Exercise answers

A1 Western Ghats

Exercise A1.1

space for time substitution

Substitution of time with space in experiments in which the effect of the passage of time on a system cannot be observed. Assumes that variables that change across time will also change across space.

Exercise A1.2

The answers to the questions in this exercise depend on which articles you choose to read. Discuss your answers with a classmate or member of your study circle to see if you agree on the answers you have given. Consult a lecturer if you are unsure about how to answer the questions.

Exercise A1.3

As a guide to this answer, an example of a spreadsheet dataset of ‘what’s in your bag’ is given. Columns S1, S2, S3, and so on are different samples (different bags).

A2 Waterscapes of India

Exercise A2.1

1. 30.1%
2. 0.16%
3. The answer to this is open ended. If there are multiple categories, stacked bars are better.

Exercise A2.2

A greater proportion of shredders and grazers will be found at the headwaters of the river than at the mouth of the river. The proportion of collectors gradually increases along the length of the river. Collectors and predators should be found in greater proportion at the mouth of the river.

Exercise A2.3

1. 1. Most likely a whirligig beetle.
   2. Most likely a freshwater mussel.
2. Streamlined or dorsoventrally flattened body; suction pads, hooks, sticky secretions all help insects to combat the pressures of living in fast moving water; air tubes in those who stay on the surface of the water; gills to respire under water. Mouthparts will be adapted to the mode of feeding according to functional feeding groups.

Exercise A2.4

1. Predator > collector > grazer > shredder
2. Around 45%.
3. Somewhat. Predators are more abundant than shredders in the lower region, as expected. But the other groups do not hold strictly true strictly.

Exercise A2.5

1. 68.5%

3. Possible factors to consider include: the localities at which the fish were caught; what kind of net was used to catch the fish; whether this year was particularly good for other fish too; and whether the commercial fisheries expanded that year.

Exercise A2.6

1. Answers will depend on the textbook being used. Here are the answers for the Campbell textbook.
   1. Biology: A Global Approach 10th Edition
   2. 2015
   3. Campbell, Reece, Urry, Cain, Wasserman, Minorsky and Jackson
   4. Harlow
   5. Pearson Education
2. It is multi-authored; it has been reviewed by an extensive list of reviewers; it is published by a reputable publishing company.
3. Campbell, NA, Reece, JB, Urry, LA, Cain, ML, Wasserman, SA, Minorsky, PV & Jackson, RB (2015) Biology: A Global Approach 10th ed. Harlow: Pearson Education.

A3 Urbanscapes

Exercise A3.1

2. If we consider an apartment complex, the energy inflows are in the form of electricity and diesel (for generators). Other inflows are material goods, such as food, water, and building materials. There is also an inflow of workers that sustain the apartment. Outflows are waste in the form of gases (carbon dioxide), liquids (sewage in the form of grey and black water) and solids (biodegradable and non-biodegradable garbage).
3. A city cannot reproduce itself; it has no hereditary material; it cannot move; it does not respond to the environment; it cannot manage its own energy transformations.

Exercise A3.3

Exercise A3.4

1. Sites R and L had similar levels, M had a higher level and H the highest but most variable level of particulate matter.
2. Site R had the greatest number, sites L and M had similar numbers although L was quite variable, and site H had the smallest number of honeybees.
3. Bees from sites R and L survived for a longer period than bees from sites M and N.
4. Particulate matter adversely affects the number of honeybees. Moderate and high levels of pollution reduce the survival rate of bees.

Exercise A3.5

The exercise has no right or wrong answers. The answers are subjective and will reflect what you feel.

Exercise A3.6

The exercise is open ended and the answers depend on what you observe.

B1 Malaria

Exercise B1.1

1. 1096.6
2. The total number of cases was mostly constant in the early 2000s. They began to decrease steadily after 2010, and dropped greatly after 2017.
3. 0.001. Possible reasons include warmer weather and increased rainfall and humidity.
4. Initially, there were similar numbers of cases reported for both P. falciparum and P. vivax. Some years in the 2000s, P. vivax was a little bit higher. From 2014 to 2017, reported cases of P. falciparum were much higher than P. vivax as these cases had reduced. From 2018 onwards, numbers of cases due to both parasites dropped drastically.

