Interaction of organisms with
their physical environment
through a flow of energy and a
cycling of nutrients. All
ecosystems run on energy
captured by:
Detritivores: Dine on detritus (small
particles of organic matter
Consumers: Heterotrophs, they feed of
tissues, wastes and remains of producers.
They are clasified by their diets:
Herbivores: Feed from plants
Carnivores: eat the
flesh from animals
Parasites: Feed of the
tissues of their living hosts
Omnivores: devour animal
and plant materials
Decomposers: feed on organic wastes and remains
Primary producers: Autotrophs or
self-feeders, they capture energy from
the sun and use it in photosynthesi
Trophic levels: Positions of
every organisms in a food
chain. Graphically represented
as ecological pyramids.
1st level: Primary producers
2nd level: Hervobores
3rd level: Carnivores
4th level: Detritivores and
consumers
Food chain: Description of who eats whom in
one path of energy flow in an ecosystem.
Flow of energy
through ecosystems:
Biomass pyramid: depicts dry weight of
orgnisms at each trophic level of an ecosystem.
Primary production: Primary producers
capture energy and convert it into biomass.
Ecological efficiency: Tends to be greatest in aquatic
systems, where primary producers usually lack lignin and
consumers tend to be ectotherms.
Energy pyramid: Diagram that depicts the energy
that enters each trophic level.
BIOGEOCHEMICAL
CYCLES:: Slow movement
of a nutrient among
environmental
reservoirs and into and
out of food webs.
Water cycle: Movement of water among
Earth’s atmosphere. Sunlight causes
evaporation, forming clouds and they fall as
precipitation (rain, snow or hail) going back
to the primary source.
Watershed: Land area that drains
into a particular stream or river.
Soilwater: Water between soil particles.
Aquifier: Porous rock layer that holds
groundwater, drained through soil layers.
Groundwater: Water in soil and aquifiers.
Runoff: Water that flows
over soil into streams.
Fresh water makes up a tiny portion of the global water supply.
Excessive water withdrawals threaten many sources of drinking
water, irrigation methods for example.
Eutrophication:
Nutrient enrichment
of an aquatic system.
Carbon cycle: Movement of
carbon, mainly between the
oceans, atmosphere and
living organisms.
1. Plants take up carbon dioxide from the air for use in photosyntesis.
2. Carbon returns to air by aerobic respiration.
3. Carbon diffuses between the atmosphere and the ocean.
(Bicarbonate forms when carbon dioxide dissolves in seawater)
4. Marine produces use bicarbonate in photosynthesis and marine
organisms release carbon dioxide from aerobic respiration.
Atmospheric cycle: Biogeochemical
cycle in which a gaseous form of
an element plays a significant role.
5. Some marine organisms incorporate carbon into their shells; when they
die become part of sediments and over-time turn in limestone and chalik.
6. Burning of fossil fuels derived from the ancient remains of plants puts
additional carbon dioxide into the atmosphere.
GREENHOUSE
GASES AND
CLIMATE CHANGE
Greenhouse effect:
Caused by excess of
carbon dioxide.
Greenhouse gas: Atmospheric gas
that absorbs heat emitted by Earth’s
surface and remits it, thus keeping
the planet warm.
2. More light energy reaches and warms Earth’s surface.
3. Earth’s warmed surface emits heat energy, some of it goes
to space and the rest is absorbed and emitted in all direction by
greenhouse gases.
1. Earth’s atmosphere reflects some sunlight energy back into space.
Global climate change:
Long-term alteration of
Earth’s climate.
NITROGEN CYCLE: Atmosphere
is 80% nitrogen. Movement of
nitrogen among the
atmosphere, soil, water and
food webs.
Nitrogen fixation: Incorporation of
nitrogen from gas into ammonia.
Ammonification: Breakdown of
nitrogen-containing organic material resulting
in the release of ammonia an ammonium ions.
Nitrification: Conversion of amonium to nitrates.
Denitrification: Conversion of nitrates or
nitrites to gaseous form of nitrogen.
Human activities disrupted the nitrogen cycle:
Burning fossil fuels releases nitrous
oxide, which is a greenhouse gas, into
the air and destroys the ozone layer.
Wastewater that escapes from
septic systems is another source of
nitrate pollution.
Use of synthetic fertilizer encourages the
production of nitrous oxide by bacteria. It is also a
source of nitrates, which pollute drinking water.
PHOSPHORUS CYCLE: Movement of
phosphorus among Earth’s rocks and
waters, and into and out of food webs.
Sedimentary cycle: Biochemical cycle in which the
atmosphere plays little role and rocks are the
major reservoir. Weathering puts phosphates into
water and producers take up dissolved phosphates.
Phosphate-rich wastes are a natural fertilizer, and
phosphate from rocks can be used to produce fertilizer on
an industrial scale.