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ECOLOGY AND CONSERVATION, Discuss the causes and consequences of…

- - - - temperature: Plant species that survive low temperatures cannot survive high temperatures.
      - territory availability and distribution of animals: tigers habitat has been lost to growing human populations.
    - - Distribution of one animal and plant species to illustrate the limits of tolerance and zones of stress:
        
        Animal: Large ears of elephants are adaptations for dissipating heat.
        
        Plants: Some species like cacti aren't adapted to survive cold temps, so they wouldn't last in northern regions.
      - The symbiotic relationship between Zooxanthellae and reef-building coral reef species.
        
        Corals and algae have a mutualistic relationship = Most reef-building corals contain algae like zooxanthallae
        (zooxanthalle responisble for unique colors of corals)
        
        the coral provides the algae with a (1) protected environment (2) and with compounds that they need for photosynthesis
        
        the algae provides the coral with (1) oxygen (2) helps the coral remove wastes (3) supplies the coral with the products of photosynthesis (glucose, amino acids...)
        
        when there is a large scale loss of zoonxathalle = coral bleeching = color loss = coral will starve and die.
        
        coral bleeching results from the loss of symbiotic zooxanthalle. most coral species have a limit of tolerance of 20ºC. corals live in very nutrient poor water and have zones of tolerance to UV, salinitity, temp...
  - - - The fundamental niche is the range of environmental conditions in which a species is technically capable of living (certain conditions for food, temperature, shelter, etc.).
        Whereas the realised niche is the range of environmental conditions (space) where the species actually lives.
    - - if two species share the same niche in the same habitat there will be interspecific competition for resources. leading to competitive exclusion (one species uses resources more efficiently) or resource partioning (divide resourcea)
      - EXAMPLE = paramecium has two species, when grown alone under ideal conditions (fundamental niche) each population grew to a maximum. when grown together under the same conditions, one population would dominate (other dies) = example of realised niche vs fundamental niches
      - the less well-adapted species will struggle to survive and reproduce and will be eventually eliminated
    - - Niche partitioning refers to the process by which species divide resources to reduce competition and coexist in a community.
    - - A keystone species is one which has a disproportionate effect on the structure of a community.
        
        they exert top-down influence on lower trophic levels and prevent species at lower trophic levels from monopolizing critical resources, such as competition for space.
      - examples = star fish (within a year of the star fish's removal the species diversity decreased)
      - keystone species determine the prevalence and activities of many other species by significantly altering their environment.
      - state in markscheme that the first othanism in the chain(producer) will be at lower quantities and the species at medium levels yk (like 1/2 consumer) higher amounts
- - - - Biome is a geographical area with a specific climate, and sustains a specific community of plants and animal species.
      - Biosphere is the total of all areas where living things are found
      - main factors affecting the distribution of biomes is temperature and rainfall. rainfall and temp varies according to (1) elavation (2) proximity to sea (2) longitude/latitude
      - (no need to rememebr all)6 major biomes: 1) deser 2) grassland 3) shrub land 4) taiga 5) rainforest 6) tundra
      - an ecosystem is the interaction between living and non-living things within a given area.
      - A climograph is a diagram which shows the relative combination of temperature and precipitation in an area. temp is x-axis
        
        biomes with dashed lines are strongly influenced by other limiting factors
    - - 2) secondary succession is the replacement of one ecosystem by disturbance to ecosystems
        
        disturbance can be natural or human induced
        
        example is a wilfire
        1) a wildfire restroys the forest
        2) the fire leaves destroyed soil
        3) grasses and plants grow back
        4) trees begin to colonise the area
        5) fast growing trees will develop and shade shade-tolerant trees
        6) short lived and shaded trees die and decomposition occurs
      - 1) primary succession is the emergence of an enirely new community (island) from a new ecosystem.
        
        gross production increases (as first colonisers are lichens on rock surfaces, the soil builds up, larger plants take root and producitvity plateaus as soils carrying capacity is reached)
        
        species diversity increases (more soils allow for more worms/detritivores + more plants take root and more death occurs --> more soil)
        
        During succession living organisms change the abtioic environment.
        
