For anyone's perusal.

1. ECOLOGY
EJC HONOURS DAY 2013
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2. What is Ecology?
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 Greek for ‘study of house’
 It is the scientific study of the relationship of living
things to each other and the environment around
them
 “The first law of ecology is that everything is
related to everything else” – Barry Commoner,
American biologist, teacher an activist.
 It is important to know and understand the various
relationships. A simple example is given in the
following story.

3. The sad story of Lake Victoria –
By Kassandra, age 11
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 Lake Victoria in in equatorial Africa is the
second largest lake in the world. It was full of
life with many species of fish, plants, trees and
other land animals. In 1858, the British found this
land and claimed it for themselves even though
there were already people living there. The
British started to make it a good environment for
themselves and cut down trees to make room for
crops like coffee, tea and banana trees.

4. The sad story of Lake Victoria (cont’d)
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 The British then looked to fishing for enjoyment. They
fished for the ngege and eventually led the species to
extinction. To replace the ngege the British introduced
the tilapia as well as the Nile Perch to Lake Victoria.
The British only added the Nile perch to make it fun
to fish. It was a huge fish which weighed up to 300
pounds. Anybody would love to catch a 300 pound
fish and have that much food afterwards. The Nile
perch was so big and it ate so much that it put most
of the other fish to extinction.

5. The sad story of Lake Victoria (cont’d)
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 But they ran into a problem. These fish were so big they
wouldn’t dry without rotting. Instead of drying in the sun
the Nile perch needed to be roasted over fire. They
never thought about the ecosystem. Many trees around
the lake were cut to provide wood for the fire. The
trees had been holding the soil together. Taking the
trees out caused erosion.
 The lake ended up getting too many nutrients and the
nutrient-rich water made it easy for algae to grow.
When the algae died it sank to the bottom of the lake
and rotted. The rotting algae used the oxygen in the
lake which the fish need to breathe. Many species of
fish died and became extinct.

6. The sad story of Lake Victoria (cont’d)
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 The water became polluted and carried many
human diseases in it. Many humans around the lake
had to suffer from the symptoms of the diseases.
 So, think back to the beginning. The British only
meant to change one thing but ended up changing
almost everything. Once you take a part of an
ecosystem away it changes the whole thing.

7. Types of Ecosystems
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 Two main types of ecosystems
 Aquatic (found in a body of water)
 Marine
 Freshwater
 Terrestrial (found only on land)
 Tundra
 Taiga
 Deciduous forest
 Grassland.

8. FRESH WATER POND ECOSYSTEM
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9. Characteristics of a Pond
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 A body of water which can be either natural or
man-made
 Usually shallow, about 12-15 feet in depth, so
sunlight penetrates to the bottom
 Plants either grow entirely underwater or partially
on the surface
 Supports a large variety of animal and plant life

10. Characteristics of a Pond
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 Examples of animal and plant life include:
 Birds
 Crayfish
 Small fish
 Frogs
 Insects
 Turtles
 Protozoa
 Algae
 Lily pads, etc.

11. Ecosystems
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 An ecosystem is formed from the cohabitation of
plants, animals, microorganisms and a surrounding
environment.
 Any group of living and nonliving things interacting
with each other can be considered an ecosystem.
 A pond ecosystem refers to a community of
freshwater organisms largely dependent on each of
the surviving species to maintain a life cycle.

12. Ecosystems
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 Within each ecosystem are habitats – the places
where different populations live – which must
supply the needs of organisms, such as food, water,
temperature, oxygen and minerals.
 In some ecosystems, a habitat is specific to a
population, while in others, e.g. a small pond (or
even an aquarium) several populations may co-exist
 A community refers to the organisms (plants and
animals) in an ecosystem and is formed when all of
the populations interact.

13. Ecosystems
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 A biome is a major class of ecologically similar
communities of plants, animals and soil organisms, often
referred to as ecosystems.
 In other words, biomes are ecosystems where several
habitats intersect. Biomes are defined based on factors
such as plant structures (such as trees, shrubs and
grasses) and are often identified with particular
patterns of ecological succession and climax vegetation.
 The Earth itself is one large biome. Smaller biomes
include deserts, grasslands and rainforests.

14. Ecosystems – Example of a Biome
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15. Ecosystems
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 Energy and water are vital to the survival of an
ecosystem and the preservation and restoration of an
ecosystem’s resources is called conservation.
 When resources become limited, conservation becomes
more important, with an increased need for recycling.
 If conservation efforts fail, then species become
endangered (not enough habitat to support all the
members of the population or too many members killed
in too short a time) and extinction can occur (habitat
vanishes and/or all members of a population die).

16. Ecosystems
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 Ecological succession
 Observed process of change in the species structure of
a community over time.
 May be initiated either by formation of new,
unoccupied habitat (e.g. landslide) or by some form of
disturbance (e.g. fire) to an existing community.
 Climax Community
 A community that has reached a steady state through
ecological succession.

17. Ecosystems
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 Eutrophication
 An ecosystem’s response to the increase in its primary
productivity. E.g. increased level of nutrients may cause
the phytoplankton to increase and disrupt the normal
functioning of the ecosystem.

