Thanks for the interesting question!

Animals, like all organisms, are a product of evolution by natural selection. This means that each organism possesses traits called adaptations that enhance its fitness, or its ability to survive and reproduce. You bring up an important point: if the environment dramatically changes, an organism may no longer be designed to best exploit its ecosystem. On the other hand, there are situations which a species moving into a new ecosystem is massively successful, so much that it damages the ecosystem. We can go over both cases.

Often, changing the ecosystem of an organism is fatal. For a dramatic example let’s consider the earth around two billion years ago. The earth back then was a very different place. In fact, oxygen was very rare and toxic to most of the lifeforms that existed at this time. One organism, called cyanobacteria, was responsible for changing the ecosystem of almost every other species. This happened because it evolved the ability to turn sunlight and carbon dioxide into energy, a process we call photosynthesis. As a side effect, however, this process also produced lots of oxygen – leading to the mass extinction of most of the life on earth at the time. So moving an animal into a different ecosystem can mean that it is not designed to survive, which can be fatal to whole species.

Other times, however, an animal moving into a new environment is more destructive to the existing ecosystem than the ecosystem is to the newly introduced animal. Newly arrived animals which damage preexisting ecosystems are called invasive species. The transport of animals around the world by humans makes invasive species a major threat to the environment of native plants and animals. For example, the brown trout, which is native to England, was introduced to rivers in California, resulting in the loss of many native fishes. Invasive species from other ecosystems can severely alter and reduce the biodiversity of local ecosystems. They survive too well and hurt the native species. Thanks for the great question!

Animals can survive if they're moved to a different ecosystem that isn't too too different. Obviously, animals would all die in an ecosystem without any oxygen. Luckily, there's no such ecosystem on Earth. Animals will survive better if the ecosystem changes gradually, without a sudden big change.

Luckily, ecosystems usually change gradually, unless there's a big storm or something that kills off some of the kinds of living things. If there's a big storm that kills off lots of corals in a coral reef, for example, the corals will gradually grow back. But now we're worried that the ecosystem for a lot of corals has been changing too much. For example, parts of the ocean have more acid, and that seems to be hurting the corals in those parts of the ocean.

When animals are moved to a different ecosystem, they are called an introduced species. Usually when an animal is introduced to a new ecosystem, it has no predators in that new ecosystem. This allows the animal to grow its population because no predator is consuming it. Most animals that are moved to a different ecosystem are able to rapidly grow their population! For example, the lionfish is from the Pacific Ocean but was moved to the Atlantic Ocean in the 2000s. It started with a 6-8 lionfish, but has spread to nearly 1,000 fish per acre in the Caribbean. The lionfish has no natural predators in the Caribbean, so only humans remove it from the ecosystem.

Many animals would not survive if moved to a different ecosystem. Animals are specifically adapted to their environment and when moved to a different environment they could face an entirely new set of challenges for survival like a different source of food or different predators. Can you think of an example? Let’s say we moved a tree frog from the rain forest into the desert; the poor tree from would likely dry out instantly and not have any insects to eat! What if we moved a desert tortoise to the rainforest… maybe it would do alright because it’d have lots of plants to eat, but it may have trouble with the greater number of potential predators. Good question!

That depends on the animals being moved, the ecosystem that they are being moved to, and the method by which they are being moved. The answer is usually 'no' without some extra help in surviving, but in some cases they survive too well and wind up destroying the ecosystem they are moved to by exploiting it to death.