End of lect 19 (4/3) Communities Ecological material at 5 different levels: Individual, Population, Community, Ecosystem, Biosphere Community: multiple species interacting in given environment - Species interactions: predation, parasitism, mutualism, competition Competition among species: Interspecific and We also discuss several other topics like smk kepong baru address
If you want to learn more check out What is the fixed cost plus the variable cost per item?
If you want to learn more check out econ 201 sdsu
We also discuss several other topics like How was setting the goals for this class?
We also discuss several other topics like What are the general characteristics of virology?
We also discuss several other topics like iowa state university mis
Intraspecific Intraspecific: competition between same species - Using up resources - Densitydependent regulation Interspecific competition: competition between different species Outcomes: 1. Lead to exclusion of a species from a locality. This influences range - Competitive Exclusion Principle: two species competing for limiting resources (housing, food, etc.) but species that uses resource most efficiently will eliminate the other 2. Reduction in niche occupancy 3. Character displacement Common garden experiment: Tansy studied 2 plants, Gallium Silvestre (found in alkaline soils) and Gallium saxaphile (found in acidic soils) to see if competition influenced their location. He wanted to see if competitive exclusion resulted in the different ranges - when planted separately in both types of soil both survived - when planted together one species outcompeted the other because it used resources more efficiently. When both in acidic soil, Silvestre won, when both in alkaline soil, saxaphile won. 2 habitats resulted in different competitive outcomes Communities, lecture 20 (4/7/17) Species interactions: competition between species, parasitism, mutualism, predation, interaction between consumer and their resources (herbivores and the plants they eat) Competition Few potential outcomes 1. Competitive exclusion 2. Reduction and niche occupancy 3. Resource partitioning and character displacement (species evolved differences that reduce competition)Competitive exclusion example: Gallium Saxatile in acidic soils but Gallium Silvestre found in alkaline soils in nature A.G Tansly determined that competition influenced the species distributions each species can grow on both soils but are found in different ones because they use resources more efficiently on one type of soil when planted together one outcompetes the other: G. Silvestre outcompetes G. saxatile on alkaline soil and G. saxatile outcompetes G. Silvestre on acidic soils 3 species of paramecium eat yeast in the bacteria grown on oatmealwhen grown together, one excludes the other P. Aurelia destroys P. Caudatum (less rigorous competitor)How competition results in reduction in niche occupancy: Barnacles can disperse and move around well in larval form but when they mature, they submerge themselves on rocks and can’t move around Two species of barnaclelive in water: balanus and thalamas balanus live in lower intertitle zone (deeper water) and thalamus live in intertitle zone (shallow water) when removed balanus off rocks, thalamus extended range to intertitle zone balanus is a better competitor because it grows beneath thalamus and pops it off the rock (interference competition) balanus struggled with desiccation (dryness) in the upper intertitle zone and thalmus did well if it didn’t compete with the other species thalamus could survive in upper and lower intertitle zone but balamus couldn’t niche: all the ways a species uses resources in its environment Fundamental niche: potential to live range of physical and chemical conditions under which the spec can persist in the absence of competitors Realized niche: what happens in reality portion of the fundamental niche that the spec uses as a result of interacting with the other species Balanus is unable to survive in upper intertitle zone so both the fundamental and realized niche are the lower intertitle zone Exploitative competition: species using resources more efficiently than other species Interference competition: aggressive interactions (punching, biting, chemical warfare,etc) Chipmunks do this Range of 4 species of chipmunks Least chipmunk could live in a region up the slope when released form competition of other chipmunks. Yellowpine chipmunk prevented them from extending their range Lodgepole chipmunk defends position on the hillside from both yellowpine and alpine chipmunk. It will fight to prevent both from extending their range up/downward Allelopathy: plants release toxins into the environment to inhibit the growth of the surrounding plants (their competition) Black walnut trees produce hydroxy juglone which inhibits enzymes in other plants. Only few species can grow under this tree Eucalyptus releases an oil that catches fire easily (fire destroys seedlings of competitors). Eucalyptus resilient to fire and survives to reproduces itself Apparent competition: predator (consumer) species mediates competition between two or more species Intertidal community in