Exercise B1.2

1. The malaria parasite cannot be seen with the naked eye. Microscopes are essential to observe Plasmodium parasites in mosquito saliva, the RBCs, or liver cells.
2. With the help of microscopes, it was discovered that the malaria parasite resides in human liver cells and that infected human red blood cells possess pigmented bodies.
3. Ross wanted to test whether the malaria parasite was transferred between humans and mosquitoes through mosquito bites.
4. He dissected and studied a mosquito that had bitten a malaria patient to show that the malaria parasite could be transmitted from a human to a mosquito. He then showed that avian malaria was transmitted from mosquitoes to birds through pigmented bodies stored in the mosquitoes’ salivary glands.
5. Ross was able to accept his original hypothesis, that malaria is transmitted from host to vector and vice versa, through a mosquito bite.
6. When Ross was sent to Calcutta, his main obstacle was in finding human malaria patients to work with, because the disease was not highly transmitted in the region. He resolved this problem by studying malaria in birds.

Exercise B1.3

1. Tu Youyou was trained in Western medicine as well as traditional Chinese medicine. The combined knowledge of both helped her find a treatment for malaria in ancient Chinese medicinal texts, and then develop it as a drug.
2. Tu believed that she would find a treatment for malaria in old Chinese medical literature that described fevers similar to those induced by malaria.
3. She read and tested more than 600 recipes for anti-malarial substances extracted from plants and animals.
4. Tu found a treatment which involved soaking Quinghao (artemisia) in water and drinking the water. The treatment only worked when the water was not boiled because heating damaged the active ingredient in the artemisia plant.
5. While testing old Chinese recipes, she found that Quinghao worked in rodents but not in humans. Tu went back to the text, paying careful attention to the language, and found that there was no mention of boiling the herb in water. The other obstacle Tu and her team faced was the urgency with which they had to develop the artemisinin drug. To save time, Tu and two others volunteered to test the drug’s safety before it was ready for clinical trials.

Exercise B1.4

Exercise B1.5

50 ug

Exercise B1.6

Discuss your survey design and questions with a friend to see if you can improve on it. Consult a lecturer if you need advice on your survey.

B2 Rotavirus

Exercise B2.1

Exercise B2.2

endocytosis

A process by which a substance outside a cell is taken into the cell.

Exercise B2.3

1. The dark red triangle at the top of the pyramid gives the risk of death. The risk is shown in figures on the right of the pyramid.
2. 1 in 31 children are hospitalised due to rotavirus.
3. 2,237,486 - 4,617,948 children visit a hospital as outpatients due to rotavirus.
4. 12.5% of children infected with rotavirus require an outpatient visit to a hospital.
5. Yes, the risk of hospitalisation due to rotavirus is higher than the risk of death, because 1 of every 13 children is far more than 1 of every 177–196 children.

Exercise B2.4

1. The Indian subcontinent and countries in west and central Africa seem to have the highest number of deaths caused by rotavirus. Europe, the rest of Asia, Australia and the Americas have the lowest number of deaths caused by rotavirus.
2. The total number of deaths is an absolute value that does not take into account the size of the population in an area. Mortality rate is a value that is standardised to the total population of the country. Countries with high populations such as India may register more deaths, but deaths as a ratio of the total population is relatively low.
3. The highest rates of death are in west and central Africa. The lowest rates of death occur in Europe, the rest of Asia, Australia and the Americas.

Exercise B2.5

\[\begin{align*} R&=R_0 \times(1-P) \\ \therefore 1&= R_0 \times(1-0.86) \\ \therefore 1&= R_0 \times(0.14) \\ \therefore R_0&=\frac{1}{0.14} \\ \therefore R_0&= 7.14 \end{align*}\]

Remember that the effective reproductive number needs to be ≤ 1 in order to achieve herd immunity. R is considered to equal 1 because that is the highest rate of transmission at which herd immunity can still be achieved.

This calculation is an estimate, not an accurate prediction. There are several arguments against taking R₀ at face value, and while we will not discuss them here, you are encouraged to do your own research and read more about them.

C1 Rice

Exercise C1.1

This exercise does not have an answer as this is an activity you must conduct yourself.

