Unit 1 Environmental Science Semester One
Assignment 1: Introduction to Environmental Science
environment the external conditions, including natural surroundings, people, attitudes,
and anything that influences the life and activities of people, plants, and
animals
environmental science the study of ways in which people and animals interact with their
environment
hypothesis educated guess based on observation and experimentation
natural resources materials taken from the natural environment, such as water, air, and
plant life
sustainability long-term maintenance of ecosystem components that allows them to
continue through future generations
science a branch of study or knowledge about the physical and material world
which is conducted through investigation and observation
theory a scientific hypothesis that has been supported by data and facts over
and over again
Unit 1 Environmental Science Semester One
Assignment 2: Earth’s History
absolute dating process of determining a specific date of an object
eon the longest unit of geological time
era a major division of geologic time that is a subdivision of an eon
geologic time the period of time covering the physical formation and development of the
earth
geologic timeline a visualization of how the earth and its lifeforms have changed through
geologic time
half-life the time required for half the atoms in an element to divide in half
mass extinction event the extinction of a large number of species in a short period of
time that is usually caused by a catastrophic global event like an asteroid
period a division of geologic time and a subdivision of an era
radioactive decay the process by which an unstable nucleus of an atom spontaneously
releases energy through the emission of radiation used in dating fossils and rocks
relative dating the process of determining the order of events in geologic time
Unit 1 Environmental Science Semester One
Assignment 3: Plate Tectonics
asthenosphere the region below the lithosphere, variously estimated as being from fifty to
several hundred miles (eighty-five to several hundred kilometers) thick, in which the rock is less rigid than that above and below, but rigid enough to transmit transverse seismic waves
convection the transfer of heat by the circulation or movement of the heated parts of
a liquid or gas
convergent plate boundary a tectonic boundary where two plates are moving toward
each other
core the central portion of the earth, having a radius of about 2100 mi. (3379
km) and believed to be composed mainly of iron and nickel in a molten state
divergent plate boundary a tectonic boundary where two plates are moving away from each
other and new crust is forming from magma that rises to the earth's surface between the two plates
earthquakes series of vibrations produced in the earth's crust by the abrupt rupture and
rebound of rocks in which elastic strain has been slowly accumulating
lithosphere a layer in the interior of earth or another planet; the Earth's the mantle is
sandwiched between the crust in the top and the core in the bottom
plates a theory of global tectonics in which the lithosphere is divided into a
number of crustal plates, each of which moves on the plastic asthenosphere more or less independently to collide with, slide under, or move past adjacent plates
transform plate boundary place where plates slide against each other
volcano a vent in the earth's crust through which lava, steam, ashes, etc., are
expelled, either continuously or at irregular intervals
Unit 1 Environmental Science Semester One
Assignment 4: Plate Tectonics
atmosphere the thin layer of gases that surrounds earth
exosphere the last layer of the atmosphere before space
mesosphere the middle layer of the atmosphere
ozone an oxygen compound (o 3) that in earth's stratosphere helps protects us
from harmful radiation originating in the sun
photosynthesis process whereby green plants use sunlight to convert carbon dioxide and
water into glucose, a high energy sugar, and oxygen
stratosphere a layer of the earth's atmosphere that contains the ozone layer
thermosphere an upper layer of the earth's atmosphere
troposphere the layer of the atmosphere just above Earth's surface, where all our
Unit 1 Environmental Science Semester One
Assignment 5: Weather and Climate
arid type of climate where precipitation is less than evaporation, which makes
it very dry
climate a description of an area's long-term average temperature and
precipitation characteristics
continental a type of climate not influenced by the oceans; occurs within the interiors
of continents
desert a landscape that receives very little precipitation
equatorial a region close to the equator that is characterized by warm temperatures
year-round; also called tropical
humid characterized by a large amount of moisture in the air
monsoonal characterized by a season of wind and heavy rain
steppe a dry place that has very little vegetation, or only grasses and small
shrubs but no trees
temperate characterized by seasonal changes in temperature, which cause distinct
seasons
tropical type of climate associated with the tropics or areas near the equator,
