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