Washington have pisaster fish Pisaster fish eat mussels, barnacles, mollusks Dr. Paine removed the sea stars and the number of prey decreased. Mussle population increased and outcompeted the other spec in the community, driving them locally extinct Pisaster fish is a keystone predator because it is responsible for increasing diversity in the community (fish present= diversity in the community) Third outcome of competition: Species evolve differences to reduce competition Character displacement/resource partitioning Anole lizards evolved to use different areas of trees as a result of adaptive radiation in Caribbean islands Some lizard species evolved to live and prey in grasses, others use the trunk, crown, or branches of the tree The character displacement is the difference in leg and tail size Character displacement seen in Darwin’s fincheswhen they live in different islands, they have similar beak sizes and eat similar things when found in sympatry, there’s a shift in beak size because they evolve to specialize in different seeds and reduce competition between speciesPredation Consumers and their resources Herbivore (consumer) eating grass (resource) Predator (consumer) and their prey (resource) Parasitism one organism parasitizing its host Chemical defenses: plants releasing toxins or disturbing the metabolism of herbivores Mustard family produces mustard oils (distasteful and toxic to insects) to reduce likelihood of being eaten Milkweed produces milky saps (disrupts heart function in insects) Evolved defense mechanisms like milky sap and mustard oils help the species not be consumed Coevolution: evolution of one species followed by evolution of another species to combat those adaptations Coevolutionary response of herbivores Circumventing plant defenses (mustard family producing toxic mustard) Cabbage butterfly caterpillars have evolved to break down the mustard oils (they have a food source just for themselves) Animal adaptation to defend against predators Chemical defenses (poison draft frog evolved toxicity and color as a warning) Defensive coloration (camouflage waved umber looks like a twig) Mimicry Nowtail butterflies Batesian mimicry: species without chemical defenses that looks toxic (tiger swallowtail butterfly that looks like the toxic pipeline butterfly) Mullerian mimicry Communities, lect 21 (4/12/17) Adaptations of prey that help decrease likelihood of being predated Batesian palatable species that mimics toxic spec. benefit: less likely to be eaten Mullerian distasteful/toxic spec look alike to increase survival Once predator eats one won’t repeat Consumer/resource relationships. Pop regulated by densityin/dependent factors Pop regulation from above (predator preys on prey) Pop regulation also coming from below Cow is both consumer (eats grass) and a resource (eaten by wolf) Densitydependent regulation coming from both directionsCyclamen mites preyed upon by Typhlodromus mites cyclamen mite feeds on strawberry fields. farmers plant strawberries and cycl. mites decimate the fields. typh. usually follows cycl. mites. Experiment looked at how important it is to regulate pop of cyclamen mites Control plot: both cycl and typh live normally Experimental Plot: typhl couldn’t invade. Put pesticides on strawberry fields if kept predator (in control), pop size of both predator and prey mite was stable low. if remove predator, get intense increase and decrease in pop size. See cycl. mite 25x less than in control plot. Predator is very important in regulating pop size of preyIn Cali, Klamath weed is detrimental so Chrysolina beetle was introduced - Weed was reduced about 1% starting numbers following introduction of beetles - Consumer regulating the resource pop Plant growth of multiple spec is reduced when allow moles to eat.. When we have consumer (predator) regulating its resource (prey), we have dif outcomes: 1) Prey pop goes extinct - Sometimes followed by predator pop going extinct 2) Predator/prey population cycles Predator regulates its prey pop to the point of extinction Showing scenario 1 Start with strong pop paramecium but when introduce predator (didinium) at day 0, see it increase because has lots of food and param. decreases example of a pop going over caring capacity. Predator pop overating food resource prey (paramecium) decreases to extinction and then the predator also does Showing scenario 2 Prey pop will increase, followed by predator pop increase and when they overshoot that Predatorprey pop cycles Synchronized cycles of prey pop numbers and predator pop numbers resource the prey numbers start to crash followed by predator numbers. Once predator pop decreases to low enough number, prey Pop recovers - Predator pop always follows prey popScientist (Elton) studied predatorprey cycles in lynx and hare He looked at fur trapping records for both. He assumed that if pop sizes were larger than the number of furs would be greater increase in prey (hare in blue)>increase in predator (lynx in red)>prey pop crashing>predator crashing>prey recovering data showed predatorprey cycles Why do we prey pop crashing and going extinct and sometimes get crashing and recovering (cycles)? Environmental