which is characterized by warm temperatures year-round
polar extremely cold areas of the earth
polar ice cap a polar area of the Earth where all twelve months of the year have
temperatures below freezing
polar tundra a polar area of the Earth with very low temperatures and a short season
of plant growth
precipitation liquid or solid water that falls from the clouds in the sky to the ground
weather the state of the atmosphere for a specific amount of time
Unit 1 Environmental Science Semester One
Assignment 6: Earth’s Water
aquifer an underground layer of earth, gravel, or sand that yields water
freshwater water that has a low salt content; springs and lakes are considered
freshwater
groundwater water within the soil that supplies wells and springs
groundwater overdraft when humans exhaust groundwater supplies before the supply
can be replenished naturally
infiltration the process by which water on the ground surface enters the soil
saltwater water that has a high salt content; ocean water is considered saltwater
salinity the salt content of a liquid
surface water water that has collected on the surface of the Earth
Unit 1 Environmental Science Semester One
Assignment 7: Water Conservation
conservation the preservation of resources through efficient and careful use
dam a constructed barrier built to hold back water from a river and for release
during times of greater need
Unit 1 Environmental Science Semester One
Assignment 8: Rock Cycle
depletion time time required to exhaust a given amount of a mineral reserve
erosion the wearing down of land or soil by water, wind, ice, or gravity
igneous rock a rock that solidified from a molten or near molten state
metamorphic rock a rock that has undergone chemical or structural changes by exposure to
extreme heat and/or pressure
mineral a naturally-occurring substance formed by geologic processes that has a
characteristic chemical composition, a highly ordered atomic structure, and definite physical properties
reserve a deposit of a mineral resource in a quantity large enough to make a profit
rock a mass of hard consolidated mineral matter
rock cycle a series of events through which a rock changes over time between
igneous, sedimentary, and metamorphic forms
sedimentation process that deposits soils or other materials on the ground or in bodies
of water
sedimentary rock rock formed by the hardening of material deposited
weathering a physical or chemical process in which rocks are exposed to weather
and worn down by water, wind, or ice
Unit 1 Environmental Science Semester One
Assignment 9: Soil
humus dark colored organic material in soil; it is left over from the decay of living
things
inorganic a substance that does not contain carbon and hydrogen atoms, such as
salts, rocks, and minerals
organic a substance that contains carbon and hydrogen atoms, such as carbon
dioxide, glucose, methane, and nucleic acid
parent material the rock material that was weathered to form the sediments in a given soil
regolith the layer of loose rock on the surface of the earth; also called mantle rock
soil the thin upper layer of Earth's crust that supports plant life
soil horizon a distinct layer of soil that has characteristic properties
soil ph a chemical property of soils that describes the measure of hydrogen ions
in a soil sample; how acidic or basic a soil sample is
soil profile a vertical section of soil that shows the horizon and parent material
soil texture a physical property of soil that describes how the soil feels, and the
relative components of sand, silt, and clay sized particles
Unit 1 Environmental Science Semester One
Assignment 10: Soil Conservation
desertification expansion of desert lands caused by human activities and drought that
accelerate soil erosion
gully erosion type of soil erosion that develops when water carves away the soil until
deep gullies are formed
rill erosion type of soil erosion that occurs when water runs over land, carving out
small channels as it flows
runoff water that does not enter the ground or get used by plants, but instead
runs over the land's surface
saltation type of wind erosion that occurs when particles are blown into the air,
travel a short distance, and then fall back to the ground, dislodging other particles as they hit the ground
sheet erosion type of erosion that occurs when large sheets of water flow over the land
and carry soil particles away
slumping fast downhill movement of soil
soil creep slow downhill movement of soil
surface creep when large soil particles bounce around on the ground's surface as a
result of wind erosion
suspension when soil particles are blown into the air by wind and travel long distances
Unit 1 Environmental Science Semester One
Assignment 11: Ecology
biodiversity a measure of the variety of species in an environment
biome a geographical area with similar climate and soils, which contains similar
organisms
biosphere all of Earth's ecosystems
community consists of all the populations of different species that live and interact in
a given area
ecology the study of connections in nature
ecological niche the role of a species in its ecosystem
ecosystem a community where populations of different species interact with one
