Niches & Community Interaction
How does the niche affect how an organism interacts with the biotic and abiotic factors in an ecosystem? Niche (page 2 of Q2 marine bio research packet)
Definition of niche What does the niche include? The way of life or role aspecies plays in itsenvironment Scientists focus on featuresthat can be readily measured: where species lives what time of day its active what it eats Range of conditions the species cantolerate Methods by which the speciesobtains resources Number of offspring a species has Time of reproduction All other interactions of the speciesin its environment Fundamental Niche vs. Realized Niche (page 2 of Q2 marine bio research packet)
Range of conditions a speciescan potentially tolerate Range of conditions species canpotentially use Not realistic Range of resources a speciesactually uses Species may have to restrictactivity to avoid predators Competition may prevent use ofa resource Generalists vs. Specialists (page 2 of Q2 marine bio research packet)
Broad niche Tolerate wide range ofconditions Use a variety of resources Virginia opossum foundacross the United States, eatseggs, carrion, fruits, plants Narrow niche Do not tolerate a wide rangeof conditions Use only a few resources Koala lives in Australia, feedson the leaves of only a fewspecies of eucalyptus trees Habitat (where an organism lives)(page 3 of Q2 marine bio research packet)
Abiotic factors Biotic factors Physical and chemical factors inan environment (non-living,never living) Temperature, humidity, pH,salinity, oxygen concentration,amount of sunlight, precipitation Influence an organism in itsenvironment Factors in an environment thatare or have been alive Determines when/how theorganisms reproduces Focus on the food a species eatsand the way it is obtained Influence an organism in itsenvironment Tolerance (page 3 of Q2 marine bio research packet)
Organisms can survive within a wide range of environmental conditions Every species has its own range of tolerance, the ability to survive and reproduce under a range of environmental circumstances Scientists can graph performance vs. the values of an environmental variable Range of Tolerance/Tolerance Curve (page 3 of Q2 marine bio research packet)
Optimum (or optimal) range typically several factors (pH, temperature, salinity) must fall within an organisms tolerance range Example The swimming speed of a species of fish is fastest at intermediate temperatures.The fish can survive and function at temperatures outside its optimal range but its performance is greatly reduced.The fish will not survive below its lower limit of tolerance and upper range of tolerance (tolerance limits). Acclimation (page 3 of Q2 marine bio research packet)
Definition of acclimation What is the difference between acclimation and adaptation? Some organisms can adjust theirtolerance to abiotic factors Goldfish raised at differenttemperatures have differenttolerance curves Living at high elevations willhelp you acclimate to reducedoxygen levels (RBCs increasein your body over time) Acclimation changes in anorganism due to environmentalfactors, occur within the lifetime ofan individual organism Adaptation genetic change in aspecies or population, occurs overmany generations Conformers vs. Regulators (page 3 of Q2 marine bio research packet)
Conformers (Ectotherms, Cold-blooded) Regulators (Endotherms, Warm-blooded) Organisms that do notregulate their internalconditions Change as the externalenvironment changes Leopard gecko and frog needa heat lamp because theycant regulate their bodytemperature Organisms that use energy to controlsome of their internal conditions Keep an internal condition within theoptimal range over a wide variety ofenvironmental conditions Humans are regulators oftemperature Salmon conformers of temp,regulators of internal saltconcentration (spend part of their lifein salt water and part in fresh water) Escape from Unsuitable Conditions (page 3 of Q2 marine bio research packet)
Dormancy Migration State of reduced activity Occurs during periods ofunfavorable environmentalconditions Winter temperatures are toocold for reptiles andamphibians to tolerate.Theyhide underground until thespring. Organism wants to escapeunfavorable conditions Move to a more favorable habitat Seasonal migration of birds to avoidlow temperatures and scarcity of food Spring and summer spent in coolerclimates and migrate to warmerclimates in the fall Return to cooler climate in thespring Resources (page 3 of Q2 marine bio research packet)
Definition of resources What determines the survival of a species in a particular habitat? The energy and materials aspecies needs to survive inan environment Suitability of environmentalconditions Availability of resources Food, energy nesting sites, water,sunlight, etc. Resources essential to survival varyfrom species to species Primary Producers: Considered the base of all food chains Autotroph: in biology, an organism capable of synthesizing its own organic substances from inorganic compounds. Autotrophs produce their own sugars, lipids, and amino acids using carbon dioxide as a source of carbon, and ammonia or nitrates as a source of nitrogen. Organisms that use light for the energy to synthesize organic compounds are called photosynthetic autotrophs; organisms that oxidize such compounds as hydrogen sulfide (H2S) to obtain energy are called chemosynthetic autotrophs, or chemotrophs. Photosynthetic autotrophs include the green plants, certain algae, and the pigmented sulfur bacteria. (photosynthesis).Chemotrophs include the iron bacteria, the nitrifying bacteria, and the nonpigmented sulfur bacteria (chemosynthesis) Heterotrophs: Organisms that must obtain their energy from organic compounds. living organism that obtains its energy from carbohydrates and other organic material. All animals and most bacteria and fungi are heterotrophic. Chemotrophs: Chemoautotrophs: use inorganic energy sources, such as hydrogen sulfide, elemental sulfur, ferrous iron, molecular hydrogen, and ammonia. Most are bacteria or archaea that live in hostile environments such as deep-sea vents and are the primary producers in such ecosystems. Competition How does competition shape a community? Competition (page 6 of Q2 marine bio research packet)
Definition of competition What is competitive exclusion? Use of the same limitedresource by two or morespecies Results from fundamentalniche overlap One organism will likely usethe resource more efficientlyand leave less resource for theother species One species is eliminated from acommunity because of competitionfor the same limited resource Species that uses the resourcemore efficiently has areproductive advantage Eventually eliminates otherspecies What is the competitive exclusion principle?
