If you think you could be pregnant, watch for these early signs and symptoms 1: missed period, headaches, tender breasts, nausea, and lower backaches. Unfortunately, these symptoms are not unique to pregnancy, and you could be pregnant without experiencing any of them.n addition to a missed period, the earliest symptoms of pregnancy might include: 1  Nausea with or without vomiting. 2  Tender, swollen breasts. 3  Increased urination. 4  Fatigue.
Climate and geography. The global climate during the Devonian period was surprisingly mild, with ocean temperatures of only 80 to 85 degrees (compared to as high as 120 degrees during the preceding Ordovician and Silurian periods).
This may have contributed to the cooling climate and the extinction event at the end of the Devonian. Animals. Arthropod fossils are concurrent with the earliest plant fossils of the Silurian. Millipedes, centipedes and arachnids continued to diversify during the Devonian Period.