Ch6: Species Interactions & Community Ecology: Part I• Spp. interactions affect function & structure of ecosystems• A small portion of energy passes between feeding levels• Communities respond differently to disturbances• Restoration is important todayI. Species interactionsA. 3 major types (Table 6.1, p. 143)1. competition (- -) = 2 or more individ. Requirea. usually noncombative; b. intraspecific interspecific c. competitive exclusion d. partitioning resources2. consumer-resource (+ -) = basis of food chains & websa. predation = - herbivore consumes - carnivore consumes 3. symbiosis = a. parasite (+ -) = b. mutualism (+ +) = mutually beneficial; both spp. benefit; c. commensalism (+ 0) = II. Ecological communities• = popns of diff. interacting spp. in the same areaA. Energy flows through organisms1. trophic level = 2. major trophic levels:a. producers plants, algae, some prokaryotes.b. consumers 1o consumer, 2o consumer, 3o consumer, 4o consumerc. detritivores = Examples? 1ENV 2100 Environmental Science, Dr. L. Kellyd. decomposers = Examples? bacteria & fungi.B. Most energy in organisms is lost as waste heat; C. trophic pyramid = D. Food webs show feeding (trophic) relationships, E. Keystone spp. play critical role in regulating biotic interactionskeystone sp. = Examples? top predators, such as F. Responses to disturbancesdisturbance = event that removes biomass &/or kills many organisms1. resistance = 2. resilience = 3. succession = pioneers = first colonizersa. primary succession = b. secondary succession = c. gives rise to climax (“stable”) G. Invasive spp. may disrupt communities 1. invasives are usually non-native (exotic)2. density-dependent Examples? 3. may be superior National Invasive Species Act of 1996H. ecological restoration = • tallgrass prairie• longleaf pine of Southeast (< 2%)• Florida everglades (4,700 m2, $7.8
View Full Document
Unlocking...