1. Two Major Components of Ecosystem
1. Abiotic
• Consists of nonliving chemical
and physical components such as water,
air, nutrients in the soil or water and solar energy.
• Physical and chemical factors that influence living
organisms in land (terrestrial) ecosystems and aquatic life
zones
Terrestrial Ecosystem Aquatic Life Zone
1. Sunlight 1. Light penetration
2. Temperature 2. Water current
3. Precipitation 3. Dissolved nutrient
concentrations4. 4. Wind (especially N and P)
5. Latitude 4. Suspended solids
(distance from equator) 5. Salinity(the amounts of
various 6. Altitude inorganic minerals or salts
dissolved
(distance above sea level) in a given volume of water)
7. Fire frequency
8. Soil
2. Biotic
• Made up of biological components consisting of living and
dead plants, animals and microorganisms
• The Major Biological Components of Ecosystem
a. Producers (Autotrophs)(self-feeders)
o Make their own food from compounds that are obtained
from their environment.
o Are the source of all food in an ecosystem
o On land most producers are green plants.
o In freshwater and marine ecosystems, algae and plants
are the major producers near shorelines
o In open water, the dominant producers are
phytoplankton (most of them microscopic) that float or
drift in the water.
o Most producers capture sunlight to make carbohydrates
(such as glucose) by photosynthesis
o A few producers, mostly specialized bacteria, can
convert simple compounds from their environment into

2. more complex nutrient compounds without sunlight a
process called chemosynthesis
b. Consumers (Heterotrophs) (“other feeders”)
o Get their energy and nutrients by feeding on other
organisms or their remains.
a. Primary consumers = are those that eat producers
(plants) as a
source of food also known as herbivores.
b. Secondary consumers or carnivores = eat other
animals
c. Omnivores = have mixed diet that include both plants
and animals
d. Decomposer
= Mostly certain types of bacteria and fungi are
specialized consumers that recycle organic matter in
ecosystems
=They do this by breaking down (biodegrading) dead
organic material to get nutrients and releasing the
resulting simpler inorganic compounds into the soil and
water, where they can be taken up as nutrients by
producers
Detritus
• Consisting of parts of dead organisms and cast-off fragments
and wastes of living organisms.
KINDS OF ORGANISM INTERACTIONS
1. Predation = situation in w/c an organism of one species (the
predator) captures and feeds on parts or all of an organism of
another species (the prey)
2. Competition = a kind of interaction in w/c two organisms strive
to obtain the same limited resource and in the process both
organisms are harmed to some extent.
a. Intraspecific competition – competition w/c is between
members of the same species
b. Interspecific competition – competition among
organisms of different species
3. Symbiotic relationships
a. Symbiosis – is a close, long lasting, physical relationship
between two different species of organisms.

3. – the two organisms are usually in physical
contact and
at least one of the organisms derives some sort of benefit
from this
contact
b. Parasitism – is a relationship in w/c one organism,
known as the parasite, lives in or on another organism,
known as the host, from w/c it derives nourishment.
1), Ectoparasite – those that live on the surface of their
host
2). Endoparasite – those that live inside the bodies of
their hosts
c. Commensalism – relationship in w/c one organism
benefits while the other is not affected. Ex Remora fish
attached to shark
d. Mutualism – symbiotic relationships that are actually
beneficial to both species of organisms involved
Module 2
ABIOTIC COMPONENTS OF THE ENVIRONMENT
Abiotic components
 The physical & chemical factors that influence the various
metabolic & physiological processes of the organisms as well
as regulate their functions
 The major abiotic factors are climatic, edaphic & topographic
factors
 These factors are classified as resources and conditions
A. Resources – are those factors that can be consumed or
directly utilized by organisms like nitrogen, phosphorus and
potassium .
B. Environmental conditions
– Are factors that are not directly utilized by the
organisms but affect the growth and survival of the
organisms.
– However, these factors can also be changed or
affected by the organisms such as temperature or
salinity
1. Climatic Factors

