1. Community Ecology
A Community Includes All Life in an Area

2. Niche: “JOB”
The sum total of all the ways as organism utilizes the resources of its environment
Such as: space utilization, food consumption, temperature range, moisture requirements, etc.
Fundamental niche – entire niche a species is CAPABLE of using
Realized niche – actual niche a species occupies

3. NOTE: Niche is NOT the same as habitat HABITAT – a physical place
NICHE – pattern of living
The niche of a lion – predator
Turkey vulture – scavenger
Cacti – drought tolerant species

4. Biotic Interaction
Competition
Predation
Symbiosis

5. Competition
Interspecific competition – two different species attempt to utilize the same resource
Intraspecific competition – two members of the same species fighting for same resource

6. Organisms may occupy more than one niche
Gauses’ Rule: No two organisms may occupy the same niche for very long when resources are LIMITING
“Survival of the fittest” – the stronger will force the weaker out of the habitat or contribute to its demise
This is known as the Competitive Exclusion Principle

7. Resource Partitioning
The reduction of competition of resources between species by “subdividing the niche”
Warblers: (5) species that fed on insects of spruce trees
One species fed on insects near branch tips
One fed on dense foliage
One fed on bases of tree branches
One on the tree top
One on the tree bottom

9. Each bird fed on different insects by feeding at different levels of the spruce tree – different niches
Sympatric species – differentiation of populations into different species within the same geographical areas (brown/green anole)
Partition resources by feeding in different portions of the habitat, utilizing different foods, feeding at different times
Believed to be driven by natural selection

10. Allopatric Populations
The differentiation of geographically isolated populations into distinct species

11. Consuming of one organism by another
Predators
Consuming of one organism by another
Predators (or lack of) can often have large effects on prey populations
Eastern Coast
- population explosions of white-tailed deer – strip the habitat of all edible plant life
Western Coast
- sea otters hunted to near extinction – sea urchin populations exploded (otters eat urchins)

12. Predation Prey ↑ = Predator ↑ Prey ↓ = Predator ↓ Predator ↑ =

13. How Would Evolution Apply?
Evolution – change in a species over time
Adaptation – species becomes better suited for survival
Natural selection - “survival of the fittest”
PREDATOR – strong selective pressure on prey
Only the strongest, quickest prey survive – prey evolve defensive adaptations
Also only the strongest, fastest predators will survive

14. Plant Defenses against Herbivores
Morphological defenses – thorns, spines, prickles, and plant hairs
Chemical defenses – toxic to most herbivores or disturb their metabolism (mustard, cabbage, watercress, radish, and horseradish, the same taste we enjoy!)

15. Animal Defenses against Predators
Defensive Coloration –
Cryptic coloration – color that blends with the surroundings and thus hides the individual from predators *usually do not live together in groups*
Warning coloration – showy coloration that shows they are poisonous
Chemical Defenses –
Poisons and Stings

16. Mimicry – looking like a harmful organism
Batesian Mimicry – palatable insects having coloration of a distasteful insect
Monarch and viceroy butterflys
Mullerian Mimicry – the resemblance of dangerous, unpalatable, or poisonous species (even unrelated species) to one another so that they become more easily recognized by potential predators
Brightly colored species of poison dart frogs

17. Coevolution
long-term mutual evolution of members of biological communities
Ex. Predator-Prey interactions
Flowers and pollinators

18. A Type of Co-evolution
Symbiotic relationships – two or more kinds of organisms live together in elaborate and permanent relationships
Example:
Fungi and roots of plants – fungi and expedite the plants’ absorption of nutrients and the plants in turn provide the fungi with carbohydrates

19. Kinds of Symbiosis
Commensalism
Mutualism
Parasitism
Saprophitism

20. Commensalism
One species benefits while the other neither benefits nor is harmed
Example:
Epiphytes on trees (epiphytes – plants that live on other plants)
Vermiliads and orchids in rain forest

21. Mutualism Both participating species benefit Example:
Cattle egret on back of cow

22. Parasitism One species benefits but the other is harmed
Ex. Tapeworm in dog
Tick on human

23. 3 Types of Parasites
External – parasites that feed on the exterior surface ex. Lice
Internal – parasites that feed on the interior
*not bacteria of fungi*
Brood – ex. Birds lay eggs in nests of other species

24. Keystone Species
Species that have a particularly strong effects on the composition of communities
Examples:
Dung beetle
Beavers

25. Succession Change in which one ecosystem is replaced by another
ex. Pond becoming a forest, field becoming a marsh

26. Primary Succession where there has been no life previously
Occurs on bare, lifeless substrate when organisms gradually move into an area and change its nature
Ex. sand dune, lava, bare rock

27. Secondary Succession where life has existed previously
a wooded area is cleared and left alone, plants will slowly reclaim the area
ex. After a forest fire, a fallow field

28. Why Succession Happens
Species alter the habitat and the resources available in it in ways that favor other species.