component 2 energy for life

if data has low accuracy it means

the data is not close to the true value

in bacteria population growth curve, what occurs in death phase

• reproduction rate is lower than death

• due to there being not enough nutrients or toxins building up

key steps to random sampling

• use 2 tape measures to divide the sampling area into a numbered grid

• select random X and Y coordinates using a random number generator

• place the quadrant and coordinate and collect data

• repeat 10x and calculate a mean

4 sections of a population growth curve for bacteria

lag phase, log phase, stationary phase and death phase

what happens in log phase of animal population growth curve

birth rate is significantly higher than death rate as population is growing exponentially

how can the reliability of data you’ve collected be improved

collect more data and calculate a mean

what happens in lag phase of bacteria population growth curve

• reproduction rate is slightly higher than death rate

• due to DNA replication, organelle replication, protein synthesis, obtaining nutrients, respiration

key steps to systematic sampling

• run a transect across the area of study

• every 1m place a quadrant

• measure the species frequency of each species

• measure an abiotic factor at each interval

random sampling may be used when

sampling an area that is uniform eg a field

stationary phase of animal population growth curve

• population size fluctuates around the carrying capacity

• when above carrying capacity, there is more competition and less reproduction so population size decreases

• when beneath carrying capacity, there is less competition and more reproduction so population size then increases

how can reliability be measured

calculating the standard deviation of the data

stationary phase of bacteria population growth curve

reproduction rate is equal to death rate due to limit of nutrients or space

if data has high reliability then

data doesn’t vary much around the mean

low standard deviation means

data doesn’t vary greatly around the mean so high reliability

explain why population growth curves look difference for bacteria and animals

bacteria are in closed systems whereas animals are in open systems

lag phase of animal population growth curve

birth rate is slightly higher than the death rate due to individuals waiting for sexual maturity, individuals finding a mate and gestation

why would systematic sampling be used

when sampling an area that isn’t uniform

population size increases due to

increase in reproduction (bacteria)/ births (animals), increase in immigration (individuals joining the population)

density independent factor

abiotic factor that could increase the death rate and they have the same effect on any population size

carrying capacity

maximum number of animals in a population that can be maintained in a habitat, can change if there are environmental changes

community

organisms of all the different species that live in a particular area

ecosystem

system of interacting biotic and abiotic factors within an environment