1. Daily Science
Water (if needed) and measure height of pea plants
Make a data table for 7 days on a notebook or notebook sheet of paper. Take your time, this will be turned in eventually for the lab!

2. Chapter 54
Community Ecology

3. Overview: A Sense of Community
A biological community is an assemblage of populations of various species living close enough for potential interaction
How many interactions are occurring here between species?

4. Concept 54.1: Community interactions are classified by whether they help, harm, or have no effect on the species involved
Ecologists call relationships between species in a community interspecific interactions
Examples are competition, predation, herbivory, and symbiosis (parasitism, mutualism, and commensalism)
Interspecific interactions can affect the survival and reproduction of each species, and the effects can be summarized as positive (+), negative (–), or no effect (0)

5. Competitive Exclusion
Interspecific competition (–/– interaction) occurs when species compete for a resource in short supply
Strong competition can lead to competitive exclusion, local elimination of a competing species
The competitive exclusion principle states that two species competing for the same limiting resources cannot coexist in the same place

6. Ecological Niches
The total of a species’ use of biotic and abiotic resources is called the species’ ecological niche
An ecological niche can also be thought of as an organism’s ecological role
Ecologically similar species can coexist in a community if there are one or more significant differences in their niches

7. A. distichus perches on fence posts and other sunny surfaces.
Fig. 54-2
A. distichus perches on fence
posts and other sunny surfaces.
A. insolitus usually perches
on shady branches.
A. ricordii
Figure 54.2 Resource partitioning among Dominican Republic lizards
A. insolitus
A. aliniger
A. christophei
A. distichus
A. cybotes
A. etheridgei

8. The presence of one barnacle affects the distribution of another
Fig. 54-3
EXPERIMENT
High tide
Chthamalus
Chthamalus
realized niche
Balanus
The presence of one barnacle affects the distribution of another
One barnacle species is removed from niche
Balanus
realized niche
Ocean
Low tide
RESULTS
High tide
Figure 54.3 Can a species’ niche be influenced by interspecific competition?
Chthamalus
fundamental niche
Ocean
Low tide

9. Predation
Predation (+/– interaction) refers to interaction where one species, the predator, kills and eats the other, the prey
What are some feeding adaptations that predators use for feeding and killing?
Answer: claws, teeth, fangs, stingers, and poison

10. Prey display various defensive adaptations, can you think of some?
Answer: hiding, fleeing, forming herds or schools, self-defense, and alarm calls
Animals also have morphological and physiological defense adaptations
Cryptic coloration, or camouflage, makes prey difficult to spot

11. Bee orchid (a) Cryptic coloration Canyon tree frog (b) Aposematic
Fig. 54-5
(a)
Cryptic
coloration
Canyon tree frog
(b)
Aposematic
coloration
Poison dart frog
Bee orchid
(c) Batesian mimicry: A harmless species mimics a harmful one.
Hawkmoth
larva
Figure 54.5 Examples of defensive coloration in animals
(d)
Müllerian mimicry: Two unpalatable species
mimic each other.
Cuckoo bee
Green parrot snake
Yellow jacket

12. Herbivory
Herbivory (+/– interaction) refers to an interaction in which an herbivore eats parts of a plant or alga
It has led to evolution of plant mechanical and chemical defenses and adaptations by herbivores

13. Concept 54.2: Dominant and keystone species exert strong controls on community structure
In general, a few species in a community exert strong control on that community’s structure
Two fundamental features of community structure are species diversity and feeding relationships

14. Species Diversity
Species diversity of a community is the variety of organisms that make up the community
It has two components: species richness and relative abundance
Species richness is the total number of different species in the community
Relative abundance is the proportion each species represents of the total individuals in the community

15. Which forest is more diverse?
Fig. 54-9
Which forest is more diverse? A B C D
Community 1
Community 2
Figure 54.9 Which forest is more diverse?
A: 25% B: 25% C: 25% D: 25%
A: 80% B: 5% C: 5% D: 10%
Answer: Forest 1

16. Trophic Structure
Trophic structure is the feeding relationships between organisms in a community
It is a key factor in community dynamics
Food chains link trophic levels from producers to top carnivores
A food web is a branching food chain with complex trophic interactions

17. A terrestrial food chain A marine food chain
Fig
Quaternary
consumers
Carnivore
Carnivore
Tertiary
consumers
Carnivore
Carnivore
Secondary
consumers
Carnivore
Carnivore
Figure Examples of terrestrial and marine food chains
Primary
consumers
Herbivore
Zooplankton
Primary
producers
Plant
Phytoplankton
A terrestrial food chain
A marine food chain

18. Species may play a role at more than one level
Fig
Humans
Species may play a role at more than one level
Smaller
toothed
whales
Baleen
whales
Sperm
whales
Crab-eater
seals
Leopard
seals
Elephant
seals
Birds
Fishes
Squids
Figure An antarctic marine food web
Carnivorous
plankton
Euphausids
(krill)
Copepods
Phyto-
plankton