        1) Primary succession begins with newly formed land such as bare rock of volcanic island.
        2) Pioneer species such as lichens colonise the rock.
        3) When these pioneer species die organic matter builds up which helps with soil formation. (detritivores decompose the pioneer species)
        4) Soil formation allows grasses and small herbaceous flowering plants to colonise.
        5) The presence of plant roots reduce soil erosion by increasing the stability of the soil.
        6) As plants die more organic matter builds up creating deeper soil which allows larger plants and shrubs to colonise.
        7) These larger plants create shade which causes decrease the number of pioneer species but an increases in biodiversity.
        8) Increasing diversity of plants subsequently increases the diversity of consumers.
        9) Eventually trees colonise and a climax community forms
  - - - NUTRIENT INPUTS INTO ECOSYSTEM: 1) nutrients from weatherd rock 2) nutrients in rainfall
        NUTRIENTS OUTPUTS/LOSSES FROM ECOSYSTEM: 1) by leaching 2) by surface runoff
        NUTRIENT FLOW: littering (from B-->L), decomposition (L-->S), nutrient upatke by plants (S-->B)
      - human interactions are not considered in gersmehl diagrams (litter is not trash)
      - NUTRIENT FLOW IN TAIGAS, RAINFOREST AND DESERT:
        1) Taiga (L): litter is the main source/most nutrients stored as litter + slow rate of nutrient transfer between stores
        2) desert (S): most nutrients are stored as soil + slow rate of transfer
        3) tropical rainforest (B): most nutrients are stored as biomass/biomass is the main store + fast rate of nutrient transfer
      - defs
        
        Soil - mineral material on the immediate surface of the Earth
        
        Litter - amount of organic matter, including humus and leaf litter
        
        Biomass - total mass of living organisms, mainly plant tissue.
    - - organic matter becomes biomass
      - The percentage of ingested energy converted to biomass is depedent on the respiration rate.
        
        NP = GP - R :star:
        
        NP = NET PRODUCTION (amount of organic matter remaining after respiration)
        GP = GROSS PRODUCTION (total organic matter produced in an ecosystem)
        R = respiration (stored energy used in cell respiration)
        
        unit of energy is kJ m^-2 y^-1 = ENERGY PER SQUARE METER PER YEAR
        
        heterotropsh consume much more energy for respiraiton than autotrophs = for movement, mantain body temp...
        
        Conversion ratio in sustainable food production practices.
        
        In commercial food production farmers use the food conversion ratio (FCR).
        
        it is a measure of an animals efficienty in converting feed mass into the deisred output (such as milk)
        
        lower feed inputs means lower energy inputs for food production
        
        FCR = mass of the food eaten (g))/(increase in) desired output (g) or mass given/mass produced
        
        the lower the FCR the more efficent the method of food production
        
        a good/low FCR is obtained by minimsing the losses of energy by respiration by
        1) minimising animal movement
        2) slaughtering animals at young age
        3) optimising feed
  - - - the efficiency of the conversion of solar energy by photosynthesis = gross production/energy in 100*
      - calculate energy los to respiration: NP = GP - R--->
        R = GP -NP
    - - Reasons for high net productivity (greater transfer of energy between trophic levels) of an ecosystem =
        1) high primary productivity menas more energy is available to the ecosystem by producers
        2) The higher the efficiency of energy transfer between trophic levels the higher the net productivity.
        high primary productivity and efficient energy trnasfers means more enegry is available to higher trophic levels, so the food chain can support more trophic levels = longer food chain (4-5 trophic levels)
    - - most natural ecosystems are open = they can exchange energy and matter with their surrnondings/environment
        (matter exchange e.g is migration of animals)
        closed systems (mesocosms) can only exchange energy and not matter. water and nutrients are recycled within the ecosystem.
      - One example of how humans interfere with nutrient cycling.
        
        Humans practices can accelerate the flow of matter in and out of ecosystems. this affects the nutrient cycling.
        
        agriculture:
        1) phosphates added to agricultural ecosystem by fertiliser
        
        2) biomass removed from agricultural ecosystem by harvesting of crops
        3) phosphates and nitrates removed from agricultural ecosystem by water run-off/leaching, resulting in eutrophication
- - - - a. competitive exclusion states two species that occupy a similar niche in the same location cannot coexist ✔
      - b. one of the two competitors will always have an advantage over the other ✔
      - c. leads to extinction/displacement/evolution of the second competitor ✔
      - d. grey squirrels have replaced/occupied niches formerly occupied by red squirrels
      - habitats favour the grey squirrel in competition for the niche ✔
      - e. the niche of one competitor/both competitors becomes narrower ✔
  - - - PROS of DDT =
        
