1. An Introduction to Ecology and the Biosphere
Chapter 52
An Introduction to Ecology and the Biosphere

2. Overview: Discovering Ecology
Ecology is the scientific study of the interactions between organisms and the environment
These interactions determine the distribution of organisms and their abundance
© 2011 Pearson Education, Inc.

3. Temperate broadleaf forest Northern coniferous forest Tundra
Figure 52.9
30°N
Tropic of
Cancer
Equator
Tropic of Capricorn
30°S
Figure 52.9 The distribution of major terrestrial biomes.
Tropical forest
Savanna
Desert
Chaparral
Temperate grassland
Temperate broadleaf forest
Northern coniferous forest
Tundra
High mountains
Polar ice

4. What environmental factors limit their geographic distribution?
The rediscovery of the nearly extinct harlequin toad in Costa Rica raises many ecological questions
What environmental factors limit their geographic distribution?
What factors (food, pathogens) affect population size?
© 2011 Pearson Education, Inc.

5. Ecology Big Idea 1 Geographic Distribution of Species
Dependent on environment
Population size
Food supply, pathogens, natural predators

6. Climate determine the distribution of an organism
Macroclimate
Solar energy
Bodies of water
Seasonality
Mountains
Microclimate
Abiotic Factors
Biotic Factors
© 2011 Pearson Education, Inc.

7. Latitudinal Variation in Sunlight Intensity
The angle at which sunlight hits Earth affects its intensity, the amount of heat and light per unit of surface area
The intensity of sunlight is strongest in the tropics (between 23.5° north latitude and 23.5° south latitude)
© 2011 Pearson Education, Inc.

8. Latitudinal variation in sunlight intensity
Figure 52.3a
Atmosphere
90°N (North Pole)
60°N
Low angle of incoming sunlight
30°N
23.5°N (Tropic of
Cancer
Sun overhead at equinoxes
0° (Equator)
23.5°S (Tropic of
Capricorn)
30°S
Figure 52.3 Exploring: Global Climate Patterns
Low angle of incoming sunlight
60°S
90°S (South Pole)
Latitudinal variation in sunlight intensity

9. Large Bodies of Water Effect on Climate
Water has a high specific heat It takes longer to heat up and cool down.
Result:
Lower temperature in summer and winter
© 2011 Pearson Education, Inc.

10. Comparing Climate – Do Now
Which of these two graphs is showing a city that is near a large body of water, AND how do you know that is the case?

11. Global Climate Change
Changes in Earth’s climate can profoundly affect the biosphere
One way to predict the effects of future global climate change is to study previous changes
As glaciers retreated 16,000 years ago, tree distribution patterns changed
As climate changes, species that have difficulty dispersing may have smaller ranges or could become extinct
© 2011 Pearson Education, Inc.

12. (a) 4.5°C warming over next century (b) 6.5°C warming over next
Figure 52.7
Current
range
Predicted
range
Figure 52.7 Current range and predicted range for the American beech under two climate-change scenarios.
Overlap
(a) 4.5°C warming over next
century
(b) 6.5°C warming over next
century

13. Sweden Finland Expanded range in 1997 Range in 1970 Figure 52.8
Figure 52.8 Northward range expansion of the silver-washed fritillary in Sweden and Finland.
Expanded range in 1997
Range in 1970

14. Mountains

15. Concept 52.2: The structure and distribution of terrestrial biomes are controlled by climate and disturbance
Biomes are major life zones characterized by vegetation type (terrestrial biomes) or physical environment (aquatic biomes)
Climate is very important in determining why terrestrial biomes are found in certain areas
© 2011 Pearson Education, Inc.

16. 30°N Tropic of Cancer Equator Tropic of Capricorn Figure 52.9
Figure 52.9 The distribution of major terrestrial biomes.

17. Interactions between organisms and the environment limit the distribution of species
Species distributions are the result of ecological and evolutionary (natural selection) interactions
Ecological time is the minute-to-minute time frame of interactions between organisms and the environment
Evolutionary time spans many generations and captures adaptation through natural selection
© 2011 Pearson Education, Inc.

18. Events in ecological time can lead to evolution
For example, Galápagos finches with larger beaks were more likely to survive a drought as they could eat the available larger seeds
As a result, the average beak size was larger in the next generation
This resulted in an evolutionary change
© 2011 Pearson Education, Inc.

19. Both biotic and abiotic factors influence species distribution
For example, climate, interspecific interactions, and other factors affect the distribution of the red kangaroo
© 2011 Pearson Education, Inc.

