The name terrapin is only used for a group of North American turtles.

Turtles can be grouped into seven main types: (1) mud and musk turtles, (2) pond and marsh turtles, (3) sea turtles, (4) side-necked turtles, (5) snapping turtles, (6) soft-shelled turtles, and (7) tortoises. Like other reptiles, all turtles are cold-blooded; their body temperature about matches the temperature of their environment. They are found living in deserts, forest, grasslands, lakes, marshes, ponds, wetlands, coastal areas, and in the oceans. Turtles live in almost all geographic regions except those which are cold year-round. They cannot remain active in cold weather, so species in regions that have harsh winters must hibernate. Some desert species survive the hot, dry periods by going into a related state of limited activity called estivation. Sea turtles spend most of their life in the water. Other species live mainly on land or in fresh water or spend about an equal time on land and in water.

There are over 250 different turtle species; about 50 live in North America. Between species, turtles vary in size from the bog turtle of about 4 inches long (10 centimeters) to the huge leatherback sea turtle, which can mature to 4 to 8 feet lengths (1.2 to 2.4 meters). Many turtles spend their entire life within a short distance from where they were hatched, but most sea turtles migrate thousand of miles. Sea turtles are also fast swimmers; but on land most kinds of turtles are slow, lumbering creatures. However, some land turtles like the smooth soft-shell specie can sometimes outrun a human. Most turtles are omnivores, that is they eat both plants and animals but the exact foods consumed vary between the species. For instance, green sea turtles and tortoises feed almost entirely on plants. A few freshwater species including the map turtle and soft-shelled turtles eat mainly other small animals.

Today over 40 species of turtles including most sea turtles and many types of tortoises are endangered, and if turtle conservation and protection does not improve, certain species will become extinct. People are their greatest threat. Historically people have sought turtle eggs and meat for food. Turtle shells have been used for ornamentation. Rare exotic turtles have been shipped and trafficked as pets. Turtles are still hunted and captured today; turtle nests are plundered. People further harm turtles by eliminating their natural living areas as forests, swamps, and other areas are transformed for farms and urban growth. Further endangerment comes from continued pollution of their living areas.

All turtles, tortoises, and terrapins are reptiles. Scientists often refer to them as chelonians, because they are in the taxonomic order called Chelonia (from the Greek word for tortoise). They all have scales, lay eggs, and are ectothermic. So why the different names? Those common names usually refer to differences in where the species live and how they use their habitat. But the names are also used differently in other parts of the world. For instance, in Australia only sea turtles are called turtles–everything else is called a tortoise! But here are some generally accepted differences between the types of chelonians.

Turtle— Spends most of its life in the water. Turtles tend to have webbed feet for swimming. Sea turtles (Cheloniidae family) are especially adapted for an aquatic life, with long feet that form flippers and a streamlined body shape. They rarely leave the ocean, except when the females come ashore to lay their eggs. Other turtles live in fresh water, like ponds and lakes. They swim, but they also climb out onto banks, logs, or rocks to bask in the sun. In cold weather, they may burrow into the mud, where they go into torpor until spring brings warm weather again.

Tortoise— A land-dweller that eats low-growing shrubs, grasses, and even cactus. Tortoises do not have webbed feet. Their feet are round and stumpy for walking on land. Tortoises that live in hot, dry habitats use their strong legs to dig burrows. Then, when it’s too hot in the sun, they slip underground.