Question Answer
cell The basic unit of structure and function in living things.
microscope An instrument that makes small objects look larger.
simple microscope A microscope that contains only one lens such as a hand lens.
compound microscope A light microscope that has more than one lens.
Transmission Electron Microscope A microscope that makes images by sending electrons through a very thinly sliced specimen.
Scanning Electron Microscope A microscope that sends a beam of electrons over the surface of a specimen.
Scanning Tunneling Microscope A microscope that measures electrons that leak from the surface of a specimen,
Cell Theory -All living things are composed of cells. -Cells are the basic units of structure in living things. -Cells are the basic units of function in living things. -All cells are produced from other cells.
Robert Hooke An English scientist who was one of the first people to observe cells through a microscope.
Anton Van Leeuwenhoek A Dutch businessman who was one of the first people to observe bacterial cells through a microscope.
Theodor Schwann A German scientist who concluded that all living things are composed of cells.
Matthias Schleiden A German scientist who concluded that all animals are composed of cells.
Rudolf Virchow A German doctor who proposed that new cells are formed only from existing cells.
magnification The ability to make things look larger than they really are.
convex lens A lens with a shape in which the center of the curved lens is thicker than the edges.
resolution The ability to clearly distinguish the individual parts of an object.
organelles Tiny cell structures that carry out specific functions within the cell.
cell wall A rigid layer of nonliving material that surrounds the cells of plants and some other organisms.
cell membrane An organelle located just inside the cell wall or, in some cases, the outside boundary that controls what substances come into and out of the cell.
nucleus A large, oval structure that directs all of the cell's activities.
nuclear membrane A structure that protects the nucleus and acts like the cell membrane.
chromatin The strands that contain genetic material and are located in the nucleus.
nucleolus The structure that is located in the nucleus and makes ribosomes.
cytoplasm The thick, gel-like fluid found between the cell membrane and the nucleus.
mitochondrion The organelle that produces most of the energy the cell needs to carry out its functions.
endoplasmic reticulum A maze of passageways that carry proteins and other materials from one side of the cell to the other.
ribosome A small, grain-like body that produces proteins.
golgi body A flattened collection of tubes and sacs that receives proteins and other newly formed materials from the endoplasmic reticulum and distributes them to other parts of the cell.
chloroplast An organelle that captures energy from sunlight and uses it to produce food for the cell.
vacuole A sac that stores food, water, and waste products.
lysosome A small, round structure that contains chemicals that break down large food particles into smaller ones.
bacterial cell A cell that is smaller than animal and plant cells, only contains a cell wall, a cell membrane, and ribosomes, and has a thick, tangled string of chromatin located in the cytoplasm.
element Any substance that cannot be broken down into simpler substances.
atom The smallest unit of an element.
compound A material formed when two or more elements combine chemically.
molecule The smallest unit of most compounds.
organic compound The name of most compounds containing carbon.
inorganic compound A compound that does not contain the element carbon.
carbohydrate An energy-rich organic compound made of the elements carbon, hydrogen, and oxygen. Some examples of this are sugars and starches.
protein A large organic molecule made of carbon, hydrogen, oxygen, nitrogen, and, in some cases, sulfur.
amino acid A molecule that can be combined with other amino acids to make a protein.
enzyme A type of protein that speeds up a chemical reaction in a living thing,
lipid An energy-rich organic compound made of carbon, hydrogen, and oxygen. Some examples of this are fats, oils, and waxes.
nucleic acid A very large organic molecule made of carbon, oxygen, hydrogen, nitrogen, and phosphorus.
deoxyribonucleic acid (DNA) The genetic material that carries information about an organism that is passed from parent to offspring.
ribonucleic acid (RNA) A type of nucleic acid that plays an important role in the production of proteins.
selectively permeable Some substances can pass through the cell membrane while others cannot.
diffusion The process by which molecules tend to move from an area of higher concentration to an area of lower concentration.
osmosis The diffusion of water molecules through a selectively permeable membrane.
passive transport The movement of materials through a cell membrane without using energy.
active transport The movement of materials through a cell membrane using energy.
transport protein method A method of active transport when transport proteins pick up molecules outside the cell and carry them in, using energy in the process.
engulfing A method of active transport when the cell membrane surrounds a particle, pinches off, and forms a vacuole from the particle.
photosynthesis The prcess by which a cell captures the energy in sunlight and uses it to make food.
