ENVIRONMENTAL SCIENCE MIDTERM STUDY GUIDE KEY
1. Levels of Organization. Define, give examples, and be able to place in the correct hierarchical order. (already in
correct order from smallest to greatest)
A. organism – an individual living thing; a single fish
B. population – all the members of the same species that live in the same place at the same time; a school of
fish
C. community – a group of various species that live in the same place and interact with each other; a school of
fish along with shrimp, algae, plankton, and sharks
D. ecosystem – all of the living and non-living factors in an area; a school of fish along with shrimp, algae,
plankton, and sharks plus the water, sand, and rocks in a marine ecosystem
E. biome – a large region characterized by a specific type of climate and certain types of plants and animal
communities; the marine biome
F. biosphere – all living organisms on Earth and their environments; about six miles above and below the
surface of the earth including the atmosphere & waters
2. Biotic/Abiotic. Biotic = living, once-living (dead), or the product of a living organism Abiotic = non-living
3. Biomes: List the characteristics of each type of biome (geographical area, abiotic factors such as climate and soil,
biotic factors such as animal/plant adaptations)
A. Tundra – near the poles, extremely cold & very little precipitation (cold desert), low-growing plants (lichens,
mosses, small shrubs), animals may have white fur, thick coats, layers of fat for insulation, and they may
hibernate (polar bear, arctic fox, snowy owl)
B. Taiga – parts of Canada and far north US, very cold with short summers, coniferous forest, animals hibernate
and/or migrate (lynx, grizzly bear, snowshoe hare, eagle)
C. Grassland – US plains states (e.g., Kansas, Oklahoma, Iowa, Dakotas) hot, dry summers, wet winters,
predominantly grasses with very few trees, animals may burrow (prairie dogs) or herd (buffalo), African
savannah animals include zebras, giraffes, cheetahs
D. temperate deciduous forest – the state of Georgia’s biome, also found on eastern US, most of Europe, parts
of Asia, mild climate, deciduous trees such as hickories, oaks, and maples with a few pines,
E. desert – Sahara in Africa, Gobi in Asia, southwestern US, dry (least amount of precipitation of all biomes),
cold nights because there is no cloud cover to help hold in the heat at night, thick-skinned plants that retain
water (cacti and succulents); small, nocturnal, burrowing animals with large ears to radiate excess heat;
reptiles have thick, scaly skin to retain moisture
F. tropical rainforest – the most biodiverse biome (many different types of animals & plants), found near the
equator (Amazon Rainforest), highest amount of precipitation, humid, hot year-round, lush vegetation,
brightly-colored birds, thin soil because nutrients wash out or are taken up by plants very quickly, large
leaves on shaded plants increases leaf area for photosynthesis
G. marine ecosystems – saltwater, 3% salt in oceans, largest biome, also very biodiverse, estuaries are a type of
marine ecosystem where freshwater rivers dump out into the ocean (mix of salt and freshwater)
H. freshwater ecosystems – rivers, ponds, streams, wetlands, <1% salt content; the faster the water flows, the
more dissolved oxygen available in the water
4. Eutrophication.
1
5. Ecological Succession
A. primary succession – occurs on rock where there has never been an ecosystem before
B. secondary succession – occurs on soil where there was a prior ecosystem; recovery of an ecosystem after a
disaster
C. pioneer species – first organisms to inhabit an area
D. climax community – final, stable ecosystem achieved after succession (e.g., a hardwood forest in Georgia)
E. What types of events precede each type of succession? Primary – glacial retreat or volcanic eruption with
lava forming rock; Secondary – natural or manmade disasters (flood, fire, bulldozing and clear-cutting)
F. Describe how lichens contribute to primary succession. Lichens are pioneer species of primary succession –
they break down rock into small pieces such that soil can begin to form
G. Explain what happens during old-field succession. When a farmer no longer takes care of a field and lets
nature take its course (secondary succession) – first, there are grasses, then shrubs, then a climax
community of tress is achieved after many, many years
6.
