Lesson 1. concept of ecology

This is the introductory lesson of the course; 'Foundation of Environmental Management' taught at the Faculty of Social Sciences and Humanities of the Rajarata University of Sri Lanka

1. Lesson 1 –Concepts of Ecology and
Environmental Biology
P.B. Dharmasena
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https://independent.academia.edu/PunchiBandageDharmasena
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Foundation of Environmental Management
Course code: EMGT 2114

2. Lesson 1 –Concepts of Ecology
and Environmental Biology
1.Ecology
2.Producers
3.Consumers
4.Feeding interactions
5.Ecological pyramids
6.Ecological Interactions between organisms

3. Ecology—the scientific study of interactionsbetween
different organismsand between organisms
and their environmentor surroundings
1. ECOLOGY

4. Environment Vs. Habitat

5. Basic Concept of Ecology

6. What influences an ecosystem
Biotic—livingfactors that influence an ecosystem
Abiotic—non-livingfactors that influence an
ecosystem

7. Producers
A. Sunlightis the mainenergy source for life on earth
B.Also called autotrophs
C. Use lightor chemical
energy to make food
1. Plants
2. plant-like protists (algae)
3. Bacteria

8. D. Photosynthesis—use light energyto convert carbon
dioxideand waterinto oxygenand carbohydrates
(Remember: 6CO
2+ 6H
2O 6O
2+ C
6H
12O
6)
E. Chemosynthesis—performed by bacteria, use
chemical energy to produce carbohydrates
Light
Energy

9. Consumers
A.Organisms that rely on other organisms for their energyand
foodsupply
B. Also called heterotrophs

10. Consumers are of 4 types
1. Herbivores—obtain energy by
eating only plants
2. Carnivores—eat only
animals

11. 3. Omnivores—eat both
plants and animals
4. Decomposers—breaks
down dead organic matter

12. Feeding Interactions
A. Energy flows through an ecosystem in one direction—
from the sunor inorganic compounds to autotrophs
(producers) and then to heterotrophs(consumers)

13. B.Food Chain—series of steps in which organisms
transfer energyby eating and being eaten
1.Arrows go in the directionof how energy is
transferred
2.Start with producerand end with top consumer
or carnivore
Ex: grasscricket frog raccoon

14. C. Food Web—networkof food chainswithin an ecosystem
Hawks
Weasels Raccoons
Mice
Grass

15. D.Trophic Levels—each step in a food
chain or food web
1. Level 1—Producers(autotrophs)
2. Level 2—PrimaryConsumers
(herbivores)
3. Level 3—SecondaryConsumers
(carnivores or omnivores)
4. Level 4—TertiaryConsumers
(carnivore—usually top carnivore)

16. Hawks
Weasels Raccoons
Mice
Grass
Food Webs

17. Ecological Pyramids
A. Diagram that shows the relative amount of energyor
organismscontained within each trophic levelof a food
chain or web

18. B.EnergyPyramid shows relative amount of energy available at each
trophic level
1. Organisms in a trophic level use the available
energyfor life processes (such as growth,
photosynthesis, cellular respiration, metabolism,
etc.) and release some energy as heat
Remember: Every chemical process that happens in your body
releases heatas a byproduct (ex: burning calories).
2. Rule of 10—only about 10%of the available energy
within a trophic level is transferredto the next
higher trophic level
C. BiomassPyramid—represents the amount of living organic
matterat each trophic level

19. Energy
Pyramid
Biomass
Pyramid
100%
10%
1%
0.1%

20. Represents amount of energy
available at each level as well
as amount of living tissue—
both decreasewith each
increasingtrophic level
Energy and Biomass Pyramid (together)

21. Heavy metals
Ex: mercury
Pesticides
Ex: DDT
(dichlorodiphenyl
trichloroethane)
Organochlorides:
Ex: PCBs

22. Ecological Interactions between
organisms
A.Competition—when two organisms of the same or
different species attempt to use an ecological resource
in the same place at the same time.
Ex: food, water, shelter

23. Monkeys compete
with each other and
other animals for
food.
Rams compete with
each other for
mates.

24. Until Americans introduced gray squirrels into parts of
England in the early 20th century, red squirrels had been
the only species of squirrel in the country. The gray
squirrels were larger and bred faster and successfully
competed for resources. Within a couple years of overlap
in an area, the red squirrels disappeared.

25. B. Niche—the ecological niche involves both the
placewhere an organism lives and the rolesthat an
organism has in its habitat.
Example: The ecological niche of a sunflowergrowing in the
backyard includes absorbing light, water and nutrients
(for photosynthesis), providing shelter and food for other
organisms (e.g. bees, ants, etc.), and giving off oxygen
into the atmosphere.

26. The ecological niche of an organism depends not only on
where it lives but also on what it does. By analogy, it may
be said that the habitat is the organism’s “address”, and
the niche is its “profession”, biologically speaking.
Ex. Worm’s Niche“Address”—Soil, Ground, etc.
“Profession”–Mix-up soil

27. C.Predation—one organism captures and feeds on
another organism
1.Predator—one that does the killing
2.Prey—one that is the food

29. D.Symbiosis—any relationship in which two
species live closely together
1. Mutualism—both species benefit (WIN-WIN)
a. Ex: insects and flowers

31. 2. Commensalism—one member of the association
benefits and the other is neither
helped nor harmed. (WIN-0)
Example: weaver bird and tree

32. Commensalism
The Remora fish attaches to
the shark and gets a free ride.
Birds build nests in trees.

33. 3.Parasitism—one organism lives on or inside
another organism (host) and harms it.
The parasite obtains all or part of its nutritional
needs from the host. (WIN-LOSE)
Example: fleas on a dog

34. Parasitism
Wasp eggs on back
of caterpillar.
Mosquito biting a
human.
Sea lampreys feed on fluids
of other fish.

35. Mutualism, Commensalism or Parasitism??

36. What is Environmental Biology?
It is the study of how the natural world works.
How our environment affects us.
And how we effect our environment.

37. Environment?
•Just the ‘natural
world’?
•Includes all the living
and non-living things
around us.
•It also includes the
man made items
•It also includes the
complex web of human
relationships
•EVERYTHING in the
Universe

38. Limits….
•Natural Resources -the various
substances and energy sources
needed for our survival
–Renewable and non-
renewable
–Renewable are either
•Unlimited -sunlight, wind,
wave
•Replenished quickly -water,
soil, food crops
–Non-renewable
•Fixed amounts -oil, gas,
land
–Consumption increases based
on life style and population

39. •Human population size
•For the most part of the
last 5 million years the
human population had
remained at several
million
•That was until two events
took place…
Limits….

40. Two events took place …….
•1) Agricultural Revolution @
10,000 years
–Change in human lifestyle -
security and children
•2) Industrial revolution @
1750’s
–Rural to urban life, with
machines aiding us with the
use of fossil fuels

42. The Scientific Method
•EB is a science and therefore the rules of scientific procedure
must be applied
•The Scientific Method is a process
–A technique for testing ideas with observations
•Make observations
•Ask questions
•Develop a hypothesis
•Make predictions
•Test the predications
•Analyze and interpret results.