pigment A colored chemical compound that absorbs light.
chlorophyll The main pigment found in the chloroplasts of plants.
stoma A small opening on the inderside of a leaf where carbon dioxide and other gases enter the plant.
autotroph An organism that makes its own food.
heterotroph An organism that cannot make its own food.
respiration The process by which cells withdraw energy from glucose.
glucose A type of sugar involved in both photosynthesis and respiration.
fermentation An energy-releasing process that does not require oxygen.
alcoholic fermentation A type of fermentation in which alcohol is one of the products.
lactic-acid fermentation A type of fermentation in which lactic-acid is one of the products.
cell cycle The regular sequence of growth and division that cells undergo.
interphase The first stage of the cell cycle during which the cell grows to its mature size, copies its DNA, and prepares to divide into two cells.
replication A process during which the cell makes a copy of the DNA in its nucleus.
mitosis The second stage of the cell cycle during which the cell's nucleus divides into two new nuclei.
prophase The first part of mitosis during which he chromatin condenses and spindle fibers form.
spindle fiber A structure that is formed during prophase and attatches to chromosomes during metaphase.
chromosome A doubled rod of condensed chromatin.
chromatid An identical rod of a chromosome.
centromere A structure that holds a chromosome together.
metaphase The second part of mitosis during which spindle fibers attatch to the centromere on each chromosome.
anaphase The third part of mitosis during which the chromosomes split into chromatids and are dragged to bothe ends of the cell by spindle fibers.
telophase The fourth part of mitosis during which the cell stretches out, the chromosomes lose their shape, and nuclear membranes form at both ends of the cell.
cytokinesis The third stage of the cell cycle during which the cytoplasm divides, distributing the organelles into each of the two new cells, and the cell splits apart to form two new cells.
cell plate A structure that forms across the middle of a plant cell during cytokinesis.
James Watson A famous scientist who figured out the structure of DNA along with Francis Crick in 1953.
Francis Crick A famous scientist who figured out the structure of DNA along with James Watson in 1953.
double helix Another name for a DNA molecule.
deoxyribose A type of sugar that makes up part of each helix on a DNA molecule.
phosphate A molecule that makes up part of each helix on a DNA molecule.
nitrogen bases Molecules that are the rungs of a DNA ladder and are made of mostly nitrogen.
adenine A nitrogen base that, most of the time, pairs with thymine.
thymine A nitrogen base that always pairs with adenine.
guanine A nitrogen base that always pairs with cytosine.
cytosine A nitrogen base that always pairs with guanine.
Gregor Mendel The famous scientist who studied genetics in circa 1850s.
trait A physical characteristic.
heredity The passing of traits from parent to offspring.
genetics The scientific study of heredity.
pistil A structure on a flower that produces female sex cells.
stamen A structure on a flower that produces pollen, which contains male sex cells.
self-pollination When plants such as garden pea plants produce pollen from the stamen and land it on the pistil of the same flower to reproduce.
cross-pollination The process Gregor Mendel used by taking one pollen from one flower and brushing it on the pistil of another flower.
purebred An organism that always produces offspring with the same form of a trait as the parent.
P generation The generation of Mendel's pea plants that consisted of the original parents.
F1 generation The generation of Mendel's pea plants that were the offspring of the P generation.
F2 generation The generation of Mendel's pea plants that were the offspring of the F1 generation
gene A factor that controls a certain trait.
allele A different form of a gene.
dominant allele An allele whose trait always shows up in the organism when the allele is present.
recessive allele An allele that is masked, or covered up, whenever the dominant allele is present.
hybrid An organism that has two different alleles for their trait.
Asa Lovejoy A man whose hometown was Boston, Massachusetts, and lost a coin toss with Francis Pettygrove.
Francis Pettygrove A man whose hometown was Portland, Maine, and won a coin toss with Asa Lovejoy.
probability The likelihood that a particular event will occur.
Punnett square A chart that shows all the possible combinations of alleles that can result from a genetic cross.
geneticists People who study genetics.
phenotype An organism's physical appearance.
genotype An organism's genetic makeup.
homozygous When an organism has two identical alleles for their trait.
heterozygous When an organism has two different alleles for their trait.
codominance When both dominant and recessive alleles are expressed in an organism's phenotype and genotype.
roan The color of a cow's hairs from a distance that is codominant.
