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1

what is ecology

the scientific study of the interactions between organisms and their environment

2

environment

all factors outside the organisms that influence it

3

environmental factors

abiotic (physical and chemical)
biotic (other organisms)

4

goal of ecology

how do abiotic and biotic factors influence the distribution and abundance of organisms?
-where are the organisms found?
-how many organisms are there?
-what do the organisms do?
Want to explain/understand the ecological processes - most interested in the processes of birth, death and migration

5

2 explanations

-proximal
-ultimate

6

proximal

patterns explained by the present environment
-how did the weather this summer influence plant growth in the region?

7

ultimate

patterns explained by the past environment
-how has the climate over the past 1000 years influenced the plant species present in the region?

8

ecology is a science
(iterative process)

1. observation/discovery
2. question
3. hypothesis
4. test hypothesis
5. conclusion
6. communicate results

9

observation/discovery

discover patterns and interconnections through observation

10

question

question the pattern and interconnections that are observed
what, why, how

11

what

questions that describe patterns or relationship

12

how

questions whether there are causes of these patterns and relationships
-proximal

13

why

questions why a system functions the way it does; examines the evolutionary basis of the pattern and relationships (ultimate)

14

hypothesis

develop possible answers/explanations to questions and express ideas about how a system works
-a prediction that can be tested
-declarative sentence
-reject or not reject (never accept)

15

null hypothesis

no change or relationship Ho

16

alternate hypothesis

prediction of change or relationship Ha

17

test hypothesis

evaluate hypothesis to determine if it can be rejected
1. sampling/observational
2. experimental studies
3. mathematical modeling

18

sampling/observational testing

-descriptive studies
-collect some measurable features of the natural world
features = variables
-natural experiment = unmanipulated
problem : does not establish cause and effect

19

experimental studies

-natural processes are allowed to proceed under conditions that are controlled (or manipulated)
-experimenter must fully understand the natural history of the organisms under study

20

mathematical modeling

examine the fit of natural processes to mathematical relationships
-high variation in nature
-mathematical models are representations of nature
-the importance of a model lies in its ability to accurately represent the essence of the relationship
-models have heuristic value

21

representations of nature

relationships may be generally but not exactly true

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heuristic value

-may reveal unexpected patterns or serve as a guide to new discoveries

23

conclusion

draw inferences about ecological processes
-high variation in nature = high uncertainty in results
-statistics = study and analysis of quantitative data
-rely on statistics to provide levels of certainty (or uncertainty)
-without quantifying the level of uncertainty - results are meaningless

24

ecology hierarchy

1. individuals
2. populations
3. communities

25

individuals

– interactions with their biotic and abiotic environment
-evolutionary ecology
-physiological ecology
-behavioural ecology

26

Evolutionary Ecology

individuals are the units of evolution
– Assumes: specializations imposed by evolutionary history

27

Physiological Ecology

individual responses to abiotic environment

28

Behavioural Ecology

individual responses to other individuals (biotic)

29

Populations:

– abundance/distribution patterns of groups of organisms: processes of birth, death,
migration
– evolutionary change occurs at the population level
• Interactions of organisms of the same species
• Interactions of two populations of different species

30

Communities:

– interactions of multiple populations of different species
• Structure and species interactions
- Ecosystem Ecology