variability plays a role Hafeker studied oranges and mites to create predatorprey cycles. Predator is typhlodromus occid. mite and prey is 6 spotted mite. Predator walks and prey floats Started with just universes (oranges) and everyone went extinct. Predators ate everyone and every1 and then died Stabilizing factrs that reduce cycling: He added variability by wrapping oranges in paper so mites can hide everyone still died but it took longer so he knew variability was associated with the time everyone went extinctHe put Vaseline between oranges to slow down walking mites and added wooden pegs on oranges so mites can climb up and jump between oranges This created a head start for prey and slowed down predators He got predatorprey cycles by increasing variability in the environmentPredatorprey cycles are better than everyone going extinct but a stable (no extreme crashes/recoveries) pop sizes is even better. No one overshooting caring capacity Stabilizing factors reduce cycling • Predator inefficiency - slowing down predator increases likelihood of predatorprey cylces rather than everyone dying - Also increases likelihood of stable pop cycles instead of predatorprey cycels • Densitydependent limitation of either the predator or prey population by factors external to their relationship - If something eating predator while it tries to eat another prey source, it cuts down predator numbers and decreases extreme cycles between predator and prey • Refuges for the prey at low densities • Reduced time delays in predator responses to changes in prey abundance - limit cycles instead of damped oscillations when we have time delays between when predator pop stops growing in response to prey abundance (helps produce stable pop) • Alternative food sources for the Over last decade common raven pop increased exponentially because of access to anthropogenic food sources - we can facilitate increases in pop range and size - we are likely to throw food away and increase the access to their food - they are also good at preying on desert tortes - since raven hasaccess to food from us, we predict that tortes should not go extinct and will recover Spec interactions: Any competition between 2 specis decreases resources so its a / interaction Predator/prey (consumer/resource) is a +/ interaction - bad for spec being eaten and good for spec eating Commensalism (+/) occurs when one spec is positively affected and other spec not effected - Spanish moss doesn’t have a negative affect when hangs on trees - Barnacles attach to whale, good for barnacles to move and doesn’t affect whales - Oxeater bird feeds on invertebrates that live on herbivores (lice on deer). Good for bird and possibly good or does nothing for the deer. But it depends on conditions. When there’s a drought, the birds pull open the deer scalp and drinks their blood, turning into parasitism rather than commensalism Parasitism (+/ interactions) ∙ Obtains nutrients from other living organisms (hosts) ∙ Invades bodies of hosts and feed on partially digested food, tissues (blood) etc ∙ Decreases fitness of host - host can mount a defense against parasite but it would lose needed energy ∙ Parasites generally don’t kill hosts - Because lives there - Long term, close associations Parasites evolved dif ways to live on host - Endoparasite (organisms that live inside body like plasmodium, tapeworm) and ectoparasites (live on outside like mosquitos, lice, deer ticks) (Plasmodium induces malaria. Tapeworm feeds off your lunch)Brain worm matures in brain of deer and produces eggs that hatch into larvae. Larvae passes through bloodstream to lungs, gets coughed up and swallowed by deer larvae travel through intestine and leaves the body through feces Snails become infected following contact with feces/ Larvae develop/grow in snails New deer become infected by eating grass/snails. Larvae penetrate the deer stomach and travel to the brain through the spinal cord Parasites have complex life cycles Adaptations of parasites: 2 variables to being successful 1. Transmission adaptations (has 3 categories) ∙ Massive reproductive output (reproduce a lot) - Schistosomes can produce 2000 offspring/day for 30 days. Increases likelihood that one will get transmitted to host ∙ Use of vectors - mosquitos are important for transmitting the parasite between hosts - Seedeating birds move mistletoes (parasite) between hosts. Parasite uses trees nutrients ∙ Host behavior manipulation 2. Adaptations to establish within host - must make it to the host and not get attacked by immune system Lect 22, Succession and Community (4/17) Succession: sequence of changes in a species composition of a community in a newly formed/disturbed habitat Series of states within the community that progresses towards a stable state climax community) Initially begin with newly formed or disturbed habitat. Next, pioneer (early successional) species colonize that habitat Pioneer species can survive in a poor environment (low on resources, very disturbed, etc.) Eventually they are replaced by better competitors, which results in the climax community Aser: series of stages in a community succession Climax community: steady state which occurs