1. The Study of Ecology
Ecology and the Biosphere

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

4. What is the Biosphere?

5. Biosphere
“The Living Globe”
The Biosphere is that part of the Earth in
which life exists

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

10. There are many different types of
ecosystems in nature…
Lake Stream
Prairie Forest Wetland

11. All Ecosystems are Interconnected!!!!
Stream

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)

17. Ecological Succession
What Does it Mean to Succeed???

19. Ecological Succession
The process by which an existing community is
gradually replaced by another community
Every organism affects environmental conditions
around it

20. Ecological Succession of a Pond Community
Begins as a thriving pond community….

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

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

30. Ecosystem Dynamics
Energy and Nutrients in the Ecosystem

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!!!!!

32. Energy
Energy……..
The ability to do work
Builds cells and tissues
Growth
Reproduction
Responding to environment

33. Ecosystem Dynamics and Energy Transfer

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

37. Classification of Consumers
Herbivore
•Eat only plants
•Primary
consumers
•Deer, caterpillars,
giraffes

38. Classification of Consumers
Carnivore
•Eat only other animals
•Secondary and tertiary
consumers
•Lions, wolves, eagles, sharks

39. Classification of Consumers
Omnivore
•Eats both plants and animals
•Can be primary, secondary, or
tertiary consumer
•Raccoons, bears

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

45. The Food Web

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

48. Pyramid of Biomass
Shows total mass of living tissue at each level

49. Pyramid of Numbers
Shows the total number of organisms at each
trophic level

50. Trophic Levels, Energy Flow, and Ecological Pyramids

51. Ecological Niche

52. Factors That Control Population Growth

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

56. Competition
Competition occurs when two or more species rely on similar
limiting resources such as space or food.

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

58. Predation
One species hunts the other and uses it for food.

59. Predator-Prey Relationship

60. Parasitism

61. Density-Independent Limiting Factors
• Operates equally well regardless of population size
• Examples include:
• Natural disasters like volcanoes, floods, etc.
• Annual climate fluctuations
• Produces “Boom or Bust” growth curves

62. Relationships in Ecological Communities

63. Symbiosis
A relationship between 2 different species
“Living together”
3 Types:
• Parasitism
• Mutualism
• Commensalism

64. Parasitism
Relationship where one species benefits and the other is harmed
• 1st species (+)
• 2nd species (-)
Ex. Tick sucking blood from a dog

65. Mutualism
Relationship where both species benefit from their interaction
• 1st species (+)
• 2nd species (+)
Ex. Bee pollinates a flower

66. Commensalism
Relationship where one species benefits and the other is unaffected
• 1st species (+)
• 2nd species (0)
Ex. Cattle Egret