1. Climate Effects on Species

2. Concept 52.4: Interactions between organisms and the environment limit the distribution of species
Species distributions are the result of ecological and evolutionary interactions through time
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

3. Events in ecological time can lead to evolution
For example, Galápagos finches with larger breaks 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

4. Both biotic and abiotic factors influence species distribution
For example, temperature, water availability, and interspecific interactions, affect the distribution of the saguaro cacti

5. BAJA CALIFORNIA BAJA CALIFORNIA SUR
Figure 52.15
ARIZONA
CALIFORNIA
BAJA CALIFORNIA
SONORA
BAJA CALIFORNIA SUR
GULF OF CALIFORNIA
Figure Distribution of the saguaro in North America N
100 km
Sonoran desert Saguaro cacti observed

6. Figure 52.15a
Figure 52.15a Distribution of the saguaro in North America (part 1: photo)

7. Ecologists ask questions about where species occur and why species occur where they do

8. Why is species X absent from an area?
Figure
Why is species X absent from an area?
Does dispersal limit its distribution?
Figure Flowchart of factors limiting geographic distribution (step 1)

9. Why is species X absent from an area?
Figure
Why is species X absent from an area?
Yes
Area inaccessible or insufficient time
Does dispersal limit its distribution?
Does behavior limit its distribution? No
Figure Flowchart of factors limiting geographic distribution (step 2)

10. Why is species X absent from an area?
Figure
Why is species X absent from an area?
Yes
Area inaccessible or insufficient time
Yes
Does dispersal limit its distribution?
Habitat selection
Does behavior limit its distribution? No
Do biotic factors (other species) limit its distribution? No
Figure Flowchart of factors limiting geographic distribution (step 3)

11. Why is species X absent from an area?
Figure
Why is species X absent from an area?
Yes
Area inaccessible or insufficient time
Yes
Does dispersal limit its distribution?
Habitat selection
Does behavior limit its distribution? No
Do biotic factors (other species) limit its distribution? No
Yes No
Predation, parasitism, competition, disease
Figure Flowchart of factors limiting geographic distribution (step 4)
Do abiotic factors limit its distribution?

12. Why is species X absent from an area?
Figure
Why is species X absent from an area?
Yes
Area inaccessible or insufficient time
Yes
Does dispersal limit its distribution?
Habitat selection
Does behavior limit its distribution? No
Do biotic factors (other species) limit its distribution? No
Yes No
Predation, parasitism, competition, disease
Figure Flowchart of factors limiting geographic distribution (step 5)
Chemical factors
Water, Oxygen, Salinity, pH, Soil nutrients, etc.
Do abiotic factors limit its distribution?
Temperature, Light, Soil structure, Fire, Moisture, etc.
Physical factors

13. Dispersal and Distribution
Dispersal is the movement of individuals or gametes away from centers of high population density or from their area of origin
Dispersal contributes to the global distribution of organisms

14. 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

15. Figure 52.17
Current
1970
1966
1965
1960
1961
1943
1958
1937
1951
1956
Figure Dispersal of the cattle egret in the Americas
1970

16. Figure 52.17a
Figure 52.17a Dispersal of the cattle egret in the Americas (part 1: photo)

17. 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

18. Behavior and Habitat Selection
Some organisms do not occupy all of their potential range
Species distribution may be limited by habitat selection behavior

19. 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
Mutualism
Parasitism

20. August 1982 February 1983 August 1983 February 1984
Figure 52.18
Sea urchin
Limpet
100
Both limpets and urchins removed 80 60
Seaweed cover (%)
Only urchins removed
Figure Inquiry: Does feeding by sea urchins limit seaweed distribution? 40
Only limpets removed 20
Control (both urchins and limpets present)
August 1982
February 1983
August 1983
February 1984

21. Figure 52.18a
Sea urchin
Figure 52.18a Inquiry: Does feeding by sea urchins limit seaweed distribution? (part 1: sea urchin)

22. Figure 52.18b
Limpet
Figure 52.18b Inquiry: Does feeding by sea urchins limit seaweed distribution? (part 2: limpet)

23. Abiotic Factors
Abiotic factors affecting the distribution of organisms include
Temperature
Water
Oxygen
Salinity
Sunlight
Soil
Most abiotic factors vary in space and time

24. 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

25. 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

26. 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
Salmon are able to migrate between freshwater and ocean

27. Sunlight
Light intensity and quality (wavelength) affect photosynthesis
Shading by leaves makes competition for light intense on the forest floor
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

28. Figure 52.19
Figure Alpine tree line in Banff National Park

29. 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

30. Data from the Field Experiment
Figure 52.UN03a
Data from the Field Experiment
Average Biomass (g/100 cm2)
Spartina patens
Typha angustifolia
Salt Marshes
Freshwater Marshes
Salt Marshes
Freshwater Marshes
With neighbors 8 3 18
Figure 52.UN03a Skills exercise: making a bar graph and a line graph to interpret data (part 1)
Without neighbors 10 20 33

31. Data from the Greenhouse Experiment
Figure 52.UN03b
Data from the Greenhouse Experiment
Salinity (parts per thousand 20 40 60 80
100
% maximum biomass (Spartina patens) 77 40 29 17 9
% maximum biomass (Typha angustifolia) 80 20 10
Figure 52.UN03b Skills exercise: making a bar graph and a line graph to interpret data (part 2)

32. Spartina patens Figure 52.UN03c
Figure 52.UN03c Skills exercise: making a bar graph and a line graph to interpret data (part 3)
Spartina patens

33. Typha angustifolia Figure 52.UN03d
Figure 52.UN03d Skills exercise: making a bar graph and a line graph to interpret data (part 4)
Typha angustifolia

34. Area inaccessible or insufficient time
Figure 52.UN04
Yes
Area inaccessible or insufficient time
Does dispersal limit its distribution? No
Yes
Does behavior limit its distribution?
Habitat selection No
Do biotic factors (other species) limit its distribution?
Yes
Predation, parasitism, competition, disease No
Figure 52.UN04 Summary of key concepts: limiting factors of distribution
Chemical factors: Water, oxygen, salinity, pH, soil nutrients, etc.
Do abiotic factors limit its distribution?
Physical factors: Temperature, light, soil structure, fire, moisture, etc.

35. Figure 52.UN05
Figure 52.UN05 Test your understanding, question 10 (kelp abundance)

36. Altitude (m) Mean height (cm)
Figure 52.UN06 75 50 25
Altitude (m) Mean height (cm)
3,000
2,000
Figure 52.UN06 Test your understanding, question 12 (plant height and elevation)
Sierra Nevada
1,000
Great Basin Plateau
Seed collection sites

37. Figure 52.UN07
Figure 52.UN07 Test your understanding, question 14 (diverse habitats)