Fauna of Europe of the Baltic Sea has led to the evolution of many slightly divergent species, such as the Baltic Sea herring, which is a smaller variant of the Atlantic herring. The most frequent benthic species are "Saduria entomon" and "Monoporeia affinis", which is originally a freshwater species. A great part of its bottom is anoxic and without animal life. The Baltic Sea and North Sea are also home to a variety of marine mammals (common seals, grey seals). Europe contains several important freshwater ecoregions, including the heavily developed rivers of Europe, the rivers of Russia, which flow into the Arctic, Baltic,
History of the forest in Central Europe oak species only three were able to return to Germany and Central Europe from their refuge areas, namely the English oak ("Quercus robur"), sessile oak ("Q. petraea") and downy oak ("Q. pubescens"). By comparison, in North America there are over 80 species of oak. Other types lost considerably in their intraspecific genetic diversity during the return migration such as the white fir ("Abies alba"). Forest flora was pushed back slowly by climatic change. The refuges of the last ice age were probably but not exclusively in southern Europe. A few species on today's Atlantic coast between England and France could