The graphics on this page were developed for the Iowa's Nature Series, a collaborative project to produce educational resources on Iowa's natural world. You can learn more about the series and download the original publications featuring these graphics at this series' website. Each graphic or commissioned photograph or map developed for the series is available for high-resolution download on this page for educational applications. Attribution to the Iowa's Nature Series and the original author is encouraged in all non-commercial educational uses of the graphics. In some instances noted below, special attribution to the original producers or data sources is required as indicated by copyrights.
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Landforms and Geology | Soils | Prairies | Forests | Aquatic Environments | Vertebrates | Invertebrates | Plants | State Symbols | Influential Voices | Supplemental figures
Landforms and Geology
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A cross-section and a stratigraphic column illustrating some key terms and concepts in geology including bedrock, outcrop, sand, silt, and till. Illustration by Travis James. |
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Timeline dating back 600 million years showing the Paleozoic Era, Mesozoic Era, and Cenozoic Era and their associated time periods. Timeline by Travis James. |
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Timeline dating back 4 billion years showing the Precambrian time period and the Paleozoic, Mesozoic, and Cenozoic Eras. Timeline by Travis James. |
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A cross-section through the upper crust of Iowa extending from southwest to northeast, showing the rock types and ages as if slicing Iowa vertically, where rock formations are like layers of a cake with the oldest layer on the bottom. This cross-section shows rocks tilting towards the west, indicating some of the oldest rocks in Iowa are exposed in the east. Illustration by Travis James. |
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Bedrock geology map showing the age of the bedrock found nearest to the surface across Iowa. The circular reference centered near the Calhoun and Pocahontas County line in the northwest is the Manson Impact structure, where a meteorite crashed into Iowa near the end of the Cretaceous Period. |
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Map of the major landform regions of Iowa: Alluvial Plains, Loess Hills, Northwest Iowa Plains, Des Moines Lobe, Southern Iowa Drift Plain, Iowan Erosion Surface, and the Paleozoic Plateau. |
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Map of the key mines in Iowa producing crushed stone, gypsum, and sand and gravel. Also shown are the areas of historical coal mining, now abandoned or re-purposed. |
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Illustration of a trilobite fossil. Trilobites are ancient seafloor creatures somewhat similar to today's horseshoe crabs. These fossils can be found in the Paleozoic rocks across Iowa. Illustration by Travis James. |
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Illustration of a crinoid showing column or stem and columnal piece. Complete crinoids are rarely found in Iowa. More frequently, the individual columnals or column segments are seen. Illustration by Travis James. |
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Common landscape elements in the Paleozoic Plateau landform region including steep bedrock bluffs overlain with less, upland sinkholes, and caves in the bedrock. One unusual feature in parts of the Paleozoic Plateau is an algific slope, where talus blocks a cave entrance. Illustration by Travis James. |
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Typical stratigraphy and landscape features of the Southern Iowa Drift Plain on the left side of the creek compared to the Iowan Erosion Surface on the right side. Till overlies bedrock in both regions. Loess covers most of the landscape in the Southern Iowa Drift Plain but is limited to thin veneer or paha ridges in the Iowan Erosion Surface. Illustration by Travis James. |
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Schematic illustration of different types of surface and groundwater resources commonly used in Iowa. The blue represents typical water levels in wells drilled into the aquifer in each stratum. Illustration by Travis James. |
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Paleogeographic map showing the position of Iowa and the early North American continent just south of the equator near the end of the Precambrian. The valley extending across the state is the Midcontinent Rift. Map produced by Ron Blakey, Global Paleogeography and Tectonics in Deep Time © 2016 Colorado Plateau Geosystems Inc. |
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Paleogeographic map showing the position of Iowa and the North American continent in the low latitudes of the southern hemisphere during the Cambrian Period. Iowa was mostly covered by a shallow sea. Map produced by Ron Blakey, Global Paleogeography and Tectonics in Deep Time © 2016 Colorado Plateau Geosystems Inc. |
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Paleogeographic map showing the position of Iowa and the North American continent in the Southern mid-latitudes during the Devonian Period. A shallow sea extended across the middle of Iowa. Map produced by Ron Blakey, Global Paleogeography and Tectonics in Deep Time © 2016 Colorado Plateau Geosystems Inc. |
