unit 3, topic 2 Flashcards
sequence and explain the transfer and transformation of solar energy into biomass as it flows through biotic components of an ecosystem
Conservation of light energy to chemical energy
Plants and algae photosynthesise using the suns energy and establish an energy structure in which all organisms depend.
Photosynthesis – involves harnessing light energy from the sun to bind molecules of water and carbon dioxide into glucose molecules. In this process the light energy is transformed into chemical energy and then locked into the high-energy chemical bonds of glucose. This energy is then made available to an organisms metabolism where it is released through cellular respiration (a complementary process to photosynthesis that breaks down glucose molecules into component parts.
what are biomass producing organisms
Producing biomass:
Autotrophs (producers) - organisms that can produce their own energy from sunlight and carbon dioxide (can photosynthesise).
Heterophs – organisms that cannot produce their own energy, and need to consume other organisms in order to gain energy.
what is GPP and NPP
GPP (gross primary productivity) - the total organic matter produced annually in an area by photosynthesis.
NPP (net primary productivity) - GPP – the amount of energy required by producers for cellular respiration.
what is a photosynthetic efficiency
and the formula
Photosynthetic efficiency – how well an autotroph/producer converts light to chemical energy of carbohydrates.
describe the energy transfer through trophic levels
Energy transfer
Food webs and food chains show energy transfer between trophic levels.
Approximately 10% of the energy at one trophic level is passed onto next trophic level.
describe energy losses
Energy losses
Remaining 90% of energy is transformed by metabolism into heat and lost to surroundings/remains as chemical energy in both uneaten portion and body waste.
Endothermic animals (animals that have a higher internal body temp then their surroundings) such as mammals and birds radiate more body heat then ectothermic animals (animals that do not maintain internal body temp and use external heat to warm themselves) such as snakes and lizards.
what are nutrient cycles and their components
Nutrient cycles – are cyclical movement of key elements through biotic and abiotic components of an ecosystem:
Biological component – that follows how the elements cycle through organisms.
A geochemical component – showing how the elements cycle through the soils, rocks, water and atmosphere.
There are three types of nutrient cycles: carbon, nitrogen and water.
explain the carbon cycle
The carbon cycle
The carbon atoms circulate compounds of living things and non-living surroundings through a number of pathways, together they form the carbon cycle.
Generally, the carbon in an ecosystem is maintained and distributed throughout an ecosystem by photosynthesis of producers, cellular respiration of consumers and combustion of organic matter.
Other sources include rising temperatures, reducing the amount of dissolved carbon atoms in the ocean and human activity removing fossil fuels and reintroducing it.
A ‘sink’ - where carbon atoms naturally accumulate away from the normal carbon cycle.
The carbon cycle does not require decomposers. Without them – carbon can still circulate throughout the ecosystem because carbon is incorporated into photosynthesis and cellular respiration and combustion of organic matter.
With decomposers – all dead matter decays.
Under aerobic/acidic conditions – decomposers are able to break down all remains/waste matter products of organisms. - then becomes fossil fuels forming a sink.
explain the nitrogen cycle
The nitrogen cycle
Nitrogen fixing bacteria – bacteria that absorbs elemental nitrogen gas from atmosphere and converts it to nitrate or ammonium ions.
Plants and animals rely on nitrogen fixing bacteria to covert elemental nitrogen into ion that they can absorb.
Two parts of nitrogen cycle:
Elemental cycle – nitrogen fixing bacteria (NFB) absorbs elemental nitrogen gas from atmosphere and releases back by denitrifying bacteria and volcanic activity.
Nitrate and ammonium ions are passed between organisms in biosphere.
Some bacteria will form a symbiotic relationship with plants:
EG: casuarinas, acacias and legumes provide bacteria with accommodation in nodules (root organs). - in exchange for protected accommodation for bacteria, the plants have a source of ionic nitrogen) - mutualism.
explain the water cycle
Water cycle
Driven by sun and gravity.
Precipitation, evaporation, condensation, transpiration (from plants).
define ecological niche
Ecological niche – the role and space that an organism fills in an ecosystem including all its interactions with biotic and abiotic factors of its environment.
distinguish between fundamental and realised niche
Fundamental vs Realised niche
Fundamental niche – is the wildest potential niche that a species could ideally occupy without predators, parasites or competition.
