bio 208 lab final
what are the 3 sampling methods
random, systematic, combination of the 2
what gives a better esimate: many small/med samples or few large samples
many small/med samples
what requires more sampling a homogenous area or a heterogenous area
a hetergenous area requires more sampling
what are two factors that affect amount of samples
type of area and distribution of population within the area
what requires more sampling random or uniform populations or clumped populations
clumped populations require more sampling
what does a performance curve plot
the cumulative mean value of a trait agaisnt number of samples taken
a cumulative mean is calculated by...
sum of total # objects occured divided by total number of samples at that point
the cumulative mean of 5 things counted by sample 1, 15 things by sample 2 is
(5+15) /2= 10
when is the true population mean reached, what would the curve start to look like
not the first few samples but as more samples are collected, the curve flattens out
when the true pop mean is reached what would the cumulative mean value start to be like...
the change in mean becomes very small with addition of another sample, additonal sampling is not neccesary
what are two common methods of estimating absolute population density
the quadrat method and the mark/recapture method
the quadrat method is used for what type of organisms
small, sessile (non motile) or relatively sedentary organisms
the mark/recapture method is used for what type of organisms
relatively large and/or mobile organisms
how are quadrats shaped
square usually of a known defined size
how do you conduct quadrat sampling
count all individuals within a number of known size sample areas, then extrapolate the average density of your samples to the entire area
to estimate the total pop size from quadrat samples the equation is
n/a= N/A
what are the variable of the qudrat total pop size equation, n,a,N,A
n= avg # of sampled in the quadrats (avg # in the total area)
a= size of single quadrat
N= total pop size
A= total area of all quadrats together
N with a hat shows that it is an estimate, what is crucial about this value
it has to be a whole number, RAISE decimals to the next whole number no matter if its 15.2 or 15.9
5 different qudrats in a forest, average of 8 spruce trees in a 10m squared of forest, if total forest size was 1000m squared what would be the esimated total pop size
800 spruce trees in the entire forest
what 3 things has to happen for thes quadrat estimates to be accurate
1. # of individuals in each quadrat must be known exactly
2. the size of the quadrats must be known
3. the quadrats must be representative of the study area as a whole
how does the systematic method of the scientific method go
observation- question- hypothesis -prediction-data collection- stat test
if hyopthesis is supported: make a new prediction or another observation
if hypothesis is not supported: make a new hypothesis
what are the 3 layers of forested areas
1: the tree layer
2: layer of woody shrubs o fna intermediate height
2: a layer of forbs (smaller non-woody plant-grasses/small herbs)
what does a soil corer do? what motion to use it
extract the core sample from soil, so soil layers can can be observed. corkscrew motion
what is good to use to meausre soemthing very small
vernier calipers
what to use to determine aspect of the slope
compass/clinometer
how to measure tree growth in consideration of diameter
DBH tape
how would you calculate the height of a tree, assuming it forma right angle
1: measure distance from partner to the base of the tree using a field tape
2: meausre the angle from ground to top of tree using clinometer
3: measure height of the base of the tree to the person eye level (hPE)
tan a= opposite/adjacent= y/d, rearranging
- y= d*tana and add hPE (all in cm)
hPE is 145cm, angle is 52, d is 850, what is the height of the tree
1232.95cm
how does an observational experiment test a hypothesis
by meausring different variable and looking for patterns in the data
how can a hypothesis be mor effectively evaluated
through a manipulative experiement by intentionally manipulating the factor that you think is driving the observations you made while controling the other competing factors
range of tolerance
entire range of conditions in which a plant can survive
what are the 3 ranges of plant performance (range of tolerance). describe the condtions
optimal performance (g and r), growth only but no reproduction (sub optimal-dec energy can only perform one), survival but no g and r (edges of range, undert stress)
can a plant live outside of its range of tolerance
no
what can plants do to live in widely varying conditons?
make morphological or phenotypic adjustments
a plant adjusting their specific leaf area to acess more or less light for photosynthesis is an example of
phenotypic plasticity
what is the 4 steps of the mark/recapture method
1. capture (sample), a number of individuals
2. mark them
3. release marked individuals back into regular pop and allow them to disperse
4. recapture a random sample of individuals, note number of marked and unmarked
what are 4 assumptions in the mark and recapture method
1. marks must not be lost/overlooked
2. change in the ratio of unmarked and marked in the pop happens bc of death,birth,immigration,emigration
3. marked and unmarked are similar in all aspects
4. probability of recapture is equal for marked and unmarked
what is the equation to estimate the total pop size from mark/recapture
M/N=m/n
from the mark/recapture equation what do the variables mean, M,N,m,n?
