Studied by 18 people
Learning Objectives
Explain how competition reduces organismal growth rates, survival, fitness, and/or population growth rates for both species involved.
-/- interaction
Competitions are when species interact with each other because of resource overlap, and in order for competition, a resource must be in limited supply.
Intraspecific- within a single species (sets K)
Interspecific- between 2 species
Can involve direct contact/fighting or it can be subtle
Can be symmetric (loses equally) or asymmetric(one loses more)
Compare and contrast fundamental and realized niches.
A fundamental niche is the full range of climatic conditions, habitats, and resources that can be used by a species.
The realized niche is the set of habitats (physical and chemical conditions) occupied and resources actually used by a species given the presence of other species with whom it interacts (competitors, predators, parasites mutualists)
Compare and contrast the conditions that favor species coexistence with those that lead to competitive exclusion
Depending on how much overlap there is in the resources used and how efficient each species is in obtaining resources can lead to competitive exclusion or species coexistence.
Species coexistence is possible when the species use different resources, are active at different times, or have few enough individuals that the resources are not limiting to their survival and reproduction.
Competetive exclusion
Prevents two species from occupying the exact same niche at the same time, it only occurs when competition is asymmetric AND niches overlap, which can lead to local species extinction.
Describe and explain the setup, results and conclusions of Connel’s field experiment on competition between two barnacle species.
Joe Connell performed a classic field experiment on biotic and abiotic factors controlling distribution of two barnacle species--Cthamalus (smaller species) and Semibalanus--on a rocky shore. Cthamalus (smaller species) was placed on a higher level than lower. Connell transplanted rocks containing Cthamalus (smaller) to lower intertidal zone. He let semibalanus colonize the rocks, and he removed semibalanus from half of each rock, monitoring survival of Cthamalus on both sides. He predicted that Cthamalus would survive. Cthamalus survived much better when semibalanus was absent, so Connell concluded that Cthamalus are competitively excluded from lower intertidal by semibalanus.
Explain how mutualism increases organismal growth rates, survival, fitness and/or
population growth rates for both species involved.
Mutualisms are +/+ interactions that involve a wide variety of organisms and rewards
Must show that both partners get a fitness benefit
Mutualism have a cost, however the benefit is greater than the cost
NOT being nice or for benefit of the other specis
Interactions can change between mutualism and parasitism as environmental conditions change
Explain how mutualisms between mycorrhizal fungi and land plants work and how the
interaction improves fitness for both the fungal species and the plant species.
Mycorrhizal fungi help plants take up phosphate and other nutrients
Pants supply mycorrhizal fungi with carbohydrates (glucose and other sugars)
Mycorrhizal fungi live in the plant roots and they help plants take up essential nutrients from the soil. Plants supply the mycorrhizal fungi with carbohydrates in the form of sugars and provide them with shelter.
Explain how mutualisms between Rhizobium bacteria and legumes work and how the interaction improves fitness for both the bacteria and the plant species. Be able to compare and contrast mycorrhizal fungi-plant and Rhizobium bacteria-legume mutualisms.
Rhizobium bacteria live in nodules on plant roots, these bacteria can fix nitrogen-take it from the atmostphere (where it is in the form of N2 gas) and convert it into amonia (whihch is converted into amonim when disolved in water) a form of nitrogen that plants can use for growth
The bacteria get sugars and a “home” in the roots of the plants
Describe some of the organisms that can fix nitrogen.
Some other bacteria, and archaea can also fix nitrogen
In the ocean trichodesmium are nitrogen fixers and also do photosynthesis
Describe the basics of plant reproduction and explain how plants and pollinators are
adapted to each other as part of plant-pollinator mutualisms.
Carpels produce ovules and anthers produce pollen. When pollen comes into contact with the stigma at the top of the carpel, it travels down a tube, called a style, to the ovary, where the ovum develop into seeds. Pollinators have adapted to flowers (and vice versa) through many events of speciation, which allows the flowers and pollinators more available resources in their niches.