under a particular set of environmental conditions Succession occurs, go from initial disturbed state or stat that’s devoid of life, have community succession across time and then we get a climax community (final state after which there is no more succession) Not every community ends in a climaxsteady state after succession occurs Succession in agricultural fields in North Carolina Tracking of succession following the abandonment of agricultural fields Farmers went in and cleared the land and planted crops, eventually ran the soil into the ground sucked all the nutrients from ground from farming and left the field behind get weeds in abandoned agricultural fields, followed by shrubs, followed by pine trees (first tree species that colonized areas), followed by hardwood trees (maple, oak, hemlock) Early success spec establish themselves:Years since field abandoned on xaxis. Stems/acre on yaxis. Have initial uptick in numbers of shortleaf pines, as hardwoods come in, see hardwoods outcompeting the pines as numbers of hardwoods go up and we lose the pines as succession continuesEarly successional spec (mirum and bluestem grass) establish themselves near a sand dune, followed by shrubs, then pines, then hardwood. The pine competitors are replaced by hardwood trees (the climax community) Primary succession: development of community in new habitat that is devoid (lacking) of life sand dune succession (the sand has no life to start with) volcanic explosion resulted in lava covering the area (nothing living left) Kettle ponds in Canada with a boreal climate boreal climate: barrier between temperate and arctic climate Cold winters and short mild summers Kettle ponds: holes in ground from glaciers moving Bog succession: establishment of aquatic plants around the ponds Sedges (aquatic plants) form atop ponds. Sedges eventually die and deposit detritus (organic matter) into ponds Detritus fills the ponds and the pond disappears Following establishment of aquatic plants and sedges, come shrubs and mosses. Spruce, birch, maples establish around ponds As detritus fills ponds, they become terrestrial habitat (how ponds transition through succession to wet terrestrial environment than a pond) Secondary succession: regeneration of a community following a disturbance with some life present agricultural fields succession (abandoned fields were disturbed but have some soybean plant or some other life left) blowout in seagrass community (storm wipes out aquatic plants in area of ocean) rhizophytic macroalgae (early succession spec) establishes itself following a blowout they help stabilize sand an environment with sand is a shifting substrate (help stabilize the environment and make it more habitable for later successional spec) rhizophytic macroalgae is followed by sholl and turtle grass early successional spec responsible for stabilizing sand and depositing their bodies in the sand (when they die) to make the area hospitable for subsequent spec colinizations why successional stages (some early, some late)? Because we cant jump around. Never an instance where there is an abandoned agricultural field and an oak pops up and starts. Characteristics and adaptations of early and late successional plants that allow them to operate early on or later on in aser. Early successional spec have many small seeds, disperse by wind or by sticking to fur, have rapid growth and low tolerance for shade (like sunlight) fast or rselected spec do well when released from competition (lots of resources available) Late successional spec have small numbers large seeds and grow slowly and like shade slow or kselected spec do well when operating close to caring capacity. Better competitors outcompete early successional spec growth rate and shade tolerance: early successional species are shade intolerant and fast growing. why does that make sense given what we know about the environ? When talking about disturbed habitat like recent volcanic interruption, or abandoned agricultural field, these are areas without shade so they have to be adapted to full sunlight. In turn, the reason they are adapted to grow faster because as they grow they create shade for spec growing beneath or around so it benefits to be adapted to full sun but also to outgrow individuals around so don’t get trapped under their shade Kselected spec are always growing from beneath other plants (from under shrubs that colonized areas around it). These late success spec must be shade intolerant because always operating with less sunlight. As result they grow slower because have lower rates of photosynthesis but still continue growing. They produce larger seeds because they are dispersed by animals. Have to be shade tolerant because grow beneath other plants. Pays to have large seeds with lots of nutrients because lacks sunlight/photosynthesis earlier in life Early successional spec are in disturbed environments that are devoid of life/recently disturbed and are not hospitable to animals so they have small seeds that can be dispersed by the wind to get around Three categories of interactions 1. Establishment: early successional (rselected) species can tolerate harsh conditions horseweed 