        affordable at killing mosquitoes that carry malaria
        
        DDT is more affordable
        
        Alternative strategies have no been succesful
        
        effective insecticide
      - CONS of DDT =
        
        can be sprayed inside homes causing health effects (cancer, infertility, liver damage)
        
        it persists in the environemnt for a long time
  - - - fill up the stomachs (of young birds) so they feel full / starve to death;
      - b. damage the digestive system / cut the gut/stomach/oesophagus/intestines
      - (leading to internal bleeding);
- - - - A biotic index compares the relative frequency of indicator species
        
        it provides an assessment of an ecosytem
        
        a change in biotic index over time indicates a chnage in the environemtnal conditions.
      - biotic index is = sum of (individuals of a species X tolerance rating) / total individuals collected
        
        a high biotic index indicated an abundance of pollution sensitive organisms = unpolluted. index of 10 = clean, 1 = very polluted
  - - - it takes into account both richness and evenness
        
        the greater the biodiversity the greater the value of simpsons index
  - - - Nature reserves are areas of ecosystems that have been protected in order conserve biodiversity.
        BENEFITS OF NATURE RESERVES:
        
        control of invasive species
        
        control of human exploitation
        
        legal protection of endagered species
        
        opportunities for research
      - Biogeographic factors affect species diversity.
        
        SIZE - larger nature reserves are better at mantaining biodiversity. large areas are able to support larger populations
        
        CONNECTED (CORRIDOR)- connected nature reserves by habitat corridors are more efficient than isolated ones.
        - the corridor effect = corridors promote biodiversity as they provide migration and the spreading of local species.
        EDGES - the reserves with less edge are better than those with more "the ecology of the edges of ecosystems is different from central areas". central areas maximise the length of a reserve.
        
        CLUST - clustered reserves are better than fragement/isolated reserves
        
        Bigger nature reserves promote biodiversity because:
        1) larger habitats
        2) more resources
        3) more niches
        4) some migration
        
        Active management of nature reserves:
        
        when humans intervene in the conservation of an area we call it active management
        
        techniques of active management:
        
        killing alien species
        
        fire clearing to kill invasive species
        
        re-planting endagered species
      - As the island size increases, so does the biodiversity.
        
        Proximity to a continental mass/country will increase biodiversity as migration of animals/platns becomes easier.
      - Strategies for the conservation of endagered species
        
        In situ conservation is the conservation of plant and animal species within the organisms natural environment. so natural habitat is conserved = mantains animals normal behavior EXAMPLE NATURE RESERVES
        
        PROS:
        
        in situ conservation reduces possibility that habitat disappears/conserves the natural habitat
        
        allows species to live in an environment for which they are adapted
        
        mantains an animals normal behavior
        
        ex situ conservation is the conservation of species outside their natura habitats/environment.
        
        examples = ZOOS/CAPTIVE BREEDING/BOTANIC GARDENS
        
        PROS:
        
        greater control of essential conditions such as climate
        
        artificial breeding (captive breeding can quickly increase number)
- - - - limiting factors are environemtal factors that controls the maximum rate at which a process (popuation growth) can occur.**
        
        Top-down factors are pressures applied by other organisms at higher trophic levels (keystone species)
        
        Bottom-up factors are those that involve resources or lower trophic levels = they limit the availability of resources at lower trophic levels
        
        Bottom-up control of algal blooms by shortage of nutrients and top-down control by herbivory
        
        an algal bloom is a rapid increase in the population of algae
        
        algal blooms can disrupt coral reef communities by blocking sunlight and preventing photosynthesis in symbtioic zoonxathallae = this causes coral bleaching = death of corals
        
        nutrients affect the rate of photosynthesis and therefore the growth of algae.
        
        nutrients are a bottom-up limiting factor. nutrient enrichment by human acitivty can cause eutrophication (rapid algal population growth).
        
        top-down control of algae = parrotfish are herbivores that feed on algae on lower trophic levels
        
        *Duckweed is a good model organism for measuring sigmoidal population growth.
        
        place a small number of plants in container
        
        count number of leaves every day
        
        plot results*
    - - The carrying capacity (K) is the maximum size of a population the environment can support. Population growth slows as it approaches the carrying capacity of the environement.
      - The phases shown in the sigmoid curve can be explained by relative rates of natality, mortality, immigration and emigration.
        
