Chapter 4 – Ecosystems and
Communities
Weather
climate help dictate what
________ and ________
organisms can live where they do
Weather
________ = the day-to-day condition of Earth’s
atmosphere at a particular time and place
Climate = the average, year-after-year conditions of
________
temperature and precipitation in a particular region
Climate is affected by several
latitude the
factors; heat, ________,
movement of heat by winds and
oceans, precipitation
___________, and the
shape and elevation of the land
Greenhouse
effect = the natural situation in which heat is
_______________
retained by a layer of greenhouse gases in the atmosphere
CO2 methane
_____,
________, and water
__________
vapor
are important in trapping heat 
let light and heat in, but only let
limited heat back out
Latitude has an effect on climate since Earth has a tilted axis
_______
Because Earth is tilted, different parts of Earth receive
radiation
different amounts of ________
patterns
Differences in angles of sunlight = different heating
___________
Earth has 3 main climate zones because of these differences;
polar, temperate, and tropical
The uneven heating of Earth
ocean currents
creates winds
_____ and ____________
Warm air _____
this is
rises and cold air _____
falls
what creates air currents
Ocean currents are similar  warm water
_____
rises and cold water ____
falls
Continents and ___________
land masses can affect winds and currents
__________
heat energy
Both winds and currents are a way to transport __________
through the biosphere
Both ______
________ things
living and nonliving
help to shape an ecosystem
Biotic factors the biological influences on organisms
____________=
within an ecosystem (living factors)
Abiotic factors = physical (nonliving) factors that shape
_____________
ecosystems
humidity wind, nutrient
Ex. Temperature, precipitation, _________,
availability, ____,
soil ________
sunlight
survival
Together, biotic and abiotic factors determine the _______
and _______
growth of an organism as well as the productivity of an
ecosystem
_______
Habitat = the area where an
organism lives  it include
biotic/abiotic factors
Niche the full range of physical and biological conditions
______=
in which an organism lives and the way in which it uses its
conditions
occupation
It can be thought of as an organisms __________
A niche includes the types of food an organism eats, how it
gets its food, and who it is food for
_________________
Physical conditions like temp and amount of water present
are a large part of an organisms niche
No two species can share the
same niche in the same habitat
 why do you think that is?
Different species can occupy
_______
similar niches
Interactions within ecosystems play an important role
___________
Competition is a natural part of an ecosystem; organisms
____________
are trying to use the same resource at the same time
Resource = any necessity of life, such as water, nutrients,
_________
light, food, or space
Direction competition results in a loser and a winner  the
loser fails to survive
The ___________________________
competitive exclusion principle states that no two
species can occupy the same niche in the same habitat at the
same time
Predation
_________ = an interaction in which one organism captures
and feeds on another organism
_______ = the organism that
Predator
does the killing and eating
Prey = the organism that
_____
gets caught and eaten
Symbiosis
_________ = any relationship in which two species live
closely together
There are 3 main classes of symbiotic relationships;
mutualism, commensalism, and parasitism
1. Mutualism = a relationship
where both species benefit
Ex. Flowers/insects
2. Commensalism = a relationship where
one member benefits and the other is
neither helped nor harmed
Ex. Barnacles/whales
3. Parasitism = a relationship where
one organism lives on or inside another
organism and harms it
Ex. Fleas and ticks/mammals
Summary:
Mutualism
How many
benefit?
How many are
harmed?
How many
needs are met?