2. Facilitation: processes by which one species increases the probability of a second species becoming established Early success spec provides shade for later succ spec (they need shade, are not adapted to full sunlighthorseweed and crabgrass established in area to create shade and facilitates shrubs to grow subsequently) 3. Inhibition: occurs when one species’ fitness is suppressed by the presence of another Hardwoods outcompeting the pines allelopathy Black walnut tree produces hydroxy juglone which is toxic to other plants around it Early success spec of alder trees alder trees show up at the same time as pines. Good for everyone who follows them because they have nitrogen fixing bacteria in their roots which help nitrogen deficient soils Once trees change the soil composition, other trees can establish and follow (spruce). When spruce trees are in nitrogen rich soils, they are better competitors than alder trees. As soon as spruce come into an area, they destroy their own chance of survival because they change the soil so that they can’t compete on itsuccession in animal communities Plant and animal community changed on crocatile island following explosion. Wiped out life on island. 3yr later there were 24 spec that made their way to island and established. 10 spec were sea dispersed Initially, all seeds that made it to island were sea or wind dispersed (early, r selected) Later enough tree spec established on island so forest grew attracting animals, bringing seeds in feces As success occurs, see changes in plants and animal community from single spider to spec diverse area. See transition from spec on wind to animal dispersed As succession progresses (yrs after disturbance), see uptick in spec diversity (number of spec present and if in equal numbers) When start transitioning, in later succs. times (when shrubs start to establish), see fewer spec or diversity When reach climax community (steady state at end of success. aser) have fewest Spec richness: number of spec present spec present because have great competitors leftSpec diversity: number and abundance of spec (and how even) present Community has high number and even spec increases when trees enter decreases when reach climax community because everyone left is great at outcompeting other spec Intermediate Disturbance Hypothesis: Communities experiencing moderate amounts of disturbance, will have higher levels of species diversity/richness than communities experiencing either little or great amounts of disturbance Two factors 1. In communities where moderate amounts of disturbance occur, patches of habitat exist at different successional stages Dif stages cause early/late succession spec to occur in an area, increasing spec richness and diversity Patches of area with dif stages succession ex: tree collapses in rainforest, succession in disturbed area is a early succession stage but environment around it is late succession (how patchiness contributes to greater spec diversity) 2. Moderate levels of disturbance may prevent communities from reaching the final stages of succession in which a few dominant competitors eliminate most of the other species Lowest spec diversity when reach climax state and left with best competitors so spec diversity and richness is lowest enough disturbance that never reach climax state good for diversity and richness lect 23 (4/19)missed it climax community: final steady state varies depending upon environmental conditions open community transient community: comes and goes pods filled but dry though summer carcus of dead animal: animals feed and invertebrates live on it but carcus will eventually be gone closed communities: distributions of many spec coincide closely and are largely separated from distribution of other spec ∙ ecotones: boundaries between closed community. Occur where there is a rapid replacement of spec - serpatine soil and nonserpatine soils have specific plants on each - ecotone has a rep - presence/absence tightly synchronized of both but some survive in any soilopen communities: local associations of spec having individuals and partially overlapping ecological distributions ∙ presence/absence not synchronized ∙ continuum concept - spec distributions often change gradually across an environment gradient - northsouth temp gradient and eastwest rainfall gradient across E. U.S - spec that need warmer temps gradually increase in abundance as go south gradient analysis: plotting and interpreting abundances of spec along an environmental gradient spec richness: number of spec in a community increases with larger area because more habitats included in sampling scale (forest vs continent) Abundance is measured by number of individuals, density or biomass in a community relative abundance (pi): proportion of individuals in a community represented by each species rank abundance curves plot relative abundance of each spec from most to least abundant spec evenness is the comparison of the relative abundance of each spec in a community Pi= # indiv in 1 spec/sum of all indiv Ranges from 1 to the total number spec - maximum value only occurs when all the species in the community have equal abundancesBiol 202, Lect 24 (4/21/17) Jaccards index: J= X/A+BX X= number spec similar A= only found in 1 spec Ranges from 0 to 1 0= no spec in common 1= identical specRainbow, common shiner, and brown trout found in 3 communities Spec richness is a reflection of spec diversity Ecosystem: organisms together in a physical and chemical envir Ecosystem characteristsics that influence spec richness: primary productvivity habitat heterogeneity climatic factorsEcosystem with intermediate levels of productivity have greatest numbers of spec Intermediate relationship between productivity and richness (more productivity=more spec) - At levels of low productivity, have few herbivores so superior competitors amongst plant eliminate most other plant species - At levels of high productivity many herbivores and only plants resistant to grazing survive - Hence, greatest numbers of species coexist at intermediate levels of productivity and herbivoryHypoth 1: variation in temp allows dif spec to thrive at dif times - Could result in greater spec richness Hypoth 2: stable temp conditions support specialized spec that would be unable to survive where the temp fluctuates and could result in increase spec richness - Species richness graph above represents hypoth 2Why do tropics have such high biodiversity? - Evolutionary age of tropical region - increased productivity (more sunlight) - stability/consistency of conditions - predation - spatial heterogeneity Equilibrium theory of island biogeography: number of species (species richness) on an island balances regional processes governing immigration against local processes governing extinction Equilibrium theory of island diversity Colonization begins=rate of colonization decreases Right side= colonization rate=0 The further the black dots, the more the spec is present How we distinguish colonization and extinction rateBiol 202 Lect 25 (4/24) Principle 2: whenever organisms use chemicalbond or light energy, some is used to convert to heat Heterotrophs: organisms that cannot synthesize their own organic compounds from inorganic precursors (organisms that cannot produce their own food/energy) - Fungi, microbes, mammals Autotrophs: synthesize the organic compounds of their bodies from inorganic precursors such as carbon dioxide, water and inorganic nitrates (organisms that can produce their own food/energy) - primary producers - Take those organic compounds from other precursors - Bunji Chemoautotrophs: obtaining energy by means of inorganic oxidation reactions - Microbes that use hydrogen sulfide available at deep water vents Photoautotrophs: use light as their source of energy< most important to ecosystem function Trophic levels: levels of organisms eating other organisms ∙ level 1 (primary producers) are at bottom take solar levels and convert to chemicalbond energy - can be used at higher trophic levels ∙ level 2 are herbivores (primary consumers) - consume level 1/primary producers - provide level 3 food - cows, deer, rabbits, etc.∙ level 3 are primary carnivores (secondary consumers) - provide level 4 food - mole eating grasshopper ∙ level 4 are secondary carnivores (tertiary consumers) - top predators - owl eating mole - lion eating hyena Trophic levels are just simplified representation. Food web is more accurate representation of who’s eating who in an ecosystem because it shows if an organisms eats more than one organisms rather than just one level - more accurate because it could show organisms that eat more than one level (i.e. omnivores) - another reason is there are spec that don’t fit in herbivore, carnivore, primary or tertiary consumer category (i.e. detritivores)Small planktivorous fish feeds on zooplankton and phytoplankton food web shows fish eating both trophic levels that simplified trophic chart couldn’t showHave blunt spec that don’t fit in trophic categories Detritivores and parasites would be better visualized in food webPrimary productivity: rate at which solar or chemical energy is captured and made available to the ecosystem by photosynthesis and chemosynthesis - Energy assimilated in each of our plants - Only 1% solar energy captured by plants Gross primary productivity: rate which energy is captured and assimilated by producers in the area Net primary productivity (NPP): rate of energy that is assimilated by producers and converted into producer biomass in the area - NPP= GPP-respiration Once captured the 1% of energy (GPP), not all energy makes it to the next tropic levels (herbivores) because all energy doesn’t go to reproduction and growth, need to put some energy to everyday functioning like metabolism - A lot of energy lost in heat via respiration - Remaining energy for growth and reproduction is left for next trophic level to use (NPP) - Energy at given trophic level that is made available to next trophic level is only the energy that has gone to growth and reproduction NPP per unit area varying across ecosystems NPP changes drastically amongst if kinds of ecosystems Result of how temp and precip drives NPP in a given area varies among ecosystems from how warm and how much moisture there isRelationship between NPP and temp (a) and NPP and precipitation (b) Mean annual temp or precip