active margins: where colliding continental and oceanic plates trigger volcanic eruptions, earthquakes, and mountain building

barkhans: sand dunes with low, curved sides; crescent-shaped dunes formed by one-directional blowing of the wind.

bipedal: walking on two legs

Bororo: "Cattle Fulani;" the name of this nomadic tribe comes from the bororo cattle they herd

carnivore: meat eating animal

carrying capacity: maximum weight that can be carried

Cenozoic Era: 65mya to present; Era associated with the development of and domination by mammals

correlation: the process geologists use to relate rock layers in area to rock layers from another area

Cretaceous Period: last period of the Mesozoic Era; time period during which dinosaurs became extinct: "creta" comes from Latin, meaning chalk

crust: earth's outer surface; ranges from 4 miles to 40 miles thick

cram-cram: low scattered grass which marks the southern end of the of the "real desert" and the beginning of the Sahel

crystal: a solid form of mineral with a regular, geometrical shape

dehydrated food: food that is dried and has most of the water taken out of it

desert: an area that receives less than 10 inches of rain a year

desertification: process of becoming a desert, either by poor land management or by climate changes

desert melon: small inedible gourd, which if eaten, will induce vomiting.

drought: long period of dry weather with little or no rainfall or snow

erg (Arabic): vast sea of huge rolling sand dunes, devoid of vegetation, usually hundreds of miles wide

erosion: wearing away of the earth's surface due to heat, wind and water

estivation: when an animal's body processes (such as breathing and heart rate) slow down in reaction to a dry season so that it will need less water (similar to hibernation)

excavate: to dig-up or unearth

femur: a bone of the leg situated between the pelvis and knee in human beings, or a functionally similar bone in the leg or hind limb of a vertebrate animal. It is the largest and strongest bone in the body. Also called thighbone.

fennec: the world's smallest fox; inhabits the Sahara. The fennec's exceptionally large ears help disperse heat and give it acute hearing.

fibula: the outer and narrower of two bones of the human lower leg, extending from the knee to the ankle, or the corresponding bone in the hind leg of an animal.

formation: a group of rock layers that are recognizable from one place to another

fossil: the remains of a living thing, or direct evidence of its presence, preserved in rocks. usually only hard parts such as bones, teeth, and shells are preserved by burial or chemical change

fossil record: the history of life on earth as revealed by fossils

Fulani: traditionally nomadic people living throughout West African savannah areas; one of the largest groups in West Africa. Pastoral Fulani rely on cattle for wealth, and exist primarily on sheep. (also known as "Wodaabe")

Fulfulde: language of the Fulani people

geographic map: depicts the location of cities, roads, major land formations

geologic column: shows rock units as they were laid down in sequence

geologic map: depicts the age of rocks (ancient, dinosaur age, or mammal age) and under what conditions the rock formed (on land, in the sea, on a volcano)

geologist: a scientist who studies the structure of the earth and its rocks

gerewol: Fulani ceremonial courtship dance

hamada (Arabic): flat, wind-swept rocky desert surface; stony desert plain

harmattan: cold, dry northeastern wind, which blows from October-February and brings dusty storms to the Sahara

Hausa: refers both to a language and a group of people. Currently, Hausa people are most commonly associated with Northern Nigeria, but Hausa people live throughout West Africa and historically dominated commercial activity. Hausa is the dominant language of commerce throughout the Central Sudan savannah

herbivore: plant-eating animal

hooded vulture: this scavenger bird is often found near oases in the Southern Sahara

humerus: the long bone of the arm or forelimb, extending from the shoulder to the elbow

igneous rocks: formed when melted rock in volcanoes or under the earth's surface cools and hardens (also known as volcanic, intrusive or extrusive)

index fossils: a fossil that provides precise correlation because it: 1)has recognizable unique features, 2) has a wide distribution, and 3)is present in the geologic record for only a limited time

inner core: a solid ball inside the middle of the earth; 1540 miles thick; intense pressure keeps the inner core solid despite a temperature of 3700 degrees Celsius

invertebrate: an animal that has no backbone. The vast majority of animals are invertebrates

Jurassic Period: second period of the Mesozoic Era; time period during which Pangaea began to rift apart . "Jurassic" comes from fossil-bearing limestone rocks found in Europe's Jura Mountains

Laurasia: northern portion of Pangaea, which consisted of the present day continents of Eurasia (Europe and Asia) North America

longitudinal dunes: caused by strong wind blowing continuously in one direction and forming troughs in the sand which run parallel to the wind; also called "seif" ("sword" in Arabic)

magma: hot molten rock formed beneath the earth's surface.

