1. Ecology

3. Distribution & Occurrence
Dispersal
Behavior
Biotic
Competition
Resource partitioning/niche differentiation
facilitation
Abiotic
Tolerance/requirements

4. Factors Influencing Distribution and Occurrence of organisms

5. Expansion of cattle egret after arrival to western hemisphere

6. Limiting Resources

7. Tolerance Range
Found in this range
minimum
maximum
Intolerant (too little)
required amount not present
org. cannot survive
Intolerant (too much)
org. cannot survive
low
high
Environmental gradient
Tolerance range is the range of a physical condition that the organisms can survive in (between the minimum and maximum)
Minimum = smallest amount the organism needs or can cope with
Maximum = largest amount the organism can cope with
Optimum = amount at which the organism does best
Populations can only become established in areas within the tolerance limit
Hibernation & dormancy are ways of avoiding periods of time where environment is outside the tolerance limit

8. Tolerance range: application of limiting resource
Limit due to requirement/tolerance
Limit due to tolerance
Tolerance range for “grass”
too dry
too wet
wet
dry
water

9. Ecological Niche
The totality of an organisms adaptations, its use of resources, and the lifestyle to which it is fitted
Physical, chemical, biological factors needed to survive
Behavior
Trophic level
adaptations
Habitat
Abiotic components of the environment

10. How an organism survives and reproduces in an environment
A variety of definitions of “niche” just to show you it is an easy idea that is hard to create a good definition for
How an organism survives and reproduces in an environment
How it does stuff and what resources it uses
The place or function of a given organism within its ecosystem. Note : Different organisms may compete for the same niche.
For example, in a forest there may be a niche for an organism that can fly and eat nectar from blossoms.
niche is the sum of the habitat requirements and behaviors that allow a species to persist and produce offspring
habitat and behavior
The niche of an organism is its place in the biotic environment, its relations to food and enemies.
Foraging/what it eats
The environmental conditions and resources that define the requirements of an individual or a species to survive and reproduce  
a niche is a term describing the relational position of a species or population in an ecosystem
the role and position a species has in its environment; how it meets its needs for food and shelter, how it survives, and how it reproduces. A species' niche includes all of its interactions with the biotic and abiotic factors of its environment.

11. Competition
Interaction among organisms that vie for the same resource in an ecosystem
Intraspecific
Competition between individuals in a population
Interspecific
Competition between individuals in 2 different species

12. Interspecific Competition: competition harms both organisms/species

13. Competitive Exclusion
Two species cannot coexist permanently in the same place if they compete for the same resource (at the same time, in the same way)
two species cannot coexist if they have the same niche
Over time, two competing species can either:
coexist, through niche differentiation (or other means)
compete until one species becomes locally extinct.

14. Fundamental (Ecological) v. Realized Niche
Green Anole (native to FL) and Brown Anole (introduced from Cuba)
Marshes and tree canopies

15. Ghost of competition past
The niche differentiation seen in the present is the result of past competition.
Past competition has resulted in:
Similar species diverging (through selection) so they do not directly compete (have different niches)
The extinction of poor competitors whose niches overlapped with the existing organisms (who outcompeted them).

16. Combined influence on distribution
The range and distribution of species is due to a combination of tolerance, competitive exclusion, and dispersal ability/opportunity

17. Tolerance range/limiting factor + Competition a simple schematic
Limit due to tolerance
too dry
Limit due to competition = competitive exclusion
Tolerance range for “grass”
Bush is better competitor in this area; excludes grass
wet
dry
water

18. Common Factors Determining Distribution (i.e., where things are found)
Found in this range
Intolerant (too much)
Predation
Out competed
Intolerant (too little)
Predation
Out competed
Also dispersal: is the organism or its offspring able to get to an area. If the organism is incapable of reaching an area (or has not yet reached an area) then it won’t be found there.
barrier to dispersal (no lizards here)
Intolerant (too little)
Predation
Out competed
disease/parasite
Intolerant (too much)
Predation
Out competed
Disease/parasites

19. The brownbarnacle competitively excludes the gray barnacle from the lower area even though the gray barnacle could tolerate that area
Tolerance ranges
Area
found

21. Character displacement
Morphological divergence in sympatric populations of similar species
Evidence of niche differentiation that can be seen in present.

22. More character displacement Stickle-back fish in lakes

23. Community Diversity, Disturbance, & Succession
Community Structure
Organismal Concept & Climax Communities
Individualistic Continuum
Non-equilibrium & intermediate disturbance hypothesis
Succession

24. Diversity = richness + relative abundance

25. Models of community composition
EQUILIBRIUM=STABILITY=reach and maintain a constant, stable species composition
ORGANISMAL (interactive) CONCEPT
Species co-exist because they have positive and necessary interactions
INDIVIDUALLISTIC CONTINUUM CONCEPT
Associations due to similarity in tolerance and requirements

27. Intermediate disturbance hypothesis

28. Wayne Sousa (1979) studied the effects of disturbance on the diversity of marine algae and invertebrates growing on boulders in the intertidal zone.
Small boulders high disturbance
Large boulder  low disturbance

30. Succession change in species structure of community over time
one assemblage of species is gradually replaced by another assemblage
Each assemblage=sere
Facilitation plays a role

31. Primary succession = bare mineral (new substrate)

32. Secondary Succession = existing soil and community disturbed
An example of Secondary Succession by stages: 1. A stable deciduous forest community 2. A disturbance, such as a wild fire, destroys the forest 3. The fire burns the forest to the ground 4. The fire leaves behind empty, but not destroyed, soil 5. Grasses and other herbaceous plants grow back first 6. Small bushes and trees begin to colonize the area 7. Fast growing evergreen trees develop to their fullest, while shade-tolerant trees develop in the understory 8. The short-lived and shade intolerant evergreen trees die as the larger deciduous trees overtop them. The ecosystem is now back to a similar state to where it began.

33. Secondary Succession of an abandoned farm field in North Carolina