Transcript Ecosystems - LaPazColegio2014-2015

What are Ecosystems?
 of all of the communities within a defined area, along
with their nonliving environment.
 study of ecosystems focuses on the flow of energy and
nutrients
 pathways of energy and nutrients to understand the
factors shape interactions within communities, and
between communities and the nonliving environment
How do Energy and Nutrients
move through ecosystems?
 Nutrients are atoms and molecules that organisms obtain
from their living or nonliving environment and that are
required for survival
 constantly cycle and recycle within and among ecosystems
 change in form and distribution
 Energy moves in a one-way flow through communities
within ecosystems
 continuously replenished
 used and transformed in the chemical reactions that
power life
 ultimately converted to heat that radiates back into space
HEAT
producers
Energy from
sunlight
HEAT
NUTRIENTS
primary consumers
detritus feeders
and decomposers
HEAT
solar energy
heat energy
higher-level
consumers
energy stored
in chemical
bonds
nutrients
HEAT
Fig. 29-1
Energy Flow Through Ecosystems
 Energy enters ecosystems
mainly through
photosynthesis
 energy stored in the
chemical bonds of sugar
molecules
 produce food using
nonliving nutrients and
sunlight
 autotrophs (or
producers)
Energy is
captured
from
sunlight
Carbon dioxide
is absorbed
from the air
photosynthesis
Water is absorbed
from soil, used in
photosynthesis, and
stored in cells
Oxygen is
released
Sugar is
synthesized
and used in
plant tissues
plant
tissues,
growth
Inorganic mineral nutrients
(nitrate, phosphate) are
absorbed from soil and
used in plant tissues
Producersenergy
from
sunlight
CO2
O2
photosynthesis
sugar
H2O
plant tissues
other
nutrients
Fig. 28-1
Energy Flow Through Ecosystems
 An ecosystem’s contribution to Earth’s productivity
depends upon both the ecosystem’s net primary
productivity per unit area and its prevalence.
open
ocean
(125)
tundra
continental (140)
shelf (360)
estuary
(1,500)
tropical
rain forest
(2,200)
coniferous
forest (800)
temperate
deciduous
forest (1,200)
grassland (600)
desert (90)
Energy Flow Through Ecosystems
 Energy passes from one trophic level to another.
 producers (autotrophs)

first trophic level
 primary consumers (herbivores)