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Paleogeographic map showing the position of Iowa and the North American continent straddling the equator during the Pennsylvanian Period, around 300 million years ago. At this time North America was part of the supercontinent Pangea. The southwestern part of Iowa was covered by a shallow sea, with rivers flowing from the northeast into estuaries across central and southern Iowa. Map produced by Ron Blakey, Global Paleogeography and Tectonics in Deep Time © 2016 Colorado Plateau Geosystems Inc. |
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Paleogeographic map showing the position of Iowa and the North American continent in the middle northern latitudes during the late Cretaceous period, around 80 million years ago. High sea levels and mountain building along the west coast led to the Western Interior Seaway extending across the continent. This was approximately the position of Iowa when the Manson Impact occurred 74 million years ago. Map produced by Ron Blakey, Global Paleogeography and Tectonics in Deep Time © 2016 Colorado Plateau Geosystems Inc. |
Soils
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Soil color, clay content, structure, and organic matter content that is expected to be found at each of the soil horizons. Illustration by Madeline Schill. |
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Soil texture triangle showing the types of soils for varying percentages of sand, silt, and clay. |
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Particle sizes of sand, silt, and clay, compared to the lead of a mechanical pencil. Illustration by Irah Dhaseleer. |
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Graphic representations of the five soil-forming factors: parent material, topography, climate, biota, and time. Illustration by Madeline Schill. |
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Map showing the distribution of the two dominant soil orders in Iowa. Mollisols are the most common and are found in areas that were historically prairie. Alfisols are more abundant in the south and east where forests were more common. Data source, U.S. General Soils Map (STATSGO 2), Natural Resources Conservation Service. |
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Map of the major landform regions of Iowa: Alluvial Plains, Loess Hills, Northwest Iowa Plains, Des Moines Lobe, Southern Iowa Drift Plain, Iowan Erosion Surface, and the Paleozoic Plateau. |
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Soil food web showing examples of producers, primary consumers, secondary consumers, and tertiary consumers that are part of the soil ecosystem. Illustration by Madeline Schill. |
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Graph showing how changes in land use have affected soil organic matter content over time. Illustration by Madeline Schill. |
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Pie chart showing the critical services that Iowa's soils provide including habitat for organisms, provisioning of food, fiber, and fuel, nutrient cycling, water infiltration and storage, foundation for human infrastructure, and storage of carbon. Illustration by Alison Peters. |
Prairies
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Map of the historic extent of prairie types showing shortgrass prairie in the western Great Plains, transitioning to mixed-grass prairie, and tallgrass prairie in the eastern Great Plains. Adapted from U.S. EPA Ecoregions. |
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Map of the historic landcover in Iowa circa 1830. Source data from General Land Office surveys summarized and distributed by the Iowa Geographic Map Server. |
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Map of the modern landcover in Iowa. Source data from 2016 National Land Cover Dataset. |
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Prairie plant gradient showing examples of species found in dry, mesic, and wet soil conditions. Illustration by Irah Dhaseleer. |
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Prairie food web showing examples of producers, primary consumers, secondary consumers, tertiary consumers, and detritivores that are part of the prairie ecosystem. Illustration by Madeline Schill. |
Forests
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Map of the historic landcover in Iowa circa 1830. Source data from General Land Office surveys summarized and distributed by the Iowa Geographic Map Server. |
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Map of the modern landcover in Iowa. Source data from 2016 National Land Cover Dataset. |
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Forest food web showing examples of producers, primary consumers, secondary consumers, tertiary consumers, and detritivores that are part of the forest ecosystem. Illustration by Madeline Schill. |
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Landscape illustration showing common places trees are found in Iowa including windbreaks, woodlots, riparian areas along rivers, and urban areas. Illustration by Travis James. |
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Landscape illustration showing five ways forests contribute to healthy waterways. Roots reduce erosion by holding soil in place. Tree material increases habitat and slows water flow. Trees slow water during floods, which helps deposit sediment. Trees soak water into the soil, reducing the speed and intensity of flooding. Forests along rivers help filter pollutants before they reach the water. Illustration by Travis James. |
