Biodiveristy pt 1+ 2 combined

Question 1

Defintion of mean

Answer 1

Average value calculated by taking the sum of all values and dividing by the total number of values.

Question 2

Definition of mode

Answer 2

Most frequent value in the set of data.

Question 3

Definition of median

Answer 3

Middle value when set of data is placed in numerical order.

Question 4

Definition of standard deviations

Answer 4

A measure that is used to quantify the amount of variation in the set of values.

Question 5

Explain the purpose of standard deviations

Answer 5

It takes into account all the values- so is less influenced by anomalies. It is a statistical that allows comparisons to be made between the means of two sets of data to see if the difference between the data sets is significant or not.

Question 6

Explain what a standard deviation close to 0 indicates and what a standard deviation that is high indicates.

Answer 6

The data points tend to be very close to the mean of the set if the standard deviation is close to 0. A high standard deviation indicates that the data points are spread out over a wider range of values.

Question 7

Explain the results of a standard deivation when overlapping occurs.

Answer 7

If the standard deviations of the 2 sets of data do overlap, then the difference between the 2 data sets is not significant, so no conclusion can be formed from the data.

Question 8

Explain the results of a standard deviation when they don’t overlap.

Answer 8

If the standard deviations of the 2 sets of data do not overlap, then the difference between the 2 data sets is significant so a conclusion can be made from the data.

Question 9

Definition of Chi-squared test.

Answer 9

Used to compare expected and observed values.

Question 10

Definition of Student-t test.

Answer 10

Used to compare means from 2 sets of data.

Question 11

Definition of Correlation co-efficient test.

Answer 11

Used to compare data from 2 different variables that have been sampled.

Question 12

What do statistical tests do?

Answer 12

They test the probability of the difference in values is due to chance or if the difference in the values is statistically different.

Question 13

What does it mean if the p-value given in the question is less than 0.05 or 5%?

Answer 13

The probability that the difference in the values is due to chance is less than 5% or 0.05. The difference in the values is sigificant.

Question 14

What does it mean is the p-valuegiven in the question is more than 0.05 or 5%?

Answer 14

The probability that the difference in values is due to chance is more than 5% or 0.05. The difference in the values is not significant so is due to chance.

Question 15

What does it mean is the p-value in a student t-test is more than 0.05 or 5%?

Answer 15

The probability that the difference in the observed and expected data is due to chance is less than 5% or 0.05. The difference in the values is significant.

Question 16

Definition of population

Answer 16

Total number of organisms of one species that occupy the same ecosystem at the same time.

Question 17

Definition of community.

Answer 17

All the organisms of all species living and interacting together in the same exosystem at the same time.

Question 18

Definition of abiotic factors.

Answer 18

Nin-living factors in a particular area.

Question 19

Definition of biotic factors.

Answer 19

Living factors in a particular area.

Question 20

Definition of an ecosystem.

Answer 20

All the abiotic and biotic factors in a habitat.

Question 21

Definition of niche.

Answer 21

Role/position of a species within a habitat.

Question 22

Definition of biodiversity.

Answer 22

The variety of organisms living in an environment.

Question 23

Definition of carrying capacity.

Answer 23

The size of population of a species that an ecosystem can support.

Question 24

Definition of a habitat.

Answer 24

The place where an organism lives.

Question 25

Definition of species diversity.

Answer 25

Number of different species and the number of individuals of each species within any one community.

Question 26

Definition of genetic diversity.

Answer 26

Variety of genes possessed by individuals that make up a population of a species.

Question 27

Definition of ecosystem diversity.

Answer 27

Range of different habitats from a small local habitat to the whole of the Earth.

Question 28

Definition of species richness.

Answer 28

Number of different species in a particular area at a given time, in a particular community.

Question 29

What is the issue with using species richness as a measure of biodiversity?

Answer 29

Itdoens’t take into account the number of individuals in the population/community or their abundance.

Question 30

What is the index of biodiversity equ?

Answer 30

Index of diversity = N(N-1) / Total of n(n-1)
N means the total number of organisms of all species.
n means the total number of organisms of each species.
E means the sum of…

Question 31

Why is the index of diversity a better measure of biodiversity?

Answer 31

It gives a numerical value so it takes into account the total number of organisms for each different species.

