Earth Science
Interrelationships in Earth/Space Systems
5.6 The student will investigate and understand characteristics of the ocean environment. Key concepts include
a) geological characteristics;
b) physical characteristics; and
c) ecological characteristics.
a) geological characteristics;
b) physical characteristics; and
c) ecological characteristics.
Earth Patterns, Cycles, and Change
5.7 The student will investigate and understand how Earth’s surface is constantly changing. Key concepts include
a) identification of rock types;
b) the rock cycle and how transformations between rocks occur;
c) Earth history and fossil evidence;
d) the basic structure of Earth’s interior;
e) changes in Earth’s crust due to plate tectonics;
f) weathering, erosion, and deposition; and
g) human impact.
a) identification of rock types;
b) the rock cycle and how transformations between rocks occur;
c) Earth history and fossil evidence;
d) the basic structure of Earth’s interior;
e) changes in Earth’s crust due to plate tectonics;
f) weathering, erosion, and deposition; and
g) human impact.
Understanding the Standard
5.6
5.7
- Oceans cover about 70 percent of the surface of Earth
- Important features of the ocean floor near the continents are the continental shelf, the continental slope, and the continental rise. These areas are covered with thick layers of sediments (sand, mud, rocks).
- The depth of the ocean varies. Ocean trenches are very deep, and the continental shelf is relatively shallow.
- Ocean water is a complex mixture of gases (air) and dissolved solids (salts, especially sodium chloride). Marine organisms are dependent on dissolved gases for survival. The salinity of ocean water varies in some places depending on rates of evaporation and amount of runoff from nearby land.
- The basic motions of ocean water are the waves, currents, and tides.
- Ocean currents, including the Gulf Stream, are caused by wind patterns and the differences in water densities (due to salinity and temperature differences). Ocean currents affect the mixing of ocean waters. This can affect plant and animal populations. Currents also affect navigation routes.
- As the depth of ocean water increases, the temperature decreases, the pressure increases, and the amount of light decreases. These factors influence the type of life forms that are present at a given depth.
- Plankton are tiny free-floating organisms that live in water. Plankton may be animal-like or plant-like. Animal-like plankton are called zooplankton. Plant-like plankton (phytoplankton) carry out most of the photosynthesis on Earth. Therefore, they provide much of Earth’s oxygen. Phytoplankton form the base of the ocean food web. Plankton flourish in areas where nutrient-rich water upwells from the deep.
5.7
- Rocks have properties that can be observed, tested, and described. Composition, grain size and textural features, color, and the presence of fossils help with identification. Classification keys (5.1) can aid this process.
- Rocks move and change over time due to heat and pressure within Earth and due to weathering, erosion, and deposition at the surface. These and other processes constantly change rock from one type to another.
- Depending on how rocks are formed, they are classified as sedimentary (layers of sediment cemented together), igneous (melted and cooled, e.g., lava and magma), and metamorphic (changed by heat and pressure).
- Scientific evidence indicates Earth is ancient — approximately 4.6 billion years old. The age of many rocks can be determined very reliably. Fossils provide information about life and conditions of the past.
- Scientific evidence indicates that Earth is composed of four concentric layers — crust, mantle, outer core, and inner core — each with its own distinct characteristics. The outer two layers are composed primarily of rocky material. The innermost layers are composed mostly of iron and nickel. Pressure and temperature increase with depth beneath the surface.
- Earth’s thermal energy causes movement of material within Earth. Large continent-size blocks (plates) move slowly about Earth’s surface, driven by that thermal energy.
- Most earthquakes and volcanoes are located at the boundaries of the plates (faults). Plates can move together (convergent boundaries), apart (divergent boundaries), or slip past each other horizontally (transform boundaries, also called strike-slip or sliding boundaries).
- Geological features in the oceans (including trenches and mid-ocean ridges) and on the continents (mountain ranges, including the Appalachian Mountains) are caused by current and past plate movements.
- Rocks and other materials on Earth’s surface are constantly being broken down both chemically and physically. The products of weathering include clay, sand, rock fragments, and soluble substances.
- Materials can be moved by water and wind (eroded) and deposited in new locations as sediment (deposition).
- Humans have varying degrees of impact on Earth’s surface through their everyday activities. With careful planning, the impact on the land can be controlled.