mammals: animals with backbones that have hair, give live birth, and feed their young milk

mantle: layer of rock between the earth's crust and outer core; 1800 miles think; semi-molten and denser than crustal rock

marine rock: rock that formed in the ocean (i.e. limestone)

metacarpals: any of the five bones between the fingers and the wrist

metamorphic rocks: are formed when igneous or sedimentary rocks are subjected to extreme heat and pressure, causing them to bend, fold, squeeze and literally, "change" shape and composition

metatarsals: any of the five bones between the toes and the ankle

Mesozoic Era: 248-65 million years ago; geologic time period during which dinosaurs lived; composed of the Triassic, Jurassic and Cretaceous Periods

nocturnal: active during the night

nomads: people who traditionally move seasonally in order to feed and water their flocks of sheep, goats and/or camels

oasis: small fertile green spot in the desert caused by groundwater coming to the surface

Ornithischians: "bird-hipped" dinosaurs with a hip structure in which the two lower bones on each side lie parallel; all ornithischians were plant eaters

outer core: layer of dense, molten rock between the mantle and the inner core; 140 miles thick; may be mainly iron and nickel

paleontologist: a scientist who studies fossils and organisms in ancient times by determining their lifestyles and relationship to other organisms

Paleozoic Era: 540-248 million years ago

Pangaea: an ancient super-continent composed of all the major continents we recognize today

passport: An official government document that certifies one's identity and citizenship and permits a citizen to travel abroad.

pelvic girdle: plate-shaped bones for limb attachment

petrified: literally "turned to stone," Petrification is the long process by which organic material is replaced by rock materials

petroglyphs: prehistoric rock carvings

phalanges: bone of a finger or toe

piste (French): track or unpaved road in the desert

plate tectonics: term geologists use to describe the study of the movement of the plates under the earth's crust. Most plates are composed of two parts: ocean floor and continental crust

prospect: to explore or search

quadrapedal: walking on four legs

radius: The bone extending from the elbow to the wrist on the side of  the thumb in human beings, or the corresponding bone in other vertebrates

rain-shadow desert: a desert formed on the side of a mountain range, sheltered from winds that carry rain

rehydrate: literally, "to add water again." Food that has been dehydrated needs to be rehydrated (allowed to absorb water) before you can cook with it.

rift: break apart

rock section: a clean surface exposing a rock layer

Sahara (Arabic): desert, or "empty grave"

Sahel: dry, sparsely vegetated area on the southern edge of the Sahara, marked by scattered grasses and low, thorny trees

Saurischians: "lizard-hipped" dinosaurs with a hip structure in which the two lower bones on each side point in opposite directions

Sauropods: large quadrupedal, saurischian, plant-eating dinosaurs, with very long necks and tails

scapula: either of two large, flat, triangular bones forming the back part of the shoulder. Also called shoulder blade.

sedimentary rocks: most form on from particles eroded from rocks on land; some form from dissolved chemicals or organic particles from shells or other living organisms

semi-arid zone: fairly dry area, with an average yearly rainfall between 10:12 inches

shesh: a headdress worn by the Touareg people and other inhabitants of the Sahara desert area.  It is wrapped around the face, loosely around the neck, and tightly around the forehead down to the eyebrows to protect against blowing sand and other desert conditions

skeleton: the internal structure composed of bone and cartilage that protects and supports the soft organs, tissues, and other parts of a vertebrate organism

skull: the bony framework of the head of vertebrates that contains the brain, jaws, and teeth

star dunes: where winds blow from all directions surface

subduction zone: area where oceanic plates move into the mantle

tarsal bones: any of the seven small bones of the human ankle

therapods: carnivorous, bipedal dinosaurs

tibia: the inner and larger of the two bones of the lower human leg, extending from the knee to the ankle, or a corresponding bone in other vertebrates. Also called shinbone.

Tomacheck: spoken language of the Touareg people

topographic map: map that depicts the changing elevation of a surface

Touareg (or Tuareg): traditionally nomadic people living in the Sahara. Touaregs have operated the main camel caravan routes across the Sahara for centuries

Triassic Period: first period of the Mesozoic Era; time period when dinosaurs first evolved; "Triassic" comes from Latin, "trias" describing three particular rock layers in Germany

ulna: The bone extending from the elbow to the wrist on the side opposite to the thumb in human beings, or the corresponding bone in other vertebrates

vaccination: an inoculation, usually a shot, to protect against a particular disease

ventifacts: sand-blasted stones with flat, smoothed surfaces that have been eroded by wind over prolonged exposure

vertebrae: bones that form the backbone vertebrate: an animal with a backbone

visa: An official authorization appended to a passport, permitting entry into and travel within a particular country or region

volcano: An opening through which molten rock comes from deep inside the earth.

wadi: steep sided valleys in desert areas that have been carved by water. These areas may experience occasional flooding