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S295/K

Module Examination 2015

THE BIOLOGY OF SURVIVAL

PART A

Short answer questions Answer all SIX questions in this first part of the exam. Write your answers in the answer book provided, limiting your answer for each part of a question to a few sentences or more. You are advised to spend no more than 1 hour 15 minutes on this Part A of the paper, which carries 30 of the total marks for the examination. Each question is worth 5 marks.

Question 1

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(a) Which types of animal produce milk to feed their young?

 

(b) List the four major components of milk?

 

(c) What other components of milk are there?

 

(d) Suggest one reason why the composition of milk might differ between species.

 

(e) What are the survival advantages of producing milk?

 

Question 2

Answer the following questions with reference to the phylogeny of bacteria, birds, marsupials and rats.

(a) Copy Figure 1 and label each endpoint. Then indicate the root, one example of a node and one example of an internode.

(b) Identify the clades comprising (a) birds, marsupials and rats and (b) marsupials and rats.

Question 3

Identify what kinds of natural selection are operating in Figure 2 a - c below. Describe what would happen to the mean of the trait subjected to each kind of selection

Question 4

(a) Autotrophs and heterotrophs fulfil their energy requirements in different ways. Briefly describe the processes involved in each.

(b) Why do autotrophs need access to mineral nutrients?

(c) Provide one example of a mineral nutrient and describe its main function.

(d) Name two different types of waste product that are produced by living organisms.

Question 5

Describe how acacias benefit from the presence of ants. Briefly describe an experiment you could use to determine the extent of this benefit.

Question 6

(a) Give a definition of the term ‘hormone’.

(b) Name one hormone from an animal and one growth regulator from a plant.

(c) Briefly describe a system in which two hormones are acting antagonistically.

Note: In this question, the terms ‘hormone’ and ‘growth regulator’ have been used interchangeably.

PART B

Data handling and interpretation question

Answer ALL parts of the question in Part B of the examination. You are advised to spend about 1 hour on this question. This part carries 25 of the marks for this examination.

Show all your working for calculations.

Question 7

The snakeshead fritillary (Fritillaria meleagris) is a rare flower found in wet grasslands on floodplains. A researcher developed a hypothesis that, given the species was found on floodplains, it would occur at greater density where the soil was more prone to flood.

To test this hypothesis, the researcher set out 12 positions across a floodplain meadow and counted the numbers of fritillary flowers in a 1 m × 1 m square at each location. She then recorded the number of weeks that the position was flooded over the following year. The data gathered are presented as Table 1.

Table 1 The duration of waterlogging and the abundance of fritillary flowers across a floodplain meadow.

The researcher decided to test whether there was any relationship between the duration of flooding and the density of flowers per 1 m2 by using a Spearman rank correlation test.

(a) Why was a correlation test chosen in preference to a Mann-Whitney U-test?

(b) What is the null hypothesis being tested by a correlation test of these data?

(c) On the sheet of graph paper provided, plot a graph to illustrate the relationship between the two variables. Remember to decide which is the independent variable and which the dependent variable in this case and plot your graph accordingly.

To use the Spearman rank correlation test, it is first necessary to rank the data. The weeks of waterlogging have been ranked in Table 2.

(d) On the separate answer sheet complete Table 2 with the ranks of the flower densities.

(e) Calculate the difference in ranks for each position.

(f) Calculate the square of the difference for each position and then add them together to give a total (?D²)

(g) The formula for calculating the Spearman rank correlation coefficient (rs) is:

 Using the value of ?D² calculated in (f), calculate the value of rs for this relationship.

(h) Compare your calculated value of rs with the appropriate critical value from Table 3 and comment on whether the relationship can be considered statistically significant.

(i) If an association is detected, does it suggest a positive or a negative correlation?

(j) What conclusions can you draw with respect to the researcher’s original hypothesis?

PART C

Question 8

Journal extract questions

Answer ALL parts of the question in Part C of the examination. You are advised to spend 45 minutes on this part of the paper. Your answers should be written concisely, but in sentences. You should include diagrams and calculations in your answer where appropriate. This part carries 20 marks.

This question relates to your reading of an extract from a published scientific journal, which was made available to you on the module website prior to this examination. The extract describes a study of urination times in mammals of varying sizes.

Now read the examination questions relating to the journal extract and refer to it throughout when answering all of the question parts. A copy of the extract is included with this examination paper as a separate insert.

(a) From the relevant cited reference, which animals were used to study a range of sizes in studies of ailments relating to urination?

(b) What main excretory function does urination serve?

(c) Describe two distinct types of urination as identified in this extract. State what size of animal is involved in each type.

(d) While this extract makes it clear that urination times do not change in proportion to body size in large mammals, is there any variability in the measurements? How do you know this?

(e) The extract states that the internal surface of the urethra is corrugated. What does this mean and how has this been established? What effect does this have on the internal cross-sectional area?

(f) Describe what Figure 2D shows, referring to other images in Figure 2 as well. Do the actual results from the rat fit the predicted results?

(g) What do symbols ρ and g represent?

 (h) Which measured parameters in Table 1 and Figure 3 from the extract show isometry?

 (i) Which Figures show differences in urination between males and females? From the text, what physical differences are there between male and female animals in urination?

 (j) Do you agree with the authors’ statement that ‘From a biological perspective, the invariance of urination time suggests its low functional significance’? Give your reasons why.

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Last updated: Sep 02, 2021 10:07 AM

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