against NPP Positive correlation because see linear relationship between increases in temp and increases in primary productivity Highest amount of NPP at intermediate precip. When too much precip, NPP decreases (nutrients can be leached out of soil)- Will come back to it but Nitrogen and phosphorus is typically limited in NPP. Nutrients based on availablity in an ecosystem allow NPP to increase or limit the amount of biomass accumulated secondary productivity: rate new organic matter is made by means of indiv growth and reproduction in all herbivores in the ecosystem - Relevant to herbivores (second trophic level) - i.e. grasshopper eats leaf: 50% chemicalbond energy lost to feces, 33% lost to everyday activity (metabolism or cellular respiration), 17% remaining goes to growth (available for next trophic level). Occurs at every trophic level. We use metabolism energy, assimilate portion available to us, and use small portion into grow and reproduce Cellular respiration: metabolic reactions that convert energy from nutrients to ATP and then release waste products Aquatic environment At every level, we lose energy through respiration and through feces or death if organism doesn’t live As a result of constant loss of energy at each trophic level, only about 10% of energy available at previous trophic level makes it (is assimilated) to the next one A lot of energy available in primary producer trophic level (photosynthetic plankton) but only tiny portion assimilated in herbivores and even small amount assimilated in to first level carnivoresContinuously losing energy limits the number of trophic levels that can be supported in any ecosystem because not enough energy to support others like super carnivore at very top Why we see ecosystems with few trophic levels Why we see small number of secondary carnivores (i.e. don’t see herds of lions) Pyramid of biomass in Cayuga Lake in NY Humans are the exception Primary producers are algae and cyano bacteria. For every 1000 calories available at that trophic level (outcome of photosynthesis), 150 were available for next trophic level (assimilated into smelt:herbivore), 30 made it into smelt (small fish), 6 made it into trout, only 1.2 made it to us when we ate the trout Takes a lot less energy to make plants than to make troutGraph shows how energy was assimilated at multiple trophic levels Trophic cascades: consumerresource interaction that influences additional trophic levels of the community (topdown and bottomup) Topdown: carnivores influence sizes of trophic levels beneath them (carnivore influencing number of herbivores) Bottomup: If trophic level 1 or larger or smaller, it will influence the levels above Graph shows different dynamic of top down and bottom up Topdown trophic cascades examples: New Zealand trout study Trout or no trout environments Depending on whether trout was present or not, saw differences in trophic levels beneath primary carnivores (next trophic level) Trout (fish)=Fewer invertebrates because trout eats them No trout= more invertebrates See opposite dynamic when have algae present (primary producers): Trout=more algae because fewer invertebrates eating the algae No trout= invertebrates not being eaten No trout= less algae because invertebrates eating themLook at 57.15 in textbook to read about the study on the no fish fish slide. Compare to New Zealand stream study Kelp forests are home to many organisms sea otters eat sea urchins and sea urchins eat kelp high pop otters= less urchins and lots of kelp low pop otters= more urchins and less kelp (bigger ecosystem issues) Kelp forest of Washington Conservation issues (will revisit): sea otter pop decreasing because orca are switching prey types and eating otters which leads to deforestation of kelp forest Bottomup trophic cascade examples: Eal river in Cali: controlled amount of primary productivity by allowing more or less light in Numbers of carnivores increase in biomass with more primary productivity (bottomup trophic cascade with trophic level 1 influencing level 3) Herbivores show slight increase in biomass but mostly flat Hard to be herbivore because need enough primary producers to eat but once herbivores grow in pop, carnivores also grow and eat them See less change in herbivore biomass as a Primary productivity increases with more light Intensity of alumination on xaxis (enclosures with no light or lots of light) Aquatic communities affect pollinators in terrestrial communitiesDragon flies begin life cycle in pond and leave to terrestrial community when they metamorphose Fish eat larval flies when in water, those that survived and left aquatic community would prey on pollinators (bees, wasps)Ponds with and without fish Fish influenced the number of dragonflies Aquatic environment: No fish= more dragonfly larvae Terrestrial environment: no fish=more dragonfly adults=less pollinatorsSee inverse relationship when we consider numbers of pollinators in terrestrial environment Wasps and bees are also veracious predators Aquatic environment: Fish=more pollinators Terrestrial environment: no fish=less pollinatorsHow topdown control (cascade) can occur in both terrestrial and aquatic environments