Explain how mutualisms between angiosperms and pollinators work and how the
interaction improves fitness for both interacting species.
Angiosperm- plants that make flowers and fruit
Plant gets movement of pollen and fertilization
Polunator gets nectar reward, eat pollen
Angiosperms provide pollinators with a food source (nectar) and pollinators aid the angiosperms with reproduction. This increases the fitness of both organisms by streamlining the processes that they require for survival and reproduction.
Explain how the nature of interactions between two interacting species can change (based
on comparison of costs and benefits) as environmental conditions change (e.g. as density
of one of the species changes).
As environmental conditions change, the nature of interactions between two species can change if the fitness advantage or cost received by one organism shifts. For example, water buffalo and egrets typically share a commensalism relationship, where the egrets benefit from the stirring up of insects by the water buffalo. However, if the egrets flee from a predator and alert the water buffalo to its presence, the relationship changes to a mutualism.
Describe how mutualisms are vulnerable to cheating, and be able to give an example of
cheating in an actual mutualism. Characterize the relationships between ants, Acacia, and
phloem-feeding insects.
Cheating occurs when one organism in a mutualism imposes a larger cost than benefit on the other. In fact, mutualisms that are loose associations among changing partners can become one-sided rather quickly. (Think of the orchid and bee example)
Ant plants are plant species that provide rewards like food and shelter for ants
Acacia trees provide proteins, nectarines that are rich in sugar, and hollow thorns in which ants can live
Ants protect plants from herbivores and plant competetors
However, rather than remove all herbivores from plants, some ants will actually raise some insects like cattle
Pholem-feeding insects can provide ants with a source if sugary sap
In come cases, the ants farming activities can be negative for the plant, and the mutualism can become a parasitism.
Given data regarding two interacting species, be able to identify the interaction as
competition, commensalism, mutualism, parasitism, or predation (or as one in which
there is not sufficient information to determine the type of interaction)
Competition is an interaction in which the use of a mutually needed resource by one individual or group of individuals lowers the availability of the resource for another individual or group.
Commensalism- someone benefits and someone is unharmed
Mutualism is an interaction between two or more species that benefits all.
Parasitism is an interaction in which organisms live in close association with another species, consuming or gaining nutrition from their hosts' tissues, generally without killing them.
Predation is an interaction between organisms in which one (the predator) consumes the other (the prey).
Explain the evidence for the theory of endosymbiosis, which explains the origin of chloroplasts and
mitochondria in eukaryotes
Mitochondria and chloroplasts are the same size as
alpha-proteobacteria and cyanobacteria, respectively.
Mitochondria and chloroplasts contain their own
genome organized as a circular DNA molecule, just as alpha-proteobacteria and cyanobacteria do.
Mitochondria and chloroplasts also divide by binary fission like bacteria do.
Mitochondria and chloroplasts also have two (or more) membranes, which is consistent with an engulfing mechanism.
Lastly and most convincingly, when biologists sequenced the genomes of mitochondria and
chloroplasts, the molecular phylogenies clearly showed that the DNA from mitochondria nested with the alpha-proteobacteria group and the DNA from chloroplasts nested with the cyanobacteria group
Chloroplasts- symbiotic cyanobacteria
mitochondria- resemble proteobacteria
Explain what the arrows represent in food chains and food webs and why the arrows go from the
organism being consumed to the consume
In food chains the food webs represent energy flow
Define how ecologists use the term “omnivory” and be able to identify primary producers, primary
consumers, secondary consumers, and omnivores in any food web
Omnivory describes organisms that consume both plants and animals; in other words, they feed on multiple levels of the trophic pyramid. Primary producers are the first trophic level, consisting of autotrophic organisms. Primary consumers are the second trophic level, consisting of herbivores. Secondary consumers are the third trophic level tertiary consumers
highest trophiuc level is the top or apex consumer
Explain what trophic pyramids represent
a graphical representation of the energy found within the trophic levels of an ecosystem. The bottom and largest level of the pyramid is the producers and contains the largest amount of energy.
