THE BIOSPHERE: AN INTRODUCTION TO EARTH’S
DIVERSE ENVIRONMENTS
I.
Ecologists study how organisms interact with their environment at
several levels
a. ECOLOGY  the scientific study of interactions of organisms
with their environment
b. ORGANISM LEVEL  examine how one kind of organism
meets the challenges of its environment
c. POPULATION  an interbreeding group of individuals
belonging to the same species and living in a particular
geographic area
d. COMMUNITY  all the organisms (all the populations of
different species) that inhabit a particular area
e. ECOSYSTEM  includes all the life-forms in a certain area
and all the non-living factors
i. ABIOTIC  “non-living”
ii. BIOTIC  “living”
II.
The biosphere is the total of all of Earth’s ecosystems
a. BIOSPHERE  the global ecosystem; the sum of all the
planet’s ecosystems
b. HABITATS  environmental areas in which communities live
III.
Environmental problems reveal the limits of the biosphere
a. Early technological development led to a misuse and
mistreatment of the biosphere
b. Concerns exist about human-kinds effect on the environment
IV.
Physical and chemical factors influence life in the biosphere
a. Some of the more important abiotic factors are
i. SOLAR ENERGY
ii. WATER
iii. TEMPERATURE
iv. WIND
b. There are more factors like natural disasters, pH, soil structure
and mineral composition
V.
Organisms are adapted to abiotic and biotic factors by natural
selection
a. The presence of a species in a particular place may come about
in two ways
i. It evolved in that location
ii. It disperses to that location and is able to survive
VI.
Regional climate influences the distribution of biological
communities
a. TROPICS  latitudes between 23.5 N and 23.5 S
b. DOLDRUMS  an area of calm or of very light wind near the
equator
c. TRADE WINDS  air moving back to the equator from 30 
latitude
d. TEMPERATE ZONES  latitudes between the tropics and the
Arctic and Antarctic circle
e. PREVAILING WINDS  major global air movement
i. Results from the rising and falling air masses and Earth’s
rotation
f. WESTERLIES  wind blowing from west to east
g. OCEAN CURRENTS  river-like flow patterns in the ocean
h. BIOMES  major type of ecosystem
VII. Oceans occupy most of Earth’s surface
a. About 75% of planet’s surface is covered by water
b. ESTUARY  area where freshwater stream merges with ocean
c. WETLAND  an ecosystem that is an intermediate between an
aquatic ecosystem and a terrestrial one
d. INTERTIDAL ZONE  the wetland at the edge of an estuary,
or ocean, where water meets land
e.
f.
g.
h.
i.
j.
k.
l.
PELAGIC ZONE  open ocean
PHYTOPLANKTON  “plant-like” drifters
ZOOPLANKTON  “animal-like” drifters
BENTHIC ZONE  sea-floor
PHOTIC ZONE  area to which light penetrates the ocean
APHOTIC ZONE  no light
CONTINENTAL SHELF  submerged part of the continent
CORAL REEFS  diverse underwater ecosystem
VIII. Freshwater biomes include lakes, ponds, rivers, streams, and
wetlands
a. Nitrogen and phosphorous are the limiting nutrients in lakes or
ponds
i. Sewage plants greatly increase these nutrients; but it can
be dangerous for the ecosystem
IX.
Terrestrial biomes reflect regional variations in climate
a. Nine major types of biomes
b. Usually named for climatic features
c. Distribution of biomes largely depends on climate
X.
Tropical forests cluster near the equator
a. TROPICAL FORESTS  occur in equatorial areas where the
temperature is warm and the days are 11-12 hours long year
round
XI.
Ecologist Ariel Lugo studies tropical forests in Puerto Rico
a. Ecosystems recover much faster from natural disasters than
from human effects
XII. Savannas are grasslands with scattered trees
a. SAVANNA  a biome dominated by grasses and scattered
trees
XIII. Deserts are defined by their dryness
a. DESERTS  the driest of all terrestrial biomes, characterized
by low and unpredictable rainfall
i. DESERTIFICATION  the conversion of a semi-arid
region to desert
XIV. Spiny shrubs dominate the chaparral
a. CHAPARRAL  a region of dense, spiny shrubs with tough
evergreen leaves
XV. Temperate grasslands include the North American prairie
a. TEMPERATE GRASSLAND  have some of the
characteristics of tropical savannas, but they are mostly treeless,
except along rivers, or streams, and are found in regions of
relatively cold winter temperatures
XVI. Deciduous trees dominate temperate forests
a. TEMPERATURE DECIDUOUS FORESTS  grow
throughout mid-latitude regions, where there is sufficient
moisture to support the growth of large trees
XVII. Coniferous forests are often dominated by a few species of trees
a. CONIFEROUS FORESTS (a.k.a. TAIGA)  cone bearing
evergreen trees such as spruce, pine, fur, and hemlock dominate
this biome
i. Characterized by long, cold winters, and short, wet
summers that are sometimes warm
XVIII. Long, bitter cold winters characterize the tundra
a. TUNDRA  areas covered permanently with ice and snow
i. PERMAFROST  continuously frozen subsoil