This document provides an overview of key concepts in ecology. It defines ecology as the study of interactions between organisms and their environments. The environment contains abiotic (non-living) factors like climate and biotic (living) factors like other organisms. Organisms have niches within ecosystems based on their roles as producers, consumers, or decomposers. Energy and matter transfer between trophic levels according to food chains and webs, following the 10% law where only 10% of energy is transferred between levels. Relationships like predation, competition, and symbiosis influence populations and communities within ecosystems.

1. WARM-UP Questions
1. What do you think the basic needs of life
are?
2. What is the environment?
3. How do you define life…what are 4 things
all living organisms have in common?

2. Ecology
Interactions in the Environment

3. What is Ecology?
 The science of ecology includes
everything from global processes
(above), the study of various
marine and terrestrial habitats
(middle) to individual interspecific
interactions like predation and
pollination (below).

4. Ecology is…
 the study of the
interactions between
living organisms and their
biotic and abiotic
environments.
 Ecology is therefore the
study of the relationship
of plants and animals to
their physical and
biological environment.

5. And the ENVIRONMENT is…
The surroundings of an organism that affect its
life and development.

6. An environment is characterized by the ABIOTIC and
BIOTIC factors.
 Abiotic factors are non-living.
 Abiotic factors include science like chemistry, physics
and geology.
 Interactions of abiotic factors result in weather,
seasonal changes, tides, air quality, and water quality
 Biotic factors are living and can be categorized
within an ecosystem structure…
Species Population Community
ECOSYSTEM: all of the communities that live in an
area together with the abiotic factors in the
environment

7. A dead tree is not
alive but not
considered
abiotic….why?

8. It was once
living!

9. Biotic features are all living things in the
biosphere.
 The biosphere is all the
parts of Earth that support
life.
 This measures
approximately 20km thick
(12.4 miles)! Most life on
Earth exists between 500m
below the surface of the
ocean and about 6km
above sea level.

10. What types of
communities make
up these
ecosystems?
What types of
abiotic factors are
influencing these
ecosystems?

11. How are Biotic Factors organized?
King Philip Came Over For Great Soup!
Kingdom - Phylum - Class - Order - Family - Genus - Species
All biotic factors are grouped into major kingdoms
based upon similar physical characteristics…we
will deal with 6.

12. Listed in descending order of
complexity:
Animalia
Plantae
Fungi
Protista
Eubacteria
Archeobacteria

13. Abiotic and Biotic factors are
intimately intertwined….
Geographic location (latitude
and longitude) determines
abiotic factors such as
temperature and
climate….which in turn, dictates
or forces a certain type of
ecosystem to exist.

14. Levels of
Organization
studied in
Ecology…

15. AN ORGANISM’S NICHE
 Habitat: the actual place an
organism lives
 Niche: both living and non-
living parts of an
ecosystem that determines
an organism’s role in the
ecosystem.
 If two species share the
same niche, they will have
various interactions.
 How can species interact?

16.  These relationships are complex. Each
population of species interacts with other
species, or biotic factors, as well as with the
all of the abiotic factors.
 The niche of an organism and it’s
interactions is determined by where it stands
in the ecological structure of the ecosystem.
-Producers
-Consumers
-Decomposers
-Scavengers

17. PRODUCERS
 Producers are autotrophic
organisms that make their
own food.
 Phototrophic organisms
use photosynthesis and
contain chlorophyll
(Carbon Dioxide + Water
+ Sunlight =Sugar +
Oxygen)
 Chemotrophic organisms
use chemicals other than
H20, such as H2S

18. PRODUCERS!!!

19. CONSUMERS
 Consumers are heterotrophic organisms that
cannot make their own food. They must ingest
(eat) other organisms.
-Herbivores feed on vegetation (producers).
-Carnivores feed on herbivores or on other
carnivores.
 Secondary carnivores feed on herbivores,
 Tertiary consumers feed on other carnivores
-Omnivores feed on both producers and
consumers
-Scavengers feed on dead or decaying
organisms

20. CONSUMERS!!!

21. Scavengers feed on CARRION (dead or injured
animal corpses) and dead plant biomass.
Scavengers reduce the size of dead organic
matter…Decomposers will finish the job!

22. DECOMPOSERS are heterotrophs that recycle small,
often microscopic bits of dead organic matter into
inorganic nutrients availbe for plants to take up from the
soil. Decomposers RECYCLE nutrients!
BACTERIA and FUNGI are decomposers…most worms
are plant scavengers!

23. Energy in the Ecosystem
 Energy from the sun enters and
ecosystem when producers
used the energy to make
organic matter through
photosynthesis.
 Glucose is the primary energy
source (carbohydrate) produced
by photosynthesis.
 Consumers take in this energy
when they eat producers or
other consumers.

24. Energy in the Ecosystem
 Plants absorb less than 1% of the sunlight
that reaches them!
 However, photosynthetic organisms make
170 billion metric tons of food each
year!
 The energy captured by producers is used
to make cells in both producers and
consumers.

