2. Topic Outline:
❑ What is a System?
❑ The Ecosystem Concept
❑ Experimentation in Ecology
❑ Types of Ecosystem
❑ Ecosystem Components
3. ➢ A system consists of interdependent parts that make up a whole.
➢ Each part has a specific function, yet the expression of the role of
the whole system is dependent upon the proper functioning of all
other parts.
➢ A whole system will fail to function unless it receives an input from
the outside on which the system can act to produce a specific
output.
➢ The components plus their interactions and with the necessary
input deliver the specific output which each part cannot do on
its own. The whole is greater than the sum of each part.
Wh a t i s a S Y S T E M ?
5. ➢ Ecosystem is defined as any unit that includes all
of the organisms in a given area interacting with
the physical environment so that a flow of
energy leads to clearly defined trophic structure,
biotic diversity, and material cycles (i.e.,
exchange of materials between living and
nonliving parts within the system).
➢ The study of ecosystems mainly consists of the
study of certain processes that link the living, or
biotic, components to the non-living, or abiotic,
components. Energy transformations and
biogeochemical cycling are the two main
processes that comprise the field of ecosystem
ecology.
The Ecosystem Concept
6.
7. Forest ecosystems,
which consist of
bacteria, plants, birds,
mammals, reptiles,
amphibians, soil, water
and air, differ from
other ecosystems in
that trees and other
woody vegetation
dominate them. Each
of these components
plays an important role
in the function and
health of the forest.
8. Linkages among components of an ecosystem
Sun
(solar energy)
Plants
Photosynthesis
Herbivores
Carnivores
Consumption
Detritivores
Decomposition
SOIL
(Nutrients and
Water)
Atmosphere
(O2, CO2 and
Water)
9. EXPERIMENTATION IN ECOSYSTEM
Until 1960S, ecological experimentation were largely descriptive
(animal behavior, species in the area)
More recently: emphasis on experimentation (trials to test phenomena).
Involves active manipulation then observe
Study of ecology is based on collection of theories that form the foundation of
our understanding of the natural world
10. ➢ In any ecology and environmental science
study, the systems or holistic approach is
used in addressing ecological problems. That
is, we look at the different natural systems,
what their component parts are and how
they interact with one another in order to
produce the outputs.
➢ This approach complements to the
interdisciplinary characteristic of ecology &
environmental science.
11. ➢ Theory – a statement of explanation of cause & effect that seems
plausible but cannot be directly confirmed or rejected by
experimentation
➢ Important because they permit the formulation of testable hypothesis
or questions regarding natural phenomena
➢ The key to the advancement of science in general and ecology is
people asking questions about nature and collecting evidence or
data to answer those questions
EXPERIMENTATION IN ECOLOGY
12. ➢ Hypothesis – a statement about cause and effect that
can be tested experimentally (e.g. change in leaf size)
➢ Reflects past experiences and knowledge regarding similar
questions; it is based on what is already known
➢ Testing a hypothesis involves collecting data by experimentation
➢ Observational or descriptive studies are limited because mere
observed phenomena do not provide evidence of cause and effect
and do not allow for rigorous hypothesis testing
EXPERIMENTATION IN ECOLOGY
13. ➢ Experiments may be performed in a laboratory (under
controlled conditions) or in the field (under natural conditions)
➢ Inductive method: from specific knowledge and expands to more
general knowledge
➢ Deductive: general – specific
➢ Two variables in controlled experiment: independent (not
affected) and dependent (affected) variable)
EXPERIMENTATION IN ECOLOGY
14.
15. T y p e s o f
Ecosystem
Terrestrial Ecosystem
Freshwater Ecosystem
Marine Ecosystem
16. Terrestrial Ecosystem
Ecosystems that exists on continents and islands of the world and comprehend a series of
dynamic open interactions of the living or non-living entities, their activities and
interrelations. It is a land-based community of organisms including forests and grassland.
17. COMPONENTS
➢ Physical Component- temperature, humidity, wind,
precipitation, light, etc
➢ Soil Component- physical (texture, etc) & chemical
properties of soil ( salinity, pH, organic matter).
Salinity is the measure of all the salts dissolved in water. Salinity is
usually measured in parts per thousand (ppt or ). The average
ocean salinity is 35ppt and the average river water salinity is
0.5ppt or less. This means that in every kilogram (1000 grams) of
seawater, 35 grams are salt.
18. ➢ Plant Component
▪ Forestland –community dominated by trees
▪ Brushland –community dominated by brushes and shrubs.
19. ▪ Cropland-community
seasonally planted with
cash crops or permanent
agricultural crops
▪ Marginal land-
community with denuded
soils and with few number
of flora and fauna living
therein.
▪ Mangrove-
community found in tidal
flats along seacoast
extending along the
rivers where the water is
brackish.
20. COMPONENTS
➢ Animal Component- –includes the mammals,
reptiles, and birds or avian groups
➢ Saprobe Component- –includes viroin, virus,
fungi (phytomycetes-damping off), and
bacteria.
21. Freshwater Ecosystem
ecosystem that exists on ponds, marshes, swamps, lakes, and streams
where living and non-living entities are interacting upon each other
to produce and exchange energy and materials to each
component
22. ▪ Lentic ecosystem–found
on lakes and ponds
▪ Lotic ecosystem found
in springs, brooks, creeks,
and rivers
▪ Wetland ecosystem –
found in marshes and
swamps
23. Freshwater Ecosystem
➢ Freshwater habitats are relatively small but their importance is far
greater than their size because:
1. Most convenient and cheapest source of water
(domestic, agriculture and industry)
2. Bottleneck in water cycle
3. Provides more convenient and cheapest tertiary
waste disposal system
Limnology – a comprehensive study of all the components of inland
aquatic ecosystems and their interrelationships.
24. Marine Ecosystem
ecosystem that exists in the oceans, shores, and estuaries where living
and non-living entities are interacting.
25. Marine Ecosystem
➢ The sea is big (covers 70% of earth’s surface)
➢ The sea is deep and life extend to all depths
➢ The sea is continuous allowing free movement of marine organisms
➢ The sea is continuously circulating
➢ It is dominated by waves and tides influenced by moon and sun
➢ Sea is salt
➢ Sea is alkaline, strongly buffer but low in nutrients
28. Marine Ecosystem
➢ Neritic zone – shallow water zone of continental shelf
➢ Intertidal zone –area bet. high and low tides (Littoral zone)The sea is
continuous allowing free movement of marine organisms
➢ Bathyal zone -trenches and canyons (Oceanic region)
➢ Hadal zone –the very deep areas of the ocean (Abyssal region)
Z O N E S
31. ➢ Seaweed component – this
includes all plants or
seaweeds living on the
seabed.
➢ Tide pool component – this
includes all organisms in the
intertidal zone of the sea.
➢ Estuaries component -
this includes all organisms
found in the semi-closed
coastal body of water
that has a free
connection with the
open sea.
32. End of topic 2
Reference: Lecture Notes in Forest Ecology by For. Martin T. Obrero