Walter Sutton An American scientist who hypothesized that chromosomes were the key to understanding how offspring come to have traits similar to those of their parents.
sperm cell A male sex cell.
egg cell A female sex cell.
hereditory fatcor Another name for a gene.
chromosome theory of inheritance Genes are carried from parents to their offspring on chromosomes.
meiosis The process by which the number of chromosomes is reduced by half to form sex cells.
fertilization When a sperm cell fertilizes an egg cell in the reproduction system.
genetic code A code formed by the order of nitrogen bases along a gene.
protein synthesis A process during which the cell uses information from a gene on a chromosome to produce a specific protein.
uracil A molecule on RNA that replaces thymine.
messenger RNA A type of RNA that copies the coded message from the DNA in the nucleus and carries the message into the cytoplasm.
transfer RNA A type of RNA that carries amino acids and adds them to the growing protein.
mutation Any change in a gene or chromosome.
antibiotic A chemical that kills bacteria.
H.M.S. Beagle Ship that Charles Darwin was on during his exploration of new species around the world in circa 1830s. (His Majesty's Ship)
Charles Darwin English naturalist who sailed on the H.M.S. Beagle in circa 1830s and created the theory of natural selection in circa 1850s. (He also created a book called the Origin of Species.)
naturalist A person who studies the natural world.
Lieutenant Robert Fitzroy Captain of the H.M.S. Beagle during Darwin's five year voyage collecting samples of new species.
species A group of similar organisms that can mate with each other and produce fertile offspring.
Galapagos Islands A group of small islands in the Pacific Ocean off the west coast of South America.
adaptation A trait that helps an organism survive and reproduce.
evolution The gradual change in a species over time.
scientific theory A well-tested concept that explains a wide range of observations.
theory of evolution The theory that natural selection, over millions of years, leads to evolution.
artificial selection The process by which humans domesticate organisms for a certain benefit.
selective breeding Another name for artificial selection.
Alfred Russel Wallace A British biologist who, along with Darwin, proposed the explanation for how evolution occurs.
The Origin of Species A book written by Darwin explaining the relationship between evolution and natural selection.
natural selection The process by which individuals that are better adapted to their environment are more likely to survive and reproduce than other members of the same species.
overproduction When a species produces far more offspring than can possibly survive.
variation Any difference between individuals of the same species.
competition When offspring compete with each other for food, water, living space, etc.
selection When an organism is "selected" to survive by using their helpful trait.
the role of genes in evolution Only traits that are inherited, or controlled by genes, can be acted upon by natural selection.
Daphne Major One of the Galapagos Islands where a 1977 study of finches took place.
geologic isolation When some members of a species become cut off from the rest of the species by a geographic hazard or feature.
Abert's squirrel A species of squirrels that was very large about 10,000 years ago.
Kaibab squirrel A species of squirrels that got cut off from the Abert's squirrel population by the Grand Canyon using geologic isolation.
marsupial type of mammal that gives birth to very small young that continue to develop in a pouch on the mother's body.
fossil A preserved remain or trace of an organism that lived in the past. (At least 10,000 years old.)
paleontology The study of fossils.
paleontologist Someone who studies fossils.
sedimentary rock A type of rock that is formed by hardened layers over millions of years. (Only type of rock fossils can be found in.)
petrified fossils Fossils that are formed when minerals gradually change the remains by replacing them.
mold A hollow space in sediment in the shape of an organism or part of an organism.
cast A copy of the shape of the organism that made the mold and formed when the mold becomes filled in with hardened minerals.
preserved remains Remains that are preserved in substances such as tar, ice, and sap. (Also desiccation= dried out.)
desiccation A type of preserved remain that is in hot or cold places, or sometimes in caves. (Also known as dried.)
carbon film When the carbon atoms in an organism form a "shadow" in rock.
trace Evidence of an organism's presence, such as a footprint or a nest.
relative dating A technique in which scientists determine which of two fossils is older.
absolute dating A technique in which scientists can determine the actual age of fossils.
radioactive elements Unstable elements that decay, or break down, into different elements.
half-life The time it takes for half of the atoms in a sample to decay.
fossil record The millions of fossils that scientists have discovered.
extinct A way to describe a species with no alive members.
invertebrates Animals without backbones.
vertebrates Animals with backbones.
Geologic Time Scale A "calendar" of Earth's history that spans more than 4.6 billion years and consists of periods and eras.
Precambrian The oldest ERA in the Geologic Time Scale that is also known as the Age of Bacteria.