25. TROPHIC LEVELS
 Trophic levels are the
different feeding levels of
organisms in an ecosystem.
Producers are the first trophic
level and consumers make
up several more.
 These relationships can be
seen in an ecological
pyramid.
 Biomass: the total amount of
organic matter present in a
trophic level. The biomass in
each trophic level is the
amount of energy- in the form
of food- available to the next

26. The Ten Percent Law
 Most of the energy that enters
through organisms in a trophic level
does not become biomass. Only
energy used to make biomass
remains available to the next level.
 When all of the energy losses are
added together, only about 10% of
the energy entering one trophic
level forms biomass in the next
trophic level. This is known as the
10 percent law.

27.  The 10 percent law is the main reason that
most food chains have five or less links.
Because 90 percent of the food chain’s energy
is lost at each level, the amount of available
energy decreases quickly.
10 PERCENT
LAW!!
MORE Ten Percent Law

28. Consumed Digested
Not Digested
Growth
Waste
Heat and Movement
Not Consumed
Decomposers
The majority of energy is lost via heat and movement!

29. ECOLOGICAL PYRAMID
PRODUCERS = Autotrophic Plants
Primary Consumers= HERBIVORES
Secondary Consumers= CARNIVORES
EATING HERBIVORES
Tertiary Consumers= CARNIVORE
EATING OTHER CARNIVORES
Remember
scavengers and
decomposers can
enter at any level!

30. Ecological Pyramids
 Relative amounts of energy are represented in an
ecological pyramid: a diagram that shows the
relative amounts of energy in different trophic
levels in an ecosystem. An ecological pyramid
can show energy, biomass, or the number of
organisms in a food web.

31. Ecological Pyramid: Energy
Shows the relative transfer of energy (joules) from one
trophic level to the next.

32. Ecological Pyramid: Biomass
Shows the relative amounts of organic matter (gram) from
one trophic level to the next.

33. Ecological Pyramid:
Number of Organisms
Shows the relative number of organisms at each trophic level.

34. Food Chains
A Food CHAIN is a
series of organisms
that transfer food
between the trophic
levels of an
ecosystem using only
one species at each
level…a simple chain.
 The arrows represent
the flow of energy
from one organism to
the next.
 The arrow points
toward the organism
doing the ‘eating’.

35. Food Webs
Ecosystems are not as
simple as shown and not
often explained by a
single food chain… Food
WEBS more accurately
show the network of
food chains
representing the
feeding relationships
among organisms in an
ecosystem.
 Most organisms feed on
more than one type of
organism at different
trophic levels.

36. How do Food Webs show complexity?
 The diversity and stability of an ecosystem is
represented by more complex webs that have
many species and many interactions (lots of
arrows) because they are more stable…more
resistant to disturbance by natural disaster or
human interference. Why?

37. Biological Magnification
 BIOLOGICAL MAGNIFICATION
 The concentration of a pollutant in organisms increases
at higher trophic levels in the food web because these
chemicals build-up in the fatty tissues of these organism
and do not dissolve or flush-out of the organism.
 DDT & Mercury examples:
 DDT is a pesticide used to kill insects like malaria-carrying
mosquitoes. However, this chemical will magnify in concentration
in larger organisms like birds and mammals and harm their
reproductive abilities.
 Bald eagle populations declined rapidly to the point of extinction
as an endangered species as mother birds were not able to
incubate or hatch their eggs because the eggs shells were too
thin and would crush and break when sat upon to keep warm in
the nest.

38. Biological Magnification
As the living
organisms eats more,
the concentration of
these substances
increases as they pass
from one trophic level
to the next.

39. The day it Rained
cats…
 A bizarre case of ecological damage from DDT
occurred in Borneo after the World Health
Organization sprayed huge amounts of the
pesticide. The area's geckos, or lizards, feasted on
the houseflies that had been killed by DDT. The
geckos, in turn, were devoured by local cats.
Unhappily, the cats perished in such large numbers
from DDT poisoning that the rats they once kept in
check began overrunning whole villages. Alarmed
by the threat of plague, WHO officials were forced
to replenish Borneo's supply of cats by parachute.

41. RELATIONSHIPS IN THE ECOSYSTEM
 Predator/Prey: One organism (predator) will
actively hunt and consume another (prey).
 Competition: two or more organisms of same
or different species compete to use the same
limited resources or basic needs

42.  Parasitism: an organism
(parasite) lives in or on another
(host) and feeds on it without
immediately killing it
 Mutualism: a cooperative
partnership between two
species (both benefit)
 Commensalism: a relationship
where one species benefits and
the other remains unaffected
Symbiotic Relationships

43. Coevolution
 When two or more species evolve in response to each
other, it is called coevolution.
 Examples of coevolution may be found between
predators and their prey.
 Plants and insects represent a classic case of coevolution — one
that is often, but not always, mutualistic. Many plants and their
pollinators are so reliant on one another and their relationships are
so exclusive that biologists have good reason to think that the
“match” between the two is the result of a coevolutionary process.