Community Ecology

Community Ecology - the study of all the organisms in a given area at a given time.

Interspecific Interactions - Table 53.1

predation	+	-
mutualism	+	+
commensalism	+	0
parasitism	+	-
competition	-	-

Competition

     Limiting factor

     Interspecific competition

Competitive exclusion

 

The Niche - Fig 53.2

     Realized niche
     Fundamental niche

 

Resource partitioning - Fig. 53.3

     Character displacement - Fig. 53.4

Predator-Prey Interactions - A predator in action - may be cyclic in nature.

Predators may have special features for detection and acquisition of prey - sight, hearing, smell, speed, claws, teeth, tolerance of chemicals

    Plant Defenses

Morphological defenses
-- Thorns and spines
-- Glandular hairs
-- Deposition of crystals in plant's tissues
Chemical defenses
-- Chemical compounds

     Defenses in Animals

Cryptic coloration - Fig. 53.5 and Deceptive coloration

Aposematic coloration - Fig. 53.6
Mimicry

*Batesian mimicry - Fig. 53.7
-- Unprotected species resemble protected ones
-- Harmful specimen is the model
-- Harmless specimen is the mimic
*Muellerian mimicry - Fig. 53.8

Symbiosis - Three Major Kinds of Relationships

Parasitism: one partner benefits (parasite), other is harmed (host)

       endoparasites - Fig 33.11
       ectoparasites

       parasitoids

       nest parasites

 

Mutualism: both participants benefit
-- Microorganisms in digestive tracts of herbivores

-- Clownfish and sea anemone - The movie
-- Mycorrhizae = fungus + plant root - plants with and without mycorrhizae - Fig 31.18 and Fig 31.19.
-- Nitrogen-fixing bacteria in nodules on the roots of legumes (Fig 37.10a)
-- Flowering plants + pollinators

-- Some species of acacia + ants - Fig. 53.9

 

Commensalism: one partner benefits, other unaffected

Coevolution

Community Structure

Species diversity - Fig. 53.21

species richness
relative abundance of species

Trophic Levels

Producers
Primary consumers
Secondary consumers
Tertiary consumers
Quaternary consumers

Omnivores
Decomposers
Detrivores

food chain - Fig. 53.10
food webs - Fig. 53.11

Dominant and Keystone Species - Fig 53.14 and Fig. 53.15

Ecological succession, disturbance and non-equilibrium

• Stability
• Disturbance - Fig. 53.18a - Mount Saint Helen's - Forest fire
• Primary succession   Image       Demo
• Secondary succession - Fig. 53.18b

Biogeography

• Biodiversity
• Relative abundance - rare vs common species - Fig. 53.22
• Species richness and latitude - Fig. 53.23
• Species-area curve - Fig. 53.25
• Island biogeography - Fig. 53.26 Galapagos Islands - Fig. 53.27