20. We will look at Kangaroo distribution and biomes on the next 2 slides.
While you look at this map and distribution think of the following things.
What part of the country has the most kangaroos/km2?
What factors would a biologist look for to identify why kangaroos are more plentiful in other areas?
What information would we need to know about biomes and the kangaroos to answer these questions?
Students should be identifying that there is greater distribution of kangaroos in savanna regions of Australia (use both slides 19 and 20 to help them get there)
Factors that they should be recognizing or questions they should ask:
Why can that one region of Australia support more than 20 kangaroos/km?
What is the diet of kangaroos that makes Savannah’s the most successful area for them?
Why are they not as successful/present at all in the tropical regions of Australia?
© 2011 Pearson Education, Inc.

22. Kangaroos/km2 0–0.1 0.1–1 1–5 5–10 10–20 > 20 Limits of
Figure 52.17
Kangaroos/km2
0–0.1
0.1–1
1–5
5–10
10–20
> 20
Limits of
distribution
Figure Distribution and abundance of the red kangaroo in Australia, based on aerial surveys.

23. Figure 52.18
Why is species
X absent
from an area?
Yes
Area inaccessible
or insufficient time
Yes
Predation,
parasitism,
competition,
disease
Does dispersal
limit its
distribution?
Habitat selection
Yes
Does behavior
limit its
distribution? No
Do biotic factors
(other species)
limit its
distribution? No
Do abiotic
factors limit its
distribution? No
Physical
factors
Chemical
factors
Figure Flowchart of factors limiting geographic distribution.
Ecologists ask questions about where species occur and why species occur where they do
Temperature
Light
Soil structure
Fire
Moisture, etc.
Water
Oxygen
Salinity pH
Soil nutrients,
etc.

24. Dispersal of Species Natural Range Adaptive Radiation
Dispersal is the movement of individuals away from centers of high population density or from their area of origin.
Natural Range
Adaptive Radiation
Species Transplant
Behavior
Biotic Factors
© 2011 Pearson Education, Inc.

25. Natural Range Expansions and Adaptive Radiation
Natural range expansions show the influence of dispersal on distribution
For example, cattle egrets arrived in the Americas in the late 1800s and have expanded their distribution
In rare cases, long-distance dispersal can lead to adaptive radiation
For example, Hawaiian silverswords are a diverse group descended from an ancestral North American tarweed
© 2011 Pearson Education, Inc.

26. Figure 52.19
Current
1970
1966
1965
1960
1961
1943
1958
1937
1951
1956
Figure Dispersal of the cattle egret in the Americas.
1970

27. Species Transplants
Species transplants include organisms that are intentionally or accidentally relocated from their original distribution
If a transplant is successful, it indicates that its potential range is larger than its actual range
Species transplants can disrupt the communities or ecosystems to which they have been introduced
© 2011 Pearson Education, Inc.

28. Behavior and Habitat Selection
Some organisms do not occupy all of their potential range
Species distribution may be limited by habitat selection behavior
© 2011 Pearson Education, Inc.

29. Biotic Factors
Biotic factors that affect the distribution of organisms may include
Predation
Herbivory
For example, sea urchins can limit the distribution of seaweeds
Competition
© 2011 Pearson Education, Inc.

30. August 1982 February 1983 August 1983 February 1984
Figure 52.20
RESULTS
100
Both limpets and urchins
removed 80
Sea urchin
Only urchins
removed 60
Seaweed cover (%)
Limpet 40
Figure Inquiry: Does feeding by sea urchins limit seaweed distribution?
Only limpets removed 20
Control (both urchins
and limpets present)
August
1982
February
1983
August
1983
February
1984

31. Abiotic Factors
Abiotic factors affecting the distribution of organisms include
Temperature
Water
Sunlight
Wind
Rocks and soil
Most abiotic factors vary in space and time
© 2011 Pearson Education, Inc.

32. Temperature
Environmental temperature is an important factor in the distribution of organisms because of its effects on biological processes
Cells may freeze and rupture below 0°C, while most proteins denature above 45°C
Mammals and birds expend energy to regulate their internal temperature
© 2011 Pearson Education, Inc.

33. Water and Oxygen
Water availability in habitats is another important factor in species distribution
Desert organisms exhibit adaptations for water conservation
Water affects oxygen availability as oxygen diffuses slowly in water
Oxygen concentrations can be low in deep oceans and deep lakes
© 2011 Pearson Education, Inc.

34. Salinity
Salt concentration affects the water balance of organisms through osmosis
Most aquatic organisms are restricted to either freshwater or saltwater habitats
Few terrestrial organisms are adapted to high-salinity habitats
© 2011 Pearson Education, Inc.

35. Sunlight
Light intensity and quality (wavelength) affect photosynthesis
Water absorbs light; as a result, in aquatic environments most photosynthesis occurs near the surface
In deserts, high light levels increase temperature and can stress plants and animals
© 2011 Pearson Education, Inc.

36. Figure 52.21
Figure Alpine tree line in Banff National Park, Canada.

37. Rocks and Soil
Many characteristics of soil limit the distribution of plants and thus the animals that feed on them
Physical structure pH
Mineral composition
© 2011 Pearson Education, Inc.