3.4.7 Investigating diversity

Question 1

Comparing the base sequences of a gene provides more information than comparing the amino acid sequence for which the gene codes. Explain why

Answer 1

Different base triplets code for the same amino acids

Question 2

What does standard deviation show?

Answer 2

Shows the spread of data about the mean

Question 3

What can be said about the data collected if the standard deviation is large?

Answer 3

less reliable (data varies a lot)

Question 4

What can be said about the data collected if the standard deviation is small?

Answer 4

more reliable (data varies very little)

Question 5

If the standard deviations of the 2 sets of data collected overlaps what can be concluded?

Answer 5

no difference in the 2 sets of data, its not significant - due to chance

Question 6

Variation is….

Answer 6

the differences between individuals

Question 7

variation is caused by

Answer 7

genetics and the environment (or both)

Question 8

Variation between organisms of the same species is due to …

Answer 8

differences in their alleles (and the environment)

Question 9

variation between organisms of different species is due to…

Answer 9

different genes (and the environment)

Question 10

When studying variation - can you study the whole population?

Answer 10

NO - take a sample

Question 11

When you sample to study variation, how should you go about collecting the sample?

Answer 11

randomly

Question 12

Taking samples at random ensures…

Answer 12

results are not biased

results are representative

Question 13

When studying variation between 2 populations, what would you calculate?

Answer 13

mean

standard deviation

Question 14

When plotting variation data, what type of graph do you get?

Answer 14

normal distribution curve

Question 15

The highest point on a normal distribution curve (that is symmetrical) is ..

Answer 15

the mean value

Question 16

If the standard deviation of the 2 sets of data DO NOT overlap what can you conclude from the data?

Answer 16

there is a difference between the data collected. It is likely significant and not due to chance?

Question 17

What could you do to data collected if you wanted to determine if data collected was significant or not?

Answer 17

carry out a statistical test (the right one!)

Question 18

When carrying out a statistical test what do you have to formulate first?

Answer 18

a null hypothesis

Question 19

When comparing means of samples what statistical test would you do?

Answer 19

t test

Question 20

When comparing observed and expected data what test would you perform?

Answer 20

chi squared test

Question 21

When looking for a correlation between two variables what test would you do?

Answer 21

spearman’s rank

Question 22

When drawing conclusions from statistical tests what words should you include in it?

Answer 22

significant or not
chance
probability

Question 23

What level of probability to Biologists refer too?

Answer 23

5% / 0.05

Question 24

If your calculate value in your tests is GREATER than the critical value in the table (at the 5% level), what can you conclude?

Answer 24

REJECT null
results are significant
less than a 5% probability that the differences are due to chance

Question 25

If your calculate value in your tests is LESS than the critical value in the table (at the 5% level), what can you conclude?

Answer 25

Accept null
difference in the mean values are significant
greater than a 5% probability the difference is due to chance

Question 26

if the P value is less than 0.02 what can you conclude

Answer 26

reject null
difference between mean values are significant
less than 2% probability that the difference
is due to chance

Question 27

removal of hedgerows reduced diversity of birds - why?

Answer 27

1. Removes species/types of plant/insect;
2. Fewer food sources;
3. Fewer habitats/niches;

Question 28

How should a person collect and process data to investigate if there is a difference is size of seeds produced by a particular tree in 2 different areas?

Answer 28

1. randomly sample seeds from both areas
2. large sample size to ensure representative (reliable mean)
3. measure mass of seed as indicator of size
4. calculate mean and standard deviation
5. T test carried out
6. determine if there is a significant difference between the means of the two samples

Question 29

Define species richness

Answer 29

number of different species in a community/habitat

Question 30

give one limitation of using a line transect to collect data?

Answer 30

may avoid certain areas

Question 31

what info does the bar representing standard deviation give about the plants in a sample?

Answer 31

spread of values around the mean height of plants

Question 32

how would you know if the difference between mean heights of the plants grown from seeds was due to genetic differences?

Answer 32

plants measured were grown under uniform conditions

Question 33

scientists collected bees using a method that was ethical and allowed them to identify accurately the species to which each belonged.

suggest a consideration the scientists had taken into account to make sure their method

allowed them to identify accurately the species to which each belonged?

Answer 33

• close examination

- key

Question 34

SUGGEST and EXPLAIN 2 ways in which scientists could have improved their method used for data collection in an investigation?

Answer 34

• collect from more sites so TO increase accuracy

- count number of individuals of each species SO to calculate index of diversity

Question 35

scientists tested their null hypothesis using the chi-squared statistical test. after 1 cycle their calculated chi-squared value was 350. the critical value at p=0.05 is 3.841

what does this result suggest about the difference between the observed and expected results and what can the scientist conclude?

Answer 35

• less than 0.05 PROBABILITY that DIFFERENCE between observed and expected due to CHANCE
• calculated value greater than critical value so REJECT null hypothesis

Question 36

in an investigation, scientists investigated the possibility of breeding red clover plants that only produced 2n gamete.

use your knowledge of how directional selection may play a part in this?

Answer 36

• scientists selected for breeding plants that produced 2n gametes
• plants passed on alleles for production of 2n gametes to next gen
• frequency of alleles for production of 2n gametes increased

Question 37

how would you collect a random sample of each population?

Answer 37

• use quadrat and transect
• use random number generator to generate coordinates
• place randomly at these intervals
• use 10 or more quadrats