Realised niche – is the actual niche a species occupies given restrictions placed on it by interactions with other species.
Competition, predation and disease place limitations that can force a species to compromise its fundamental niche, resulting in a much narrower realised niche.
explain resource partitioning
Resource partitioning:
The use of space and time that reduces competition between species and allows many unique ecological niches to exist in the same place.
EG: birds feed on the same tree at different heights.
describe competitive exclusion principle
Competitive exclusion principle – states no two species can occupy the same niche in the same eco system. If they have an overlapping niche, they compete until the winner outcompetes the other species, who retreats.
define carrying capacity
Carrying capacity – the size of populations that can be supported indefinitely on the available resources and serves of that ecosystem.
distinguish between keystone species and dominant species
Keystone species – a plant or animal that plays a unique and crucial role in the way an ecosystem functions. Their presence prevents anyone species from monopolising resources.
Without a keystone species the ecosystem will collapse.
The dominant species is different to the keystone species – it is the most abundant species in an ecosystem, but is not necessarily the keystone species.
define population
Population – total number of species that lives in a particular place at a particular time.
explain why the carrying capacity of a population is determined by the limiting factors.
As a population size increases, the demand for resources (water, food, shelter space) also increases. Eventually there will not be enough resources. Therefore, there is a limit of individuals who can occupy an environment.
Populations can rely on balanced relationships between their biotic and abiotic components (which can vary over space and time).
The maximum populations that an ecosystem sustain depends on the biotic and abiotic limiting factors at any given place or time.
identify biotic factors that limit carrying capacity
Biotic factors:
Competition for resources, disease, number of predators, food abundance, number of mates, disease-causing organisms.
Loss or introduction of a species can also change carrying capacity.
identify abiotic factors that limit carrying capacity
Abiotic factors:
Availability of nutrients, pollution, space, natural disasters, extreme climatic events, shelter, refuge from predators, light, nesting sites.
Abiotic factors change quickly in floods, fires and cyclones.
Abiotic factors change slowly in temperature change and droughts.
define migration
Migration – movement of individuals of a species from one place to another.
what is an open and closed ecosystem
Closed ecosystem – population changes only depend on birth rate and death rates, migration does not affect it.
Open system – population depends on birth and death rates, as well as migration.
define the types of migration
Types of migration
Immigration – movement of individuals of a species into a place.
Emigration – movement of individuals of a species out of a place.
what is an increasing and decreasing population
Increasing population – if the birth and immigration rate exceeds the death and emigration rate.
Decreasing population – if the death and emigration rate exceeds the birth and immigration rate.
what is the population growth formula
Population growth
Population growth = (br + ir) - (dr + er)
what are the ways of measuring a population
Ways of measuring population:
Direct observations – directly observing ecosystems and taking records to measure abundance (normally for immobile species).
Sample – a small group of individuals out of a whole population.
Lincon index (capture-recapture method): estimating population of mobile species.
Method:
Capture – animals are captured.
Animals are recorded and marked, then released.
Recapture – animals are recaptured and those who are already marked are recorded.
Formula: N = M × n/m
M = number of animals caught and released initially.
N = number of animals caught in second sampling
Lowercase m = number of animals recaptured that were marked.
what are the ways of measuring distribution
Ways of measuring distribution:
Random distribution: organisms are spaced irregularly, location does not affect the location of other organisms. (EG: plants).
Uniform/continuous distribution: spaced evenly, the presence of one organisms determines how close or distant another organism will be. (EG: animals with breeding territories).
Clumped/grouped: number of individuals are grouped together and a make up a whole. (EG: school of fish).
what is a logistic growth S curve
Logistic growth S-curve:
When few members colonise a habitat quickly, the population increases rapidly. This cannot be sustained as resources are used, therefore the population begins to level off.
Population approaches zero as the carrying capacity nears.
Not typical because it assumes resources are abundant which is not always the case in the real world.
what is an exponential growth J curve
Exponential growth J-curve:
Unstable, unpredictable ecosystems (such as after fire or land clearing). Opportunistic species ty to move and colonise as quickly as they can – population increases exponentially.
what are the 2 modes of distribution
logistic growth S curve
exponential growth J curve
define environmental resistance
Environmental resistance – biotic and abiotic factors that limit a species population from growing out of control.