Explain how interactions among species can generate indirect effects
Indirect effect- the effect of one species on another mediated by a third species
Distinguish among keystone species, dominant species, and ecosystem engineers
Keystone species- have an effect on communities that is disproportionate to their abundance or biomass
Dominant species- Very common and have a large effect on the community composition
Ecosystem engineers- Physically change habitat
Explain how keystone species impact community structure and composition
Keystone species, also called apex predators, regulate the structure and composition of the communities in which they live. By controlling the populations of the organisms on which they feed, they allow other organisms to survive and reproduce in the community.
Explain how trophic cascades can affect community composition
Trophic cascade- top predator influences the density of species all trophic levels below it
Trophic cascades can have large effects on community composition. When an apex predator is removed, the organisms that they typically consume grow out of control, and eliminate their own food source. Thus the elimination of one species cascades down the food pyramid
Explain how omnivory complicates our ability to make predictions about the effects of consumer
removal on food web dynamics
Omnivory is common in food webs, and it increases the number of indirect effects and makes it challeneging to make predictions about the outcome of removing a cinsumer from a food web.
If the consumer we are removing is a trphic omnivore, to make accurate predictions about the effects on community dynamics, we would need data on the strength of the direct as a well as the indirect effects of the omnivore on its prey species.
Explain how parasites can impact community structure
Parasites feed at every level of the trophic pyramid. If a parasite significantly decreases the fitness of organisms at one trophic level, it may cascade to affect other trophic levels of the community as well
Interpret food chains and food webs, and be able to locate a food chain within a food web
Practice
Explain how consumption efficiency, assimilation efficiency, and production efficiency combine to
determine trophic efficiency.
Multiply each CE*AE*PE*=TE
CE=The fraction of productions at one trophic level that is consumed by the next
AE- the fraction of food that is sconsumed that is assimilated
PE= the fravtion of food that is assimiliated that is turned into consumer biomass
As you go up the food web you lose about 10% of energy
Explain which abiotic factors affect the biological community, and how those abiotic factors
influence energy flow through an ecosystem.
The soil, climate, atmosphere, and the particular matter and solutes in water are abiotic factors that affect the biological environment. Energy flow links four components in every ecosystem: primary producers, abiotic environment, consumers, and decomposers. Therefore, because they are linked they affect the primary productivity which can increase energy flow in the ecosystem. The abiotic factors influence energy flow because if one of these factors is negatively affecting the ecosystem then it affects the flow of energy to the next trophic level. For example, if the soil does not have enough nutrients in it to support enough plants for herbivores then there will be less herbivores and therefore less consumers. To some degree all factors are all limited from what's there like the amount of sunlight. Energy flow is bonded by abiotic factors, you need soil and the right climate for plants to grow, a resource that even primary producers depend on.
Describe the major groups of primary producers, including being able to place them in the
three domains of life; contrast which producers are dominant in terrestrial vs. aquatic habitats
Autotrophs: an organism that produces complex organic compounds from simple substances present in its surroundings, generally using energy from light or inorganic chemical reactions; Chemoautotrophs: organisms which obtain energy not from sunlight, but from chemical energy stored in chemical bonds of inorganic molecules such as hydrogen sulfide; unique prokaryotic metabolism; Domain: bacteria and archaea; Photoautotrophs: organisms that capture energy from sunlight; the energy of sunlight to convert carbon dioxide and water into sugar and oxygen, Macroscopic: Eukarya, Microscopic: split between bacteria and eukarya, Terrestrial: non-algal plants, mosses, gymnosperms, and angiosperms, Aquatic: primarily microbes, dominant groups: cyanobacteria, eukaryotic algae (green algae and diatoms)
Describe the defining traits of land plants, vascular plants, seed plants, and angiosperms.
Land Plants- an alternation of generations, with a multicellular haploid stage followed by a multicellular diploid stage
Vascular Plants- Having a vascular system compromised of xylem and phloem that can transport water and nutrients respectfully.