Aquatic environments
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Map of Iowa's major rivers and lakes and Iowa's major landform regions. |
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Landscape illustration showing the diversity of aquatic ecosystems that can be found in Iowa including a lake, headwaters, pothole wetland, riverine wetland, farmed wetland, fen, oxbow wetland, and river. Illustration by Natasha Orton. |
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Water droplet teeming with life, featuring some of the many organisms that can be found in a single droplet including tardigrades, flagellates, filamentous green algae, flatworms, hydra, roundworms, and paramecium. Illustration by Irah Dhaseleer. |
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Aquatic plant gradient showing examples of emergent, floating-leaved, and submersed plants. Illustration by Irah Dhaseleer. |
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Aquatic food web showing examples of producers, primary consumers, secondary consumers, tertiary consumers, and detritivores that are part of the aquatic ecosystem. Illustration by Madeline Schill. |
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Comparison of a landscape with beavers and without showing why beavers are considered ecosystem engineers by illustrating that their activities increase plant and wildlife diversity, increase floodplain connectivity, and result in a higher water table. Illustration by Alison Peters. |
Vertebrates
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Vertebrate taxonomic tree showing the phylogenetic relationships among reptiles, birds, mammals, amphibians, ray-finned fish, and lamprey. Features examples from each group including a milk snake, common yellowthroat, Virginia opossum, northern leopard frog, Iowa darter, and American brook lamprey. Illustration by Madeline Schill. |
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Anatomical illustration of a western fox snake showing the Jacobson's organ in relation to the brain, nerves, roof of mouth, and tongue. Illustration by Alison Peters. |
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Life phases of a chestnut lamprey showing eggs, larval metamorphosis, and adult. Illustration by Madeline Schill. |
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Life phases of a fathead minnow showing eggs, sac-fry, advanced larva, juvenile, and adult. Illustration by Madeline Schill. |
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Life phases of a tri-colored bat showing mother nursing a baby, juvenile, and adult. Illustration by Madeline Schill. |
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Life phases of a smooth green snake showing eggs, juvenile, first shed, and adult. Illustration by Madeline Schill. |
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Life phases of a bald eagle showing eggs in a nest, nestling, juvenile, and adult. Illustration by Madeline Schill. |
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Life phases of a tiger salamander showing eggs, larva with gill buds, larva with forelimbs, larva with forelimbs and hindlimbs, and adult. Illustration by Madeline Schill. |
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Life phases of a northern leopard frog showing eggs, tadpole, tadpole with hindlimbs, tadpole with forelimbs and hindlimbs, and adult. Illustration by Madeline Schill. |
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Landscape illustration showing 26 vertebrates and the many places they can be found in Iowa including a city, wetland, prairie, agricultural field, farmstead, forest, and stream. Illustration by Natasha Orton. |
Invertebrates
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Invertebrate taxonomic tree showing the phylogenetic relationships among protozoa, arthropods, nematodes, annelids, mollusks, and flatworms. Features invertebrate examples including a crayfish, common eastern bumble bee, American giant millipede, zebra jumping spider, soil nematodes, earthworm, land snail, planarian, and amoeba. Illustration by Madeline Schill. |
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Worker ant with labels for the antennae, head, thorax, and abdomen. Illustration by Madeline Schill. |
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Zebra jumping spider with labels for cephalothorax, abdomen, and eight legs. Illustration by Madeline Schill. |
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Sowbug with labels for two pairs of antennae, cephalothorax, and abdomen. Illustration by Madeline Schill. |
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Millipede with labels showing 20 or more body segments and two pairs of legs per segment. Illustration by Madeline Schill. |
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House centipede with labels showing flattened, long body and one pair of legs per segment. Illustration by Madeline Schill. |
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Earthworm with labels showing a segmented, wormlike, soft body that is characteristic of annelids. Illustration by Madeline Schill. |
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Leech with labels showing a segmented, wormlike, soft body that is characteristic of annelids. Illustration by Madeline Schill. |