Exercise C1.2

This exercise does not have an answer as this is an activity you must conduct yourself.

Exercise C1.3

1. White rice has a lower protein and fat content and a higher carbohydrate content than brown rice.
2. Pearl millet and foxtail millet have more protein, more fat and less carbohydrate content than brown and white rice.
3. The glycemic index (GI) is much lower in the millets than in white rice. White rice would result in a more rapid increase in blood glucose levels.

C2 Cotton

Exercise C2.1

1. Similarities: Lobed leaves, flower shape, fruit shape. Differences: G.arboreum leaf is divided into five narrow lobes, while G. hirsutum leaf has three broader lobes.
2. Hibiscus and bhendi are two plants that are from the same family as cotton and show similar leaf and flower shape.
3. The study of cotton has a long history and it is good for us to be aware of it. The images are from a book published in 1907 and has detailed information on Indian cotton species.

Exercise C2.2

1. There are many ways to draw the flow chart. The image below is one way.

2. Some points you should mention are:
   • Hybrid crop plants benefit from heterosis (hybrid vigour) because they have more copies of favourable dominant genes.
   • Because they are tetraploid, gene redundancy allows duplicated genes to be used for other functions.
3. Hybrid-4 has the following advantages:
   • high degree of heterosis as seen by its high productivity (yield)
   • improved bearing capacity
   • bigger boll size
   • profuse and continuous flushes (flowering) that overlap with each other
   • yields were 216% higher than a parent line under optimised conditions.

Exercise C2.3

1. Berg wanted to use viruses as a vehicle to insert foreign DNA into mammalian cells. Refer to the iBiology video.
2. The recombinant plasmid would contain both kanamycin and tetracycline resistance genes. This recombinant plasmid was used to transform an E. coli strain that was grown on media containing both antibiotics. Only bacteria that integrated the recombined plasmid could grow on such a medium.
3. A possible flowchart is provided.

Exercise C2.4

1. 54.89%
2. Gujarat produces 19 lakh more cotton bales than Maharashtra does.
3. Maharashtra’s productivity is 51% of Gujarat’s productivity. This means that Gujarat’s productivity is twice that of Maharashtra. Possible reasons are that Maharashtra allocates more land to growing other more profitable crops, for various business, political and economic reasons; or that cotton crops have lower yields in that region; or that Maharashtra has less access to technology and high-yield seeds.
4. 1. Punjab’s area under cotton is 2.34% of the All India area under cotton.
   2. Punjab’s yield is 3.1% of the All India total.
   3. Punjab is one of the first states that was part of the green revolution. The state has access to irrigation, high-yield seeds and agriculture is well developed.

D1 Feline fables

Exercise D1.1

1. Ethiopian/African biogeographic region.
2. Radiation. All species of the caracal lineage are found only in Africa, therefore they evolved by radiation in Africa.
3. Palearctic and Nearctic biogeographic regions.
4. Africa, because the main population of lions occurs in Africa.
5. The ocelot ancestor migrated along land bridges to the Neotropical region. It radiated within the Neotropical region into the present seven species. All the species occur only in the Neotropical region.

Exercise D1.2

This is an open-ended question. The outcome of the exercise will depend on your observations. The activity is meant to give you an opportunity to observe an organism and engage with the concept of territoriality introduced in the chapter.

Exercise D1.3

1. Area of toe no. 3.
2. Length of minor axis of toe no. 3.
3. Distance between toe no. 2 and toe no. 3.
4. Length of minor axis of toe no. 2.
5. Distance between main pad toe to toe base-line.
6. Angle between toe no. 2 and toe no. 3.
7. Heel to lead toe length.
8. Distance between notch 1 and notch 2.
9. Total width of pugmark.
10. Distance between front foot and back foot pugmarks on the same side of the body = stride length.
11. Distance between left and right pugmarks = straddle width.

Exercise D1.4

There are no right answers to this exercise. Your answers will depend on how you conduct the experiment.

