C5 Terrestrial & Aquatic Ecosystems Flashcards
open system
a system that can exchange mass + energy (usually heat)
- e.g. tree, ecosystem
SYSTEMS
- what is a system
- open system
- closed system
- isolated system
an assemblage of parts + the relationship between them, which together constitute as a whole
OPEN: a system that can exchange mass + energy (usually heat)
- e.g. tree, ecosystem
CLOSED: a system that can exchange energy but not mass
- e.g. Earth, terrarium
ISOLATED: a system that can exchange neither mass nor energy
- e.g. thermos
systems approach vs reductionist approach
systems: a way of visualising a complex set of interactions by looking at it as a whole
reductionist: divides systems into parts, which are studied separately
Why is a systems approach important?
In order to understand our impact on an ecosystem, we must understand how it works as a whole (all interactions and relationships within it).
levels of organisation
- individual: one organism
- population: group of organisms from the same species
- community: a group of populations living together in the same geographical area
- ecosystem: all the biotic and abiotic factors within an area
- biome: a large geographical area with distinct flora/fauna, found across different regions
- biosphere: the zone of Earth where life is supported
abiotic vs biotic
- provide examples (3, 5)
ABIOTIC: all factors that are non-living.
- climate (temp, rainfall, wind, light intensity)
- chemical (pH of soil/water, salinity, availability of gases)
- other resources (landforms, soil type, water drainage, nesting materials etc)
BIOTIC: all factors that are living.
- animals
- plants
- fungi
- bacteria
- protists
Provide examples of small and large scale ecosystems.
Small:
- decaying log
- under a rock
- rock pools
Large:
- tropical rainforest
- savannah/grassland
condensation
water vapour changes state from gas to liquid
evaporation
water changes state from liquid to gas
evapotranspiration
describes the movement of ALL water evaporating from the land into the atmosphere, including:
- transpiration from plants
- evaporation from water bodies
- evaporation from land surface/soil
transpiration
water evaporates from plants (i.e. leaves)
vapor
a gas floating in the air
runoff
when fluid overflows from an area
precipitation
water in ALL states that falls to Earth, including:
- rain
- snow
- sleet
- hail
water cycle
the movement of water between land, bodies of water, and the atmosphere
groundwater
the water present beneath the Earth’s surface, located in rock and soil pore spaces
perlocation
the movement of water through the soil and fractured/porous rock
infiltration
the entry of water into a soil or rock surface
sink
a reservoir that provides storage for water, such as lakes, ponds, and the ocean
primary productivity
the process of creating organic compounds by autotrophs
autotrophs
organisms that use photosynthesis to make their own energy
- producers
- drive primary production
Includes:
- plants + algae
- some protists
- some bacteria
organic compound
- a carbon-based compound
- at least one carbon is bonded to an atom of another type (usually N, H or O)
- e.g. carbs, lipids, proteins, nucleic acids
State the chemical equation for photosynthesis.
6 CO2 + 6 H2O -> (via sun’s energy + chlorophyll) → C6H12O6 + 6 O2
State organisms that drive productivity in:
- oceanic/marine environments
- freshwater
Oceanic/marine: single celled plants, algae/protists, bacteria (PHYTOPLANKTON)
Freshwater: commonly plants + algae
Describe factors that would limit productivity (4)
- not enough reactants (water or carbon dioxide)
- not enough required nutrients available for autotroph growth (iron, calcium, nitrates, phosphates)
- too cold
- not enough light
photic vs aphotic
Photic: the zone of the ocean that receives sunlight (usually to about 200m down)
Aphotic: the zone that does not receive sunlight
chemosynthesis
using chemical energy to make energy + oxygen
- using chemical E instead of light, to produce the products of photosynthesis
- some bacteria perform this
nutrient upwelling
when cold, deep, nutrient-rich water is forced up into the photic zone
- results in massive boost of productivity
estuarine environment
where a river meets the sea
- salinity changes regularly (tide in = higher salinity, tide out = lower salinity)
- organisms must be very tolerant of changing conditions to survive there
viscosity
the thickness of a medium
- water more viscous than air
- most aquatic organisms have a streamlined body shape to move easily through the water
buoyancy
the force giving upward thrust
- air: little upthrust, organisms need a skeleton to support their weight
- water: more upthrust, organisms can float and do not necessarily need a skeleton
turbulence
the fluctuations/movement of a body of water
- the more turbulence, the more oxygen is dissolved into the water
pressure
a continuous physical force exerted against something
- air: the higher the altitude, the less dense the air, the lower the pressure
- water: the deeper the water, the higher the pressure
3 types of aquatic ecosystem
- freshwater (rivers, lakes, ponds)
- estuarine (river meets sea
- marine (reefs, rocky shore, open ocean)
heterotrophs
- do not make their own food
- consumers
decomposers
- a type of consumer
- CRITICAL to an ecosystem
- ‘recycles’ organic matter
- broken down by decomposers, nutrients/components are returned back to the soil, become available again
Includes:
- scavengers
- detritivores: decompose vis oral ingestion of material
food chain
a linear sequence of organisms
- arrows show movement of energy + biomass from producer -> heterotrophs (primary consumer, secondary consumer, etc)
- must label with producer, primary/secondary/tertiary consumer etc
apex predator
the top organism of a food chain - no natural predators
trophic levels
the levels at which organisms exist within an ecosystem
- form a pyramid
- producers on bottom
- apex predator on top
- energy loss at each stage
Why are trophic pyramids usually limited to 4-5 levels?