M= total # marked in the pop
N=total pop size
m= # marked in the sample
n= total # in the sample
if you want to know if two means are significantly different from each what stat test would you use
t-test
from the t test equation what do each of the variables mean, x, s2, N
x= means
N= the sample size
s2= variability
when would you use a chi-sq goodness of fit test or a t est
chi-sq goodness of fit test: count data (discrete)
t test: continous data (comparing means)
how would you format a tstat statement
(t= x.00, df= y, p= x.0000z)
what part of studying disease is prevalent to disease ecology
the relationship between host and disease prevalence
draw a disease triangle (the 3 requirements for a disease/infection) to occur
susceptible host
disease
conductive environment pathogen
what can disease ecology tell you (3)
- how diseases arise
- how they move between hosts (within & between populations)
-predict how the disease will spread locally and globally
how does disease population bio differ from standard pop bio
bc the pathogen pop size will be affected by factors WITHIN hosts and factors that affect how they move BETWEEN hosts
within a host, the size of the disease pop depends on (3)
- the availibilty of resources needed for growth
-competition of those resources with other diseases
- the hosts own immune response
what are the two parts determining how quickly a disease spreads
-rate of transmission (determined by life history of the pathogen)
- ecology and pop bio of the host
diseases transmitted human to human the rate of infection/distribution is decribed by their (4)
-life history
-pathogenicity
- transmittion rate
-host density
what is an example of vectored disease
hantavirus an RNA virus vectored by species of mice and rate, the virus can be fatal to humans but rodent individual remain asymoptomatic to the virus.
how in hantavirus a good represenation of the spread of the disease being directly linked to the ecology of these rodents (4)
- more likely to live in rural areas (farmers/forest people more likely to contract disease)
-postive correlation of disease to larger mouse pop size
-rodent pop size linked to food availability
-rodents widley herbivorous-- food availability linked to environmental condition that promote plant growth (precipitation)
a relationship is defined by two possible scenarios
- both variables are responding to a common cause (not directly causative to each other)
- one variable causes direct changes to the other (direct cause-and-effect)
when can we have a hypothesis of a cause-effect relationship
after we have established a significant correlation between two variables but still correlation shouldn't be confused causation
when should you use the term correlation vs relationship
- correlation: conducted correlation stat analysis
-relationship: results when using a linear regression
when do we do regression analysis
when a cause and effect is already suspected
what is the key feature of liner regression
the line of best fit that minimizes the distance of data points, this line is represented by an equation that describes relationship of x on y
general equation of straight line
y= a +bx
what are the varaibles of the line of best fit, y, x, a, b
y= dependent varaible
x= independent variable
a= y intercept
b = slope
what can the linear regression show in stat analysis (2)
strength of linear relationship and reliability of the equation
a measure of the strength of the relationship is ....
the coefficient of determination (r 2)
the coeffcient of determination indicates wether data points fit closely to the line or wary on each side. the value of r2 at 0 (small) means? and at +1?
0= weak relationship
+1= strong linear relationship
a measure of reliabilty of the line of best fit equation is expressed by ....
p value (probability of obtaining this linear relationship if the null hypothesis were true)
how do you format a regression analysis statement
( r2= 0.xxx, df= 5, p=0.xx)
what test should be used if you have more than two means to compare
one- way analysis of variance (ANOVA)
ANOVA calculates an F-stat, what is that?
ratio of variation between a group of means relative to the variation within the groups
when can the null hypothesis be rejected in anova
if atleast one of the means is significantly different
what can ANOVA not tell you
which groups are different from which
what type of test can you tell what groups are significantly different from each other, what does it preform
a post-hoc test like the tukey honest significant difference post hoc test
- preforms pairwise comparisons of the means
how is an ANOVA analysis statement formatted
( F between group df, within group df (subscript)= 10.xx, p= 0.00024)
after a tukey HSD test means that are not sig different are represented by... and the ones that are... make sure figure caption..
the same letter for no difference unique letter for difference
- make sure caption says that letters represent significance grouping
when is carbon dioxide assimilated by plants
through photosynthesis and is converyed into organic compounds like simple sugars or more complex carbs
what releases CO2 back into the atmosphere
respiration, when plants are eaten, die, decompose carbs are broken down
what 4 major reservoirs play important roles in the carbon cycle
- rock (sedimentary (primarily), fossil fuels ( oil and coal)
- the atmosphere (CO2, methane, water vapor)
- the ocean (dissolved carbon)
- all life ( both alive and dead, and broken down matter in soil)
what are the two respirations that carbon from organic matter is recycled back into carbon dioxide and continue the carbon cycle
soil respiration and plant respiration
soil respiration can be defined as ... it happens when...
use of oxygen and/or release of CO2 by living organisms in the soil .
