C4 Interaction and Interdependence of Ecosystems Flashcards
What is a population?
Interacting group of organisms of the same species at the same time
What is the population size?
Number (or estimated number) of individuals at that area at one time
What is a random sample?
When the zone/area is decided arbitrarily (rather than a predictable pattern)
What is a sampling error?
difference between estimations and actual population size (hard to quantify but can calculate degree of error)
What is quadrant sampling?
When a quadrant (sqaure of a particular dimension) is placed in a random location in the area. Organisms must be completely in the same quadrant
What information does standard deviation tell us about a population?
how spread out data is from each other
Small - most were close to mean
What is the Capture-Mark-Release-Recapture method?
Mark as many as possible. Release + see how many are recaptured (so none are doubled counted/missed)
What type of organisms use the CMRR method?
those that move
What is the formula for the Lincoln Index’?
Size of population = (size of 1st sample x size of 2nd sample)/Number of recaptures in second sample
P = N1 x N2 / R
What is the process of quadrat sampling?
- Put one/two measuring tape down along the target area
- Generate random numbers within the measurements of the transects. First number is the horizontal distance. Second number is the vertical distance
- Place quadrat at that intersection
- Count every organism that falls completely in the quadrat
- Repeat
- Multiply sample area to represent total area
What is the process of Capture-Recapture?
- Capture as many organisms as possible within time limit in determined area
- Mark each organism
- Release organisms and wait. Assume no-one died, no movement, marks did not dissolve
- Recapture
- Plug numbers into Lincoln Index
What is the criteria for what you can mark organisms with, in Capture-Mark-Release-Recapture?
Non-toxic
Non-washable
Does not increase visibility
What does a high percentage of animals recaptured mean in the CMRR method?
Small population
What are the three types of population distribution?
Random, uniform, clumped
What population type would have the highest standard deviation in mean number per quadrats, if sampled with quadrats?
Clumped
What population type would have the lowest standard deviation in mean number per quadrats, if sampled with quadrats?
Uniform
What is carrying capacity?
Maximum number of organisms an environment can consistently support in terms of food/water/shelter
What happens if the population goes above carrying capacity?
Death will increase until the population stabilises
What is a limiting factor?
An finite resource of the habitat that is needed for survival for many individuals in a community, that limits population size
Examples of limiting factors
competition
predation
parasitism
natural disasters
What is a density-dependent factor?
A factor that becomes more problematic as population size increase (
Examples of density-dependent factors
Spread of disease, competition, increased predator attraction to area
What is a density-independent factor?
factor that is unrelated to the crowdedness of a population size/ affects all populations regardless of size
Examples of density-independent factors
Natural disasters
Climate change
What feedback loop do density-dependent factors operate on?
Negative feedback loop
What are the three stages of a Sigmoid-shaped curve of population growth?
Exponential
Transitional
Plateau
What occurs in the exponential stage of a Sigmoid-shaped curve of population growth?
Size and rate increases.
rapidly increasing population growth that occurs when a small number of organisms inhabit a new area
What occurs in the transitional stage of a Sigmoid-shaped curve of population growth?
Size increases, rate decreases.
growth rate slows as resources become more limited. Still increasing but at slower pace
What occurs in the plateau stage of a Sigmoid-shaped curve of population growth?
population will stabilise at a size sustainable for the area
What are the two types of population growth curve diagrams?
Exponential growth
Sigmoid growth curve
In an exponential growth curve, what is the pattern?
Continually increases at a continually increasing rate, because of abundant resources.
What are the only limiting factors in an exponential population growth pattern?
density-independent
What does K stand for in terms of a Sigmoid growth curve?
K = carrying capacity. Population stabilises. Birth rate ~ death rate
What feedback loop does an exponential population growth operate on?
positive
What feedback loop does overshooting the carrying capacity operate on?
negative
What is a key feature of the resources in a sigmoid population growth curve?
Limited resources
What types of factors impact the Sigmoid population growth curve?
Density-dependent and density-independent
What is the formula for percentage change?
((Final - initial) / initial ) x 100
What is a community?
All populations in an area interacting with each other / biotic factors of a habitat
What is herbivory?
primary consumers feeding on producers. doesn’t kill producers.
How is herbivory different to predation?
Herbivory doesn’t kill the producers, while predation kills the prey
what is predation?
one consumer species (predator) killing another consumer species (prey). Involves ingestion and crucial for ecosystem stability
What is mutualism?
symbiotic relationship where both species benefit. Often with two different types of organism
What is parasitism?
Symbiotic relationship where parasite benefits and host is harmed. Parasite doesn’t ingest host (unlike predation) but does receive nutrients from it
What is pathogenicity?
Ability of an organism to cause disease. A pathogen lives within its host (causing disease)
Why is pathogenicity not long-term?
Host either dies or prompts an immune response
What is an endemic species?
Species naturally found in that area. Density-dependent factors maintain population size at around carrying capacity
What is an invasive species?
an alies species that can use new prey opportunities and no predators to successfully survive and outperform endemic species
What is an intraspecific relationship?
