Midterm 3 Flashcards
What kind of ecological interaction is parasitism?
+/- interaction
What is parasitism?
The use of another organism as a resource while they are still alive.
Do parasites cause death?
They cause harm but not immediate death
How many parasites are there on earth?
Parasites may outnumber free-living species 4:1
What are hosts?
- both a food and a habitat
- tightly associated with their parasites (opportunity for co-evolution)
What are the ecological and evolutionary responses of a host to their parasite?
Ecological: immunity
Evolutionary: resistance
What is a definitive host?
-host where parasite reaches sexual maturity
What is an intermediate host?
-host where a parasite may grow, develop or reproduce asexually
What are examples of micro parasites?
-viruses, bacteria, protozoans, fungi
What are the traits of a micro parasite?
- reproduce in a host
- found within cells, blood or guts of host
- short generation time
- many individuals
- usually need high host densities to persist
What are examples of macroparasites?
- parasitic worms
- lice
- fleas
- ticks
What are traits of macroparasites?
- found in cavities, between cells, or on the surface of the body
- may use more than one host
- longer generation time
- chronic re-infection possible
- endo and ectoparasites
What is vertical transmission?
-infection passed from mother to offspring
What is horizontal transmission? What are the types of horizontal transmission?
- all other mechanisms other than vertical
- direct: host to host
- indirect: usually a third party involved (vector)
What is a vector?
-an organism that carries the parasite between hosts
What are the individual effects of parasites on hosts?
- reproduction
- mortality (directly and via predators)
What are population effects of parasites on hosts?
- cause mass mortalities
- depress growth rates and population size
- can drive population cycles
What is a disturbance?
Abrupt change in the ecosystem, community or population structure and resource availability, substrate availability or the physical environment
What is succession?
- directional change in community composition or structure overtime following a disturbance
- progress from pioneer species to a climax community
What is primary succession?
Occurs after a catastrophic disturbance, and in newly formed habitats
(No plants or organic soil)
What is secondary succession?
Occurs after disturbances that remove plants, but the soil and nutrients remain (moves away from climax community)
How do you study succession?
- collect data at regular intervals following a disturbance
- experimentally induce disturbance or create ‘new habitat’ and monitor species colonization
- do chronosequencing
What is chronosequencing?
-when you compare communities in the same location with different ‘start times’
What is a pioneer species?
-adapted and able to survive as first colonists
What is a climax community?
- final group of species
- end point of succession
- assumed to be stable (until next disturbance)
What are endemic species?
-those found only in a single area
What does the species area curve show?
-bigger islands have more species than small islands
Occurs in other “island like” habitats
What is the species area curve equation?
S=c*A^z
C is constant
(Z is slope) (~0.3 on most islands)(~0.15 for land areas)
How is island richness determined?
-by colonization and extinction rates
When does species richness decrease?
- with isolation
- the more isolated islands are the less likely they are to receive colonists
What were the results of simberloff and Wilson’s island experiment?
- species richness on islands returned to levels similar to before defaunation
- closer, larger islands had more species
- precise species identity was not consistent, only the total number of species
What are metapopulations?
- collection of sub populations of 1 species
- proportion of sites occupied is determined by colonization and extinction rates at each site
- individual site dynamics are variable, but overall ‘metapopulation’ is stable
What is an ecosystem?
- all of the interacting parts of the biological and physical worlds
- a spatially explicit unit of the earth that includes all of the organisms, along with all components of the abiotic environment within its boundaries
What is ecosystem ecology?
-the study of natural systems from the standpoint of the flow of energy and the cycling of matter
What is energy conservation?
Energy can be neither created or destroyed
What is mass conservation?
-mass can be neither created or destroyed
What is the equation for mass balance approach for ecosystems?
Inputs= Outputs + Storage
What is Gross PPR?
Rate at which energy is captured and assimilated in an area
What is Net PPR?
-rate at which energy is assimilated and converted into producer biomass in an area
What is ecological efficiency?
% of the net production moving from one trophic level to the next
What is assimilation efficiency?
-how much energy (%) is assimilated compared to the amount ingested
What are production efficiencies?
The % of energy ingested that is used for growth
What are the approximate ecological efficiencies?
~5-20% per trophic level
What are energy traits of small streams?
- closed in by canopy
- low light, low primary production
- energy primarily terrestrial
- allochthonous (other/different production)
What are energy traits of big rivers?
- large and sunny
- lots of primary production
- terrestrial inputs are small
- autochthonous (self production)
What do nitrogen fixers do?
- move nitrogen out of the atmosphere and into the biosphere in forms that are biologically available (NH3)
- critically important to succession following a disturbance
What is driving climate change?
Increases in greenhouse gas emissions
What is phenology?
The study of the timing of life cycle events
What are some examples of phenology?
- timing of bud burst in the spring
- timing of northern migration of birds in spring
- timing of leaf drop in the fall
What is happening as changes in phenology occur at different rates between species?
-some ecological interactions are becoming decoupled in time and space
What happens when predators and prey are matched?
Survival of the predator is high and recruitment is high
What is the match/mismatch hypothesis?