4. Climate
– is the result of interplay of the seasonal factors like
temperature,
humidity, precipitation and light conditions in a particular
area
– it places the greatest constraint on the organisms and it
influences the
weather condition in a local area.
– a region’s general pattern of atmospheric or weather
conditions over a
long period
– is the long term average pattern of weather
– it determines the availability of heat and water, influences
the amount of solar radiation that can be captured by the
plants
Weather
– is a temporary condition of the atmospheres, a combination
of
temperature, pressure, humidity, precipitation, sunshine wind
direction
and speed, cloudiness and other atmospheric conditions at
specific
time and place
Climate and weather are directly affected by energy and physical
process in the environment is also influenced by the activities of living
organisms.
a. Solar radiations
 Is the amount of light intercepted by the earth that causes
thermal patterns.
 Energy that travels through space in the form of waves of
particles.
 The solar radiation travels through the space as waves
describe as wavelength,
 The amount of solar radiation varies over the earth
surface depending on the latitude and altitude
 The higher the latitude the lesser solar radiation is
intercepted because the radiations are spread over larger

5. area. This explains why temperature is higher in tropic
than at the poles.
 The seasonality of solar radiation, temperature and day
length also increases with latitude.
 The Artic and Antartic region have varied daylengths from
continuous daytime during summer solstice.
 The equatorial region receives the most radiation and
equal occurrence of day and night.
 The pattern controls the mean annual temperature around
the globe
 The rotation of the earth and its movements around the
sun generates the wind and ocean currents. These
movements influence the distribution of rainfall.
b. Temperature
 Is the degree of heat that is natural to the body of living
things.
 It has pervasive influence on life on earth by affecting
the rates of photosynthesis and stored energy in plants
 It also influences the amount of moisture and the need for
it by the organisms because it takes part in the chemical
reactions in all living organisms.
 Variation in the environmental temperature affects the
distribution and abundance of organisms.
 Temperature varies depending on the latitude, altitude,
season, and continents, microclimatic variation and depth
variation.
 Air temperature decreases with altitude, the higher the
altitude the lower the temperature, decreasing by 0.6°C
every 100 meters.
 It then influences the growth of plants; the higher the
altitude the greater is the pressure thus plants become
stunted.
 Temperature also affects the function of plants and cold-
blooded animals by controlling the rate of their metabolism.
 Plants can tolerate extreme cold by frost hardening its
body part but the response is for short period only.

6.  Prolonged exposure to extreme conditions like heat and
cold could affect their physiological processes and may
cause death.
 Plants living in desert have thick barks and small leaves
to reduce the loss of water.
 Some plants were able to survive in very low temperature
by their creeping habits to avoid too much exposure to
extreme low temperature.
 Animals on the other hand can maintain a fairly constant
internal body temperature by using their behavioral and
physiological means but they are still categorized into three
major groups;
a. Poikilothermic (variable body temperature)– have
variable body temperature influenced mainly by the
existing temperature. Ex Sea lamprey
b. Homeothermic (constant body temperature) – are
organisms that have body temperature that are
independent of the environment Ex birds, mammals
c. Heterotherms – organisms that can switch to
endotherms (source of their body heat is internal) and
homoethermic. During environmental extremes, some
animals may enter a state of torpor (state of mental and
motor inactivity with partial or total insensibility) by
reducing their metabolism, heartbeat and respiration to
reduce their energy cost and stay warm or cool.
Hibernation – seasonal torpor over winter. Condition
especially mammals, of passing the winter in a torpid
state in w/c the body temperature drops nearly to freezing
and the metabolism drops close to zero.
- Amphibians move in and out the water while desert
animals burrow their bodies to the ground to seek shade.
- Some desert animals also use hyperthermia to reduce
the
difference between body and environmental
temperaturewhile others employ countercurrent
circulation in the blood to reduce heat loss.
c. Humidity
 The amount of water vapor in the air

7.  The amount of water in the air expressed as the percentage
of saturation vapor pressure is relative humidity
 Temperature plays a role in climate and to the amount of
water it can hold
 Warm air can hold more water than cold air. If the cool air
have constant amount of moisture, the relative humidity
increases and if it reaches the saturation vapor pressure it
will condense and becomes cloud.
 When the particles of water or ice become too heavy in the
air, it will fall as rain or snow.
 The relative humidity of the atmosphere greatly influenced
the land organisms The greater the humidity the lesser is the
risk of dehydration in the organisms
 Humidity and shortage of available water are very much
linked. Areas with low water such as desert have also low
humidity.
 Other factors such as temperature and wind significantly
affect the rate of evaporation that affect the humidity.
 The capability of the organisms to adapt to these variable
moisture condition influences their distribution in a habitat.
 Organisms that have poor water control lives in damp habitat
while organism that have the ability to regulate their water
intake survive in desert environment.
d. Movement of air and water
 The global pattern of circulation is the vertical movements of
the air masses and this is due to the heating and cooling air
mass that rise and sink.
 As the earth spin on its axis, it deflects the air and water to
the right of Northern hemisphere and left of the Southern
hemisphere called as Coriolis effect.
= the effect produces the three types of global wind pattern
a. the westerlies
b. the northeast trade winds
c. the easterlies
 The movement of air and water significantly influence the
ventilation of an organism thus it affects the distribution and
survival of organisms

