1. Office Hours: MW 2 to 4 pm or by appointment
Welcome!
BIO 340 – General Ecology
Dr. Thomas M. Gehring
Room 181 Brooks Hall
Office Hours: MW 2 to 4 pm or by appointment

2. Wildlife Ecology Research at CMU
Develop & test tools that might lead to a successful coexistence of humans & wildlife

3. Wildlife Ecology Research at CMU
Current studies examining population & spatial ecology of carnivores
Current tests of various non-lethal management tools on wolves

4. Ecology BIO 340 What is Ecology
The scientific study of the interactions that determine the distribution and abundance of organisms

5. Introduction
What is not ecology?

6. Biological Disciplines Relating To Ecological Study
PHYSIOLOGY
BEHAVIOR
GENETICS
EVOLUTION 7

7. 18th Century
Thomas Malthus Exponential Growth

8. 19th Century
Natural History Human Demography

9. Ernst Haeckel Defined “ecology,” “phylum”
Coined phrase “ontogeny recapitulates phylogeny”
Studied Foraminiferans
Controversial ideas

10. 20th Century Lotka & Volterra (1920’s) Model population growth
Gause (1920’s)
Manipulative Experiments

11. 20th Century Leopold (1930’s) Natural Resources MacArthur (1960’s)
Mathematical Ecology
Geographical Ecology

12. 20th Century Lindeman (1942) Trophic Dynamics Hutchinson (1950’s)
Niche Concept

13. 21st Century ?
Turner
Landscape Ecology
BIO 340 Student

14. Introduction Major Questions Where are organisms found?
Where aren’t organisms found?

15. Introduction
Major questions
How many are found there?

16. Introduction Major questions
Why are organisms found here and not there?
alvar

17. Introduction
Levels to ask questions
Individuals
Behavior
Physiology

18. Introduction Levels to ask questions Populations Change in size
Temporal & Spatial

19. Introduction
Levels to ask questions
Communities
Biotic interactions

20. Introduction Levels to ask questions Ecosystems
Community & Physical Environment

21. Introduction
Levels to ask questions
Landscapes
Spatial patterns

22. Introduction
Levels to ask questions
Biosphere

23. Organization of Biological World
Biosphere
Landscape
Ecosystem
Community
Population
Individual
Organ
Tissue
Cell
Organelle
Atom
INCREASED KNOWLEDGE
INCREASED COMPLEXITY

24. Figure 1.1
“…the community is an abstraction representing a level of organization rather than a discrete unit of structure in ecology.”

25. Types of Ecological Study
AUTECOLOGY
Study of individuals
Physiology /Environment

26. Types of Ecological Study
SYNECOLOGY
Study of groups of organisms
Community level and above

27. Introduction
How to look at a question
Proximate explanation

28. Introduction How to look at a question Ultimate explanation
“Nothing in biology makes sense except in the light of evolution”
Theodosius Dobzhansky

29. Introduction
Major Advances
Mathematical Models

30. Introduction
Major Advances
Evolution

31. Introduction Major Advances Hypothesis Testing
Testing ideas about how the natural world works
A hypothesis is developed to explain an observed phenomenon.
Example: giraffes have long necks because the long necks enable them to reach food that is unavailable to others.

32. Testing Ideas about How the Natural World Works
Null Hypothesis
Hypothesis of no difference
Example: The length of a giraffe’s neck does not influence the height at which it forages.
Alternative Hypothesis
Example: The length of a giraffe’s neck does influence the height at which it forages.
Figure 1.9b
Caption:
(b)Although it is common to see photos of giraffes straining to reach leaves high in trees, these almost always depict dominant bull giraffes, which feed high in vegetation much more frequently than do other individuals. Dominant bulls are a small proportion of the total population

33. Percentage of feeding bites
Most feeding is done below neck height.
Males
Females 7 7 6 6 5 5 4 4
Feeding height (meters) 3 3
Figure: 1.9a
Caption:
(a) These data plot the proportion of bites that male and female giraffes take at different heights. The drawings show the average size of a male and female. 2 2 1 1 20 40 20 40
Percentage of feeding bites

34. Testing Ideas about How the Natural World Works
Null Hypothesis
Hypothesis of no difference
Example: The length of a giraffe’s neck does not influence the height at which it forages. ACCEPT
Alternative Hypothesis
Example: The length of a giraffe’s neck does influence the height at which it forages. REJECT
Figure 1.9b
Caption:
(b)Although it is common to see photos of giraffes straining to reach leaves high in trees, these almost always depict dominant bull giraffes, which feed high in vegetation much more frequently than do other individuals. Dominant bulls are a small proportion of the total population

37. Testing Ideas about How the Natural World Works
Null Hypothesis
Hypothesis of no difference
Example: The length of a giraffe’s neck does not influence the height at which it forages. ACCEPT
So why do they have such long necks?
Alternative hypotheses
suggest a different explanation
Example: giraffes have long necks because long necks are effective weapons for one male against another during mating (Simmons and Scheepers).

38. Hypothesis Testing and Experimentation
Testing Ideas about How the Natural World Works
The predictions made by each hypothesis are determined.
Observations are made and/or an experiment is designed, to obtain data regarding the predictions.
Conclusion: the observational data support the Sexual Selection hypothesis.