happens when microrganisms in the soil decompose detritus (esp lead litter)
what is the sequential process of the decomposition of plant litter (3)
1) LEACHING (of water soluble minerals/simple sugars (like glucose) from the material
2) FRAGMENTATION (of the litter into smaller pieces mechanically or biologically)
3) MINERALIZATION ( the conversion of larger organic compounds to simpler inorganic forms)
what are abitoic factors that affect temp and how
oxygen: neccesary for respiration (direct effect)
temp: inc temp inc rate of metabolism of microorganisms
water availability
composition : dif types of carbon compounds break down at different rates
whats easier to break down lignin, glucose, cellulose, put on a spectrum easy to hard
glucose, cellulose, lignin
what does cellulose digestion require
organisms to produce specific cellulose degrading enzymes to reduce it to simpler compound that microbes can metabolize
where does cellulose breakdown happen
extracellulary when enzymes are secreted to depolymerize the cellulose
what does lignin do, only what can break it down (using what), time to breakdown?
-lignin is a complex plant polymer which porvides structural support in woody plants
-only broken down by fungi through extracellular decomposition
- long period of time
how does glucose breakdown
they are small and soluble in water, quickly lost by leaching or are immediately consumed by microbes
what ratio can also affect soil respiration rate
C:N
why is nitrogen important
neccesary source of nutrient for decomposers
leaves with a low C:N ratio tend to be
high in Nitorgen so higher in nutrients and softer, so faster to decompose where as high C:N means high in C so tough and slower to decompose
greenhouse effect is...
CO2 in the atmosphere acts as an insulating blanket trapping solar heat in the earths atmosphere
early paleozoic era green house effect
CO2 in atmosphere was much higher than it is today , the greenhouse effect caused the polar region s of the earth to even have a tropical climate but as plants evovled there was a dramatic dec of atmospheric CO2
when after the paleozoic did CO2 conc begun to increase again and why. what happened to annual temp since this point
since the industrial revolution in the mid 1800s, from burning coal,oil,gas and wood to keep up with the demand for energy as our pop grows
- annual temp has inc as well with the last 3 decades being the warmest in 400 years, rate of warming also inc
how does the artic permafrost compound the problem of climate change
- climate change is not happening uniforming, the rate of warming affecting the artic at double the global average this is causing the artic permafrost to thaw at an inc rate which accelarates carbon transfer to the atmosphere by releasing trapped methane gas and making previously frozen organic material avaiblbe to decomposers
examples of abiotic stressors for soil respiration (5)
drought, flooding,salinity, alkalization and changes in nutrient avaibility
what is the relationship betwen temp and ph, what about the soil does it depend on
with inc temp comes a risk of soils being more saline as evaporation cause salts left behind. the ph of soil is predicted to change with inc temp
- depends on depth of soil, type of region, warming combined with precipation
what are further downstream effects of these soil issues
increased fertilizer run off as farmed combat food insecurity and decreases yield
rate of soil respiration units
(ppm CO2/g/min)
how can you compare means for multiple groups for multiple independent variables
multifactor ANOVA
what can a multifactor anova examine
the interaction between the two manipulated variables and their combined effects on the responding variables
how should format the stat statement for a multifactor anova
(F df, within df = , p=)
there are 3 p values for a 2x2 ANOVA they are...
1 for each independent variable (main effects)
1 for the interaction effect
when does a statistical interaction occur
the effect of 1 independent variable on the dependent variable changes depending on the level of another independent variable
what does the 2x2 ANOVA test not tell you
the directionality of any of the effects, you need to graph the means to see this
a significant interaction with non significant main effects means
cant reliabily interpret main effects because the interaction is affecting them
population
group of individuals from the same species that co-occur in space and time
what is population ecology a stepping stone between
individual ecology (how a single organism interacts with its environment) and community ecology ( how multiple different species of organisms interact between themselves and their environment)
where is pop ecology important
in resource based economies like forestry or fishiers, dyanimcs of pop important to know for the success and protection of the resources
Nt+1= Nt + B + 1 - D - E is the equation. what does each variable mean
BIDE equation
Nt (# indivs at time t)
B (born)
D (died)
I (immigrated)
E (emigrated)
what type of species would have curve 1 in a survivor ship curve
humans. few numbers of offspring, invest in high care of offspring, high survival rate of offspring
what type of species would have curve 2 in a survivorship curve
birds. have an equal death rate throughout all stages of their life
what type of species would have curve 3 in a survivorship curve
many marine fish. produce high # of offspring, invest little in securing their survivability , high mortality rate in young offspring
how is a survivor ship curve plotted
x axis: age
y axis: number of survivors (logarithmic)
Cohort life table, refers to a cohort as
group of individuals that are born around the same time and move through life within the same period
to create a cohort life table you need to... this is difficult so instead you can...
follow each member of the cohort through their entire lifetime and track the age at which each individual dies
- create an age distribution or a static life table
in a static life table
the age at a time of death is recorded for a group of individuals that were born at different times
static life table variables (x), (nx), (lx)
x= age
nx= # of indivs surviving to day x
lx= proportion of indivs surving until day x
when does exponential pop growth happen
when pop size is small or when there is little to no competition for resources
the dN/dt= rN calculates , variables mean?
rate of pop growth (dN/dt) under exponential conditons
r= per capita rate of inc
N= pop size
Nt= N0ert equation , variables mean?