Between species in a shared habitat
What is an interspecific relationship?
Between different species in same community
How do invasive species relate to the competition exclusion principle?
Can establish niche and thrive, leading to endemic specific losing niche
Definition of symbiosis
2 different species having a long-term close association, with at least one benefiting
What are two types of intraspecific relationships?
cooperation
competition
Examples of cooperation
Huddling for warmth
Pack hunting
Schooling fish
Parenting young
What is intraspecific competition?
Competition within a spcies, in the same niche. Limited resources meant not all survive, which overtime helps species due to natural selection (net positive). Stabilises population at carrying capacity
What is interspecific competition?
competition for a shared resources between different species, leading to the competitive exclusion principle being relevant. Leads to either elimination or niche partioning
What are three examples of mutualism?
Rhizobium bacteria grow in nodules in plant roots
Myeorridge fungi growing on orchid roots
Zooxanthallae algae and coral polyps
What does each species receive in the mutualistic relationship between Rhizobium bacteria + plant roots?
Rhizobium bacteria grow in nodules in plant roots
BActeria gets sugar from plant photosynthesising; shelter/home in roots; protection from consumers
BActeria take nitrogen from atmosphere and fix it into ammonium + nitrates that plant can use. Prevents nitrogen deficiency
What does each species receive in the mutualistic relationship between Myeorridge fungi + orchid roots?
Myeorridge fungi grows on orchid roots.
Fungi get sugar from plants photosynthesising
Fungi help absorb nitrogen and phosphorous, help absorb carbon compounds, make plant better at absorbing water, etc
What does each species receive from the mutualistic relationship of zooxanthallae algae + coral polyps?
algae gets home (close to light), protection from predators, CO2 source from cell respiration, etc.
coral get sugar from algae photosynthesising
How does information from quadrat testing provide insights into relationships between two species?
Positive: in same quadrants i.e. both or neither
Negative: diff. quadrants
No relationship: random
What is the null hypothesis (H0) in terms of species association?
No trend, data is random, species distributed independently, no relationship
What is the alternative/experimental hypothesis (H1) in terms of species assocation’?
Species are associated
What statistical tool is used to detrmine if an association is statistically significant?
Chi Square Test for Association
Difference between an experiment and an observation
experiment involves manipulating a variable and investigating impact / comparing a control group to one with manipulation variables.
observation does not involve any manipulation. Instead, it is recording, measuring and quantifying
Strengths of an experiment compared to an observation
Experiments are stronger and more reliable because able to conclude one thing caused another.
Observations make it harder to define exact cause but more effective and more authentic in long term
What question does a Chi Square aim to answer?
Is a difference between two data sets ‘big enough’ to suggest an important difference?
i.e. in test of assocation, observed data v.s. expected data?
What are the steps of a Chi Square Test of Association between two species?
- State null and alternative hypothesis
- Make a contingency table based on observed data
- Use contingency table to calculate expected values based on the null hypothesis, with the formula: (row total x column total) / total. Round to whole number
- Calculate chi square value (χ2), using the expected values and observed values.
For each scenario, use the formula (O-E)^2 / E + add up all scenarios. The result is the chi square value - Compare x2 to a critical value, from chart.
Df (degrees of freedom) = (#columns - 1)(#rows - 1) = 1.
P (probability) = 0.05 for most - IF the x2 is more than the critical value, reject the null hypothesis (associated species). If it is less, fail to reject null hypothesis (no relationship)
What are the patterns seen in negatively associated species in Chi Square Tests?
Expected > observed with both or neither
expected < observed with individual
What are the patterns seen in positively associated species in Chi Square Tests?
Observed > expected for both
Observed < expected from neither
What is an allelopathy?
Release of chemicals by plants into environment that negatively impacts another plants
What is an antibiotic?
Release of chemicals by a microorganism negatively impacts nearby bacteria
What is cyclical oscillation in predator and prey relationships?
Repeating rises and falls in population size overtime because predator and prey are density-dependent factors to each other.
What is the cycle of populations in predator/prey relationships?
An increase in predator -> decrease in prey -> reduction in predators -> increase in prey -> increase in predators
What are the key features of a cyclical oscillation graph?
Time on x-axis
Population biomass on y-axis
Prey > predators
Time lag between cycles
What is top-down control of populations?
Predators can impact stability of a community. negative feedback
Higher trophic levels impact population of low ones (i.e. more predators = less prey = more producers)
What is bottom-up control of populations?
Amount of available producers determines population size of entire community. Lower trophic levels impact populations of higher ones (more producers = more prey = more predators). Positive feedback
What are primary metabolites?
Molecules necessary for basic life functioning (growth/development/reproduction) -> shared by many/all species
What are secondary metabolites?
Molecules not involved in life functioning. Non-essnetial only made by some. Usually released into the environment
What population control balances an ecosystem?
Bottom-up
Top-down control
What is eutrophication?
