2. Ecology
Ecology is the study of the interactions of
organisms with one another and with their
physical environment
3. Ecology comes from the Greek Word “oikos”, which
means “house”
The Earth is our house. The “house” includes the
environment in which organisms live, the interactions of
organisms with one another, and the interaction of
organisms with the nonliving environment
7. Biosphere
Includes all land, air, and water
Extends from about 8 km above the
Earth’s surface to as far as 8 km
below the surface of the ocean
Living organisms are not distributed
uniformly (few in polar regions and
many in tropical regions)
8. Ecosystems
Ecosystems are small ecological units
Consist of a given area’s physical features and
living organisms
Nonliving Physical Features are called abiotic factors
Water, sunlight, soil type, rocks, temperature, humidity, elevation,
and rainfall
Living organisms are called biotic factors
Bacteria, reptiles, fish, birds, animals, plants, and fungi
All of the biotic and abiotic factors in a given area make up an
ecosystem
9.
10. There are many different types of
ecosystems in nature…
Lake Stream
Prairie Forest Wetland
12. Ecologists who study ecosystems identify
the living organisms as part of a…..
Population: a collection of individuals of the same
species in a given area who can breed with one another
13. Ecologists who study ecosystems identify
the living organisms as part of a…..
Community: all the populations of organisms living in a
given area (all of the biotic factors)
19. Ecological Succession
The process by which an existing community is
gradually replaced by another community
Every organism affects environmental conditions
around it
21. Ecological Succession of a Pond Community
The pond begins to fill with organic matter like leaves,
and silt, a fine soil…..
22. Ecological Succession of a Pond Community
Over a period of time, the pond fills and
becomes a marsh…..
23. Ecological Succession of a Pond Community
Eventually the marsh becomes dry land
inhabited by a stable community called a
climax community
24. Succession often leads to a fairly stable collection
of organisms
The Biomes of the World are Large Climax Communities
with a Stable Collection of Characteristic Plant and
Animal Life!
25. There are 2 types of succession that occur in
nature…..
Primary Succession
Secondary Succession
26. Primary Succession
•Occurs in places where no living community existed before (on a
newly formed volcanic island)
•Pioneer species begin to grow
Hardy organisms that can tolerate harsh conditions
27.
28.
29. Secondary Succession
• Occurs in areas where natural disasters or human activities have
wiped out an existing living community
•Pioneer species colonize the area and gradually change
conditions so that they are favorable for other species
31. All living things are made up of….
Chemical Elements Chemical Compounds
Carbon (C) Water (H2O)
Hydrogen (H) Glucose (C6H12O6)
Oxygen (O) Proteins (CHON)
Nitrogen (N)
And use ENERGY!!!!!
34. Energy
Energy is passed from organism to organism by feeding
relationships in the ecosystem!!!
Trophic Levels
Each step in the transfer of
energy in a community
•Producers
•Consumers
•Decomposers
35. Producers
Organisms that can make their own food
Autotrophs (Self-Feeding)
• Use photosynthesis to convert sunlight chemical energy
• Produce carbohydrates for immediate use or storage for later
• Examples include plants, algae, and some bacteria
36. Consumers
Animals, fungi, protists, and most bacteria that
cannot make their own food
Consumers are Heterotrophs (obtain food by eating
other organisms)
Types of Consumers:
•Primary Consumers
•Secondary Consumers
•Tertiary Consumers
40. More About Consumers
Some consumers are scavengers
•Scavengers are animals that eat the flesh of dead organisms
•Biological “clean-up crew”
•Vultures, hyenas, crows
41. Decomposers
Decomposers are organisms that
obtain their energy from dead
organisms
•Break down complex organic matter (decompose or decay)
•Nutrients from break down of tissues are returned to the soil
•Nutrients are recycled (carbon, nitrogen, phosphorus)
•Bacteria, earthworms
42. The Flow of Energy
Energy flows through an ecosystem. From the sun to producers
to consumers to decomposers, energy powers the interactions
of ecosystems.
43. Food Chains
•Shows the flow of energy
from one organism to another
through each trophic level
•Energy flow is represented by
an arrow
•Arrow goes in direction of
energy
44. Food Web
•A food web is a
representation of all of the
interconnected food chains
in an ecosystem
•Food webs show multiple
feeding relationships
46. Ecological Pyramids
Ecologists use ecological pyramids to represent
the relationships among trophic levels
There are 3 types of ecological pyramids:
• Pyramid of Energy
• Pyramid of Biomass
• Pyramid of Numbers
47. Pyramid of Energy
Shows total amount of incoming energy at each
trophic level
The 10% rule
predicts that only
10% of the energy
in one trophic level
is available to the
next level
53. In nature, population growth is limited to the
carrying capacity of the environment
Carrying capacity
is determined by
a variety of
limiting
factors.
54. Population Limiting Factors
• Factors that control population growth
• Maintains population levels between extinction and
overpopulation
• Two types:
• Density-dependent limiting factors
• Density-independent limiting factors
55. Density-Dependent Limiting Factors
• Operate only when a population is large
• Examples include:
• Competition
• Predation
• Parasitism
• Overcrowding
• Stress
57. Competitive Exclusion Principle
When two species are competing for the same resources, one must
– migrate to another area
– shift its feeding habits or behavior
– suffer a sharp decline in population or become extinct
