Genes – Variation and Human ReproductionWatch this video as an introduction to the topic: https://www.youtube.com/watch?v=sNU30T2EmQ8

Year 7 Science Home LearningActivity pack

BiologyPart 2

Instructions: You normally have four hours of Science lessons every week.This activity pack has been divided up into 8 lessons. Try and complete one lesson on each day when you would have had a Science lesson on your timetable. Don’t worry if you can’t complete all the tasks. Choose things that are at a level you feel confident at. The relevant Year 7 textbook pages have been included at the start of every lesson. Read through them to familiarise yourself with the content and remember to look up any unfamiliar words and write out definitions for any that you come across.There are also some extension activities at the end of the pack to have a go at.After each lesson you should mark your work using the answer booklet.

Lesson 1 – Looking at VariationLesson 2 – Causes of variationLesson 3 – Importance of variationLesson 4 – Female reproductive system and fertilityLesson 5 – Male reproductive system and fertilisationLesson 6 – How a foetus developsLesson 7 – Factors affecting a developing foetusLesson 8 – Communicating ideas about smoking in pregnancyAnswers

Lesson 7 – Factors affecting a developing foetus

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Lesson 7 – Factors affecting a developing foetus

1. Read through the textbook pages2. Answer questions 1-4 from the textbook pages (extension: Q5)3. Complete the activities on the following worksheets

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Factors affecting the foetusHere is a list of all factors that can potentially affect a developing foetus. Arrange the list into factors which are harmful to the foetus and factors which help the foetus.

a) alcohol b) nicotine c) folic acid d) regular but moderate exercise by the mother e) carbon monoxide f) healthy, balanced diet g) drugs like heroin

h) fish oils

Reviewing evidence from case studiesLook at the following case studies investigating the effect of alcohol drunk during pregnancy on the subsequent development of children.

Study A: A research study looked at the findings from investigating over 10 000 children aged between 6 months and 14 years old, found that mothers who were binge drinkers during pregnancy produced children with problems in making some mental connections.

Study B: The results from three studies involving 11 900 children aged 9 months to 5 years from mothers who were moderate drinkers during pregnancy, found that these children were more prone to behavioural problems.

Study C: Children from1628 women who drank alcohol regularly during pregnancy were tested at the age of 5 years old. They were tested for general intelligence, attention and ability to perform certain tasks. There were found to be significant effects from their mothers’ alcohol consumption as the majority of the children did not perform normally.

Harmful to the foetus Helpful to the foetus

From reading these case studies, what are the possible effects for the children of alcohol consumption by the mother while pregnant?

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Evaluating case studiesLook at the case studies again.

a) Place the studies in order of most reliable to least reliable. Explain your choice.

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b) Discuss any issues with each of the studies.

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Lesson 8 – Communicating ideas about smoking in pregnancy

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Lesson 8 – Communicating ideas about smoking in pregnancy

1. Read through the textbook pages2. Answer questions 1-4 from the textbook pages (extension: Q5)3. Complete the activities on the following worksheets

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End of topic questions

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Extension activities: choose some of these to have a go at to extend your understanding of this topic.

Task Description

1

Create a family tree for your family looking at one inherited

characteristic for example noting down the eye colours of each member

next to their name.

2 Explain how sexual reproduction promotes variation.

3 Research the reasons why variation is beneficial within a species

4Define the following key words (in terms of biology): variation,

inherited, characteristics, classification, adaptations, habitat, species

5Make a poster showing the different types of variation (inherited and

environmental characteristics) with examples for each.

6

Choose two closely related species that live in two very different

environments. Compare and contrast the variations between these

species.

7

Research the classification system we use to classify living organisms

today. Create a short project about its history and how the species are

grouped. Evaluate this system of classification.

8Make a game based on this topic that could be used as a revision

activity for year 7 pupils preparing for their assessment.