another and with their non-living environment
habitat the place where an organism lives and reproduces
organism a single living thing
population a group of interacting individuals of the same species occupying a specific
area
species a group of organisms that live together and can interbreed
Unit 1 Environmental Science Semester One
Assignment 12: Evolution and Biodiversity
adaptation an inherited trait that gives an organism an advantage or helps it survive
in its given environment
biological evolution process by which a species changes over time
extinction when all members of a species die off
genetic diversity description of the differences within members of a single species
mutation a random change in the DNA of an organism
natural selection the process by which those individuals best adapted to their environment
tend to survive better and pass their genes on to future generations, and those that are least adapted tend to be eliminated
speciation occurs when a new species forms because separate groups that have
different adaptations within a population become reproductively isolated
species diversity description of differences between all the species on Earth
Unit 1 Environmental Science Semester One
Assignment 13: Energy Flow in Ecosystems
autotroph an organism capable of producing its own food through photosynthesis or
chemosynthesis
biomass biological material; all the plant and animal materials in an ecosystem
carnivore organisms that only eat other consumers
consumer an organism that must eat to get energy indirectly from the sun
food chain a linked feeding series that shows how organisms are connected to each
other by feeding relationships
food web all of the individual food chains of an ecosystem that are interconnected
together
herbivore organisms that only eat plants
heterotroph an organism that cannot produce its own food so must eat to get energy
indirectly from the sun
omnivore consumer that eats both plants and animals
primary production biomass manufactured by photosynthetic organisms
producer an organism that can produce its own energy from the sun or chemical
source
productivity amount of biomass produced in a given area during a given period of time
secondary production biomass manufactured by organisms that eat plants or other
animals
trophic level an organism's feeding status in an ecosystem
Unit 1 Environmental Science Semester One
Assignment 14: Nutrient Cycles
ammonification process that occurs when bacteria convert organic materials into simple nitrogen-containing compounds such as ammonia
carbon cycle the circulation and reuse of carbon atoms, especially via the processes of
photosynthesis and respiration
dentrification process that occurs when ammonia and ammonium ions are converted
back to nitrogen gas
nitrification an oxidation process whereby soil bacteria convert ammonia and
ammonium ions first to nitrite ions, which are toxic to plants, and then to nitrate ions, which are used by plants
nitrogen cycle the circulation and reuse of nitrogen atoms
nitrogen fixation process whereby nitrogen from the atmosphere or soil solution is
converted to ammonia that can be converted to plant nutrients
phosphorus cycle circulation and reuse of phosphorus atoms
Unit 1 Environmental Science Semester One
Assignment 15: Water Cycle
drainage divides a boundary between adjacent watersheds
hypoxia a condition of oxygen depletion in a body of water caused by an excess of
nutrients
water cycle describes how water moves between Earth's surface and the atmosphere
and back to the surface in a never-ending cycle
watershed all the land that drains into a given body of water
Unit 1 Environmental Science Semester One
Assignment 16: Population Ecology
age structure the proportions of individuals in a population at various ages
biotic potential a population's capacity to grow
carrying capacity the maximum population of a given species that a particular habitat can
sustain without degrading the habitat
environmental resistance all the factors that act to limit the growth of a population
intrinsic rate of increase the rate at which a population would grow if it had unlimited
resources
k-selected species species that have few offspring and have slower population growth than
r-selected species
population density the number of individuals in a population found in a given area
r-selected species species with a high capacity for population increase
Unit 1 Environmental Science Semester One
Assignment 17: Community Ecology
camouflage blending in with one's surroundings
chemical warfare using chemical substances to kill or injure predator or prey
commensalism association in which one organism is benefited and the other organism is
neither benefited nor harmed
indicator species species that serve as early warnings of damage to a community or
ecosystem
interspecific competition competition between species for shared or limited resources
invasive species that migrate or are deliberately introduced into a community
where they would not normally live
keystone species species that play critical roles in their communities and help determine the
