an association of pops of different species interacting with one another in the same location, habitat or environment.
defining feature of communities
abiotic interactions between climate, topography and habitat, and their affects on community members
the specific role that each species plays in its community, including its habitat resource requirements (food, nutrients, energy, shelter) and the kinds of interactions with other species.
organisms that produce the food or chemical energy that sustains the community. includes photoautotrophs and chemoautotrophs.
organisms that feed on other members of the community to obtain their energy and resources.
interaction occurs between members of one or more species utilizing the same resources (e.g. light, space, nutrients, etc) of a given habitat which are in limited supply.
Competitive exclusion principle
document by G.F Gause studies of two species--paramecium---which formulates ___ ____ _____ that no two species can indefinitely occupy the same niche at the same time.
the gradual and orderly process of change in an ecosystem brought about by the progressive replacement of one community by another until a stable (climax) community is established. (get pioneer species--most plants are going to be annuals)
plants that produce a lot of seeds, seeds dispersed, germinate, plant grows for one cycle, then parent plant dies back. Next group of plants referred to as perrenials (persist from one year to the next)
succession that occurs in newly exposed or created barren habitats that have no prior history of plant or animal life
succession that occurs in disturbed habitats where plant and animal communities previously existed.
watering and soil formation are critical; pioneer species include bacteria, algae, lichens, mosses; accumulation of dust and organic mater contribute to soil developmen; progressive habitat modification or improvement allows new successional species to invade and take over; may take ~1000 years.
primitive vascular plants that appear to grow on stones--actually grows on poor soil (no water in rock--so dry out but rehydrate during next available rainfall)
Agricultural land succession
soil is already formed; seeds of many pioneer species are already present in the soil, others invade; pioneers include weedy annuals, then weedy perennials.
Relay Floristics Models
groups of species migrate to habitat at the same time, then occupy and modify habitat for the next association; the same climax community is eventually established; aka the facilittation model
Initial floristic composition model
almost all species are randomly present at abandonment; abundance depends on how fast they mature and reproduce; slower, long-lived species eventually dominate; aka the "tolerance model"
a dynamic, often changing web of interactions between all the living (biotic) species or components of a specific habitat, including their interactions with the non-living (abiotic) physical components of the environment associated with that habitat.
breakdown organic matter after detritivores got to it; break down the last of it and release minerals
flows through ecosystem in every possible way; law of thermodynamics says no ___ ____ is not 100%
source of energy in all ecosystems--captured by plants which is reflected back by water, clouds, etc. 20% absorbed by the atmosphere. Rest of it used to heat the land/water.
a pathway (or process) by which nutrients (or chemicals) and abiotic (lithosphere, atmospher and hydrosphere) components (or compartments) of an ecosystem.
this flow is often modeled after carbon flow. Once Photosynthesis occurs, we have something to estimate ___ ____ in the ecosystem.
Balanced by P = E + T + R + I (Evaporation + Transpiration + Runoff + Infiltration)
amount of water transpired in an oak forest--removes moisture from soil and moves back to the atmosphere--cools the leaves
how botanists measure the amount of moisture in a plant; uses standard inverted pipettes (equilibrium stuff that measures mm increments).
in oak trees, they measure transpiration by making a huge cut in the tree and making a giant ____. Build scaffolding around it to support tree. put a huge vessel beneath it and pour water continuously.
device plant ecologists use to measure transpiration in cut plant parts. (DOES NOT MEASURE EVAPO-TRANSPIRATION)
the cycle of CO2 through the atmosphere; use biomass to measure reduced carbon that measures energy
Limestone (carbonate ion), fossil fuels (coal, oil)
the forms of the largest amount of carbon reserve on Earth.
creates the greatest flux of carbon on earth. 120 tons move from atmosphere to plants.
represents the same amount of carbon (60 gigatons each) back to the atmosphere that photosynthesis takes away (120)
microbial--(4N2+6H20-->4NH3) how atmospheric nitrogen gets introduced into the ecosystem in bacteria and animals; chemical (N2+3H2-->2NH3)--requires high temp and pressure--convert nitrogen and hydrogen into ammonia--processed for fertilizer.
conversion of ammonia or ammonium to nitrate. Plants prefer nitrate--biological activity to convert this--two step reaction. Step 1: (2NH4 + 3O2 --> 2NO2 + 4H + 2H2O); Step 2 (2NO2 + O2 -->2NO3)
conversion of already reduced ammonia (nitrogen) in form of amino acids back to ammonium-->ammonium plus one charge easily coverts to ammonia gas.
N Deficiency in corn
corn is one of the most nitrogen intensive crops we have typically in form of nitrate; patches of yellow in the crop is due to ___.