Glaciations

While individual continents and their species had to adapt to new climates as they drifted, they also faced a different type of climate change. The Earth has periodically shifted between very cold ice ages across the planet, to extremely hot conditions. These changes are due to various things such as slight changes to our orbit around the sun, changes in ocean currents, and the build up of greenhouse gases such as carbon dioxide, among other internal sources. No matter the cause, these sudden, or gradual, climate changes force species to adapt and evolve.

Periods of extreme cold usually result in glaciation, which reduces the sea levels. Anything that lives in an aquatic biome would be affected by this type of climate change. Likewise, rapidly increasing temperatures melts ice caps and raises the sea levels. In fact, periods of extreme cold or extreme heat have often caused very quick mass extinctions of species that could not adapt in time throughout the Geologic Time Scale.

There have been several known ice ages in the Earth's history, with the Earth experiencing the Quaternary Ice Age during the present time. Within ice ages, there exist periods of more severe glacial conditions and more temperate referred to as glacial periods and interglacial periods, respectively. The Earth is currently in such an interglacial period of the Quaternary Ice Age, with the last glacial period of the Quaternary having ended approximately 11.700 years ago with the start of the Holocene epoch.