- if predators and prey become out of sync the survival of the predator is low and recruitment is low
- can occur as a result of climate change driven shifts in phenology
What are some assumptions of the match/mismatch hypothesis?
- predators and prey must have pulsed abundance
- the mismatch must occur at a limiting life history stage for it to limit population productivity
- food must be limiting at that life stage
What is the salmon example of the match/mismatch hypothesis?
- increased survival through early marine period means that there will be an increased number of adult returns
- food is limiting
- species outmigration is happening at different rates
- zooplankton blooms are highly variable across years and are getting earlier in the year with climate change
How are pathogen or parasite abundance maintained?
-maintained if there are other hosts to act as reservoirs for the parasite
What is the bumblebee example of indirect mortality from pathogens and parasites?
- bumblebees infested with protozoan parasite crithida bombi have weakened abilities to recognize rewarding flowers based on their colour
- this causes them to be worse foragers
What is aquaculture?
The farming of aquatic organisms
What is sea lice?
- native ectoparasites to BC
- fee on the surface tissue and mucus of fish
- salmon farms act as year round reservoirs for lice
What is the hydrologic cycle?
Provides a physical model of element cycling in ecosystems
What are the largest pools in the hydrologic cycle?
- > 98% water content in oceans
- second largest pool of water is in sedimentary rocks near the earths surface
Where are the largest pools in the carbon cycle?
-limestone and dolomite
How are nutrients distributed in ash and oak forests?
-large amounts of phosphorous and nitrogen are stored in the soil
What is the distribution of nutrients in tropical forests?
- phosphorus and nitrogen are stored in living vegetation
- very little amount in soil
Why are mycorrhizae important in nutrient recycling?
- theirs associations with plants enhances their abilities to extract nutrients from the environment
- secrete enzymes into surrounding soil mobilizing mineral nutrients
What happens when you clear cut a deciduous forest?
- can cause the ecosystem to become ‘leaky’ and especially loose a large amount of nitrogen
- can cause implications for aquatic ecosystems downstream
What controls nutrient recycling in lakes?
- regeneration from sediments and deep water layers
- consumer based recycling
- vertical stratification (impedes nutrient mixing from deep water)
What controls nutrient recycling in oceans?
- regeneration from sediments and deep water layers
- consumer based recycling
What hinders the vertical mixing of water?
-the vertical mixing of water from the sediment to the surface can be hindered whenever surface waters have a different temperature and therefore a different density than that found in deep waters
What causes a lake to mix? (Vertical mixing)
-when temperatures become equal, spring and fall winds that blow along the surface of the lakes cause the entire lake to mix
What causes ocean water to circulate?
- sunlight can slowly cause the surface waters to evaporate and leave salt behind
- at some point, the surface water becomes saltier than deeper water and the surface water sinks
What are major drivers of NPP?
- temperature
- precipitation
What happens when an ecosystem receives too much precipitation?
- the ecosystem will experience a decline in NPP
- nutrients leach away from the soil and the rates of decomposition are reduced because of waterlogged soils
What nutrients constrain NPP?
- nitrogen
- phosphorus
Where does a large amount of the energy and nutrients in a small stream come from?
-in the form of allochthonous inputs such as dead leaves that drop from the surrounding terrestrial environment
What is a mass extinction?
> 75% of species become extinct in 2 million years
What are the major drivers of biodiversity loss?
- Exploitation
- Invasive/exotic species
- Land modification
- Appropriation of fresh waters
- Nutrient pollution
- Contaminant pollution
- Stratospheric ozone depletion
- Climate warming
What is serial depletion?
-start with the biggest organism, and when it gets depleted we move on to the next largest organism
What is the danger of introduced species?
-have the potential to cause widespread effects on native species and ecosystems
How fast is soil eroding?
-globally, soil is eroding ~5x higher than it is being replaced
What happen is during irrigation in deserts?
- irrigation can turn deserts into productive farmland
- accumulation of dissolved salts in water concentrate in irrigated soils
- causes the soil to be less productive
What happens on coasts near highly urbanized areas?
-high algae outbreaks due to increased nutrient accumulation
What are the biological impacts of climate change?
- Advance of spring events (bud burst, migration, breeding)
- Poleward range shifts (expansions of warm-adapted communities)
- Can disrupt predator-prey and insect-plant interaction
- Shifts in abundance’s/range of parasites, and their vectors are beginning to influence human disease dynamics
- Evolutionary responses can’t keep up
What is the goal of the IPCC?
-to stabilize greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic interference with the climate system
What are the characteristics of a early successional plant?
- many seeds
- small seed size
- dispersal by wind
- long seed viability
- rapid growth rate
- small side
- low shade tolerance
What are the characteristics of a late successional plant?
- few seeds
- large seed size
- dispersal by gravity
- short seed viability
- slow growth rate
- large mature size
- high shade tolerance
How does species diversity change with latitudinal gradients?
-higher species richness at low latitudes
What are some hypotheses for the latitudinal gradients in species diversity?
- time since glaciation/major disturbance
- energy due to constant climate, highest solar radiation flux, greatest rates of plant production
