Marine Biology Honors

Chapter 2

Habitats (2.1)

The natural environment where an organism lives.

Density (2.1)

The mass of a given volume of a substance.

Core (2.1)

The innermost layer of Earth.

Mantle (2.1)

The semiliquid region between the crust and the core of Earth. The outer layer of tissue that secretes the shelf of molasses.

Crust (2.1)

The outermost layer of Earth.

Basalt (2.1)

The dark-colored rock that forms the sediment, or oceanic crust.

Granite (2.1)

The light-colored rock that forms most of the continental crust.

What are the three main layers of Earth? (2.1)

The three main layers of Earth are the core, the mantle, and the crust.

What is the main difference between oceanic crust and continental crust? (2.1)

Continental crust is light in color and Oceanic crust is younger.

What are the characteristics of each layer of Earth? (2.1)

The core is the innermost layer of the Earth, and it is mostly iron. It is made up of a solid inner core and a liquid outer core. The mantle is the layer outside Earth’s core. Most of the mantle is thought to be solid, but it’s almost at a melting temperature. The crust is the outermost layer, and it is extremely thin.

Continental Drift (2.2)

The movement of continental masses on the surface of Earth.

Plate Tectonics (2.2)

The process in the movement of large plates on Earth’s crust.

Mid-Ocean Ridge (2.2)

The continuous chain of volcanic submarine moutains that extends around Earth.

Faults (2.2)

A crack in Earth’s crust is usually formed when pieces of crust move past each other.

Trenches (2.2)

A narrow, deep depression in the sea floor.

Sediment (2.2)

Loose material like sand and mud that settles on the bottom.

Magnetic Anomalies (2.2)

Magnetic bands in the seafloor that run parallel to the mid-ocean ridge.

Rifts (2.2)

A crack in Earth’s crust formed as pieces of the crust separate.

Seafloor Spreading (2.2)

The process by which new seafloor is formed as it moves away from spreading centers in mid-ocean ridges.

Tectonic Plates (2.2)

Regions of Earth’s lithosphere that move together over the asthenosphere. There are approximately 20 total plates.

Subduction (2.2)

The downward movement of a plate into the mantle that occurs in trenches, which are also known as subduction zones.

Shear Boundary (2.2)

The boundary between two plates that move past each other on Earth’s surface. Creates earthquakes

Lithogenous Sediment (2.2)

Sediment that is derived from the weathering of rocks.

Weathering (2.2)

The physical and chemical breakdown of rocks.

Biogenous Sediment (2.2)

Sediment is made up of the skeletons and shells of marine organisms. Also see calcerous and siliceous ooze.

Calcerous Ooze (2.2)

A type of biogenous sediment that is made of the calcium carbonate shells and skeletons of marine organisms.

Siliceous Ooze (2.2)

A type of biogenous sediment that consists mostly of the silica shells and skeletons of marine organisms. Also see diatomaceous ooze and radiolarian ooze.

Microfossils (2.2)

The microscopic shells and other remains of marine organisms make up biogenous sediments.

Carbon Dating (2.2)

A procedure used to determine the age of recent fossils.

How does seafloor spreading explain the features of mid-ocean ridges? (2.2)

Seafloor spreading explains the features of mid-ocean ridges when the sediment gets thicker and the rocks get older, moving away from the ridge, and it also explains the pattern of magnetic stripes.

How does seafloor spreading occur? (2.2)

Seafloor spreading happens at divergent plate boundaries where molten magma rises from the Earth’s mantle to fill the gap as tectonic plates pull apart.

Why are subduction zones important? (2.2)

Subduction zones are important because they drive plate tectonics, recycle Earth’s crust, create continents, and sustain the carbon cycle, which makes Earth habitable.

World Ocean (2.3)

A concept that is used to indicate that all oceans on Earth are interconnected.

Continental Margins (2.3)

The edge of a continent; the zone between a continent and the deep-sea floor. Also see active and passive continental margins.

Continental Shelf (2.3)

The shallow, gently sloping section of the continental margin that extends from the shore to the point where the slope gets steeper.

Continental Slope (2.3)

The steeper, seaward section of the continental margin.

Continental Rise (2.3)

The gently sloping area at the base of the continental slope.

Shelf Break (2.3)

The section of the continental shelf where the slope abruptly becomes steeper, usually at a depth of 120 to 200 m.

Active Margin (2.3)

A continental margin that is colliding with another plate and as a result is geologically gradient.

Passive Margin (2.3)

A continental margin that is located at the “trailing edge” of a continent and, as a result, shows little geological activity.

Abyssal Plain (2.3)

The nearly flat region of the deep-sea floor.

Abyssal Hills (2.3)

Topographic features of the deep-ocean floor.

Central Rift Valleys (2.3)

A depression in the mid-ocean ridge.

Hydrothermal Vents (2.3)

A deep-sea hot spring where heated seawater forces its way up through the crust.

Black Smokers (2.3)

A chimney-like accumulation of mineral deposits that is found at hydrothermal vents.

What are the three main regions of continental margins? (2.3)

The three main regions of continental margins are the continental shelf, continental slope, and the continental rise.

What are the main features of the deep-sea floor? (2.3)

The main features of the deep-sea floor are vast, flat abyssal plains, towering underwater mid- ocean ridges, and seamounts.

What are the characteristics of the continental shelf, the continental slope, and the continental rise? (2.3)

The continental shelf makes up 8% of the ocean’s surface area, it is the richest area of the ocean in terms of the number of species, and the shelf ends at the shelf break at a depth of 120-400 meters. The continental slope can be thought of as the “edge” of a continent. It begins at the shelf break and extends to the deep-sea floor, and it is much steeper than the continental shelf and the continental rise. The continental rise is formed by sediments that have been pushed down from the continental shelf and slope.

How do hydrothermal vents form? (2.3)

Hydrothermal vents form when cold seawater seeps through cracks in the ocean floor, is heated by magma, and then re-emerges as superheated, mineral-rich water, often at spreading centers or subduction zones.