Year 7 GenesActivity pack

Answers

Lesson 1 - Answers to student book questions1. A group of organisms with similar features that can produce fertile young.2. Humans: e.g. eye colour (discontinuous); ear shape (continuous); hair colour (discontinuous); height (continuous); foot size (continuous); dogs: e.g. tail length (continuous); ear position (discontinuous); height (continuous); leg length (continuous); colour (discontinuous).3. See answers in brackets in answers to question 2.4. Continuous: the feature changes gradually over a range of values; discontinuous: individuals have one form of a feature or another.5. Suitable graph for both tongue rolling and arm span. Tongue rolling: discontinuous; arm span: continuous.6. Steps include: randomly pick a sample of 20+ leaves, from same tree; measure their lengths; count the spikes; plot a scatter graph.7. The larger the sample size, the more accurate the investigation.

Answers to Snails worksheetThree of: colour of shell; size of shell; bands/no bands; thickness of bands; number of bands.

Colour = count; size = measure; bands/no bands = count; thickness of bands = measure; number of bands = count.

a) Height; weight; eye colour; hair colour; skin colour; any suitable feature. b) Height and weight are continuous; eye colour, hair colour and skin colour are discontinuous. c) i) Line graph ii) 120–140 g iii) 146–157 g iv) Variety 1 = 130 g; variety 2 = 149.5 g v) Continuous

Lesson 1 worksheetsvariations – These are differences between living things.reproduce – Members of the same species can mate and ...species – If living things have enough similar features, they belong to the same ...

2 a false b true c true d false

3 a Correct differences, for example:Dog A has long fur/small pointed ears/short tail.But dog B has short fur/floppy ears/long thin tail.

b Correct similarities, for example:Dog A and dog B both have four legs/two ears/ two eyes/tail/nose.

c Correct differences, for example:Dog C has small ears/long tail.But dog D has very long ears/short tail.

Lesson 2 - Answers to student book questions1. Inherited: eye colour; shape and size of ears; etc.; environmental colour of nails (varnish); scars; tattoos; etc.2. Any of: coat colour; coat pattern; length of mane; length of tail.3. Each child gets a set of genetic information from their father and a set from the mother; the combinations are different.4. a) Straight hair; face shape; skin colour; eyebrow shape. b) Eye colour; shape of nose; mouth shape; thickness of eyebrows; hair colour.5. Height; weight; hair colour. 6. In the long term, genetic variation is more important than environmental, because only genetic variation is passed on to offspring. In the short term, the environmental variation may be more important if an organism is to survive (e.g. the coat colour of the stoat).

Answers to Lesson 2 worksheeta) i) Variation passed on from parents. ii) Variation caused by the environment that the organism lives in.

Inherited: female; blue eyes; shoe size; can roll tongue; Environmental: can speak French; good at tennis; has pierced ears; has a tan; both: height; blonde hair.

They are different ages; they have inherited different combinations of information from their parents; they also have environmental differences (e.g. hair style).

Answers to final worksheet1 a natural hair colour, eye colour, size of ear lobes, boy or girl, skin colour, left or right handedb language spoken, fitness, thin, pierced ears, hair stylec Any suitable inherited features.d Any suitable environmental factors.

Lesson 2 – Causes of variation answers

inheritanceenvironment

environmentinheritance

Circle the features that have been passed on in the sex cells. These are inherited features.

Lesson 3Answers to student book questions1. Because it couldn’t escape from predators/the population of other species on the island changed.2. Colour of squirrels varies, height of giraffes varies. The red squirrel is better camouflaged in the woods and so has an advantage. The taller giraffes can reach leaves higher in the trees or may be able to spot predators more easily. 3. In unpolluted conditions, white moths are better camouflaged; in polluted conditions, dark moths are better camouflaged. The species doesn’t die out because one variety is always camouflaged as conditions change.4. Bacteria that have resistance to certain antibiotics have an advantage when that medicine is used and are more likely to survive and reproduce. 5. Because more bacteria have evolved that are resistant to methicillin.

Answers to Worksheet - Importance of Variation1. Vary; survival; camouflaged; more; extinct; dodo.2. Accurate graph drawn showing two lines plotted, suitable scale, labels.3 a) Number of light moths decreases over time; number of dark moths increases over time, plus any further description of gradual changes.

b) Pollution in industrial areas caused changes in the bark of trees. This led to light moths being less well camouflaged and dark moths being better camouflaged. Light moths became more likely to be preyed upon by birds; dark moths were less likely to be preyed upon by birds.

c) The populations would remain more stable. This is because there is less of a decrease in light moths and less of an increase in dark moths because less pollution means tree trunk colour was less likely to change.

d) Light moths do not ‘change into’ dark moths or vice versa. It is more accurate to explain as ‘a change in the surroundings (colour of tree bark) meant that dark moths more likely to survive/light moths less likely to survive (to reproduce to pass on their genes)’.

