Chapter 54 Flashcards
Community Ecology
interactions between members of different species in a location and how such interactions impact community structure
Community structure refers to
number of species
the specific species present
relative abundance of species
Competition
negative effect on both species (-/-)
Predation
exploitative, positive effect on predator, negative effect on prey (+/-)
Herbivory
exploitative interaction, (herbivore and plant/algae) (+/-)
Parasitism
exploitative interaction (parasite and host) (+/-)
Mutualism
both species benefit (+/+)
Commensalism
benefits one species but neither benefits nor harms others (+/0)
Ecological niche
specific set of biotic and abiotic environmental resources it uses
Predator adaptations
claws, fangs, or poison
Mechanical defense
Porcupine
Chemical defense
skunk
Aposematic coloration: warning coloration
poison dart frog
Cryptic coloration: camouflage
canyon tree frog
Batesian mimicry: A harmless species mimics a harmful one
Nonvenomous hawkmoth larva and venomous green parrot snake
Mullerian mimicry: two unpalatable species mimic each other
Cuckoo bee and yellow jacket
Species richness
number of different species in the community
Relative abundance
proportion each species represents of all individuals in the community
two communities can have the same species richness but
different relative abundance
trophic structure
the feeding relationships between organisms in a community
Foundation species
most abundant or highest biomass
often, competitively dominant
Keystone species
exert strong impact on a community, more than size alone would suggest
Ecosystem engineers
create or dramatically alter their physical environment
Bottom-up controls
organisms can be controlled by what they eat
Top down controls
organisms can be controlled by what eats them
Disturbance
an event that changes a community by removing organisms from it or altering resource availability
Intermediate disturbance hypothesis
states that moderate levels of disturbance foster greater diversity than do high or low levels of disturbance
Ecological succession
refers to the pattern of colonization and species replacement that occurs in a community following a severe disturbance
Primary succession
lifeless area, such as a new volcanic island
Secondary succession
involves the recolonization of an area after a major disturbance has removed most but not all of the organisms
Factors that affect latitudinal gradients
evolutionary history and climate
Island Equilibrium model
species richness on islands represents a balance between immigration of new species and extinction of established species
Pathogen effects on community structure
white band disease and protist that killed trees, swine flu
Zoonosis
those that are transferred to humans from other animals
Example-Lyme disease
Vectors
the transfer of pathogens can be through direct contact or an intermediate species
Example-avian flu
