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Ecology - Coggle Diagram

- - - - the number of individuals surviving through each life stage can be taken from a life table and plotted
      - 3 general shapes
        
        type I- high overall survivorship through adulthood bit steep declines late in life (concave shape), typically low reproductive rates but parental care to offspring
        
        Type II- constant risk of mortality at all ages (curve is linear)
        
        Type III- low survivorship early in life and higher survivorship once they reach maturity (curve is convex), they tend to produce many offspring with littel to no parental care
  - - - all populations have potential if resources were unlimited with no migration or mortality
      - Nt=N0 x e^(rt)
      - most populations will slow until b=d and so r=0
      - logistic growth
        
        most growth will slow until b=d, so r=0
        
        log growth means r changes with population size
        
        rN=dN/dt
    - - difficulty in determing boundary of the populaition
      - full census performed on African Bush elephant population of Samburu adn Buffalo Springs by monitoring elephants for 21 months and learned to recognises 760 individuals
      - can use quadrats or transects to measure sessile organisms, mark recapture methods can be used for mobile organisms (equation assumes proportion of marked individuals in second sample is roughly equal as proportion of individuals in sampling area first captured)
- - - - occurs after catastrophic event
      - example- Alaska:
      - mosses develop substrate allowing germination
      - this creates soil moisture
      - mutualistic bacteria establish roots that perform nitrogen fixation to increase seedling growth
      - dense shage forms and spruce outcompetes other species
    - - occurs when an event removes the individuals of an established communities (cause can be disturbance event or removal of biomass)
- - - - fixed carbon in plant biomass minus respiration loss
      - it is the amont of biomass incorporated into hte tissues of primary producers after respiration
      - Satellite-based optical sensing techniques now help scientists detect the amount of primary production on land and in ocean at global scale
      - terrestrial ecosystems have NPP of 426g C/m2/year adn ocean have 140 g C/m2/year; but large ocean area means it taken
        s up 48% of total amount of carbon taken up
      - low NPP in arid regions (30 degrees latitude) and in poles (90 degrees), NPP rises slightly at mid-latitudes (especially North since larger land area)
      - In the oceans NPP is highest at mid-latitudes and along coasts especially those with upwelling (and is higher in South where ocean area is larger)
      - NPP increases as average arinfall increases up to around 240cm/year, the decrease after this is likely becasue of less sunlight or nutrient loos or flooding
      - NPP increases with average temperature; equator has ideal conditions but desert limited by rainfall
      - The FACE experiment artificially increased CO2 concentrations in pine cone tree areas to test what was the limiting factor, they found that trees are generally more responsive than herbaceous species
      - In oceans, NPP is limited by iron, nitrogen and phosphorous. Experiments in Galapagos archipelago and Southern Ocean showed that NPP was up to 10 fold higher in water that received iron and that iron limitation is major factor in ability to absorb CO2
      - Lake NPP is typically limited by phosphorous, studied in NA and Europe lakes the effects of eutrophication
    - - it is the amount of biomass obtained from consumption of other organisms and depends on how much plant tissue is consumed, and how much can be digested and how much is used in metabolism
      - can be affected by consumption, assimilation and production efficiency
      - some cannot be consumed- heat, faeces etc
      - production efficiency
        
        larger mammals have lower metabolic rates and higher production efficiencies than smallers mammasl and birds, whose greater SA:biomass ratios result in more heat loss and higher metabolic rates
        
        endotherms have lower production efficiency than ectotherms since the endotherms have higher body temperature they have higher metabolic rates so less energy left over to devote to growth and reproduction
        
        Production efficiency affects growth so changes can lead to population declines (Steller sea lions declinde 85% over 25 years due to change from eating herrign (rich in fat), cod and pollock to just cod and pollock when herring decreased. Cod and pollock have half energy per gram as herring)
    - - energy is lost as metabolism especially between producer and primary consumer
      - biomass lost because it cannot be supported
      - trophic efficiency is the proportion of energy reaching higher levels (energy at one one level/eneryg immediately below)
      - Aquatic systems
        
        their trophic efficiencies are much higher
        
        teh phytoplankton (primary producers) grow and reproduce much more rapidly than zooplankton and small fishes that consume them so the small biomass can support the larger biomass
      - a 3 level food web with a secondary consumer feeding on both primary consumer and producer should have lower NPP than food web with no omnivory; because even though the secondary consumer indirectly benefits the primary producer by feeding at the primary consumer level it partially negates this by directly feeding on primary producer
    - - Amount of NPP entering the system
        
        this hypothesis suggests that bottom up factors influence structure
        
        given that a large amount of energy is lost from one trophic level to the next, the number of trophic levels will be limited by the amount of energy that can sustain a populaiton
      - Amount of disturbance
        
        this hypothesis suggest longer food webs are less likely to recover from disturbances than short
        
        because the short food webs can reassemble more quickly since less species involved
      - evolutionary constraints on top predators
        
        this hypothesis suggests that no organism today has evolved to capture apex predators like sharks adn polar bears
        
        teh evolutionary constraints maintaining these predators means the number of higer trophic levels is limited
  - - - primary fixes carbon from atmosphere
      - carbon sequestration (carbon sinks)
      - decomposition, respiration and fires are natural sources
      - land use change adn fossil fuels are human sources
    - - cycled by nitrfying and denitrifying bacteria
      - nitrates and nitrites are taken up by denitrifying bacteria and plants
      - N-fixing bacteria break triple bond of atmospheric nitrogen to produces ammonia and ammonium
      - eutrophication is result of fertilisation and NOX gases from fossil fuels
  - - - grassland plot where productivity measured with plant cover as it shows niche packing
      - total plant cover increased with species richness and remaining soil nitrogen declines
      - increase in niche packing uses nitrogen more efficiently since more likely one will contribute a disproportionally large amount to ecosystem function
  - - - Keystone- strong/disproportional effect to size
      - Foundation- abundant and have large ecosystem effect
      - engineering- physically affect environment
      - Sea otters
        
