Post Midterm COPY Flashcards
whats the formula for toxic units (TU)?
TU = [exposure] / LC50 or EC50
what is the community-conditioning hypothesis?
ecological communities retain information about unique events in their history; akin to the population bottleneck theory; may account for persistence of toxicant effects long after degradation
Differentiate between observational and experimental studies
observational studies use biomonitoring, surveying, epidemiology. Experimental studies are manipulative, they change things.
these ecosystems are typically antagonistic, some synergistic
freshwater
explain the stability hypothesis for increased tropic biodiversity
tropics are more stable/predictable, species can specialize
why are aquatic systems typically more sensitive?
because they have high NPP but low biomass
in the river continuum concept, upstream is ___trophic and downstream is ____trophic
heterotrophic, autotrophic
what is QSAR
quantitative structure-activity relationship: method used to attempt to group chemicals that are structurally related by their mode of action or chemical properties using stats
what is the intermediate disturbance hypothesis?
researchers have found that exposure to intermediate disturbance or stress will maximize species diversity and stability
explain the heterogeneity hypothesis for increased tropic biodiversity
tropics are more physically complex, more habitats for specialization
Define community ecotoxicology
the study of the pollutant effects on species abundance, diversity and interactions in a common environment
What is trophic cascade
Lethal or sublethal pollutant effects on predators, grazers, or scavengers leading to cascading effects at lower trophic levels
What is the “salting out effect”?
increased salinity in water increases persistence of pesticides and POPs
What are the shannon and simpson diversity indices individually sensitive to?
shannon to rare species, simpson to dominance
These types of effects usually decrease organism abundance (indirect or direct)
Direct effects
what is dose-ratio dependent deviation
shift between synergism and antagonism dependent on ratio of mixture constituents
name four major ecosystem process that can be affected by contaminants
(1) decomposition (2) nutrient cycling (3) primary production (4) energy flow
name 5 community characteristics that can influence stability and recovery
community complexity, community maturity, community history, recolonization ability, and life history traits of community members
What is competitive release
When a pollutant resistant species wins or gains advantage. Niche overlap, interspecific competition