        with limited environmental resistance a population will grow exponentially.
        1) exponential phase = natality is higher than mortality
        2) in the transition phase = natality approaches mortality rate
        3) the population growth plateaus as it appraoches teh carrying capacity (plateay, mort=nat)
        4) carrying capacity, morality exceeds natality
  - - - Lincoln index is a capture-mark-recapture method for estimating population size:
        1) 1st capture ---> mark individuals --> release them
        2) 2nd capture
        3) count the number of marked and unmarked individuals
        POPULATION SIZE = (number caught and marked) X (total caught)/ marked and recaptured
        can be used to compare populations of different species at one time
      - assumptions in lincoln: (1) all individuals have an equal chance of being captured/sampling is random (2)marked individuals are randomly distributed after release
        accuracy is improve if the sample size increases and if repeated samples are carried out
      - EVALUATION OF METHODS TO ESTIMATE POPULATION SIZE:
        1) capture-mark-release-recapture method is useful in lakes and rivers but not in oceans
        2) fish catches are useful
- - - - rhizombium is a bacteria that fixes nitrogen and converts it into a usable organic form
        
        the bacteria converts n2 in the soil to nh3, ammonia is needed for the production of amino acids.
        
        the plant passes carbohydrates to the bacteria for usre as an energy source.
    - - denitrification reduces the availability of nitrogen compounds to plants.
        it is the reduction of nitrtrate into nitrigen.
        denitriyfing bacteria can use oxygen or nitrate as an electron acceptor
    - - Soil can become waterlogged through floodings. This makes oxygen absent, encouraging the process of denitrification by bacteria.
      - waterlogging leads to denititrication. oxygen is in short supply, and water reduces the levels of nitrates and nitritres in the soil
        - waterlogged soils lose nitrates to denititrication and it reduces the oxygen avaibility in the soil
      - Insectivorous plants as an adaptation for low nitrogen availability in waterlogged soils
        
        wetlands have waterlogged soils and are therefore nutrient deficient due to dentitrification and low availability to oxygen.
        
        an adaptation of plants in waterlogged soils is to become insectivorous and obtain nitrogen throigh extracellular digestion of animals.
        
        insecticides stick to the tips of long tentacles and enzymes secreted by tentacles diges the animal
        
        modified leaves have evolved to trap insects
        
        the products of digestion are absorbed by the modified leaves
    - - pools = litter biomass soil.
        fluxes shows the rate of nutrient flow
        assimilation is the process by which inorganic nitrogen compounds are used to form organic nitrogen compounds (amino acids)
      - BE ABLE TO DRAW THE NITROGEN CYCLE
  - - - marine organisms dissolve phosphate --> phosphate found in sediments --> sediments develop into rock --> rock is mined --> phosphated is extracted and converted to fertilizer --> fertilizer applied to crops --> crops --> soil --> phosphate in soil passes into water strams by leaching
    - - fertilizer is then applied to crops, this process removes phosphrorous from one pool and transports it into another pool/sink
      - phosphate minerals are a non-renewable resource because phosphate minig is being carried out at a much faster rate than the rocks can natualy form phosphate.
      - the availability of phospahte may become limitng in the future because
        (1) there are no sources of phosphate fertilizer other than mniming minerals
        (2) there is no synthetic way of creating phosphate fertilizers (amonia can be created in the haber process)
      - Leaching of mineral nutrients from agricultural land into rivers causes eutrophication and leads to increased biological oxygen demand (BOD)
        
        Rainfaill leaches water-soluble nutrients from soil and carriers them into rivers and lakes.
        the nutrients can come either from artifical fertilisers or natural
        nitrates dissolved in water can result in runoff and enter other water streams
        the nutrient enrichment of water is known eutrophication
        eutrophication leads to algal blooms due to water nutrient enrichment
        algal blooms block light, preventing algae from photosynthesising.
        this increases the biological oxgen demand resulting in the deoxygenation of the water supply by saprortrophic bacteria
        CONSEQUENCES OF ORGANISMS TO LOW O2 LEVELS:
        (1) death of oxygen sensitive organisms/fish
        (2) reduction in biodiversity
        (3) decrease in water transperancy
      - To assess the nutrient content of a soil sample soil quality kits are used
        
        the kits involve adding a chemical to a soil sample, a color is produced that can be compared to the key: used to identify (1) soil ph (2) nutrients (3) texture (4) water content
        
        used by farmers to assess the nutrient content of soil