Final answer:
The relative dominance of foraminifera species indicates past climate conditions, being sensitive to changes such as ocean temperatures. Fossils serve as a proxy for determining the climate during different geological periods, and as the global mean temperature rises, species distributions change correspondingly.
Step-by-step explanation:
The presence and relative dominance of different species of foraminifera (‘forams’) are excellent indicators of historical climate conditions. Forams are sensitive to climate and ocean conditions, thereby their fossil record helps scientists understand past climates. The species Neogloboquadrina pachyderma, for instance, changes the coiling direction of its shell in response to water temperature, making it a useful proxy for determining historical ocean temperatures.
Additionally, fossils as a climate proxy serve as a vital tool in paleoclimate research. Fossils from different periods, such as the fossils of palm trees from the Eocene, provide evidence for the climate in historical periods based on the organisms that lived then. These data, combined with oxygen isotope records and other sources, offer a comprehensive view of Earth's climatic past.
As the global mean temperature rises, predicted by the Intergovernmental Panel on Climate Change (IPCC), species distributions are expected to shift, particularly moving towards the poles. This response to climate change affects not only terrestrial species but marine ecosystems at a much faster rate. The number of forams varies between samples due to changes in climate, as they represent the living conditions of their time.