Environmental Science Unit 1 Study Guide
1. Explain the relationship between the amount of water in an ecosystem and its biodiversity. Cite an example
ecosystem to support your answer.
Water is essential for all life. The more water in an ecosystem, the more life it can support; hence, ecosystems with
large amounts of water tend to be more biodiverse. The tropical rainforest is the most biodiverse terrestrial biome
because it is the wettest terrestrial biome.
2. a. Define abiotic.
not living
b. Define biotic.
alive, the product of something alive, or once-living (dead)
c. Abiotic or Biotic? Write A or B in front of the example.
B Bacteria
_____
B Grass
_____
B Feathers
_____
A Oxygen
_____
A Sand
_____
A Air
_____
B Dead Leaves
_____
A Minerals
_____
B Dog
_____
A Sunlight
_____
A Heat
_____
B Feces
_____
A Water
_____
B
_____Tree
B
A Moisture _____Fur
_____
B
_____Twig
B Pinestraw
_____
d. List five abiotic factors which affect terrestrial ecosystems. Explain the importance of each.
1. Oxygen-all organisms that undergo cellular respiration require oxygen (e.g., animals, insects, worms)
2. Water-all living things require water to survive
3. Sunlight-producers (photosynthesizing organisms, i.e., autotrophs) require sunlight to make energy
4. Carbon dioxide-required by plants in the process of photosynthesis
5. Temperature-all living things are adapted to withstand a certain temperature range
e. List five abiotic factors which affect aquatic ecosystems. Explain the importance of each.
1. Dissolved oxygen-provides organisms with the oxygen they need for cellular respiration (e.g., fish take in
oxygen through their gills)
2. Dissolved carbon dioxide-required by photosynthesizing aquatic organisms (e.g., phytoplankton)
3. Dissolved nutrients-such as phosphorus and nitrogen are incorporated into aquatic plants and cycle through
the environment in nutrient cycles
4. Water clarity-affects how deeply sunlight will penetrate the water, limiting photosynthesizing organisms to
living near the surface where there is plenty of light
5. Salinity-organisms are adapted to tolerate a certain percentage of salt in the water
f. Label the following hypotheses according to whether they refer to abiotic (A) or biotic (B) causes.
B Certain insects can be used to control other insect pests on crop plants.
_____
A During drought conditions, crops will not grow as well.
_____
A Crops will not grow well in soil that has been depleted of nutrients.
_____
B Corn genetically modified to produce a natural biological pesticide will grow better than non-genetically
_____
modified corn.
B A coral’s survival depends on the symbiotic relationship it has with photosynthetic algae.
_____
3. List, define, and give an example of each of the six levels of ecological organization beginning with the least complex.
1. organism-an individual living thing; a seagull
2. population-a bunch of the same organism in one area; a flock of seagulls
3. community-several populations in one area; a flock of seagulls, hermit crabs, and sea oats
4. ecosystem-a community plus the abiotic factors surround it; a flock of seagulls, hermit crabs, and sea oats plus
sand and the ocean
5. biome-large regions of the earth with similar climate and plants and animals with similar adaptations; desert
6. biosphere-that part of the earth’s crust, waters, and atmosphere which supports life
4. List the key characteristics of the following biomes. Include a general description, location, relative amounts of
precipitation (wet, moderate rainfall, dry), relative average temperature (very cold, cold, mild), typical animals &
plants and their adaptations.
a. Tundra – near the Arctic Circle with permafrost and poor, thin soil; little precipitation, “cold desert”; long,
extremely cold winters; polar bear, arctic fox, arctic hare have white fur as camouflage, layer of fat for
insulation; low-growing shrubs and grasses clump together to protect each other from winds and are dark
(sometimes red) to absorb solar radiation
b. Taiga – Canada; moderate amount of precipitation in the form of snow; short summers and long, cold winters;
moose & elk migrate to warmer climates in winter (for food & to escape harsh cold); evergreen trees have
waxy coating on needles to help them conserve moisture
c. Temperate Deciduous Forest – Eastern US (GEORGIA) with four distinct seasons and rich, moist soil; moderate
rainfall; moderate temperature; bears hibernate and birds migrate in winter; plants lose leaves to avoid having
them freeze in winter and to conserve water loss through transpiration
d. Desert – Southwestern US & Mexico; very dry; temperatures can range from hot to cold; mammals like the
desert fox have large ears to radiate (lose) heat; plants have spines to prevent them from being eaten
e. Grassland – Midwestern US; fertile soil, hence it’s the “breadbasket” of the US where many farms are located;
wet winters but long, dry summers; moderate temperatures but winters tend to be more severe and summers
tend to be hotter than in Georgia; buffalo live in large herds for protection (not many places to hide since it’s
just grass); narrow leaves on grass prevent it from losing too much water
f. Tropical Rainforest – most biodiversity of all terrestrial biomes; Amazon in South America; poor, thin soils; huge
amounts of rain; warm year-round; brightly-colored birds such as toucans blend in with environment (brightlycolored flowers), like camouflage; large leaves on plants such as elephant ears provide more surface area for
photosynthesis in shady areas
g. Marine – lots of biodiversity; oceans & saltwater cover 70% of the earth’s surface; the most photosynthesis on
earth occurs in the marine biome due to the large numbers of phytoplankton; fish gills take in dissolved oxygen;
whales have blubber for insulation; plants adapted to withstand high salinity
h. Freshwater – ponds, lakes, streams; faster moving water has higher dissolved oxygen content but fewer
nutrients; slower moving or still water has lower dissolved oxygen content and more nutrients (nitrogen &
phosphorus); fish may have camouflage to help them blend with their environment; phytoplankton (also in salt
water) have many projections that increase their surface area to allow for greater photosynthesis rates
5. a. What is an estuary? where freshwater meets saltwater, i.e., where a river dumps out into the ocean
b. What is special about organisms that live in an estuary? they must be adapted to survive changes in salinity and
possible exposure to air due to changes in tides
6. What is camouflage? How might fish exhibit camouflage? How might mammals exhibit camouflage?
Camouflage is body color that allows an organism to blend with its surroundings. Fish may have body colors or fin
colors that are similar to the rocks or sand where they live, allowing them to hide from predators. Polar bears are
white, allowing them to blend in with the snow in the arctic.