second trophic level
feed on producers
 secondary and tertiary consumers


third and fourth trophic levels
meat-eating predators
energy from
sunlight
heat
producers
heat
Mg
O
P
Ca
S
H2O
H
N
primary
consumers
nutrients
heat
detritus feeders
and decomposers
higher-level
consumers
solar energy
heat energy
energy stored in
chemical bonds
nutrients
heat
Fig. 28-2
Energy Flow Through Ecosystems
TERTIARY CONSUMER
(4th trophic level)
PRIMARY CONSUMER
(2nd trophic level)
SECONDARY CONSUMER
(3rd trophic level)
PRODUCER
(1st trophic level)
(a) A simple terrestrial food chain
Energy Flow Through Ecosystems
SECONDARY CONSUMER
(3rd trophic level)
Phytoplankton
PRODUCER
(1st trophic level)
Zooplankton
PRIMARY CONSUMER
(2nd trophic level)
TERTIARY CONSUMER
(4th trophic level)
(b) A simple marine food chain
Energy Pyramid for a Grassland
Fig. 28-6
biological magnification
 Because of the inefficiency of energy transfer, certain
persistent toxic chemicals become increasingly
concentrated in the bodies of animals that occupy
increasingly higher trophic levels by a process called
 Mercury taken up by producers can be highly
concentrated in carnivores such as swordfish, and are a
health hazard to humans as a result
Nutrients Cycles
 nutrients do not flow down onto Earth in a steady
stream from above
 Macronutrients are required by organisms in large
amounts and include water, carbon, hydrogen, oxygen,
nitrogen, phosphorus, sulfur, and calcium
 Micronutrients, including zinc, molybdenum, iron,
selenium, and iodine are required in trace amounts
Nutrient cycles
(biogeochemical cycles)
 describe the pathways nutrients follow between
communities and the nonliving portions of ecosystems
 Reservoirs are sources and storage sites of nutrients
 Major reservoirs are usually in the abiotic environment
Hydrologic (water) cycle
 Water is essential for all terrestrial communities because
other nutrients must be dissolved in it before they can be
used
 major reservoir in the oceans
 travels through the atmosphere, to reservoirs in
freshwater lakes, rivers, and groundwater, and then back
again to the oceans
 The oceans contain more than 97% of Earth’s water
 Solar energy evaporates water, and it comes back to
Earth as precipitation
The Hydrologic Cycle
reservoirs
processes
water vapor in
the atmosphere
precipitation
over land
precipitation
over the ocean
evaporation
from land and
transpiration
from plants
evaporation
from the
ocean
evaporation from
lakes and rivers
lakes and rivers
seepage into soil
runoff
from rivers
and land
water in
the ocean
extraction for
agriculture
groundwater,
including
aquifers
Fig. 28-7
carbon cycle
 Chains of carbon atoms form the framework of all organic
molecules, the building blocks of life
 major reservoirs in the atmosphere and oceans
 Moves through producers and into the bodies of
consumers and detritus feeders, and then back to its
reservoirs
reservoirs
CO2 in the
atmosphere
The Carbon Cycle
processes
trophic levels
burning
fossil fuels
CO2 dissolved
in the ocean
respiration
fire
photosynthesis
producers
consumers
detritus feeders
and decomposers
decomposition
fossil fuels
(coal, oil, natural gas)
Fig. 28-8
nitrogen cycle
 Nitrogen is a crucial component of proteins, many
vitamins, nucleotides (such as ATP), and nucleic acids
 major reservoir in the atmosphere
 reservoirs of ammonia and nitrate in the soil and water,
through producers and into consumers and detritus
feeders, and then back again to its reservoirs
 nitrogen gas (N2) makes up 78% of the atmosphere, this
form of nitrogen cannot be utilized by plants
 Plants utilize nitrate (NO3–) or ammonia (NH3) as
their nitrogen source
 N2 is converted to ammonia by specific bacteria
during a process called nitrogen fixation
 Denitrifying bacteria break down nitrate, releasing
N2 back to the atmosphere
The Nitrogen Cycle
reservoirs
processes
trophic levels
N2 in the
atmosphere
burning
fossil fuels
lightning
application of
manufactured fertilizer
consumers
ammonia and
nitrates in water
producers
uptake by
producers
detritus feeders
and decomposers
nitrogen-fixing
bacteria in soil
and legume roots
decomposition
denitrifying
bacteria
ammonia
and nitrates
in soil
Fig. 28-9
phosphorus cycle
 Phosphorus is a crucial component of ATP and NADP,
nucleic acids, and phospholipids of cell membranes; it is
also a major component of vertebrate teeth and bones
 major reservoir in rock bound to oxygen as phosphate
 moves from phosphate-rich rocks to reservoirs of
phosphate in soil and water, through producers and into
consumers and detritus feeders, and then back to its
reservoirs
reservoirs
The Phosphorus Cycle
phosphate
in rock
processes
trophic levels
geological
uplift
application of
manufactured
fertilizer
runoff
from rivers
consumers
producers
detritus feeders
and decomposers
decomposition
runoff from
fertilized
fields
uptake by
producers
phosphate
in water
phosphate
in soil
phosphate
in sediment
formation of
phosphate-containing
rock
Fig. 28-10
Human Disruption
 Many of the environmental problems that plague
modern society are caused by human disruption of
biogeochemical cycles.
 industrial processes transfer toxic substances such as lead,
arsenic, mercury, uranium, and oil into the environment
 addition of herbicides and pesticides to lawns and shrubs
 farm fields, gardens, and suburban lawns, ammonia,
nitrate, and phosphate are supplied by chemical fertilizers

eutrophication – adding nutrients to water
 combustion of fossil fuels releases sulfur dioxide and
nitrogen oxides into the atmosphere

acid rain
 Carbon emmisions
Fig. 28-11
Acid Deposition is Corrosive
Fig. 28-12
Acid Deposition Can Destroy
Forests
Fig. 28-13
Greenhouse Gases and Global Warming
5 Most heat is radiated
back into space
Sun
1 Sunlight energy
enters the atmosphere
6 Some atmospheric heat is
retained by greenhouse gases
2 Some energy
is reflected back
into space
volcanoes
3 Most sunlight strikes
Earth’s surface and is
converted into heat
vehicle
emissions
4 Heat is
radiated back into
the atmosphere
agricultural
activities
forest
fires
power plants
and factories
homes and
buildings
Fig. 28-14
Global Warming Parallels
Atmospheric CO2 Increases
Fig. 28-15
Glaciers Are Melting
Fig. 28-17