1. Welcome to BIOL 207 – General Ecology Fall 2010/2011

2.
Know that site. 3

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5. Extra Credit 8 5

6. Extra Credit
Be sure to write your full name and the course code with any comment – eg: [First Name, Last Name (BIOL 207)] 8 6

7. 9 7

8. Index cards for chapter 1?
Remember: we’re using a new book this semester 2

9. Chapter 1: Introduction10

10. ?
“Where we humans fit in a less than perfect world is a judgment each of you must make, guided by your own sense of values and moral beliefs. Regardless of your own stand, it will be more useful to you and to human kind in general if your judgment is informed by a scientific understanding of how natural systems work and the ways in which humans are a part of the natural world.” 12 10

11. other important questions
what is ecology
what do ecologists do
what are ecologists interested in
where did ecology emerge from in the first place
... what is its relationship to my life? 11

12. What is Ecology? …. Oikos = home
“By ecology, we mean the body of knowledge concerning the economy of nature -- the investigation of the total relations of the animal both to its organic and to its inorganic environment; including above all, its friendly and inimical relation with those animals and plants with which it comes directly or indirectly into contact -- in a word, ecology is the study of all the complex interrelationships referred to by Darwin as the conditions of the struggle for existence.” Ernst Haeckel, 1870. 13 12

13. So, what is ecology?
Ecology is the science by which we study how organisms (animals, plants, and microbes) interact in and with the natural world.
in that case - ecology is the oldest science!
early ecologists were applied ecologists. how so?
ecology is also a ‘pure’ science - understanding for the sake of understanding
ecologists strive to develop an understanding of very basic and apparent problems in a way that recognizes the uniqueness and complexity of all aspects of nature but seeks patterns and predictions within the complexity 14 13

14. Ecology - A Science for Today
We have a great need for ecological understanding:
what are the best policies for managing our environmental support systems -- our watersheds, agricultural lands, wetlands?
we must apply ecological principles to:
solve or prevent environmental problems
inform our economic, political, and social thought and practice
Example? 15 14

15. So what do ecologists do?
They try to explain and understand
Two different classes of explanation in biology: proximate and ultimate
Proximate explanation: what is going on ‘here and now’
The present distribution and abundance of a particular species of bird may be ‘explained’ in terms of the physical environment that the bird tolerates, the food it eats, and the parasites and predators that attack it
Ultimate explanation: answer in evolutionary terms
How did this bird come to have these properties that now govern its life…
Ecologists must describe before they explain…
Ecologists also try to predict what will happen to x under y

16. Scales, diversity, and rigor
Ecological phenomena occur at a variety of scales
Ecological evidence comes in a variety of different sources
Ecology relies on truly scientific evidence and application of statistics

17. Questions of Scale: Ecological Systems Large and Small
Individual Organism (“No smaller unit in biology ... has a separate life in the environment...”)
Population (many organisms of the same species living together)
Guild (a group of populations that utilizes resources in essentially the same way)
Community (many populations of different kinds living in the same place)
Ecosystem (assemblages of organisms together with their physical environment; community + physical environment)
Biosphere (the global ecosystem, all organisms and environments on earth) 17 17

18. ecological systems 18

19. Ecological systems… human view19 19

20. Perspectives of Ecologists: Organism Approach
How do form, physiology, and behavior lead to survival?
Focus is on adaptations, modifications of structure and function, that suit the organism for life in its environment:
adaptations result from evolutionary change by natural selection, a natural link to population approach…
? - Why are trees the dominant plants in warm, moist environments – and shrubs the dominant plants in regions with cool, wet winters and hot, dry summers? 21 20

21. Perspectives of Ecologists: Population Approach
What determines the numbers of individuals and their variations in time and space?
Focus is on processes of birth and death, immigration and emigration, influenced by:
the physical environment
evolutionary processes
interactions with other populations, a natural link to community approach…
? – Why have mosquitoes increased in number and in extent? 22 21

22. Perspectives of Ecologists: Community Approach
How are communities structured from their component populations?
Focus is on the diversity and relative abundance of different kinds of organisms living together, affected by:
population interactions, promoting and limiting coexistence
feeding relationships, responsible for fluxes of energy and materials, a natural link to ecosystem approach...
? – what is the relationship between birds, crops, and insects? 23 22

23. Perspectives of Ecologists: Ecosystem Approach
How can we account for the activities of populations in the common “currencies” of energy and materials?
Focus is on movements of energy and materials and influences of:
organisms large and small
climate and other physical factors, including those acting on a global scale, a natural link to biosphere approach...
? – movement of Nitrogen… ? 24 23

24. Perspectives of Ecologists: Biosphere Approach
How can we understand the global movements of air and water, and the energy and chemical elements they contain?
Focus is on the global circulation of matter and energy, affecting:
distributions of organisms
changes in populations
composition of communities
productivity of ecosystems
? – climate change ?! 25 24

25. Questions of scale: time scales
Ecologists also work on a variety of time scales
Ecological Succession – the successive and continuous colonization of a site by certain species populations, accompanied by the extinction of others
Can be studied from weeks (decomposition?) … to thousands of years (ice age to present)
Migration
Can be studied in butterflies (days…) or in forest trees (thousands of years … or decades)

26. Systems and Processes: Dimensions in Time and Space
Nothing in nature is static: anything we can measure (conditions, number of organisms) exhibits variation.
Variation has temporal and spatial components.
Variation in each measurement has a characteristic scale; for the same degree of change:
air temperature varies over hours
ocean temperature varies over weeks or months
(weather vs climate?) 47 26

27. Temporal Variation Consider two kinds of temporal variation:
predictable, cyclic variations (daily, seasonal)
unpredictable, irregular variations
A temporal “rule of thumb”:
the more extreme the condition, the less frequent (compare cold fronts and hurricanes) … but…
but frequency and severity are relative terms that depend on the organism! 48 27

28. Spatial Variation
Spatial variation occurs at very small (forest sunflecks) and very large (latitudinal variation in solar flux) scales.
Scale of variation importance is a function of the organism:
the two sides of a leaf are different to an aphid
a moose eats the whole leaf, aphid and all 49 28

29. Time and Space A few generalizations:
moving organisms experience spatial variation as temporal variation
the faster an individual moves:
the smaller the scale of spatial variation
the more quickly it encounters new environments
the shorter the temporal scale of variation
spatial and temporal scales are correlated
frequency is inversely related to extent/severity 50 29

30. Diversity of ecological evidence
Observations and field experiments
Controlled Laboratory experiments
Simple laboratory systems
And mathematical models