- there is a continuous loss of energy within a food chain
- only 10% of the energy at one trophic level is available to be passed to the next
- therefore trophic levels are limited as organisms at too high of a level would not have enough energy available to sustain their population
food webs
- a diagram displaying a complex set of interactions within organisms in an ecosystem
- organisms are arranged in rough rows according to trophic level
- producers at bottom, apex predators at top
- arrows show movement of energy + biomass from producer -> heterotrophs (primary consumer, secondary consumer, etc)
- must label with producer, primary/secondary/tertiary consumer etc
niche
an organism’s role within it’s community, including it’s interactions with other species, habitat, and zone of tolerance
fundamental vs realised niche
Fundamental: the area an organism could theoretically occupy (set by abiotic factors)
Realised: the area an organisms actually occupies (set by biotic factors - other species)
generalists vs specialists
Generalists: large niche
- non-specific requirements
- live on a varied diet
- less vulnerable to extinction
Specialists: narrow niche
- specific requirements
- unique habitat/diet
- more vulnerable to extinction
Describe the ecological relationship of competition, providing examples. (2 types)
- competition between organisms for food, habitat, or resources
Intraspecific: within a species (Tas devils competing for food, owls competing for nesting)
Interspecific: between different species (dolphins and sharks competing for fish, rabbits and bandicoots competing for habitat)
Describe the ecological relationship of predation, providing examples.
- one species hunts and eats the other
- involves predator-prey cycles (stable negative feedback loop)
- dolphins and fish, feral cats and bandicoots
Describe the symbiotic relationship of parasitism, providing examples.
+/-
- one organism benefits at the expense of another
- ectoparasites (on surface), endoparasites (inside host)
- are not in interests to kill host, just gain off it
- tapeworms inside organisms eat food, fleas and lice feed off organism
Describe the symbiotic relationship of mutualism, providing examples.
+/+
- two organisms live together/interact and both benefit
- clownfish and anenome (fish cleans anenome, anenome provides camoflage), bees and flowering plants (nectar food, spreads plant pollen for reproduction)
Describe the symbiotic relationship of commensalism, providing examples.
+/0
- one species benefits, the other is unaffected
- whale shark and remora (shark provides food without being affected)
sampling
using a large range of techniques to estimate population numbers of a species
- needed when total counts are unable to be made
What is a transect?
Describe the 2 different types.
- a transect is a line, strip or area used to count/map the distribution of species along the line
- can be random or follow an environmental feature
- shows how the diversity of a species changes
LINE TRANSECT: line created with a rope or tape measure, the species along the line are recorded
BELT TRANSECT: a measured strip
density
the number of organisms per unit area
carrying capacity
the maximum population size an area can support
State the four contributing causes to population size.
- births
- deaths
- immigration
- emigration
Describe the factors that determine the carrying capacity of an ecosystem.
(using the acronym: PANDA PAW)
Density Dependent:
- Predators
- Availability of resources
- Nutrient availability
- Disease/pathogen spread
- Accumulation of wastes
Density Independent
- Phenomena (natural disasters)
- Abiotic factors
- Weather conditions (general)
What type of graphs display how the population of an ecosystem changes over time?
population growth curves
- time as IV, pop size as DV
- once curve reaches stability: carrying capacity
J curves vs S curves
display the relationship between time and how a population size
J CURVES
- exponential growth
- there are no limiting factors on pop size
- unlimited resources
- suitable abiotic factors
- pop size skyrockets, followed by a crash due to overshooting the carrying capacity
S CURVES
- starts with exponential growth
- pop growth slows due to limiting factors (biotic or abiotic)
- pop reaches carrying capacity
Why does the population size fluctuate around the carrying capacity line once it has reached it?
