1. Chapter 54: Community Ecology

2. You Must Know:
The difference between a fundamental niche and a realized niche.
The role of competitive exclusion in interspecific competition.
The symbiotic relationships of parasitism, mutualism, and commensalism.
The impact of keystone species on community structure.
The difference between primary and secondary succession.

3. ___________________ = group of populations of different species living close enough to interact

4. Interspecific interactions
Can be positive (+), negative (-) or neutral (0)
Includes:
_________________________ (-/-)
_________________________ (+/-)
_________________________
Parasitism (__________)
Mutualism (__________)
Commensalism (__________)
_________________________ (+/+ or 0/+)

5. Interspecific Interaction
Description
Two or more species compete for a resource that is in short supply
One species, the ________________, kills and eats the other, the _________. Predation has led to diverse ___________________, including mimicry

6. Interspecific Interaction
Description
Herbivory
An __________________ eats part of a plant of alga. Plants have various chemical and mechanical __________________ against herbivory, and herbivores have specialized adaptations for ____________________

7. Interspecific Interaction
Description
Symbiosis
Individuals of two or more ___________ live in close contact with one another. 3 types:
Parasitism
(+/-)
The _________________ derives its nourishment from a second organism, the ___________, which is harmed.
2) ______________
(+/+)
Both species __________________ from the interaction
3) ______________
(+/0)
One species __________________ from the interaction, while the other is ________________________ by it.

8. Interspecific Interaction
Description
Facilitation
(+/+ or +/0)
Species have __________________ effects on the survival and __________________ of other species without the intimate contact of a symbiosis

9. _______________________________________: resources are in short supply between competing species
Species interaction is _________
_______________________________________: Two species __________________ coexist in a community if their ______________ are identical.
The one with the slight reproductive advantage will eliminate the other
______________________________: differences in niches that enable similar species to coexist

10. Ecological niche: the sum total of an organism’s ___ of abiotic/biotic ____________ in the environment
______________________niche = niche __________________ occupied by the species
__________________ niche = portion of fundamental niche the species ________ occupies
Chthamalus
fundamental niche
High tide
Low tide
Ocean
realized niche
Balanus

11. Predation (+/-) Defensive adaptations include:
________________ coloration – camouflaged by coloring
________________ or warning coloration – _______________ color of poisonous animals
_______________ mimicry – _____________ species mimic color of _____________ species
_______________ mimicry – 2 bad-tasting species resemble each other; both to be avoided
________________ – plants ___________ this by chemical toxins, spines, & thorns

12. Symbiosis: 2+ species live in direct contact with one another
Parasitism (+/-), mutualism (+/+), commensalism (+/0)
Commensalism
Mutualism

13. parasitism

14. Community Structure Species diversity =
____________________(# of different species) + ________________________(# of each species)

16. Community Structure Which is most diverse?
Species diversity = species richness+ relative abundance
Which is most diverse?
Community 1: 90A, 10B, 0C, 0D
Community 2: 25A, 25B, 25C, 25D
Community 3: 80A, 5B, 5C, 10D
Shannon Diversity Index: calculate diversity based on species richness & relative abundance
Highly diverse communities more resistant to __________________________________

17. Invasive Species
Organisms that become established outside native range
___________ – vine plant from Japan, noxious weed that kills trees & shrubs

18. Invasive Species Dutch elm disease – __________ carried by beetles
Arrived in U.S. on logs imported from Netherlands
Death of many elm trees across U.S., Europe, Canada
Try to cultivate resistant strains of elm trees

19. Invasive Species
______________________– fungus-like disease caused Irish Potato Famine in 1840’s
Arrived in Ireland from ships coming from U.S.
Only 1 species of potato planted in Ireland  all susceptible to disease
1 million people died
Problem with ________________ & lack of genetic diversity of crops

20. Trophic Structures
The trophic structure of a community is determined by the _________________ between ____________________ organisms.
Trophic levels = links in the trophic structure (________________________)
The transfer of food energy from plants  herbivores  carnivores  decomposers is called the _________________________.

21. What limits the length of a food chain?
___________________ ___________________ along chain
Long food chains less ___________ than short chains
Fig

22. Two or more food chains linked together are called ___________________
A given species may weave into the web at more than one trophic level.

23. ____________________ species: has the highest biomass or is the most abundant in the community
____________________ species: exert control on community structure by their important ecological niches
Loss of sea otter  increase sea urchins, destruction of kelp forests
Grizzly bear (transfer nutrients from sea  land by salmon diet)
Prairie dogs (burrows, soil aeration, trim vegetation)

24. Disturbances influences species diversity and composition
A disturbance changes a community by removing ___________________ or changing ___________________ availability (fire, drought, flood, storm, human activity)
____________________________________: transitions in species composition in a certain area over ecological time
Involves species facilitation

25. Primary Succession
Plants & animals invade ___________ _______________________________
Ex. colonization of _______________ island or ___________________

26. Primary Succession

27. Secondary Succession
Occurs when existing community is cleared by a disturbance that ________________________
Ex. abandoned ___________, ________________
Soon after fire. As this photo taken soon after the fire shows, the burn left a patchy landscape. Note the unburned trees in the distance.
One year after fire. This photo of the same general area taken the following year indicates how rapidly the com-munity began to recover. A variety of herbaceous plants, different from those in the former forest, cover the ground.

29. Biogeographic Factors
Important factors:
Latitude: species __________ diverse in _______________ than poles
Area: __________ areas more __________
Biogeographic islands = natural labs for studying species diversity
Influenced by _________ and _____________
___________________ islands  greater immigration, lower extinction rates
____________ from mainland  less immigration, higher extinction rates