Download Chapter 4: Ecosystems and Communities

Chapter 4: Ecosystems and
Communities
Chapter 4: Ecosystems and
Communities
Vocabulary
• Weather
• Climate
• Greenhouse
• Niche
• Habitat
• Symbiosis
• Succession
• Biomes
Key Concepts
• What factors
determine climate?
• How does competition
shape communities?
• How do communities
change over time?
• What biotic and
abiotic factors
characterize biomes?
4.1 Climate
• Both weather and climate involve variation in
environmental changes such as temperature and
precipitation
So what’s the difference??
• Weather includes day to day changes and
conditions
•Climate refers to averages over long periods of
time
•Climate tends not to be
uniform within a region
and microclimates can
be created
•Northern Hemisphere, the
south side facing trees
receive more sunlight
creating warmer, drier area
Factors that Affect Climate
1) Greenhouse Effect – gases (CO2,
methane, water vapor) in atmosphere allow
light energy in but trap heat
• we need this to keep Earth at livable
temperature
• If concentration of greenhouse gas increases,
temperature rises
• If concentration decreases, temperatures lower
Factors that Affect Climate
2) Latitude
• Sun hits the earth more directly at the equator
than at the poles
- Causes more tropical environment at
equator
•Due to the curvature of the sun, the energy is
spread over a much larger area
Factors that Affect Climate
3) Heat Transport in
Biosphere
•Unequal distribution of heat
creates currents and wind
- Transports moisture and heat
- Warm air less dense and rises,
cold air more dense and sinks
Winds
• Up and down
movements of the
air masses create
winds
Currents
• Similar heating and cooling patterns also
create ocean currents
4.2 Niches and Community
Interactions
• Organisms occupy different places due to
varying conditions that allow them to grow
and reproduce
• Varying conditions help define where
organisms can live
• 2 factors that shape where and how
organisms live are biotic and abiotic
factors
• Any of these biotic or abiotic factors that
restricts the number of organisms, their
distribution, existence, or ability to
reproduce is called a limiting factor
• An example of limiting
factor is the timberline
– Elevation, winds,
shallow soil, etc..
• Factors that limit one
population may have
an indirect affect on
other populations
within that community
– Lack of water,
decreases seed
production, affects
mice that are
dependent on those
seeds
• Range of Tolerance
– The ability of an
organism to withstand
fluctuations in biotic
and abiotic factors
– Catfish can withstand
warmer water than
trout or bass
Organisms in Ecosystems
• Habitat
(address) =
area where an
organism lives
– Includes biotic
and abiotic
factors
Organisms in Ecosystems
• Niche (job)=full range of physical and
biological conditions in which the organism
lives and the way the organism uses those
conditions
– Ex: place in the food web, range of
temperatures the organism needs to
survive, food the organism eats
• If two species try to occupy the same niche, it
creates competition
– Result: one species will not survive
extinction
• No two species can share the same niche in
the same habitat
• Different species can occupy different niches
that are very similar
Interactions
• Organisms in an ecosystem interact constantly
– Shapes the ecosystem
• Ways of interaction
– Competition
– Predation
– Symbiosis
• Mutualism
• Commensalism
• Parasitism
Resource=necessity of life
• Competition= when
organism try to use a
resource at the same
place/time
– Two lizards want to eat
the same type of insect
• Predation= one
organism captures and
feed on another
– Bald Eagle (predator)
eating fish (prey)
• Keystone species = change in a single
species within a population can cause
dramatic changes in community
– Examples: wolves of Yellowstone, sea otters,
black-footed ferrets
Symbiosis= two species live
closely
Mutualism= both species benefit
from the relationship
Flowers and insects
Commensalism= one species
benefits, the other is not helped
or harmed
Whales and barnacles
Parasitism= One organism lives
on/inside the other and harms it
Tapeworm , trichinella
4.3 Succession
• Ecosystems change—human intervention, natural
disaster
• Series of predictable changes that occur in a community
over time = ecological succession
• Primary succession= occurs on surfaces where there is
no soil
– Volcanoes build up an island
– Pioneer species= 1st organisms to populate
• Once a community becomes stable, mature, and little
change in species, it is known as a climax community
• Secondary succession = some kind of change happens,
but soil remains
– Fire
– Land cleared/plowed
• Change in species is also slow, as in primary
succession, but…
– Seeds in the soil from previous vegetation takes over
4.4 Biomes
• Biome = large group of ecosystems that
share similar climax community
• Biomes are located on land (terrestrial)
and in water (aquatic)
• Aquatic Biomes
1. Marine
-
Refers to salt waters (oceans, seas)
Contains the largest amount of biomass (living
material)
Photic zone: shallow, sunlit
-
-
Rocky shores, sandy beaches, mudflats
Aphotic Zone: deeper, no sun light
• Areas where salt water and fresh water
meet are called estuaries
– Salinity (amount of salt) ranges between very
salty to fresh water
– Changes with the tides
• Tides
– Rise and fall of ocean tides are caused by the
sun and moons gravitational pull.
– Intertidal zone: portion of shoreline that is
between high and low tides
• Size varies depending on slope of land and height
of tide
2. Freshwater biomes
- streams, lakes, ponds
- limiting factors: light and temperature
Terrestrial Biomes
• Two abiotic factors that affect terrestrial
biomes are temperature and precipitation
• 6 different types of biomes
– Tundra, taiga, grassland, deciduous forests,
rain forests, and deserts