8.  It can serve as dessicating medium especially in windy areas
of mountains.
 The greater is the density and viscosity of the water the
slower the movement and so its dessicating effect.
 The wave action in shore also affects the distribution of the
different species.
 Heavy water with high breaking action is damaging to the
organisms in the areas.
2. Edaphic Factors
 Are the physico-chemical properties of soil that limit the
abundance and distribution of living organisms
 Soil is a natural product of unconsolidated mineral and organic
matter on Earth’s surface. It is the medium in w/c plant grows
and the site of the decomposition of organic matter.
 Soil served as the habitat of animals and the anchoring
medium of plants and source of their nutrients and water
a. Soil Characteristics
o Soil is a complex mixture of eroded rock, mineral nutrients,
decaying organic matter, water, air, and billions of living
organisms, most of them microscopic decomposers.
o Soil is a renewable resource
o Soil was formed from the weathering of rocks and minerals
through mechanical or physical weathering for a very long
time.
o Plants and animals have pronounced influence on soil
development when they colonize the weathered rocks
o The roots of the plants penetrate the soil and pump up the
nutrients converting this to organic form through
photosynthesis
o When plants die, the bacteria will decompose the debris
into inorganic nutrients.

9. o Some invertebrates like millipedes, earthworms and mites
consume the fresh materials in the soil and leave the
partially decomposed in the soil through their excreta
thereby increasing the amount of inorganic materials in the
soil.
o Mature soils area ranged is a series of zones called soil
horizon, each with distinct texture and composition that
varies with different types of soils
o A cross-sectional view of the horizons in a soil is called a
soil profile
o Most mature soils have at least three of the possible
horizons
1. The Surface Litter Layer, or O Horizon (Top Layer)
 Consists mostly of freshly fallen and partially
decomposed leaves, twigs, animal waste,
fungi, and other organic materials
 Normally it is brown or black.
2. The Topsoil Layer or A Horizon
 A porous mixture of partially decomposed
organic matter called humus(this material helps
retain water and water-soluble nutrients, w/c can
be taken up by plant roots) and some inorganic
mineral particles.
 It is usually darker and looser than deeper
layers.
 A fertile soil that produces high crop yields has a
thick topsoil layer with lots of humus. This helps
topsoil hold water and nutrients taken up by
plant roots
 The color of its topsoil tells us a lot about how
useful a soil is for growing crops. For example
darkbrown or black topsoil is nitrogen-rich and
high in organic matter. Gray, bright yellow, or red
topsoils are low in organic matter and need
nitrogen enrichment to support most crops.
3. The B Horizon (subsoil) and the C Horizon (parent
material)

10.  Contain most of a soil’s inorganic matter, mostly
broken-down rock consisting of varying mixtures
of sand, silt, clay,and gravel
 The C Horizon lies on a base of unweathered
parent rock called bedrock
 As the water seeps down, it dissolves various
soil components in upper layers and carries
them to lower layers in a process called
leaching (process in which various chemicals in
upper layers of soil are dissolved and carried to
lower layers and, in some cases, to the
groundwater)
b. Substrate texture and structure
o Texture is determined by the proportions of
the soil particles of different sizes; the sand (medium-size
particles) silt (fine particles), gravel (coarse to very coarse
particles) and clay (very fine particles). Soils with roughly
equal mixtures of clay, sand, silt, and humus are called
loams
o Loams are the best soils for growing most
crops because they hold lots of water but not too tightly for
plant roots to absorb
o It is important in the movement and
retention of water in the soil.
o Soil particles, particularly clay-humus
complex are important to nutrient availability and to the
carbon exchange of the soil
o Color is also another identification of soil,
pale brown to reddish and yellowish color indicates good
drainage of water while dark brown and blackish color
indicates poor drainage.
o Though the dark colors may indicate the
presence of organic matter it does not always indicate its
richness in organic matter because some rocks that are
volcanic in origin have dark color as well.
c. Ph