types and numbers of other species in a community
mimicry an adaptation in which an animal is protected against predators by its
resemblance to a different animal
mutualism a relationship between two kinds of organisms that benefits both
native species those species that normally live and thrive in a particular community
parasitism a relationship in which one organism lives in or on another organism and
benefits from that relationship while the host organism is harmed by it
Unit 1 Environmental Science Semester One
Assignment 18: Ecological Succession
climax communities final, relatively stable communities, believed by most ecologists
today to be unattainable because of the fact that community change is
almost always guaranteed
ecological succession order of changes in the composition or structure of an ecological
community over time
pioneer species the first species to colonize an area at the beginning of either primary or
secondary succession
primary succession involves the establishment of communities where there is no soil and no
life
secondary succession succession that occurs after a disturbance, such as fire or flood
Unit 1 Environmental Science Semester One
Assignment 19: Threatened and Endangered Species
biomagnification the accumulation of substances, such as pesticides or other organic
chemicals, in an organism
endangered the species has so few numbers left that it may soon become extinct
habitat fragmentation occurs when large areas of habitat are divided into small isolated patches
intrinsic value the value given to an object (like the Earth) simply because it exists,
regardless of its use to us, and therefore should be protected
instrumental value the value that comes from the numerous goods and services that
biodiversity provides people; these include jobs, food, medicines, paper, textiles, recreation, and tourism
threatened the species currently has sufficient numbers, but their numbers are
declining and they may face extinction if action is not taken to bring the numbers back up
Unit 1 Environmental Science Semester One
Assignment 20: Protecting Biodiversity
wilderness large, undeveloped areas of land
wildlife sanctuary places set aside where hunting and fishing are prohibited or strictly
controlled in order to protect given species from extinction
Unit 1 Environmental Science Semester One
Assignment 21: Terrestrial Biomes
alpine high mountain biome
arid land a desert, a biome with little precipitation and arid conditions
chaparral coastal area near a desert with small shrubs and occasional trees
northern coniferous forest a type of forest biome with cool temperatures and dominated by
coniferous trees
savanna a type of grassland with a few clumps of trees
steppe semi arid grass-covered plain
temperate forest a type of forest biome with seasons and even precipitation levels
terrestrial biomes a large area of land characterized by similar climate, soil, and living
organisms
tropical forest type of forest biome with high rainfall and year-round warm temperatures
tundra biome type with harsh winters and a short growing season
Unit 1 Environmental Science Semester One
Assignment 22: Aquatic Life Zones
abyssal zone the deepest part of the ocean
bathyal zone zone of the ocean below the euphotic zone
benthos the animals in a body of water that dwell at the bottom
estuary place where ocean water and freshwater from an incoming river are
mixed
euphotic zone zone in a body of water through which sunlight can penetrate
intertidal zone coastal area close to the shore, where tides and waves dominate
nekton strong swimmers, like fish, turtles, and whales
phytoplankton drifting photosynthetic organisms like algae
ultraplankton very small photosynthetic bacteria that live in water
zooplankton weakly swimming, free-floating animals like jellyfish
Unit 1 Environmental Science Semester One
Assignment 23: Freshwater Life Zones
benthic zone the bottom zone of a lake
culturally eutrophic a lake with excess nutrients from urban or agricultural land
eutrophic a lake with a large amount or excess of nutrients
limnetic zone the open water zone of a lake or pond
littoral zone the zone of a lake or pond near the shore
oligotrophic a lake with very few nutrients in it
profundal zone deep open water zone of a lake or pond; too dark for photosynthesis
Unit 1 Environmental Science Semester One
Assignment 24: Population Age Structure
age structure diagram a graphical representation of the different proportions of individual
ages in a population
post-reproductive the members of a population that are past the age of being able to
reproduce and are no longer able to produce offspring
pre-reproductive a member of a population that is younger than the age of reproductive
maturity
reproductive the members of a population that have reached reproductive maturity, that
is, they can produce offspring
Unit 1 Environmental Science Semester One
Assignment 25: Effects of a Growing Human Population
exponential growth growth characterized by a slow start and then rapid increase
fertility the number of births to a woman over her lifetime
replacement-level fertility the number of children a couple must have to replace themselves