D2 Figs

Exercise D2.1

1. Adult male wasps emerge from their gall.
2. Male wasps mate with female wasps as they emerge from their galls.
3. Male wasps die.
4. Pollen-laden mated female wasps leave the fig syconium in which they developed.
5. Female wasps are attracted to a fig tree of the correct species.
6. A female wasp enters an immature syconium through its ostiole.
7. The ostiole closes immediately after a female wasp enters.
8. The female wasp pollinates female flowers inside the syconium.
9. The female wasp lays eggs in the ovaries of some flowers inside the syconium.
10. Female wasps die.
11. The eggs hatch into wasp larvae.
12. Pollinated flowers that do not have larvae produce seeds.
13. Flowers that have larvae form a hard gall around the larvae.
14. The larvae feed and grow inside the gall, eventually pupating.
15. The gall breaks open, releasing male wasps first.

The twelfth and thirteenth sentences can be reversed or placed side by side.

Exercise D2.2

Exercise D2.3

Exercise D2.4

1. Germination rate is simply how fast seeds germinate over a fixed period of time. Make sure you treat both monocot and dicot seeds the same way. Some factors that may influence germination are moisture, temperature and sunlight.
2. 1. The values are compared to a control.
   2. A negative value means that time to germination and percentage of seeds that germinate are lower than the control value.
   3. Both control and seeds passed through the gut have the same unit, so they cancel each other.
   4. The zero value indicates that the effect of the experimental treatment (seeds passed through gut) is no different from the control.
   5. Frugivore.
   6. No obvious relationship. But those seeds that had highest germination also had lower germination times.
   7. One can infer that frugivore monkeys facilitate seed germination. A greater proportion of seeds germinated if they passed through a monkey’s gut than seeds from intact fruits. They also germinated faster. Germination percentage was highest in strictly frugivorous primates compared to any other feeding group. Germination time increased in the insectivore–frugivore group, implying that passing through the guts of largely insectivorous primates may not be advantageous to the seeds.

Exercise D2.5

Steps for making a podcast include:

1. Select a topic or a theme: Think about what excites you. Research the topic that interests you.
2. Structure your podcast: Do you want it to be some kind of interview? Or do you want to narrate the podcast? 
3. Sound: Small sound clips add richness to your podcast. Try recording sounds relevant to your story. Most mobile phones will have a built-in recording facility or you can download free apps for recording sound. 
4. Script: Write a script. If you have decided that it is an interview, then write down what questions the interviewer will ask. Do not make the script complicated or long. 
5. Record: Choose a relatively noiseless, echo-free room to record the voices. You may be nervous about recording your own voice, and it may not come out well the first time. But you can always delete and repeat. You can either use your mobile phone or a microphone if that is available.
6. Produce: Production will involve mixing and editing all the sound files you have recorded, so that it sounds seamless and natural to the listener. You can use free sound mixing software like audacity to do this.

Hosting platform: You can simply send your recorded podcast on Whatsapp as Dr Sharma did, which is possibly the most convenient and easy way to distribute your podcast. But you can also upload your podcast on a platform. There are some free platforms, but most paid versions can be bought by your school or university too.

D3 The kingdom of fungi

Exercise D3.1

Exercise D3.2

1. The data can be shown as a bar graph. If proportions of genera are to be compared, a stacked bar graph or pie chart can be used.
2. From the table, we can see that some phyla have nearly ten times as many genera as others. This clearly shows that the phyla are not equally diverse.
3. Of the 7270 genera recorded, 2080 have been observed in India (\(\frac{2080}{7270} \times 100\% \approx 29\%\)). So, for each phylum, one would expect ~29% of genera to be present in India. Ascomycota have a percentage closest to 29% (\(\frac{745}{2000} \times 100\% \approx 37\%\)). With the exception of Deuteromycota, other phyla are present in higher proportions. With Deuteromycota, only 468 out of 4100 genera have been observed in India (~11%).

Exercise D3.3

1. The brand can be found using the logo which is usually visible in the front. The model is usually written in the back of the vehicle. Other characteristics that can be considered are size and shape, the type and location of headlights or rear indicator lights and the sound made by the engine. If you know what to observe, you may even be able to distinguish between the same model of car manufactured in different years.
2. For comparison of two locations, perform a rarefaction analysis to compare the diversity of cars in the two locations.

Exercise D3.4

2. The control provides evidence that the bacterium can grow in the absence of the fungal isolate.