Explain how the complexity and diversity of living things has changed over time. Use evidence from the text, boxes of fossils and rock strata diagram and scientific reasoning to support your response. this is the reading that goes with it
The Precambrian: In Maryland the rocks found from the Precambrian period are metamorphic and igneous. No fossils have been positively identified from these rocks thus far.

The Paleozoic: The Paleozoic era in Maryland was a time of changing sea levels. The sedimentary rocks contain abundant marine fossils, indicating the presence of warm, shallow seas. A period of uplift and mountain building occurs later in the area and was followed by a time of erosion and subsidence (the gradual sinking of land). During times of subsidence, the seas returned and flooded the lands. These cycles of uplift and flooding led to alternating deposition of non-marine and marine sediments. Brachiopods and bryozoans were abundant in the sea, while horsetail rushes and scale trees thrived in the warm, humid, Late Paleozoic climate on land.

The Mesozoic: Plate movement pulled apart the supercontinent of Pangea. The area that is now Maryland filled with sediment creating a coastal region where fossils of plants and dinosaur footprints can be found. Late in the Mesozoic (Cretaceous), seas advanced and retreated across the coastal plain numerous times, providing habitats that ranged from land organisms to deep sea organisms. Fossils of plants and dinosaurs are common in the terrestrial deposits, while marine fossils include mollusks and brachiopods.

The Cenozoic: During the Early Cenozoic in Maryland, sea level fluctuated, leaving marine deposits in coastal areas. The climate cooled later in the Cenozoic, vast ice sheets advanced and retreated across North America, and sea levels dropped as the glaciers expanded. The cooler temperatures encouraged the growth of new types of plants, while mastodons and other cold-adapted animals roamed the state. During warmer climate periods (interglacial), sea levels again rose to cover the eastern part of the state. Fossils of marine clams, oysters, and snails are abundant in the rocks formed during these interglacial episodes.