Lesson 4 Answers

Answers to Student Book questions1. In the ovary.2. To help push the baby out.3. Hormones cause the egg to mature and ovulation to occur. 4. External factors – don’t drink alcohol, take drugs or smoke during pregnancy.

Problems with ovulation – use hormone treatment to correct the imbalance.

Endometriosis – surgery is needed to remove cysts.Blockages in the oviduct – surgery is needed to remove blockages.

uterus

oviduct

ovary

cervix

vagina

Strengths and weaknesses of the female reproductive system

Ovary – where egg cells are made and released from

Uterus – where the developing baby grows

Oviduct – the tube that carries the egg from the ovary to the uterus

Cervix – narrow opening to the uterus, can extend to allow the baby to pass through

Vagina – muscular tube that extends up to the uterus, can extend to allow the baby to pass

through during birth

• The cervix is made of strong muscle to help push the baby out.• The oviduct is lined with ciliated epithelial cells that help push the egg to the uterus.• The uterus has a good blood supply so it is ready for fertilisation to take place.Problems that cause female infertility: blockages can occur in the oviduct; fertilisation can occur in the oviduct, which is dangerous for the foetus; cysts can occur around the ovary, preventing the egg from being released.

lining

period

fertilised

ovary

ovulation egg

28

egg

uterus

fertilised

days

FALSE

TRUE

TRUE

TRUE

Lesson 5 Answers

Answers to Student Book questions1. Cell = sperm; organs = testes, prostate gland.2. Correctly labelled diagram; path of sperm from testes; through sperm duct; past prostate; through urethra into penis.3. Plants = anther; human = testes.4. Fertilisation takes place in the uterus; where the developing foetus will grow.5. The egg cell contains nutrients essential for the early development of the foetus if the egg is fertilised.6. Ovulation is the release of an egg from the ovary; fertilisation is a sperm cell fusing with the egg cell in the uterus.

Lesson 5 Answers

Lesson 5 Answers

sperm

egg

half

different

Lesson 6 Answers

Answers to Student Book questions1. Growth occurs when cells divide to make new cells.2. They have the ability to become any cell in the body.3. Between 8 and 12 weeks. The increase for that 4 week period is 60mm whereas for other 4 week periods, the maximum increase is less.4. The placenta transfers materials such as oxygen and glucose from the mother’s blood to the baby’s blood; and removes waste from the baby’s blood to the mother’s blood.5. This stops the baby from bumping about in the uterus when the mother moves around.6. The pregnant uterus contains a placenta, umbilical cord, amniotic sac and amniotic fluid. It has expanded to become up to 20 times its normal size.

Umbilical cord

Placenta

Wall of the uterus

Amniotic fluid

Amniotic sac

Mucus plug

Cervix

Vagina

b) Complete the following passage using the words from this list: protect, uterus, reproducing, amniotic fluid, placenta, oxygen,

nutrients, umbilical cord

Growth means that the cells are reproducing. The foetus attaches to

the wall of the uterus; this connection develops into the placenta. The

foetus connects to the placenta through the umbilical cord. This

provides glucose, oxygen and nutrients from the mother. As it gets

bigger, a sac filled with amniotic fluid grows around the developing

foetus. Its job is to protect the foetus from bumps.

2

4

8

a) Placenta – where blood from the mother exchanges oxygen, nutrients and carbon dioxide with blood from the foetus.

b) Umbilical cord – carries the foetal blood to the placenta and blood with nutrients, oxygen and glucose from the mother to the foetus.

c) Amniotic fluid – a fluid surrounding the baby that protects it from damage and harm, cushioning the movements of the mother.

d) Uterus – the part where the developing baby grows; the muscles are the strongest in the body to help push the baby out of the womb during birth.