Paleozoic The second-oldest ERA in the Geologic Time Scale that means " old life" and is also known as the Age of Fish.
Mesozoic The third-oldest ERA in the Geologic Time Scale that means "middle life" and is also known as the Age of the Dinosaurs.
Cenozoic The most recent ERA in the Geologic Time Scale that means "new life" and is also known as the Age of Mammals.
Cambrian The oldest period in the Geologic Time Scale that occured during the Paleozoic ERA.
Ordovician The second-oldest period in the Geologic Time Scale that occured during the Paleozoic ERA and is when the oldest fish fossils were found.
Silurian The third-oldest period in the Geologic Time Scale that occured in the Paleozoic ERA.
Devonian The fourth-oldest period in the Geologic Time Scale that occured during the Paleozoic ERA and is when the oldest amphibian fossils were found.
Carboniferous The fifth-oldest period in the Geologic Time Scale that occured during the Paleozoic ERA and is when the oldest reptile fossils were found.
Permian The sixth-oldest period that occured during the Paleozoic ERA.
Triassic The seventh-oldest period in the Geologic Time Scale that occured during the Mesozoic ERA and is when the oldest mammal fossils were found.
Jurassic The eighth-oldest period in the Geologic Time Scale that occured during the Mesozoic ERA and is when the oldest bird fossils were found.
Cretaceous The ninth-oldest period in the Geologic Time Scale that occured during the Mesozoic ERA.
Tertiary The most recent period (besides modern) in the Geologic Time Scale that occured during the Cenozoic ERA.
MYA Millions of Years Ago.
gradualism A theory proposing that evolution occurs slowly but steadily. (Thought by Darwin, continental drift.)
Stephen Jay Gould A scientist who, along with Niles Eldridge, proposed a new theory that agrees with the fossil record.
Niles Eldridge A scientist who, along with Stephen Jay Gould, proposed a new theory that agrees with the fossil record.
punctuated equilibria A theory that states species evolve during short periods of rapid change.
appendix A tiny organ attached to the large intestine.
homologous structures Similar structures that related species have inherited from a common ancestor. (Bones, DNA, embryos.)
humerus The top and largest bone right above the radius and the ulna.
radius The bone on the left of the ulna.
ulna The bone on the right of the radius.
carpals The group of bones below the radius and the ulna.
metacarpals The bones located below the carpals. (On a human hand, all of first bones of the five fingers except for the thumb are these.)
phalanges The bones located below the metacarpals. (On the hand of a human, the only finger that is 100% this is the thumb.)
embryo An organism before it hatches, is born, or germinates.
branching tree A diagram that shows how scientists think different groups of organisms are related. (Common ancestor, how closely related organisms are, when organisms evolved.)
phylogenetic tree Another name for a branching tree.
Surtsey An island located south of Iceland.
geologists Scientists who study the forces that make and shape planet Earth.
rock The material that forms Earth's hard surface.
geology The study of planet Earth that began in the late 1700s.
constructive forces Forces that shape the Earth's surface by building up mountains and landmasses.
destructive forces Forces that slowly wear away mountains and, eventually, every other feature on the surface.
continents Great landmasses that are surrounded by ocean.
seismic waves Waves produced by earthquakes that scientists study to interpret the layers of Earth.
pressure The force pushing on a surface or area.
crust A layer of rock that forms Earth's outer skin.
oceanic crust The crust beneath the ocean.
basalt A dark, dense rock with a fine texture that makes up oceanic crust.
continental crust The crust that forms the continents.
granite A rock that has larger crystals than basalt, is not as dense as basalt, is usually a lighter color than basalt, and makes up continental crust.
mantle A layer of hot rock below the boundary below the surface of the earth.
lithosphere A rigid layer consisting of the crust and the uppermost part of the mantle.
asthenosphere The soft layer below the lithosphere that can bend like plastic.
outer core A layer of molten material that surrounds the inner core.
inner core A dense ball of solid metal located inside of the outer core.
magnetic field A force surrounding Earth that causes the planet to act like a giant bar magnet.
heat transfer The movement of energy from a warmer object to a cooler object.
radiation The transfer of energy through empty space.
conduction Heat transfer by direct contact of particles of matter.
convection Heat transfer involving the movement of liquids or gases.
density A measure of how much mass there is in a volume of a substance.
convection current The flow that transfers heat within a fluid.
Alfred Wegener A German meteorologist who had the idea of continental drift.