Commensalism
Parasitism
Ecosystems are constantly changing in response to natural
and human disturbances
___________________
Ecological succession = the
series of predictable changes
that happen over time
Primary
succession = succession that
________________
occurs on surfaces where no soil exists
Pioneer
species = the first species to populate the area for
_____________
primary succession
Lichens (fungus and algae that can grow on bare rock) are
_______
often pioneer species and help break up the rock
Ex. Surfaces formed after
volcanoes erupt
Secondary
succession = succession that occurs after an
__________________
ecosystem has been changed by a large event like a fire, flood,
or human destruction
Succession seems to go through predictable stages to produce
climax community – a very stable community
a “________________”
Section 4-3:
Biomes
A
biome = a complex of terrestrial communities that covers
_______
a large area and is characterized by certain soil and climate
conditions and particular assemblages of plants and animals
Not every species can live in every
biome, it depends on their
___________
adaptations
Adaptation = an inherited characteristic that increases an
___________
organism’s ability to survive and reproduce
_________
Tolerance = the ability to survive and reproduce under
conditions that differ from their optimal conditions
There are at least 10 different major biomes
1. Tropical rain forest
Home to more species than all other biomes combined
The tall trees for a dense covering = the canopy
The second layer under the canopy = understory
Hot and wet year-round with a lack of nutrients in soil
2. Tropical dry forest
Warm year-round, wet and dry seasons, rich soil
During the dry season almost all the trees drop their leaves to
save water
__________
Deciduous tree = a tree that sheds its leaves during a
______________
particular season
3. Topical savanna
Characterized by a cover of grass
Spotted with trees and groves of trees
Warm temps, seasonal rainfall, compact soils, frequent fires
4. Desert
25 cm of precipitation a year
Very dry with less than ______
Low precipitation, variable temps, mineral rich soil (low in
organic material)
5. Temperate grassland
Usually have a large mix of grasses and fertile soils
They once covered a vast area of the Midwestern/central US
Warm/hot summers and cold winters, seasonal
precipitation, fertile soils
6. Temperate woodland and shrubland
Tend to have a mix of large wooded areas and grasslands
Hot/dry summer, cool/moist winters, thin soils, periodic
fires
7. Temperate forest
Has a mix of both deciduous and coniferous trees
Coniferous trees = trees that produce cones and most have
_______________
needle-like leaves
Cold/moderate winters, warm summers, year-round
precipitation
8. Northwestern Coniferous Forest
Moist air from the ocean helps create rain for the biome
Mild temps, much precipitation most of the year, cool/dry
summers
9. Boreal forest (taiga)
Experience bitter cold winters, but summers are warm
enough for growth
Long/cold winters, mild summers, high humidity, moderate
precipitation
10. Tundra
Characterized by _______
tundra – a layer of permanently frozen
subsoil
Thawing and freezing of soil if rough on plant roots, limiting
plant growth
Strong winds, low precipitation, long/cold/dark winters,
permafrost
Some areas of Earth don’t fall into a specific biome, like
mountain ranges and polar icecaps
There is no definite line when crossing from one biome to
another, habitats can gradually change
Water covers almost ¾ of Earth, so
many organism live in aquatic habitats
Aquatic ecosystems are determined by
depth flow, _____,
temp and chemistry of the
______,
water
________
Latitude is also an important factor for
aquatic biomes; polar, temperate, and
tropical oceans can be very different
Freshwater ecosystems are divided into 2 main types;
flowing-water and standing-water
Flowing-water ecosystems – made up
of rivers
_____, streams, creeks
______, and brooks
Organisms must be adapted
to the flowing water
Near the source of the flow there is lots of _______________
dissolved oxygen
in the water and little plant life
Farther downstream, water slows and sediment
________ builds up
leading to more plant life
Standing-water ecosystems –
made up of lakes
_____ and ponds
_____
The relatively still water provides
habitats for many organisms
Plankton
________ = general term for the tiny free-floating
organisms that live in fresh and salt water
Phytoplankton = unicellular algae plankton
_____________
Zooplankton = animal plankton
____________
Wetland = an ecosystem in which water covers the soil or is
________
present at or near the surface of the soil for at least part of
the year
standing fresh, salt, or ________
brackish
Water can be flowing or ________;
Estuaries wetlands formed where rivers meet the sea
_________=
They have both fresh and salt
water and are affected by the tides
____
Most are shallow so photosynthesis
____________
can take place
Much of the organic material
ends up as _______
detritus – tiny
pieces of food
Salt marshes = temperate-zone
____________
estuaries dominated by salttolerant grasses and seagrasses
Mangrove swamps = coastal
________________
wetlands that are widespread across
tropical regions; dominated by salt
tolerant trees called mangroves
Marine ecosystems generally refer to salt-water ecosystems
Light is an important factor in
_____
marine ecosystems – it can only
reach so far
Photic zone = the well-lit
__________
upper layer of water where
photosynthesis is limited to
(only about 200 meters deep)
Aphotic
zone = the permanently
___________
dark zone of water
The ocean is also divided into zones based on the
depth and distance from shore; the intertidal zone,
the coastal ocean, and the open ocean
zone covers the ocean floor, so it is not specific
The benthic
___________
to any of the 3 zones
Benthos = organisms that live attached to
________
or near the bottom of the ocean
The _____________
intertidal zone – experiences
regular and extreme changes
Tides and currents create the extreme changes
Competition among organisms in the rocky
intertidal zone often leads to ________
zonation – the
prominent horizontal banding of organisms
that live in a particular habitat
The ___________
costal ocean – extends from the low-tide
mark to the outer edge of the continental shelf
The continental shelf is usually shallow
enough that it is in the photic zone
__________
Coral reefs and __________
kelps forests
are very productive habitats
that are found in this zone
The __________
open ocean – begins at the edge of
the continental shelf and extends outward
It is the largest marine zone and
90% of the ocean
covers about _____
A lot of photosynthetic
It generally has low levels of activity happens here due to
nutrients and low productivity large surface area