Excess nutrients in aquatic environment (run-off) that cause plant overgrowth, to the detriment of animals (i.e. cannot access oxygen)
What is the first law of thermodynamics?
Law of conservation.
Energy can neither be created or destroyed, but can change forms
What is the second law of thermodynamics?
Disorganisation of a system increases when energy is transformed / when energy transforms form, it often goes to a less usable form
What is a producer?
Organisms that produce their own food, creating carbon compounds from energy sources (usually light). They are eaten for their carbon compoundsW
What is a consumer?
Organisms that kills and ingest living organisms, obtaining energy from carbon compounds on which they feed
What are decomposers?
ORganisms that release enzymes and break down unconsumed/decaying organisations for use. Prevent build up of waste + produce compounds for soil
What are trophic levels?
positioned occupied in a food web / how many organisms energy has flown through
What is assimilation?
Post-digestion. Process of using digested food that contains carbon-based compounds to build new things for body
What is an open system?
New matter can leave/enter ecosystem.
What is a closed system?
No new matter, only recycled.
What is a food chain?
linear network of links in a food web, showing direct flow of energy
What is a food web?
Interlinking food chains in an ecosystem
How do photoautotrophs create organic energy substances?
Take light every from Sun, combine it with water + CO2. Synthesise their organic molecuels (glucose via photosynthesis) from this
How do chemoautotrophs create organic energy sources?
Take CO2 + oxidise inorganic compounds for an energy source to make glucose. Oxidise chemicals
What are autotrophs?
Organisms that use energy to convert gaseous CO2 into solid carbon compounds.
What are heterotrophs?
organisms that rely on other organisms to obtain C compounds
Use holozoic nutrition: consumers
Use saprotrophic nutrition: decomposers
How do Giant Tubeworms survive hydrothermal vents?
Through a mutualistic relationship with bacteria. The bacteria live inside the tubeworms, that use hydrogen sulfide as an energy source, which releases energy and sulfur for the tubeworms to use
What is primary production?
Accumulation of carbon compounds in biomass by autotrophs
Gross primary production: all made
Net primary production: all stored as biomass, available to consumers
What is secondary production?
Accumulation of carbon compounds in biomass by heterotrophs.
Gross: all consumed’
Net: all stored as growth + available to next trophic level
What is energy loss throughout trophic levels?
Only a small amount of energy consumed by one trophic level is available to the next consumer
What are the main forms of energy loss between trophic levels?
Incomplete consumption (only some parts are eaten)
Incomplete digestion (only some are absorbed, others pass through as faeces)
Cellular respiration: carbohydrates consumed break apart to form ATP + released as CO2
What are the origins of heat loss in organisms?
Cellular respiration (carbohydrates -> ATP) is not 100% effective -> heat loss
When ATP is used (hydrolysed), heat goes to environment
Some heterotrophs have adaptations to increase heat loss (for warmth)
Why are food chains limited in their length?
Because so much energy is lost between each trophic level.
What percent of energy consumed is passed on to the next trophic level?
10% is stored as body tissue
90% is converted into ATP, lost as heat, etc
What is a carbon pool?
Reserve/storage of carbon
What is a carbon sink?
carbon pool that absorbs more carbon than is released
What is carbon flux?
Process that transfers Carbon from one pool to another
What are three types of carbon fluxes due to living things?
Photosynthesis: absorption of CO2 + conversion to organic compounds
feeding: transfer of organic carbon compounds from one to another via feeding
respiration: break down of glucose and release of carbon into air as CO2
What classifies a carbon source?
Net carbon release. respiration > photosynthesis
How was natural gas and oil formed?
deep burial of partially decomposed organic matter under sediments. High temps caused chemical changes + produced gas/oil
How was coal formed?
Accumulation of wood + other plant materials in swamps, buried under other sediments
How was peat formed?
incomplete decomposition of plant matter due to acidic/anaeorbic conditions in waterlogged swamps
How does combustion impact the carbon cycle?
Involves burning (in air) of any carbon sink that releases energy. Naturally requires very high temperatures only achieved by lightning, but human activities have lead to a large increase of CO2 in the atmosphere
What are the different types of carbon compounds?
CO2: gas in atmosphere and ocean
Organic compounds: solid, food
Biomass: body parts of plants and animals (stored energy)
Waste + rots: undigested/uneaten parts.
FOssil fuels: coal, oil/gas, formed from waste + rots
Where does data from the Keeling curve come from?
Mauna Loa Observatory in Hawaii
What is the annual pattern of change in CO2 concentrations in the Keeling Curve?
Decrease between May-October. This is summer time = more light = more photosynthesis = more carbon dioxide
What is the long term pattern of annual change in CO2 concentrations?
Increasing, with rate of increase gradually increasing. Due to human activities such as deforestation/burning of fossil fuels
What are some elements cycled through ecosystems by living organisms?
Carbon, hydrogen, oxygen, nitrogen, phosphorus, calciu, potassium, sodium, iron