18. Habitats of a Pond Ecosystem
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 Shore
 May be rocky (won’t allow plants to grow), sandy or
muddy (attract grasses, worms, insects and
microorganisms)
 Surface Film – top 6 inches of water on pond’s
surface
 Excellent breeding ground for mosquito larvae, water
striders, marsh traders, free-floating organisms and
organisms that can walk on the surface of water.

19. Habitats of a Pond Ecosystem
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 Open Water
 Hosts the following:
 Fish (feed on plankton)
 Plankton (organisms that inhabit the water column of oceans,
seas, and bodies of fresh water and provide a crucial supply
of food to most aquatic life)
 Phytoplankton (various types of algae) and
 Zooplankton (insect larvae, rotifers, small crustaceans and
invertebrates) .

20. Habitats of a Pond Ecosystem
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 Bottom Water
 Varies depending upon the pond's depth. Shallow ponds
with sandy bottoms provide a nesting environment for
earthworms, snails and insects. Deep-ended ponds have
muddy bottoms, which allow various microorganisms such
as flatworms, rat-tailed maggots and dragonfly nymphs
to reproduce and survive. These animals feed on dead
organic matter that makes its way to the bottom.

21. Food Chain of a Pond’s Ecosystem
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 Basic trophic levels (the position an organism occupies in
a food chain)
 Level 1
 Producers & Autotrophs e.g. phytoplanktons and plants
 Prepare their own food through photosynthesis and using
nutrients in soil and water
 They do not eat other living things
 Level 2
 Primary Consumers or Herbivores e.g. insects, crustaceans
 Inhabit the pond and consume plants

22. Food Chain of a Pond’s Ecosystem
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 Level 3
 Secondary consumers or Carnivores which feed on both
the plants and herbivores atop the first and second
trophic levels.
 Level 4
 Decomposers or saprotrophic organisms
 Located on the bottom of the food chain
 Help decompose dead plants and animals, as well as
animal waste, and turn them into chemical nutrients
which plants will take up through their roots.

23. Food Chain of a Pond’s Ecosystem
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 Level 4 (cont’d)
 These nutrients supply the necessary life force for the
first trophic level organisms to produce food for the
second trophic organisms, etc. which results in the
perpetual flow of energy in the pond's ecosystem.

24. Factors of an Ecosystem
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 Non-biological (or abiotic) factors include sunlight,
water, air and soil
 Water – also an essential element to life
 Air – provides oxygen, nitrogen, and carbon dioxide to
living species and allows the dissemination of pollen
and spores
 Soil – a source of nutrition as well as physical support.
 Temperature – should not exceed certain extremes,
even if tolerance to heat is significant for some species
 Light – provides energy to the ecosystem (e.g. through
photosynthesis).

25. Factors of an Ecosystem
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 Biological (or biotic) factors include animals, humans
and plants
 A balanced ecosystem is one in which the types and
number of organisms are consistently maintained.
 Symbiosis is a close ecological relationship between
the individuals of two (or more) different species.

26. Relationships in an Ecosystem
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 A symbiotic relationship in which:
 Both species benefit
 Mutualism
 One species benefits and the other is unaffected
 Commensalism (e.g. bird living in a tree)
 One species benefits and the other is harmed
 Parasitism
 Neither species benefits
 Competition
 Both species interact but neither is affected
 Neutralism.

27. Relationships in an Ecosystem
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 Ecological Pyramid (also known as trophic pyramid or
energy pyramid)
 A graphical representation designed to show the biomass or
biomass productivity at each trophic level in a given
ecosystem. It begins with producers on the bottom and
proceeds through the various trophic levels, the highest of
which is on top.
 Food chain
 A diagram showing a linear relationship of the feeding
connection between species in an ecological community. It
begins with a species that eats no other species and ends
with a species that is eaten by no other species (in that
community).

28. Example of a Bird’s Ecosystem
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29. Example of Terrestrial Ecosystem
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30. IMPORTANT NOTE
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 One of the requirements for this honour asks you to
include ecological pyramids for a mammal, bird,
amphibian and reptile. Do not simply reproduce the
pyramid below:

31. IMPORTANT NOTE
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 At least ensure that you also give examples of
appropriate organisms which can be found at each
level in the pyramid for the animal you are
focussing on.

32. SOURCES
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 http://www.thewaterpage.com/pond-ecosystem.htm
 http://en.wikibooks.org/wiki/Adventist_Youth_Hono
rs_Answer_Book/Nature/Ecology
 http://eng.me.go.kr/content.do?method=moveCont
ent&menuCode=res_kid_eco_ecosystem
 http://www.fi.edu/tfi/units/life/habitat/

33. SOURCES
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 http://wwf.panda.org/about_our_earth/teacher_r
esources/webfieldtrips/ecological_balance/eco_int
eract/
 http://www.hubbardbrook.org/mirrorlake_kids_tou
r/what_is_ecology.htm
 http://en.wikipedia.org/wiki/Pond
 http://masho0oq.blogspot.com/2006/02/ecosyste
m.html