States that no two species canoccupy the same niche in the samehabitat at the same time Direct competition between speciesalmost always produces a winnerand a loser Losing species dies out Two species or paramecia thrive when grown separately. P. aurelia is a more efficient predator of bacteria so when the two species are grown together, P. aurelia thrives and P. caudatum dies out. This is an example of competitive exclusion. Classic Example - Barnacles
Two species of barnacles that both live in the intertidal zone (portion of the shore that is exposed during low tide). Each species formed a distinct band.Chthamalus live higher on the rock than Balanus.Difference due to competition. Chthamalus was transplanted to the lower zone and was able to tolerate the conditions in the lower zone.Balanus eventually crowded out Chthamalus. Competition eventually restricted the range of Chthamalus. Semibalanus restricted to lower zone because it dries out too much at the higher zones. Character displacement Resource partitioning
Competition & Community Structure (page 6 of Q2 marine bio research packet) Character displacement Resource partitioning Competitors evolve nichedifferences or anatomicaldifferences to lessen theintensity of competition Darwins finches different beak sizes inseed eating finchesreduces competitionbetween species Pattern of resource use Competition most intense betweenclosely related species that require thesame resources Similar species only use part of theavailable resources Three species of warblers, eachspecies feeds on insects in adifferent section of spruce or firtreees Resource partitioning Predator-Prey Relationships (page 8 of Q2 marine bio research packet)
The hunter captures, kills,and consumes another organism Predators survival dependson its ability to capture food Adaptations that improveefficiency of predators areacted on by natural selection Predator-prey relationshipsdetermine relationships in foodweb The hunted organism that iscaptured, killed, and consumed Preys survival depends on itsability to avoid being captured Natural selection favorsadaptations that allow prey toavoid, escape, and ward offpredators Energy Flow in an Ecosystem (page 11 of Q2 marine bio research packet)
Every community has atrophic structure (pattern offeeding relationships) One organism eats another,molecules are metabolized,energy is transferred Trophic structure is a keyfactor in community dynamics Trophic levels indicatesand organisms positionin the sequence of energytransfers Most ecosystems onlycontain 3 or 4 trophiclevels Energy Flow in an Ecosystem (page 11 of Q2 marine bio research packet)
Example phytoplankton benthic invertebrate sea duck bald eagle Of the 100 units of energy available in the phytoplankton, on average, only about 10 (or 10%) would reach the benthic invertebrates and only about 1 (or 10%) of that would reach the sea ducks and then only 0.1 (or 10%) would reach the bald eagles.So, in the long run, 0.1% of the energy in the phytoplankton would reach the bald eagle. Energy Flow in an Ecosystem(page 11 of Q2 marine bio research packet) What are food chains?How do these relate to food webs? 10% rule of energy transfer 10% of the total energy consumed in one trophic level is incorporated into organisms in the next level Energy Flow in an Ecosystem (page 11 of Q2 marine bio research packet)
Why is the percentage of energy transfer so low? Some organisms in atrophic level escapebeing eaten. Some molecules inthe food source cantbe broken down. Some energy is lostas heat. Example phytoplankton benthic invertebrate sea duck bald eagle Of the 100 units of energy available in the phytoplankton, on average, only about 10 (or 10%) would reach the benthic invertebrates and only about 1 (or 10%) of that would reach the sea ducks and then only 0.1 (or 10%) would reach the bald eagles.So, in the long run, 0.1% of the energy in the phytoplankton would reach the bald eagle. Biomagnification (talk about this concept when discussing in abiotic factors)
The process ofbioaccumulation /biotransfer ofcontaminate from onetrophic level to the next Tissue concentrations of a contaminant increase as it passes up through the trophic levels DDT, mercury, pesticides Energy Transfer How does energy move through the ecosystem? Producers vs. Consumers (page 13 of Q2 marine bio research packet)
1st trophic level (primary) Autotrophs Most are photosynthetic Can be chemoautotrophs Heterotrophs - all animals & fungi, mostprotists & bacteria Herbivores, carnivores,omnivores Detritivores (scavengers) consumersthat feed on the garbage of anecosystem (ex. turkey vulture) Decomposers cause decay, break downcomplex molecules in dead tissues andwastes into simpler molecules Primary Producers: Considered the base of all food chains Autotroph: in biology, an organism capable of synthesizing its own organic substances from inorganic compounds. Autotrophs produce their own sugars, lipids, and amino acids using carbon dioxide as a source of carbon, and ammonia or nitrates as a source of nitrogen. Organisms that use light for the energy to synthesize organic compounds are called photosynthetic autotrophs; organisms that oxidize such compounds as hydrogen sulfide (H2S) to obtain energy are called chemosynthetic autotrophs, or chemotrophs. Photosynthetic autotrophs include the green plants, certain algae, and the pigmented sulfur bacteria. (photosynthesis).Chemotrophs include the iron bacteria, the nitrifying bacteria, and the nonpigmented sulfur bacteria (chemosynthesis) Heterotrophs: Organisms that must obtain their energy from organic compounds. living organism that obtains its energy from carbohydrates and other organic material. All animals and most bacteria and fungi are heterotrophic. Chemotrophs: Chemoautotrophs: use inorganic energy sources, such as hydrogen sulfide, elemental sulfur, ferrous iron, molecular hydrogen, and ammonia. Most are bacteria or archaea that live in hostile environments such as deep-sea vents and are the primary producers in such ecosystems.