Nt= # of indivs at a given time (t)
N0= intial number of indivs
r= per capita rate of inc
t= # of time intervals
e= constant
when there is no limitation on growth what stays constant and what gets successively larger in each time interval
r= per capita rate of inc remains constant
Nt= gets successively larger
exponential growth vs logistic growth
exponential growth: time vs pop size, continues to inc curve
logisitic growth: has a K= carrying capacity value which is an upper limit to pop growth
what does the K value indicate
factors like resource availability, space and inter or intra specific comp can put a limit of the max size of a pop
factors that put an upper limit on growth are called
density depndent becuase their effect depends on the density of the population
what is K, where does it happen on the graph
the theoretical max size of the pop at particular location
- happens where the logistic curve flattens out
dN/dt= rmaxN(1-N/K) is the equation for , how is it different from exponential pop growth (2)
the logistic population growth
- theres a max on the per capita rate of increase under ideal conditons and the term (1-N/K) which accounts for limiting resources
the logistic population growth equation is rearranged to solve for pop size Nt= K/ 1+ (K/N0-1) e-rmaxt, its different from exponential how
factors in the effect of K and rmax on pop growth
what needs to be included in the figure caption
groups, data/units, sample size, error bars
what needs to be in the introduction
background info, objective, hypothesis and prediction
results should have
patterns,trends, supporting stats, signifcance and directionality
where should a caption for a table be
caption above for tables
primary literature has what that secondary literature doesn't
methods and results section
the lab manual, textbooks and science magazines are examples of
tertiary literature
xi/ n is
mean calculation
xi: sum of indiv observations
n= # of osbervations
the sqaure root of the variance gives us
the standard deviation
the shape of a normal distribution is
bell curved
can we ever know the true population mean
no
what does the size of the confidence interval depend on
size and variabiltiy of sample
a less variable sample implies
the sample mean is close to the actual pop mean, smaller confidence interval
values outside of the confidence interval are
less plausible locations for the true population mean
the cut of for significance is known as a (alpha) (0.05) when and when not is it significant
higher than 0.05 is not signifcant
continous data is
decimals, measurements, means/averages
discrete data is
counted values/whole numbers
expeirments can either be
observational or manipulative
what are the 3 R's of experimental design
randomization, replication, reducing noise
randomization
randomly allocate treatments to experimental units, helps enutralize any other effects that are happening not due to your treatment. most stat tests assume this
replication
repititon of treatments, quantifies the natural variation between experiemntal units, helps with accuracy.
reducing noise
control other conditions as much as possible
independent/manipulated variable
variable that will cause a change in the variable we are meausing , goes on x axis
dependent/responding variable
what we suspect will have changes, y axis
challenges of a static life table
getting data for all data points, some records don't indicate age/birth year, getting data into a form that is useable
what is harder static or cohort life table
cohort, almost impossible to follow a whole cohort of people from birth to death
why would a typical survivorship curve 1 deviate?
chosen a pop that was biased in some way (disease, WW2 etc)
in an exponentail graph as r inc what happens to pop size
pop size inc
in an exponential grap, inc in intial pop growth makes the graph
lag less before pop growth explodes
a long period of almost no growth- flat curve, r and No are
both low for a flat curve
a long period of slow but aceelerating growth , steeper near the end means r and N0 are
intermediate r and low N0 for a slow but accerlating curve
extreme rapid growth means r and N0 are
both high r and N0 for extreme rapid growth
does the exponenetial model reflect realtiy
no, because it predicts that there is no upper limit on growth
what factors could act to limit pop growth (exponential) (6)
habitat degradtion, food limitation, hunting/poaching, disease, pollution, natural disaster
a r increase in logistic graphs what happens to the time it takes to the reach carrying capacity
as r inc the time it takes to reach K decreasezs
what factors affect the carrying capacity and what two do not affect it
predators, resource availability, disease, competion NOT N0 or growth rate
what is not accounted for in logistic models that could affect pop growth (3)
age distribution, sex distribution, reproductive potential
wherever the yield flattens out shows what about the densityb
that density of plants is the msot optimal anymore won't add any benefit