Pangaea A single landamass that, according to Wegener, existed 300 million years ago.
continental drift Wegener's idea that the continents slowly moved over Earth's surface.
The Origin of Continents and Oceans Wegener's book published in 1915 that contained his evidence for continental drift.
Mesosaurus and Lystrosaurus The fossils that, when they were alive, could not swim in salt water.
Glossopteris The fossil that, when it was alive, had very fragile seeds that could not travel in water.
Spitsbergen An island that lies in the Arctic Ocean north of Norway.
mid-ocean ridge The longest chain of mountains in the world.
sonar A device that bounces sound waves off underwater objects and then records the echoes of these sound waves.
Harry Hess An American geologist who studied the mid-ocean ridge.
sea-floor spreading The process that continually adds new material to the ocean floor.
Alvin A small submersible built to withstand the crushing pressures four kilometers down in the ocean.
magnetic stripes Stripes in the ocean rock that create a pattern for scientsts to use.
Glomar Challenger A drilling ship built in 1968.
deep-ocean trenches Deep underwater canyons formed when oceanic crust bends downward.
subduction The process by which the ocean floor sinks beneath a deep-ocean trench and back into the mantle.
J. Tuzo Wilson A Canadian scientist who observed that there are cracks in the continents similar to those on the ocean floor.
plates Separate sections in the lithosphere.
plate tectonics The geological theory that states that pieces of Earth's lithosphere are in constant, slow motion, driven by convection currents in the mantle.
faults Breaks in Earth's crust where rocks have slipped past each other.
transform boundary A place where two plates slip past each other, moving in opposite directions.
divergent boundary The plates where two plates move apart, or diverge.
rift valley A deep valley that forms along a divergent boundary.
Great Rift Valley rift valley in east Africa that marks a deep crack in the African continent that runs for about 3,000 kilometers.
convergent boundary The place where two plates come together, or converge.
topography The shape of the land.
elevation The height above sea level of a point on Earth's surface.
relief The difference in elevation between the highest and lowest parts of an area.
landform A feature of topography formed by the processes that shape Earth's surface.
landform region A large area of land where the topography is similar.
plain A landform made up of flat or gently rolling land with low relief.
coastal plain A plain that lies along a seacoast.
interior plain A plain that lies away from the coast.
Great Plains The broad interior plain of North America.
mountain A landform with high elevation and high relief.
mountain range A group of mountains that are closely related in shape, structure, and age.
Bitterfoot Mountains A rugged mountain range in Idaho.
mountain system All the different mountain ranges in a region.
Rocky Mountains A mountain system that includes the Bitterfoot Mountains.
mountain belt A long, connected chain of mountain ranges and mountain systems.
plateau A landform that has high elevation and a more or less level surface.
island A small landmass on the lithosphere.
atmosphere The mixture of gases that surrounds the planet.
hydrosphere All of Earth's oceans, lakes, rivers, and ice.
biosphere All of Earth's living organisms in the air, in the oceans, on the ground, and under the surface.
map A model on a flat surface of all or part of Earth's surface.
globe A sphere that represents Earth's entire surface.
scale A ratio that relates distance on a map to a distance on Earth's surface.
symbols Pictures on a map that stand for features on Earth's surface.
map key A list of all the symbols used on a map with an explanation of their meaning.
legend Another name for a map key.
compass rose Something on a map that helps the map user to relate directions on the map to directions on Earth's surface.
equator An imaginary line halfway between the North and South poles that circles Earth.
hemisphere One half of the sphere that makes up Earth's surface.
prime meridian An imaginary line that makes a half circle from the North Pole to the South Pole.
degree 1/360 of the way around a full circle.
latitude The distance in degrees north or south of the equator.
longitude The distance in degrees east or west of the prime meridian.
map projection A framework of lines that helps to show landmasses on a flat surface.
Mercator projection A map projection that has lines of latitude and longitude appearing straight and parallel, forming a rectangle.
equal-area projection A map projection that correctly shows the relative sizes of Earth's landmasses.
topographic map A map showing the surface features of an area.
contour line A line on a topographic map that connects points of equal elevation.
contour interval The change in elevation from contour line to contour line.
