The flora and fauna in the Empire are an interesting mixture of Earth plants and animals and indigenous plants and animals. The portal that brought the Yamari's ancestors to Thyra was not the only portal to ever exist and the portals didn't always stay in the same place. So many Earth creatures and Earth plants were already thriving on Thyra when the ancestors put in their appearance.
Some Earth animals did not make it over, however, and below is a list of these and their surrogates, if there are any:
Chickens - Chickens did not happen to migrate into any portals. The corresponding fowl that is now raised on Thyra and other Yamari worlds was given the name "chickey" by the ancestors. It looks a bit like a chicken except it is more the size of a turkey. The chickey's eggs are twice the size of a chicken egg and quite delicious.
Bees - If bees ever came to Thyra, they did not make the transition. There is an indigenous pollenator who fulfills the same function as bees but they are not hive dwellers and do not make an edible product. There is an insect that makes a product that is as near as nevermind to honey. They are simply called "honey bugs." Honey bugs do live in hives and except for the fact that they are brown fuzzy bugs, you'd think they were bees. Honey bugs are kept by commercial honey growers and are also found in the wild.
Elephants - There are no elephants on Thyra or any other Yamari world. There are no other land animals the size of elephants. Evolution in this universe seemed to opt for more varieties of smaller herbivores rather than a few big ones.
Ocean Fish - Most Earth-type ocean fish did not come through any portals and those that did were probably eaten by the indigenous fish. It is not certain if the river fish found in Yamari were once Earth river fish or are indigenous, but they are so close to Earth-type river fish that it makes no difference and they were given the same common names. Here are some of the commerical fish that are found in Yamari oceans:
Plants: Most Earth-type plants which were carried over as seeds in animal and insect intestinal tracts thrive on Thyra and other Yamari worlds. These plants are easy to distinguish from their indigenous cousins. Earth plants are much greener than plants indigenous to Thyra and the other planets. The indigenous plants are more greeny-gray than green. Many of the indigenous plants are much the same as their Earth cousins and serve much the same purpose. There are, however, a few that do not have an Earth equivalent and deserve mention (or warning).