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Land snail with labels showing soft, unsegmented body and muscular foot. Illustration by Madeline Schill. |
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Soil illustration with soil nematode popout, demonstrating that these organisms are very small. Illustration by Madeline Schill. |
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Springtail life cycle showing no metamorphosis or ametabolous life cycle. Ametabolous insects hatch as miniature versions of the adult and grow with little or no change except in size. Illustration by Madeline Schill. |
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Two-striped grasshopper life cycle showing the three stages of simple metamorphosis: egg, nymph, and adult. Illustration by Madeline Schill. |
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Stag beetle life cycle showing the four stages of complete metamorphosis: egg, larva, pupa, and adult. Illustration by Madeline Schill. |
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Freshwater mussel life cycle showing males releasing sperm, females releasing larvae, larvae on the gills of a fish, and juveniles releasing from the fish to mature in the substrate. Illustration by Madeline Schill. |
Plants
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Plant classifications showing several ways plants can be categorized including spore-producing and seed-producing plants, vascular and non-vascular plants, and flowering and non-flowering plants. Features plant examples including liverwort, ostrich fern, white pine, and wild rose. Illustration by Madeline Schill. |
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Diagram of the parts of a flower. Reproductive parts include the female pistil, which is comprised of the stigma, style, and ovary, and the male stamen which is comprised of the filament and anther. Non-reproductive parts include petals, sepals, and the receptacle. Illustration by Travis James. |
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Illustration of the process of photosynthesis in which chloroplasts in plant cells combine carbon dioxide and water, producing glucose and oxygen. Illustration by Madeline Schill. |
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Comparison of the fibrous root system of prairie cordgrass with the taproot system of cylindrical blazing star. Illustration by Alison Peters. |
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Pouring milkweed seeds into an oil extractor at Iowa State University. Photo from Iowa State University Library Digital Collections. |
State Symbols
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Composition of the official state symbols of Iowa: the oak tree, American goldfinch, wild rose, and geode. Illustration by Travis James. |
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Map showing the Manson Impact site in northwest Iowa and two radii indicating the 130-mile distance at which the impact would have ignited anything that would burn and the 650-mile distance at which most animals would have likely been killed. |
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Pieces of the silver set commissioned for the USS Iowa, featuring Iowa's state flower the wild rose. The silver set is now housed at the State Historical Museum in Des Moines. Photo by Christopher Gannon. |
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Pieces of the silver set commissioned for the USS Iowa, featuring Iowa's state flower the wild rose. The silver set is now housed at the State Historical Museum in Des Moines. Photo by Christopher Gannon. |
Influential Voices
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George Washington Carver graduation photo taken in 1893. Photo from Iowa State University Library Digital Collections. |
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Louis H. Pammel (left) and his wife Augusta standing with Tuskegee Institute Presiedent Robert R. Moton and George Washington Carver (right). Photo from Iowa State University Library Digital Collections. |
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Ada Hayden standing in College Pasture in 1926. Photo from Iowa State University Library Digital Collections. |
Supplemental Figures
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Classifications of plants, vertebrates, and invertebrates featuring example organisms from Iowa. Illustration by Madeline Schill. |
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County map labeled with 32 locations where people can go see features of Iowa's landforms and geology. Download the Geological Places to Visit article to identify each of the numbered locations. |
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Bedrock age map labeled with 32 locations where people can go see features of Iowa's landforms and geology. A diversity of bedrock ages from different periods in Iowa's history are visible at many places throughout the state. Download the Geological Places to Visit article to identify each of the numbered locations. |
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Landform regions map labeled with 32 locations where people can go see features of Iowa's landforms and geology. The map highlights at least one place to visit on each of Iowa's major landform regions. Download the Geological Places to Visit article to identify each of the numbered locations. |