        regulate urchin populations which maintains kelp populations
        
        hunting of otters increases urchin populations
- - - - predator almost always kill prey they consume so strategies to maximise this and minimise their own risk
      - strategies can be "active pursuit" to for search and capture, or can be stealthy ambush
      - snakes have jaws to swallow prey larger than their head, short-tailed shrews produce venomous saliva to paralyse earth worms
      - Prey strategies
        
        crypsis allows species to resemble objects that they consider inedible (katydid looks like a dead leaf) and some play possum
        
        chemical defences usually used by smaller prey (Bombardier beetles eject hot noxious chemical spray from abdomen tip), but predators can overcome this (garter snakes insensitive to rough-skinned newt), some use defense against them (seas slugs incorporate sponge toxins and posion dart frogs sequester prey poison)
        
        warning signals can be visual (nudibranchs and frogs use bright colours or patterns) or acoustical (rattlesnake)
        
        Mimicry
        
        Batesian mimimcry- an edible species mimics a dangerous species
        
        Mullerian mimicry- 2 or more species converge on common warning signal and all benefit from providing a strong recognition signal (genome sequencing of Heliconius species showed the optix gene that codes a TF so changing expression creates similar colour)
        
        behaviour (lionfish slowly approach their prey and direct jets of water and use distraction to capture)
    - - more than 90& of herbivorous insects are specialists that feed on
        few, taxonomically related plants; and generalists feed on many hundred unrelated plants
      - herbivores rarely kill plants and only remove small amount of biomass, so dificult to say they have strong selection pressure but can reduce fitness
      - Plant defence
        
        plants in mustard family produce secondary metabolite to reduce herbivory
        
        thorns and spines make it physically difficult to eat
        
        coralline algae contain calcium carbonate in tissues which deters many except sea urchins that have articulated jaws and long huts to process
      - Herbivore adaptations
        
        Saint-John's wort requires sunlight exposure for optimal toxicity so insects roll its leaves so it is in the dark
        
        the caterpillar of the diamondback moth eats plants in cabbage family which are rich in toxic mustard oil glycosides, and have an enzyme for break down
        
        some herbivores store plant toxins in specialised organs so can be used aginst their predators (caterpillar of monarch butterfly is insensitive to neurotoxic glycosides in its milkweed host plant)
    - - it is an interaction in which a predator lives on or in the prey and consumes certain tissues
      - microparasites
        
        they are many magnitudes smaller than host and generally live in the host
        
        they usually acquire nutrients at expense of host and are so pathogens, but often reach a stable state of coexistence as resistance increases and virulence decreases
        
        myxoma virus was introduced to control European rabbit population, 99.8% of infected rabbits died but then slowly evolved resistance, now deadly strains are required
      - Microparasites
        
        ectoparasites live outside the host body(Whale lice have claws that pierce host skin and feed on algae or flaking skin)(Japanese macaque is prine to lice that lay eggs on back, arms and legs; macaques maintain social bonds for grooming)
        
        endoparasites spend at least part of their life cycle in the host
    - - cycling of Canada Lynx and snowshoe hare population, with peaks at 10 year intervals and lynx population lags behind hare by 2-3 years. However, a long term study by Charles Kreb revealed that if lynx are absent of food or other food for lynx then the cycle continues so underlying cause may be environmental
      - Robert Paine experiment showed that a mussel species dominated certain zones when sea star predator was low; Paine showed that teh ecosystem can be controlled by a "Keystone" species
- - - - mostly done by photosynthesis
      - NPP is highest at warm wet areas
    - - plants are immobile so need to adapt
      - certain growth forms do better in certain climates
  - - - aseasonal or monsoonal rain, no season is unsuitable for growth
      - plant growth continuous
      - structurally complex (heterogenus), up to 500 tree species per sq km and home to half known species
    - - centred in 2 bells at 30 degrees
      - precipitation low so plants adapt water storing and prevent water loss, animals are nocturnal and water-conserving
    - - relatively dry with lots of perennial non-woody plants
      - topsoil is nutrient rich so agriculture
    - - seasonal fluctuations
      - broadleaved leaves fall off in winter and many shared plant genera across the biome
      - animal migration or hibernation common
    - - occurs greater than 50 degrees
      - lond dry winters and short warm summers
      - dominated by coniferous evergreen trees, seeds and cones are important food source
    - - high latitudes, low temperature and short growing season
      - biome underlain with permafrost
      - slow decomposition and large carbon sink
  - - - nothofagus is a tree group that has vicariant distribution and found at most temperate forests (SA and NZ)
      - Evidence of fossilized Nothofagus pollen from 55 to 34 million years ago has also been found in Australia, New Zealand, western Antarctica, and South America, suggesting that beeches originated in Gondwana
    - - analogous structures evolve similar form and structure but absent in last common ancestor
      - desert biomes- succulence, spines, no leaves, photosynthetic stems are evolved traits
    - - some species (arctic fox, lapland longspur, crowberry) have distribution across continents
  - - - energy and productivity higher at equator
        
        species require minimal amount of energy to remain viable
        
        if energy limits number of individuals then more energy means more productivity
        
        higher productivity can sustain more species
        
        NPP declines with latitude
      - Species diversification rate
        
        temperature, water availability and biome area may determine evolutionary species, so lineages evolve and speciation faster in warm wet tropics so more species
        
        and more area available at equator
      - stability
        
        tropic area are more stable climate, opposed to changes in glacial periods in north