Lesson 7 Answers

Answers to Student Book questions1. The mother takes these chemicals into her body.2. It would die; it would not be able to obtain oxygen, glucose or nutrients.3. If the mother drinks alcohol, smokes, takes unsuitable drugs such as marijuana or cocaine, or has a poor diet lacking in nutrients (in particular folic acid), the development of the foetus can be adversely affected.4. The advice is given because there is evidence that following these guidelines will increase the chances of having a healthy baby. Advice should include: do not smoke, drink or use drugs during pregnancy; take folic acid.5. a) Not very reliable; only 127 babies were investigated; the amount of alcohol was not recorded.

b) Not very reliable; the sample size is small; twice as many smokers were sampled as non-smokers.

Answers to Worksheet 1. Harm the foetus: alcohol; nicotine; carbon monoxide; drugs like heroin.

Help the foetus: folic acid; fish oils; regular but moderate exercise; a healthy, balanced diet.2. Problems making mental connections; behavioural problems; lower intelligence and attention span; reduced ability to perform certain tasks.3. a) B, then A, then C; B has the largest sample size; C has the smallest.

b) Case study A: How many mothers were binge drinkers? What were the backgrounds of the children?

Case study B: How much alcohol did the mothers consume during pregnancy? How many children came from poor backgrounds?

Case study C: Were children from the same background tested, where the same number of mothers did not drink?

What was the actual performance of the children in the tests? Could other factors explain why they did not do as well?

Lesson 8 Answers

Answers to Student Book questions1. That smoking can be beneficial to women, including pregnant women. Smoking is not harmful to an unborn baby.2. The adverts are from tobacco companines, which did not want to reduce sales, and it was in their interest to persuade people that smoking is not harmful/is beneficial.3. Smoking in pregnancy can increase the risk of babies born with low birth weight.4. Suggestions similar to Table 1.10.8, linked with a study of a large sample of babies and weights when born to compare and show that they are more likely to be born weighing less if the mother is a smoker.5. a), b), c). An opinion expressed with evidence to support opinion stated and reasoning given.

d) Opposite opinion stated and some arguments against this opinion.

Answers to Worksheet1 a) 1 c; 2 d; 3 a; 4 b 2 i Opinion; ii Claim; iii Bias because only shared a positive about the

cigarettes; iv Evidence2 a) i Smoking in pregnancy increases the risk of offspring becoming drug users, or similar.

ii In monkeys, nicotine does not have an effect on birth weight of babies, or similar.

b) i Suggestions such as: larger sample, similar numbers in sample and control.

ii Suggestions such as: consider evidence in humans, identify sample size (and possibly increase sample size). 3 a) Sensible suggestions of a claim such as ‘Enerise makes you feel less tired’, ‘Enerise makes you feel more energetic’.

b) Suggestions of evidence that would support the claim such as: large group trials; control group that didn’t drink Enerise as comparison; measures of e.g. amount of sleep over periods of time; difference in activity levels; way of comparing energy through a measured activity.

c) Advert showing a claim and use of persuasive images and/or language and mention of evidence.

End of topic questions:1 a

2 Genetics and the environment

3

• A species with no variation is vulnerable if there is an adverse change (e.g. new disease, change in the environment)

• If organisms do not adapt to the change, the species will die out• Variation means some organisms have a favourable feature• This gives them a survival advantage

4 a5 b

6

Day 1: the lining of the uterus breaks down and first blood loss occursDay 5: the lining begins to build up again; blood loss ceasesDay 14: ovulation occurs; the egg moves from the ovary into the oviductDay 21: the egg has now reached the uterus; if it is not fertilised, it will die and uterus lining will break down again

7 d

8 Any disadvantageous feature for a predator (e.g. albinism; blunt teeth; poor sense of hearing and smell)

9 Decrease variation (1) and if these roses are then grown in different soil, they won’t grow well (1)

10 c

11 d

12 Fertility – increases the number of eggs produced (1)Contraception – prevents ovulation (1)

13

a) 118b) sizes 6 to 16c) Continuous d) 11

14 Large sample size

15

Sketch should be a bar graph • Smoker and non-smoker mothers on x-axis; weight of foetus on

y-axis• Higher bar for non-smoker mothers• Carbon monoxide passes across the placenta of smoker mothers

and reduces the amount of oxygen reaching the foetus• With less oxygen, the cells of the foetus do not grow as well