The Physical World

Terms:
species, population, community, ecosystem, solar constant, ozone layer, greenhouse effect, circle of illumination, solstice, equinox, albedo, Hadley Cell, coriolis effect, ocean gyres, rainshadow effect

albedo:  Reflectivity of the earth’s surface that can influence local climate/temperature.  

circle of illumination: That half of the earth, at any one point in time, that is illuminated by the sun due to earth's orbital and rotational position.

community:  An association of interacting populations at the same place and same time.

coriolis effect:  When a moving object tends to move to the right in the Northern Hemisphere, and the left in the Southern, in relation to the earth's surface due to angular momentum caused by earth's rotation.

ecosystem:  A community plus the abiotic environment with which it interacts via energy flow and nutrient cycling.

equinox: The two days during a year when, due to earth's orbital and rotational position, the circle of illumination passes through the poles and all points on earth have daylength = nightlength; 21 March and 22 September.

greenhouse effect:  The process by which CO₂, evaporated H₂O, methane (CH₄), and other trace gases trap heat, usually from infrared radiation, to warm the air that surrounds the earth.

Hadley cell:  A large cell of circulating air formed by infrared radiation at the earth’s surface causing warm air to rise.  The rising  air cools and falls back to the surface. 

ocean gyres: Large ocean circulatory movements caused by winds and coriolis effect.

ozone layer: A thin layer of O₃ molecules that encircle the earth at an altitude between 15-25 km.

population: A group of individuals of the same species that interact with each other in the same place at the same time.

rainshadow effect:  The process by which rising air on one side of a mountain releases all of its moisture so that the opposite side, or rainshadow, receives only dry air.  

solar constant: The average amount of light energy from the sun, in calories/cm²/minute, that hits the outer atmosphere; usually given as 1.98 cal/cm²/min, but also as 0.140 watt/cm².

solstice: The two days during a year when, due to earth's orbital and rotational position, the polar circles are either exposed to 24 hr. of daylight or darkness, and lower latitudes experience either the longest or shortest days of the year.  Northern Hemisphere: 21 June, longest day; 22 December, shortest day.

species:  A group of individuals of common ancestry that closely resemble each other and interbreed to produce fertile offspring.