Seed plants(gymnosperms and angiosperms)- group is the production of pollen and seeds
Angiosperms- is the production of flowers and seeds
Describe the sources of energy used by primary producers, and explain the difference between
photoautotrophs and chemoautotrophs
Sources of energy: sunlight, chemical energy stored in chemical bonds of inorganic molecules
Photoautotrophs: organisms that capture energy from sunlight; the energy of sunlight to convert carbon dioxide and water into sugar and oxygen
Chemoautotrophs: organisms which obtain energy not from sunlight, but from chemical energy stored in chemical bonds of inorganic molecules such as hydrogen sulfide.
Explain the distinction between NPP and GPP, describe ways in which ecologists measure
these, and understand the relationship between NPP, GPP, and respiration
GPP: Gross Primary Production (GPP) is the total amount of chemical potential energy produced by photosynthesis or chemosynthesis in a particular ecosystem.
NPP: Net Primary Production (NPP) is calculated as GPP minus respiration. That is, NPP is GPP minus the chemical potential energy transformed into other forms of energy when producers carry out cellular respiration. NPP is also described as the
amount of producer biomass that is available to consumers when they eat the autotrophs.
Relationship with respiration: A proportion of the total chemical energy produced by primary producers is used in cellular respiration by the primary producers. NPP = GPP - respiration (R)
Explain the global patterns in primary productivity and what causes these patterns
declines away from equator to poles because high temperature and precipitation (except for deserts where there is low water but high temperature)
-highest in ocean because such a huge area
-highest on coasts because there is runoff and upwelling which brings more nutrients to the surface
because of fertilizer, upwelling
Describe the nutrients that typically limit primary productivity in terrestrial, marine, and
freshwater habitats
terrestrial: sun, water, nutrients, heat
freshwater: phosphorous
ocean: iron/nitrogen
Explain what trophic pyramids (pyramids of energy) represent
shows the transfer of energy between trophic levels and how it's inefficient
Explain why primary production is an ecosystem service
Ecosystem service is a benefit or processes that are beneficially to humans, example: pollination, food, forests and roots of trees prevent erosion and flooding, recreational use of forests. Primary production provides the initially energy in a food web and the energy flow cannot occur without the primary producers.
Explain why primary production is necessary for energy transfers and how
chemoheterotrophs obtain both energy and carbon atoms
primary producers create the energy that consumers get by eating them --> only 10% of their energy can transfer
-use inorganic carbon as a carbon source
Explain why energy flows within and between ecosystems, and why energy does not cycle
Energy flows because primary producers and consumers cannot use the nergy released from higher trophic l levels
Explain how energy is transferred between trophic levels
10% of energy moves to the next higher trophic level the most energy is at primary producer
Explain why the transfer of energy among trophic levels is not efficient and explain how this
limits the length of food chains; describe how much energy (average value, expressed as %) is
transferred from one trophic level to the next trophic level in ecosystems.
Energy is lost as heat used to do work (chemical reactions reduce heat, not all organisms in the trophic level are consumed)
Explain in general how a biogeochemical cycle works, including how nutrients enter
ecosystems and how they are altered within ecosystems
Elements like nitrogen, phospherous, and carbon move through organisms in food webs and back into the abiotic enviorment. A bigeochemical cycle is the path that an element takes as it moves from one compartment or pool to another within an ecosystem
Nutrients enter the cycle by decomposers break down organic material into inorganic material that goes back into the soil nutrient pool.
Nutrients are altered within ecosystems by nitrogen changing forms into gas, ammonium, and then into nitrate, and once it is in the body it is used to build molecules within the body.