- the population has reached the maximum size the area can support
- small changes in factors lead to small changes in pop size, but overall it will remain relatively stable
positive vs negative feedback
- feedback is a circular process
- output serves as input
POSITIVE
- a CHANGE in the system
- additional, increasing change (like a snowball)
- the system is altered away from the equilibrium
- does not mean a positive effect
NEGATIVE
- STABILITY in the system
- counteracts any change away from the equilibrium
- e.g. predator prey cycle
State the key abiotic factors of aquatic environments.
- salinity
- temp
- dissolved O2
- light penetration
- acidity (pH)
- exposure
- tides
Describe how being in the tidal zone affects aquatic biotic factors.
- organisms must be adapted to withstand impact of water movement
- predation opportunities
- filter feeding opportunities
- zonation occurs
ecological tolerance
- the range of conditions an organism can endure before injury or death
Optimal range: there is the optimum amount of abiotic factor to produce the highest population
Zone of physiological stress: the organism is under stress, due to abiotic factor being too high or low to support normal potential
Zone of intolerance: population is unable to survive, abiotic factors are too extreme
State the main vegetation types in Tassie.
- wet sclerophyll
- dry sclerophyll
- temp rainforest
- grasslands/woodlands
- alpine
wet sclerophyll
- infrequent, high intensity fires: wetter, denser forest means less fires, biomass builds up, when fire occurs it burns intensely
- tall canopy eucalypts (>30m), dense understory layer
- regenerates via fire (wipes out understory and some canopy trees, new seedlings cover forest floor, competition within these, new dense understory, some grow large to fill gaps of canopy)
sclerophyll forest
eucalypt dominated forest
Outline some adaptations of eucalypt trees that encourage fire in their ecosystems.
- oil in leaves: highly flammable
- open tree canopy: allow increased oxygen exposure to fuel fire
- bark: trees drop bark, which piles up and is carried by wind, increasing fire risk and intensity
dry sclerophyll
- frequent, low intensity fires: dryer, more sparse forest means more fire, not much biomass, fires burn less intensely
- eucalypt canopy trees of many different heights/ages due to fire
- regenerates via fire
rainforest
- lots of rain, very dense forest
- not dominated by eucalypts
- fern/moss/lichen understory
- regenerates via natural mortality of older trees: creates gaps in canopy, light is then available to smaller trees, who grow to fill canopy gap
- not adapted to regenerate after fire
grassy woodlands
- low rainfall
- fertile soil
- widely spaced trees
- under threat due to being cleared for farming
alpine
- most tree species do not survive over a certain altitude due to: poor soil, extreme climactic conditions
- vegetation is low lying: grasses/sedges
State the abiotic factors that affect vegetation distribution.
- what happens when these factors are overlapped
- rainfall
- temp
- soil fertility/geology
- aspect (slope)
- light availability
- fire
- overlapping of factors results in mixed forest
Describe how a low fire frequency will change a sclerophyll forest over time.
- eucalypts do not have the presence of fire to regenerate
- they do not grow, are overtaken/replaced by temperate rainforest species
- given enough time, the ecosystem could transition to a complete temperate rainforest
State the 1st Law of Thermodynamics and how it relates to ecosystems.
“Energy can neither be created nor destroyed, only change form.”
- energy enters via sunlight and is passed/transferred through the trophic lvls
Compare the movement of matter with the movement of energy in an ecosystem.
- both move through ecosystems through consumption, passed up through the trophic lvls
- in both there is loss/waste at each stage
- matter is a closed system
- energy is an open system
State the factors affecting productivity (Phs) in an ecosystem, and their relationship.
- sunlight availability (proportional, then plateau)
- CO2 conc (proportional, then plateau)
- nutrients (proportional, then plateau)
- temp (proportional, then decrease)
- H2O (proportional, then decrease)
Describe how in an ecosystem how consumers access the energy that producers fix (via Phs).
- consuming plant material (or animals that have consumed plants
- cellular respiration: releases glucose for energy
Outline how energy moves through an ecosystem.