11. o The acidity or alkalinity of a soil, as measured by its pH
influences the uptake of soil nutrients by plants
o The ph of the soil or water influences the distribution and
abundance of organisms
o A ph that is either too low or too high is damaging to the
organisms.
o It may also indirectly affect the organism by affecting the
nutrient and concentrate the toxin in the soil.
o Acidic soil may build up toxic ions while alkaline conditions
may trap the nutrients in the soil
3. Salinity
• Salinity is the measure of salt in the water
• It can exert very significant effects on the abundance
and distribution of species because of difference in water and
ionic control abilities of organism
• Hypotonic organisms such as bony fish find it very hard
to live in normal seawater because they have high risk of water
loss.
• Salt tolerant plants (halophytes) tolerate high salinity by
concentrating electrolytes in the cell vacuoles while the
cytoplasm are left normal.
4. Contaminants and pollutants
• Contaminants and pollutants are materials that maybe
present in the environment that may or may not cause negative
biological effects to the organisms
• Such materials may be derived from natural and or
anthropogenic sources to w/c the organisms may respond
differently.
• Some species may develop tolerance and protection from
the polluting substances such as that of the tolerance of
bacteria against antibiotics and that of the insects with the
pesticides.

12. B. LIMITING RESOURCES
 The resources are the materials that are utilized by the
organism for the maintenance of their bodies such as solar
radiation, nutrients, food and space
 Resources may be categorized as essential or
substitutable.
 Essential resources are not replaceable by an
alternatives such as nutrients while substitutable are resources
that can be partly or wholly replaced when the consumption of
the resources has exceeded its maximum ability to support.
1. Light
 Light is a resource continuum that is comprised of spectrum of
different wavelengths that are usable for photosynthesis.
 Plant utilizes only the wavelength between 400-700 nm and this
band is called photosynthetically active radiation (PAR) and
falls within visible spectrum.
 Solar radiation differs from other resources because it passes
through the system only once and if it is not captured and used
immediately, it is lost.
 Variation in the amount of solar radiation however, varies
depending upon the latitude.
 Radiation is greatest at low latitudes while seasonal variation is
greatest at high latitudes.
 Systematic variation may influence the control processes of the
organism to develop diurnal and seasonal rhythms.
 Random variations due to cloud cover, shading and reflections
of waves affect the plants species by limiting the potential for
optimal utilization of light.
2. Inorganic materials
Three inorganic materials are considered vital for the living
organisms in the environment.
a) Water molecules
o Needed by all organisms to survive thus influence their
distribution and abundance.
o It is needed by plant for transpiration (loss of water vapor at
the aerial portion of the plant like leaves) and photosynthesis
(process where in plants convert radiant energy to chemical

13. energy) while animals used water as a medium for many
metabolic activities in their body.
o Animals usually drink water or obtain it from food it takes while
plants usually obtain water from the soil using their elaborate
root system.
b) Carbon dioxide
o Is fixed by plants into living materials through photosynthesis
c) Oxygen
o Becomes a limiting factor in aquatic or water logged sediments
because of its role in aerobic respiration of animals
1. Nutrients
• Macro and micronutrients are required by organisms to
function properly & they obtain these from the food, soil or
surrounding water.
• Macronutrients include nitrogen, phosphorus, sulfur,
potassium, calcium, magnesium and iron
• It is required by all organism in large quantities that it
become a limiting factor to some organism when it is
limited in the environment
• The extraction by plants of nutrients from the soil is done
through the root system
• These are close relationship between water and minerals,
so lack of water can make the mineral unavailable
2. Food
• The heterotrophic organisms require foods and each
organisms is alternately a consumer or a prey within the
food chain (series of organisms in w/c each eats or
decomposes the preceding one)or food web(complex
network of many interconnected food chains and feeding
relationships).

14. • Some organisms are specialist, feeding upon a single
species only thus these are restricted closely to source of
prey and force to live in patches
• Moreover, many food sources are seasonal and the
nutritional value may vary with season.
• Carnivores have difficulties finding, capturing and handling
prey items and most of times, their prey have developed
physical or behavioral defenses against their consumers.
This process is called coevolution
3. Space
• All organisms require space within w/c they can live
• Plants may require only small space but the top carnivores
require bigger space.
• Space becomes an important resource because it contains
other resource such as food.
• However, space is also required by other organisms for their
growth, breeding, hibernation and for nesting.