Question 32

Describe how to calulate the index of diversity

Answer 32

1. Calculate N- add up the total number of individuals in the table given.
2. Calculate (N-1)- take away 1 from the value.
3. Calculate N(N-1)- multiply those numbers together.
4. Calculate (n-1)- look at the numbers for each species in the rows.
5. Calculate n(n-1).
6. Finally divide the value 1 by value 2- this answer must be greater than 1.

Question 33

What does a stable ecosystem look like?

Answer 33

1. A large variety of different plant and/or animal species.
2. No monoculture all the population sizes are roughly the same.
3. A large variety of habitats and niches for nesting and feeding.
4. Large variety of different food sources available.

Question 34

Definition of random sampling.

Answer 34

Reduces human bias, results are representative of whole area.

Question 35

Definition of sampling bias.

Answer 35

The selector may be influencing the area/organisms within the habitat that are being sampled. Random sampling aims to reduce this.

Question 36

Definition of chance.

Answer 36

How likely an event can occur. Humans can influence chance by introducing bias to results.

Question 37

Describe how to carry out random sampling.

Answer 37

1. Set up a grid axis using 2 tape measures at right angles to one another.
2. Each meter is a marker.
3. Using a random number generator, select two random numbers as co-ordinates.
4. At these co-ordinates, place a frame quadrat.
5. Organisms are identified using a key, animals can be counted/collected to give information on abundance, absence or presence of species.
6. Repeat procedure at different times of the day, season, month, e.c.t…
7. Collect data on % cover using a fram quadrat.

Question 38

Why is random sampling beneficial?

Answer 38

1. Use a large sample size- this will reduce the influence of chance and anomalies and allow the mean to be calculated, which makes the results more precise.
2. Analyse the data collected to determine the influence of chance on the data collected. Carry out statistical tests to make your results more valid.
3. Use random sampling instead of systematic sampling. Random sampling reduces human bias.

Question 39

Describe random sampling.

Answer 39

A method for identifying species richness of non-mobile organisms. If the area is large and uniform with no clear pattern/species, random sampling would be used because it is important that results are unbiased and representative of the whole area.

Question 40

Describe systematic sampling.

Answer 40

This is used where there is a gradual change in the communities of plants and animals takes place. Sampling is doen along a line that runs through these changing areas to identofy change in species present.

Question 41

Describe how to carry out systematic sampling.

Answer 41

1. To monitor change along a habitat/area (environmental gradient).
2. Place a line or belt transect across a length of area.
3. Quadrat is placed at refular intervals.
4. Organisms are identified using a key, animals can be counted/collected to give information on abundance, absence or presence of species.
5. Repeat procedure at different time of the day, seasons, month, e.c.t…(ensures a true representation).

Question 42

Describe how to work out the percentage cover when randomly sampling plants.

Answer 42

1. Split quadrat into equal number of squares.
2. Work out % represented by each square by dividing 100% by the number of squares in the quadrat.
3. Depending on how much of the organism covers the square, depends on what percent it counts as.
4. Then add all the squares together to work out the total % cover of the organisms within the whole quadrat.

Question 43

Describe the AFCOR scale.

Answer 43

Used when sampling plant species. It is a much more subjective method and analysis is limited due to it being a qualitative method. This is an estimation for the total percentage of quadrat covered by each species of plant.

Question 44

Describe how to carry out the Mark-release-recapture method.

Answer 44

1. Catch a sample of animals and count them.
2. Mark each one- the mark shouldn’t impair the animal’s ability to survive in the natural world and mark should remain.
3. Release back into the habitat.
4. Leave for 1-2 days so they can mix back in with their population.
5. Catch a second sample.
6. Count the total and the number which are marked.

Question 45

What is the equation for calculating the total numbers of animals in a population?

Answer 45

Total numbers of animals in a population = (number in sample 1 x number in sample 2) / (number of marked animals in sample 2).

Question 46

What are the 6 assumptions that must be correctly follwoed for the Mark-release-recapture calculation to be accurate?

Answer 46

1. Marked individuals between sample 1 and sample 2 are proportional.
2. Marked individuals from sample 1 distribute evenly.
3. No immigration or emigration.
4. Few births/deaths i populations.
5. Marking is not toxic or conspicuous.
6. Marking not lost/damaged.