Measuring Diversity

Question 1

Define species richness

Answer 1

a measure of number of species compared to the number of individuals in a given sample

Question 2

How do you calculate species richness?

Answer 2

S = s/sqaure root N

S = species richness 
s= total no. of different species in a sample 
N= total no. of individual organisms in a sample

Question 3

Define species evenness

Answer 3

a measure of number of individuals of a particular species in relation to total number of individuals of all specie in the area
measure of distribution

Question 4

What are ways to calculate species evenness?

Answer 4

individual population count, % cover, Lincoln Index and Shannon Diversity Index

Question 5

Define percentage cover

Answer 5

A measurement of proportion of an area covered by an organism
generally used for estimating distribution of plants in particular area but can be used for other organisms such as corals, barnacles (organisms fixed in a permanent position)

Question 6

How do you calculate species frequency?

Answer 6

number of quadrats in which species is found/total number of quadrats

Question 7

How do you calculate Simpson’s Diversity?

Answer 7

D = sum of n(n-1)/ N(N-1)

Question 8

What does the result of Simpson’s Diversity tell you about the ecosystem?

Answer 8

Probability that two randomly selected individuals come from the same species

Question 9

How do you calculate SDI?

Answer 9

1 - D

Question 10

What does the result of SDI tell you about the ecosystem?

Answer 10

probability that two randomly selected individuals are from different species

Question 11

What are density dependent factors?

Answer 11

biotic factors that affect population growth as the number of individuals increases (e.g species interactions - competition, predation, disease, crowding, parasitism)

Question 12

What are density independent (limiting) factors?

Answer 12

abiotic factors that are independent of density of population but can affect the size of a population (e.g habitat destruction, climate change, drought)

Question 13

How do you calculate the rate of growth?

Answer 13

r = (b+i) - (d+e)

Question 14

What are the two modes of population growth?

Answer 14

exponential (J-curve) and logistic (s-curve)

Question 15

What are factors of exponential growth?

Answer 15

isolated population, no immigration/emigration, plentiful resources, no predators or disease, no limiting factors

Question 16

What are factors of logistic growth?

Answer 16

recognizes that numbers will decrease due to limiting resources

Question 17

How do you calculate the net reproductive rate?

Answer 17

((b+i) - (d+e))/pop size

Question 18

What is the carrying capacity?

Answer 18

the size of the population that can be supported indefinitely on the available resources and services of that ecosystem

Question 19

How do you calculate Lincoln Index?

Answer 19

N = no. in 1st sample (all marked) x no. 2nd sample/ no. of marked individuals recaptured in 2nd sample

N = Mxn/m