Ecological Relationships
A. Competition – two organisms try to use the same resource at the same time (e.g., compete for shelter)
B. Predation – one organism kills another for food
C. Symbiosis – two organisms live together and have a dependent relationship (e.g., mutualism,
commensalism, parasitism)
D. Mutualism – both organisms benefit
E. Commensalism – one organisms benefits from the relationship, but the other is neither harmed nor helped
F. Parasitism – the parasite benefits, but the host is harmed. Usually the host is not killed
G. native species – naturally occur in an area (e.g., oaks and hickories in our area)
H. non-native species – species which were introduced to an area, either by humans or accidentally brought in
by other animals (e.g., flowering azaleas brought from Japan)
I. invasive species – non-native species which experience exponential growth and outcompete native species
(e.g., kudzu)
7.
Population Growth
A. growth rate = (birth rate + immigration) – (death rate + emigration)
B. exponential growth – unrestricted growth that occurs in the absence of limiting factors; j-curve
C. carrying capacity – the number of individuals an area can support given the amount of resources in that area
– the flattened part of the s-curve
D. limiting resources – limiting factors – things that will slow down population growth (limited food, water,
space, disease, etc.)
E. density-dependent factors that regulate population growth – food, water, disease
F. density-independent factors that regulate population growth – natural disasters, unusual weather
(exceptionally hot, dry, or cold)
8.
Climate
A. Distinguish between climate and weather. Climate is the expected average conditions, and weather is the
actual conditions we see from day to day
2
B. Explain the relationship between latitude and altitude with regards to climate. In general, the farther away
from the equator you go, the colder it gets (the poles are the coldest). Also, the higher you go in altitude,
the colder it gets
C. Identify four factors that determine climate. (1) latitude, (2) altitude, (3) proximity to oceans, (4)
topography (proximity to mountain ranges), (5) prevailing wind patterns, (6) proximity to ocean currents
(e.g., Gulf Stream)
D. Distinguish between El Niño and La Niña. El Nino is warm phase of ENSO; La Nina is cold phase
E. What would be the consequences of rising global temperatures? Rising sea levels & melting ice caps
9.
Energy Flow in Ecosystems
A. Photosynthesis – producers use light energy and covert it to chemical energy (stored in the bonds of
glucose) that other organisms can use
B. cellular respiration – process of converting carbohydrates into energy
C. producers – plants, algae, phytoplankton, some bacteria (photosynthesizers), base of the food chain; can
make their own energy
D. consumers – must eat in order to get their energy
E. heterotrophs – consumers
F. autotrophs – producers
G. carnivore – eats animals
H. herbivore – eats plants
I. omnivore – eats plants and animals
J. decomposers – break down dead organisms to get energy (e.g., fungus and some bacteria)
K. food chain – links organisms together in an ecosystem, arrows point in the direction of the consumer
showing the direction of energy flow
L. food web – many interconnected food chains from an ecosystem
M. trophic levels – “feeding” levels – producers are 1st trophic level, primary consumers are 2nd trophic level,
etc.
N. percentage of energy lost between trophic levels = 90%
O. Describe how energy is transferred from the sun to producers and then to consumers. Sun to producers
through photosynthesis, from producers to consumers by being eaten, only 10% of the energy from one
trophic level gets transferred to the next
P. Describe how consumers depend on producers. Producers are the only things that can convert the energy
from the sun into some form that all other organisms can use (food) Without producers, there is no food
chain
Q. Explain why an energy pyramid is a representation of trophic levels. Most energy is at bottom of pyramid
(producers) and energy is lost as it is transferred from trophic level to trophic level such that the top of the
pyramid (top trophic level) has the least energy
R. Why are there rarely more than five trophic levels in a food chain? Since so much energy is lost between
trophic levels, it would be difficult for there to be enough energy at the top of a pyramid with more than five
trophic levels to support those organisms at the top; there is just not enough energy in the ecosystem to
support more than five trophic levels
3
4