Global Positioning System (GPS) Technology that surveyors, pilots, and mapmakers rely on to determine locations precisely.
weathering The process that breaks down rock and other substances at Earth's surface.
mechanical weathering The type of weathering in which rock is physicaly broken into smaller pieces.
abrasion The grinding away of rock by rock particles carried by water, wind, ice, or gravity.
ice wedging The process in which water seeps into the crack in a rock, freezes, and expands to widen the crack.
wedge A simple machine that forcs things apart.
chemical weathering The process that breaks down rock through chemical changes.
oxidation The process in which iron combines with oxygen in the presence of water.
rust The product of oxidation.
carbonic acid A weak acid that results from carbon dioxide dissolving in rainwater.
lichens Plantlike organisms that grow on rocks.
permeable A term meaning that a material is full of tiny, connected air spaces that allow water to seep through the material.
erosion The process by which natural forces move weatherd rock and soil from one place to another.
sediment The material moved by erosion.
deposition A process by which agents of erosion lay down sediment.
gravity The force that moves rock and other materials downhill.
mass movement Any one of several processes that move sediment downhill.
landslide A type of mass movement that occurs when small amounts of rock and soil slide quickly down a steep slope.
mudflow A type of mass movement that occurs when a mixture of water, rock, and soil moves rapidly downhill.
slump A type of mass movement that occurs when a large mass of rock and soil suddenly slips down a slope.
creep A type of mass movement that occurs when rock and soil slowly moves downhill, bending or uprooting objets in their path.
runoff All the remaining water that moves over Earth's surface.
sheet erosion When runoff flows in a thin layer over the land, eroding the land at the same time.
rills Tiny grooves in the soil formed by runoff traveling downhill.
gully A large groove, or channel, in the soil that carries runoff after a rainstorm.
stream A channel along which water is continually flowing down a slope.
creek + brook Two other names for a stream.
river A large stream.
tributary A stream that flows into a larger stream.
drainage basin The land area from which a river and its tributaries collect their water.
divide The high ground between two drainage basins.
rapids Areas of rough water.
flood plain The flat, wide area of land along a river.
meander A looplike bend in the course of a river.
oxbow lake A meander that has been cut off from the river.
alluvial fan A wide, sloping deposit of sediment formed where a stream leaves a mountain range.
delta A landform formed by sediment being deposited near the mouth of a river.
groundwater The term geologists use for underground water.
caves Large holes underground that can be formed by groundwater making holes in rock.
cavern Another name for a cave.
stalactite A deposit that hangs like an icicle from the roof of a cave.
stalagmite A cone-shaped deposit on the ground formed by the slow dripping of a stalactite.
sinkhole A depression in the ground caused by a cave roof collasping.
karst topography A type of landscape in which there is a sinkhole.
glacier Any large mass of ice that moves slowly over land.
valley glacier A long, narrow glacier that forms when snow and ice build up high in a mountain valley.
continental glacier A glacier that covers much of a continent or large island.
ice ages The times when glaciers covered large parts of Earth's surface.
surge When a valley glacier slides down more quickly than usual.
plucking A process by which glaciers pick up rocks as they flow over the land.
till The mixture of sediments that a glacier deposits directly on the surface.
moraine A ridge formed by till on the edges of a glacier.
terminal moraine The ridge of till at the farthest point reached by a glacier.
prairie potholes Shallow depressions in till that were formed by flowing water as a continental glacier melted.
fiord A landform that is formed when the level of the sea rises and fills a valley that was once cut by a glacier.
arete A sharp ridge separating two cirques.
cirque A bowl-shaped hollow eroded by a glacier.
horn A sharpened peak that is the result of glaciers carving away at the sides of a mountain.
drumlin A moraine that has been slid over by ice.
waves The major forces of erosion along coasts.
headland A part of the shore that sticks out into the ocean.
sea cave A hollow area in the rock of a steep coast.
wave-cut cliff The result of the rock above a steep coast collasping.
sea arch A feature of wave erosion that is formed when waves erode a layer of soft rock that underlies a layer of hard rock.
sea stack A pillar of rock rising above the water.
beach An area of wave-washed sediment along a coast.
longshore drift The process by which currents move beach sediment along the coast.
spit A beach that projects like a finger out into the water.
sandbars Long ridges of sand parallel to the shore.
barrier beach A formation similar to a sandbar that is formed when storm waves pile up sand above sea level.
sand dune A deposit of wind-blown sand.
wind The weakest agent of erosion.
deflation The process by which wind removes surface materials.
blowout A bowl-shaped hollow formed by deflation where there is already a slight depression in the ground.
loess The fine, wind-deposited sediment.