Identify the major groups of decomposers; place decomposers on the tree of life
Bacteria, Archaea, and Fungi (which are Eukarya). All throughout tree of life
Recognize fungi as one major group of decomposers, identify their Domain, and describe
basic aspects of their biology: how they acquire nutrients, their cell wall structure
Domain: Eukarya. Chemoheterotrophs (carbon and energy source from organic molecules), release digestive enzymes and then absorb nutrients from the environment or other organisms.Have cell walls made of chitin( same as in arthropod exoskeleton)
Explain the abiotic factors that limit rates of decomposition in terrestrial and aquatic
ecosystems
Abiotic factors like temperature and soil water content limit decomposition of detritus which limits the rate at which nutrients move through an ecosystem. An increase in temperature increases decomposition rates and a decrease in temperature decreases it. For example, a decomposition occurs quickly in a rainforest that is damp and warm but slowly in the arctic where it is dry and cold.
Explain how decomposers influence nutrient cycling and why ecosystem services, such as
primary production, would cease without them
Decomposers cycle nutrients from detrital pool back to abiotic environment.
Their ecosystem service is that they break down complex organic molecules into inorganic forms which are used by producers.
Primary production would cease without them because plants cannot grow without nutrients in the soil and decomposers return nutrients from dead organisms back to the soil.
Describe the form of phosphorus that can be used by primary producers, why heterotrophs
need P atoms, how phosphorus moves up a food chain, and how excess phosphorus links with
eutrophication
Primary producers can use PO4-.
Heterotrophs need phosphorus atoms because it is a key component in ATP, the main biological energy currency, nucleic acids, phospholipids
. Phosphorus moves up a food chain through consumption. Decomposers move phosphorus between pools through decomposition of the detrital pool, which moves phosphorus back into soils for uptake by primary producers.
Explain the global N cycle: describe the major atmospheric pool of nitrogen, the forms of
nitrogen that can be used by primary producers, why heterotrophs need N atoms, how
nitrogen moves up a food chain, and how decomposition moves nitrogen between pools
Major pool is in the atomoshpere
Primary producers can use ammonium (NH4+) or nitrate (NO3-). Heterotrophs need nitrogen atoms because it is used in proteins and nucleic acids. Nitrogen moves up a food chain through consumption. Decomposition moves nitrogen between pools by decomposing the detrital pool, moving nitrogen back into the soil for uptake by primary producers.
Describe how humans have altered the nitrogen cycle, and be able to link this with
eutrophication
Humans have altered the phosphorus cycle by mining rocks rich in phosphorus for creation of fertilizers. When these fertilizers are spread onto fields, some of the phosphorus is washed away in runoff. This runoff reaches the nearest river, which eventually dumps into the ocean. The enhanced nutrients in the mouth of the river encourages eutrophication, or the increase of populations of algae or cyanobacteria due to an excess of nutrients.
Explain the processes that drive the short-term carbon cycle, and be able to draw a figure
representing how carbon dioxide concentrations change seasonally.
Photosynthesis and respiration drive the short-term carbon cycle using biological pools. Decomposition allows carbon to be released back into the atmosphere, so it is short-term because the carbon does not stay in the organism forever. During summer there is more sunlight and photosynthesis so there is less carbon in the atmosphere. Winter CO2 is higher.
Describe the major reservoirs of carbon, the major fluxes of carbon, the forms of carbon that
can be used by photoautotrophs, how carbon moves up a food chain, and how decomposition
moves carbon between pools.
Reservoirs: sediments/rocks (largest), surface water, atmosphere, terrestrial organisms, organic matter (a lot here), deep sea water (second largest); Decomposition allows carbon to be released back into the atmosphere, so it is short-term because the carbon does not stay in the organism forever. Fluxes: photosynthesis and respiration (terrestrial and marine), change in land use, fossil fuels; Forms of carbon used by photoautotrophs: take in CO2 and release O2; Most of biomass is made of carbon; there is carbon in protein, fat, and glucose, when you eat an organism you harvest the carbon from the organism to build protein.
