1

Ecology

BIO 2215

Oklahoma City Community College

Dennis Anderson

2

Ecology

• Study of the interactions of living organisms with each other and their environment

3

• Scales of Life– Populations—All members of a single species that live

together in a specified geographic region.– Communities—All species that potentially interact with

one another, in a given region.– Ecosystems—Communities of living things and their

nonliving environment. – Biosphere—Entire interactive collection of the Earth’s

ecosystems.

4

Biosphere

Ecosystem

Community

Population

Organism

5

• The Ecosystem: The Fundamental Unit of Ecology– Ecosystem—A self-sustaining community of organisms

and the physical environment with which they interact.– Consist of biotic (living) and abiotic (nonliving) factors.– Depend on Sun for ultimate source of energy; there’s

one-way flow of energy through an ecosystem.– Some nutrients and water are taken up by living

organisms and then cycled back to the abiotic component of an ecosystem.

6

7

Producer

• Produces food• Energy from sunlight

converted into chemical energy

• Plants• Algae

8

Consumer

• Consume food by eating

• Primary• Secondary• Tertiary

9

Decomposer

• Decompose dead bodies and organic matter

• Fungi• Bacteria

10

Producers

Consumer

Consumer

Consumer

1,500,000

200,000

90,000

1

Pyramid of Numbers

11

Producers

Consumer

Consumer

Consumer

809 g/m2

37 g/m2

Pyramid of Biomass

11 g/m2

1 g/m2

12

Alfalfa

Cattle

Man

13

Alfalfa

Cattle

Man

Rice

Man

14

15

1st trophic level

2nd trophic level

3rd trophic level

4th trophic level

producers(photosynthesizers) Primary

consumers(plant predators)

Secondary consumers

(herbivore predators)Tertiary

consumers(carnivore predators)

16

kingfisher

great blue heron

merganser otter

dipper

steelheadroach stickleback

newt caddis fly larva

snailfrog tadpolewater scavengerbeetle larva

tuft midge

diatomsgreen algae

blue-green algae

crayfish

garter snake

17

Abiotic Components of an Ecosystem

• Carbon

• Nitrogen

• Water

• Temperature

• Sunlight

• Etc

18

fossil fuels

plants animals

dead organismsdecomposition bybacteria and fungi

2 respiration

respiration

1 photosynthesis

burning of fossil

fuels

5

4 3

atmospheric CO2

THE CARBON CYCLE

19

1 nitrogen fixation5

denitrifyingbacteria

3 decomposition by bacteria and fungi

atmospheric N2

bacteria inroot nodulesof plants, and in soil

nitrate (NO3)

4 nitrifying bacteria

ammonia (NH3)ammonium NH4+)

animal wastedead organisms

THE NITROGEN CYCLE

assimilationinto animals assimilation

into plants2

20

21

THE HYDROLOGIC CYCLE

precipitationover ocean

evaporation

watervapor

90% 10%

surfacerunoff

ocean

precipitationover land

transpiration,evaporation

groundwater

groundwaterrunoff

22

Consumer

Consumer

Consumer

Producer

Decomposer

Sun

1,000,000

Calories

20,000

10,0005,000

5,000

2,0001,000

2,000

1,000500

500

300200

6,700

Total 20,000

23

Energy

• Does not cycle in an ecosystem

• Usable energy lost at each trophic level

• Sun is the source of energy

24

25

26

Habitat

• Where an organism is found– Marine– Fresh water– Tree tops– Under ground– etc

27

Niche

• How an organism obtains food and resources to survive– “occupation”

• Black rhino feeds on leaves and woody plants

• White Rhino feed on grasses and herbs

28

Competitiveexclusion

Pop

ula

tion s

ize

P. aurelia

P. caudatum

Time (days)

Time (days)Pop

ula

tion s

ize

Resourcepartitioning

P. aurelia

P. bursaria

29

Territory: Area defended against others of the same species.

30

31

peak

peak

AugustAprilJanuary December

Month

0

400

800

1200

0

4

8

12

16

Song level

Test

ost

ero

ne level

O

CH3

CH3OH

32

Animal Societies

33

Advantages of Group Living

• Easier to detect predator

• Easier to repel predator

• Protect young• Easier to find food• Easier to find a mate

34

Disadvantages of Group Living

• More competition• More disease

35

Dominance Hierarchy

• Each member has a rank in the pack

• Alpha—highest rank• Beta—second rank• Omega—lowest rank

36

Dominance Hierarchy

• Reduces conflict• Promotes social order

37

38

39

Predator and Prey

40

Predators Benefit Prey

• Prevent overpopulation

• Remove weak and sick from population

41

Snowshoe Rabbit and Lynx

42

Snowshoe Rabbit and Lynx

43

Coyote and Jackrabbit

44

45

Symbosis

• Living together• Parasitism• Commensalism• Mutualism

46

Parasitism

• Parasite benefits• Host harmed

47

MutualismBoth benefit

48

Commensalism

• Shark and Remora• Remora benefits

49

Populations

• Capacity to grow exponentially

2-4-8-16-32-64

128……1,000,000

50

Population Growth

• Birth rate

• Death rate

• Example– Population of 100– 10 births and 8 deaths– Rate of growth is 2%

51Time

Number in Population

Lag Phase

Log Phase

Carry Capacity

52

Carrying Capacity

• Optimum number of individuals an ecosystem can support for an extended period of time.

53

Environment Resistance

• Food

• Space

• Disease

• Predators

54

TYPES OF POPULATION GROWTH

exponential growth

logistic growth

Time

more complex growth

K

K

Pop

ula

tion s

ize

J shaped growth

S shaped growth

55

Population Crash

• 1944 29 reindeer introduced to St. Matthew island

• 1964 population increased to 6,000

• Crashed to only reindeer 42

• All died a few years later

56

Kiabab Forest1907 population = 4,000

1925 population 100,000

57

Easter Island

58

Link for today's human population

59

Challenges of Expanding Human Population

• 250,000 babies born each day

• 19,000 people starve to death each day

• Carrying capacity for American lifestyle is 2.5 billion

• 2 billion people do not have enough food, water and clean air.

60

Expanding Economies Stress Ecosystems

61

62

Biodiversity

• Diversity of species• Decrease Biodiversity

– Habitat destruction– Pollution– Excessive

• Hunting• Fishing• poaching

63

Coral Reefs

• 10% of coral reefs lost in 1992

• 27% of coral reefs lost in 2000

• Global warming• Over fishing• Mining• Pollution

64

The End