eco lab Flashcards
(44 cards)
Identify initial concerns regarding collecting a representative sample of a population.
how big of a sample should you have, is the sample random, is it representing the area well enough, and can it be replicated.
Explain why descriptive statistics are necessary in ecological studies.
Reporting every single measurement in a data table would be truthful, but not very useful, because the human mind cannot easily take in long lists of numbers. A more fruitful approach is to take all the measurements of our fish and systematically construct a composite numerical description, or statistic, which conveys information about the population in a more concise form . (this is what the lab manual said)
Standard Deviation
to measure the amount of variation around the mean, this helps determine if the data is normally distributed
Investigate fundamental issues of experimental design (e.g., how many samples?)
1) what sampling method can be used to collect the needed data, 2) how do we select sampling locations to limit potential bias and obtain best estimates of target parameters, and 3) how can we minimize the number of samples we take while still providing an accurate estimate of parameters?
Precision
How clumped together/close they are
Accuracy
how close to the target are they
what are the three different types of sampling
Plot sampling
pointer-quarter
belt transect
plot sampling
Counting the number of organisms of interest in a defined area (quadrant).
what are the problems with plot sampling
size of sampling plot, how plots will be placed, and number of plots to be sampled.
Plants in a long leaf pine forest
wire grass
longleaf pine tree
bracken fern
oak tree
what are the three types of dispersion
random
even( uniform)
clumped
why does clump happen
Indicate that a species responding to the fine gradient in the environment or that it has a form of reproduction that keeps juveniles near adults also this clumped pattern is a result of distribution of resources (think about tree and its seed and how it germinates close to its parent, also think of a wolf and its pack)
why does Uniform
Territory, or interaction between organisms
Why are control fires important
gets rid of organic matter on the forest floor. They also do controlled fires because it prevents uncontrolled fires from happening. (Low intensity fires occur naturally in these systems, but due to human development we now conduct controlled fires to reduce extreme wildfires. Also, without periodic fires, hardwood trees such as oaks would grow tall enough to form a canopy over the pine trees and inhibit them from receiving a sufficient amount of sunlight.)
Normal distribution
is a typical bell curve with the peak of the curve corresponding to the mean
What are some important things to know about a t-test
p-value at .05
if the value is at .00-1 then it will be significant and you accept your hypothesis
D.f
observed groups - 1
Important thing to know for a chi square test
if alpha is .05 then the significant level is 3.84
if value is great than 3.84 then?
you reject your null hypotheses and accept your hypothesis
if its less than 3.84 then?
you accept your null
What are the steps for mark and recapture
- Portion of population captures
- The organisms are marked
- Organism is released
- Another portion of pop is captured at a later time and any marked ones are counted
what are the assumptions for mark and recapture
- After capture, mark and release- can’t have a higher mortality rate, free to interact within the pop, appropriate time between capture, Can’t be “ trap-happy” or “trap-shy”
- Tags do not become lost or unrecognized
- There is no emigration or death of tagged individuals
what the equation for mark and recapture
N1=(M1N2)/M12
what does N1 stand for
number of individuals in that population