Describe how carbon dioxide is added to and removed from the atmosphere
Added: respiration (major), burning fossil fuels, burning wood, change in land use, decomposition; Removed: photosynthesis, attempt to sequester carbon and store it, change in land use
Describe how we measure current and estimate historical levels of atmospheric CO2
Historical: ice core drilled from glacier in antarctica, glacial ice contains small bubbles that trap samples of air and scientists can measure the CO2 in the bubbles; Current: measure the amount of carbon in the air with an IR sensor, Infrared sensing
Explain how greenhouse gases cause the greenhouse effect.
Greenhouse gases are like a blanket over the earth that makes it warmer and traps heat.Sun's rays penetrate atmosphere, earth's surface radiates heat, greenhouse gases absorb some heat and re-emit it back toward earth, increase greenhouse gas traps more heat near earth's surface
Describe how humans have altered the carbon cycle; define climate change and distinguish
between weather and climate.
CO2 driven by growing season in northern hemisphere (changes in photosynthesis), the northern hemisphere has large fluctuation of CO2 in the winter because of more land mass and their season has a disproportionate affect on the overall carbon cycle.
Climate: long term patterns of temperature, humidity, wind, etc. in an area; influenced by latitude, altitude, terrain and nearby bodies of water.
Weather: short-term state of temperature, humidity, wind, etc. in an area;
Give evidence demonstrating that climate change is happening now and that it impacts more
than just temperature.
2018 defence funding bill: “CLimate change is a direct threat to the national security of the United States”
Recent analysis of Exxon’s research and communications on climate change
between 1997 7 2014, 80% of Exxons research and internal communications related to climate change acknowledged that climate change is real and caused by humans
Sea levels are rising
oceans are getting mire acidic
more extreme heat waves and droughts
Heavy precipitation events are happening more frequently
Give evidence that climate change is caused by humans.
CO2 levels remained consistent for thousands of years but began increasing with the industrial revolution (1750) and is still increasing at an unprecedented rate; Current CO2 level is not natural; fluctuations used to be caused by changes in earth's orbit around the sun but the level now is so abnormal that it has to be caused by something else; Clear increase in CO2 emissions due to fossil fuel burning and deforestation; 87% of global energy consumption 2013 was from fossil fuels
Explain what the best way is to slow climate change.
Reduce the amount of greenhouse gas production quickly, reduce burning of fossil fuels we are adding to the pool of atmospheric CO2, even if you balance the carbon flux the energy flux will still be a net increase. We need to stop putting carbon into the atmosphere but we also need to pull that carbon out of the atmosphere as well.
Give examples of how climate change is currently impacting species and ecosystems.
Coral bleaching: zooxanthellae algae live in corals and photosynthesize which give the corals color, and when water is too hot the corals expel the algae they lose their color, Organisms move and become extinct locally, Organisms stay and adapt: plasticity or genetically change over generations, Melting of arctic ice pack and loss of glaciers, Rising sea levels, Changes in species ranges, Changes in phenology (timing) of biological events, Decreased NPP in terrestrial and ocean ecosystems
Explain the possible responses organisms can have to climate change.
Organsisms can
move
requires times, dispersal ability, and contiguous habitat
Stay, but adjust via
platicity
adaptation
If they can’t move or adjust: extinction
Give examples supporting the statement “Climate change affects human health”.
Increased food insecurity, Increased PTSD and depression from catastrophic events, People die when it gets too hot, Ozone exceeds healthy limits, More asthma, More vector-borne-diseases
Explain the different features of a climate literate person and apply those features to new
scenarios
Understands the essential principals of earth climate system
Knowns how to asses scientifically credible information about climate
Communicates about climate and climate change in a meaningful way
Is able to make informed and responsible decisions with regard to actions that may affect climate
Explain what needs to be done to halt climate change and how changes in renewable energy
generation and storage mean that is feasible
Stop burning fossil fuels and use renewable sources of energy in order to reduce carbon emissions
-Renewable energy: solar energy, wind energy, hydropower, nuclear energy
Give examples of individual level actions and of societal level actions that can be taken to
address climate change.
Be active in schools and in the community in conservation issues
-Make decisions about how to live and work in a way that sustains the biological resources of the planet
-Vote
Note 
Flashcard (20)