1. Ecology and the Biosphere
Chapter 52 ~ An Introduction to Ecology and the Biosphere
I am the Lorax.
I speak for the trees.
I speak for the trees,
for the trees have no tongues.

2. Overview: Ecology These interactions
Ecology is the study of interactions between organisms and the environment
These interactions
Determine both the distribution of organisms and their abundance

3. Ecology Is an enormously complex and exciting area of biology
Reveals the richness of the biosphere
Figure 50.1

4. Environmental components Affect the distribution and abundance of organisms
Kangaroos/km2
> 20
10–20
5–10
1–5
0.1–1
< 0.1
Limits of distribution
Climate in northern Australia
is hot and wet, with seasonal
drought.
Red kangaroos
occur in most
semiarid and arid
regions of the
interior, where
precipitation is
relatively low and
variable from
year to year.
Southeastern Australia
has a wet, cool climate.
Southern Australia has
cool, moist winters and
warm, dry summers.
Tasmania
Figure 50.2

5. Ecology
Components: •abiotic~nonliving chemical & physical factors •biotic~living factors
Population~group of individualsof the same species in a particular geographical area
Community~assemblage of populations of different species
Ecosystem~all abiotic factors and the community of species in an area
Rachel Carson, 1962, Silent Spring

6. Abiotic factors Biosphere~the sum of all the planet’s ecosystems
Biome~ areas of predominant flora and fauna
Temperature
Water
Sunlight
Wind
Rocks & Soil
Periodic disturbances
Ecotone: biome grading areas

7. Dispersal and Distribution
Is the movement of individuals away from centers of high population density or from their area of origin
Contributes to the global distribution of organisms

8. Interactions between organisms and the environment limit the distribution of species
Biogeography
Provides a good starting point for understanding what limits the geographic distribution of species
Species absent
because
Yes No
Dispersal limits distribution?
Behavior limits distribution?
Biotic factors (other species) limit distribution?
Abiotic factors limit distribution?
Area inaccessible
or insufficient time
Habitat selection
Predation, parasitism, competition, disease
Water Oxygen
Salinity
pH Soil nutrients, etc.
Temperature Light
Soil structure
Fire Moisture, etc.
Chemical
factors
Physical
Figure 50.6

9. Behavior and Habitat Selection
Some organisms
Do not occupy all of their potential range
Species distribution
May be limited by habitat selection behavior

10. Species Transplants Species transplants
Include organisms that are intentionally or accidentally relocated from their original distribution
Can often disrupt the communities or ecosystems to which they have been introduced

11. Slide by Kim Foglia

12. PROBLEMS CAUSED BY ZEBRA MUSSELS
Clog power plant and public water intakes and pipes, costing taxpayers millions of dollars · Damage boat engines · Blanket shorelines with their sharp shells and foul smell · Consume available food for
native species and smother
native mussels · Threaten water-based
recreational activities

13. Varying combinations of both biotic and abiotic factors
Abiotic and biotic factors influence the structure and dynamics of aquatic biomes
Varying combinations of both biotic and abiotic factors
Determine the nature of Earth’s many biomes
Biomes
Are the major types of ecological associations that occupy broad geographic regions of land or water

14. The examination of biomes will begin with Earth’s aquatic biomes
Tropic of Cancer
Equator
30S
Continental shelf
Lakes
Coral reefs
Rivers
Oceanic pelagic zone
Estuaries
Intertidal zone
Abyssal zone (below oceanic pelagic zone)
Key
Tropic of
Capricorn
Figure 50.15

15. Aquatic biomes
Account for the largest part of the biosphere in terms of area
Can contain fresh or salt water
Oceans
Cover about 75% of Earth’s surface
Have an enormous impact on the biosphere

16. Freshwater biomes
Littoral zone~ shallow, well-lit waters close to shore
Limnetic zone~ well-lit, open water farther from shore
Profundal zone~ deep, aphotic waters
Lake classification: •oligotrophic~ deep, nutrient poor •eutrophic~ shallow, high nutrient content •mesotrophic~ moderate productivity
Wetland~ area covered with water
Estuary~ area where freshwater merges with ocean

17. Marine biomes Intertidal zone~ area where land meets water
Neritic zone~ shallow regions over continental shelves
Oceanic zone~ very deep water past the continental shelves
Pelagic zone~ open water of any depth
Benthic zone~ seafloor bottom
Abyssal zone~ benthic region in deep oceans

18. Four major abiotic components make up climate
Climate largely determines the distribution and structure of terrestrial biomes
Four major abiotic components make up climate
Temperature, water, sunlight, and wind
Climate
Is particularly important in determining why particular terrestrial biomes are found in certain areas

19. The distribution of major terrestrial biomes
Tropic of
Cancer
Equator
Capricorn
30S
Key
Tropical forest
Savanna
Desert
Chaparral
Temperate grassland
Temperate broadleaf forest
Coniferous forest
Tundra
High mountains
Polar ice
Figure 50.19

20. Tropical forests~ equator; most complex; constant temperature and rainfall; canopy
Savanna~ tropical grassland with scattered trees; occasional fire and drought; large herbivores
Desert~ sparse rainfall (<30cm/yr)
Chaparral~ spiny evergreens at midlatitudes along coasts
Temperate grassland~ all grasses; seasonal drought, occasional fires; large mammals
Temperate deciduous forest~ midlatitude regions; broad-leaf deciduous trees
Coniferous forest~ cone-bearing trees
Tundra~ permafrost; very little precipitation