- enters via sunlight
- is converted to biomass via photosynthesis (producers)
- passes through food chains
- is lost through inefficient energy transfer resulting in waste (e.g. heat)
ecological pyramids
diagrams that represent numerical values of an ecosystem’s trophic levels
- pyramid of numbers (the individual organisms at each lvl)
- pyramid of biomass (dried mass of biomass at each lvl)
- pyramid of energy (the flow of energy at each lvl)
pyramid of numbers
- the number of organisms at each lvl
- NOT ALWAYS a pyramid (no ‘set’ relationship between trophic lvl and number of organisms)
pyramid of biomass
- the total dried mass of living organisms at each lvl
- USUALLY a pyramid
- measured in grams/sq m (g/m^2)
- measured at a singular moment in time
pyramid of energy
- the flow of energy at lvls, over a year
- ALWAYS a pyramid
- measured in joules/m^2/year)
- sunlight not usually shown
Describe how to draw an ecological pyramid.
- producers at bottom, follows food chain up the lvls
- must be scaled as best as possible
- each lvl must be centred on the one below it
- must label each level next to it with species name, number value, and units
State the 2nd Law of Thermodynamics and how it relates to ecosystems.
“Energy conversions are never 100% efficient, there is always energy lost as waste.”
- less E available at higher lvls
- less organisms at higher lvls (i.e. more producers than consumers)
= food chains are only limited to 4-5 trophic lvls, there would be insufficient E available to sustain a population
Why does the total amount of energy decrease the higher the trophic lvl?
- respiration
- heat loss
- moving
- excretion
- not all material is consumed/digested
- this is why (roughly) only 10% of energy available at any trophic lvl is available to be passed on to the next.
Describe a special case in pyramids of biomass.
Marine biomass pyramids
- is an inverted pyramid
- at higher trophic lvls, organisms have more biomass
- producers do not have much mass (phytoplankton, zooplankton)
CARBON CYCLE
- how FF are formed
- processes contributing to atmospheric CO2
- processes decreasing atmospheric CO2
FF
- dead matter is buried and not decomposed - turns to FF
CONTRIBUTES
- combustion (burning of FF)
- deforestation
- CR (from organisms)
- decomposition of dead matter
- diffusion from water bodies
eruptions:
- shells (calcium carbonate) turn to sediment
- buried, compacted, undergo pressure and heat
- turn to limestone
- tectonic plate movement brings limestone to surface volcanoes = eruptions
DECREASES
- Phs
- diffusion/dissolving into water bodies
nitrogen (why is it, and its cycle, important)
- need for survival (to make protein and DNA)
- very common (78% atomsphere) however most organisms cannot use this
- N must be fixed before use
- nitrogen cycle occurs in all ecosystems
State the key processes in the nitrogen cycle.
- nitrogen fixation
- ammonification
- nitrification
- assimilation
- denitrification
nitrogen fixation
- what?
- 3 types
atmospheric N is put into a biologically available form, by combining with O or H
3 types
- atmospheric fixation
- industrial fixation
BIOLOGICAL FIXATION
- nitrogen fixing bacteria in soil and roots concert N2 + H2 into ammonia (useful)
- ammonia reacts with water to form ammonium (used by plants
ATMOSPHERE - BACTERIA IN SOIL/ROOTS - AMMONIA
ammonification
- decomposers break down AAs from dead organic matter
- form ammonia/ammonium
DEAD MATTER - BACTERIA IN SOIL/ROOTS - AMMONIUM
nitrification
- nitrifying bacteria in soil/roots turn ammonium ions to nitrites/nitrates (used by plants)
AMMONIUM - BACTERIA IN SOIL/ROOTS - NITRATES/NITRITES
assimilation
- nitrates/nitrites are taken up by plants via roots
- plants convert them to proteins/nucleic acids
- plants are consumed by herbivores
- plants die - ammonification
denitrification
- denitrifying bacteria convert nitrates/nitrites back to N gas, released to atmosphere
- occurs in O poor environments (soil, groundwater, etc)
phosphorus (why is it important)
- not found in atmosphere
- plays a vital role in plant/animal growth
- production of DNA/RNA
- formation of cell membranes + ATP
phosphorus cycle
- describe all steps (4), that occur
WEATHERING
- P in rocks is broken down via rain + natural weathering
- is washed into soil and water bodies
ABSORPTION
- P is absorbed by plants/animals and used for growth
- P in water is drunk by animals, taken up via plant roots, animals eat plants
- occurs in ocean too
DECOMPOSITION
- dead or waste matter is broken down by decomposers
- P is converted from organic to inorganic (mineralisation)
SEDIMENTS
- over time P gets compacted, with pressure and heat, turns into rock
Why does the water/air become less acidic (i.e. have a higher pH) when Phs rate is higher?
- CO2 makes water acidic (lower pH)
- Phs uses CO2 in the reaction, removing it from the water
- this makes water less acidic (higher pH)
