BIOLOGY Form 5 Chapter 6

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4551/2 Chapter 6: Variation

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6.1Variation in organism Aspect Definition Identify

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State the meaning of variation The differences between organism of the same species are known as variation

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Table shows three example of variation between individual A and Individual B Use a tick in the correct boxes to show the type of each variation

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- discontinuous variation - discontinuous variation - continuous variation

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Diagram show two varieties of rabbit,Lepus alleni and Lepus articus

State whether the different chracteristic between Lepus alleni and Lepus articus are example of variation No

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State the reason for your answer Because they are not the same species.

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Diagram 5.1 (i) and (ii) show the leaves plucked fomr a plantand ear ;pbes of human respectively

State the type of variation shown in diagram (i) and (ii) (i) Continuous variation (ii) Discontinuous variation

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Give other example of variation that youhave named in question 5 (a) above2 (i) Height /body weight (ii) Blood group /type of hair /ability to roll tongue/thumbprint/any relavant example

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Figure 5.1 and figure 5.2 show the height and types of blood group of from 5 students

Name the type of variation shown in figure 5.1 and figure5.2 figure 5.1 : Continuous variation figure5.2: discontinuous variation

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Diagram 5.3 (a) shows the variation of human ABO blood group. Diagram 5.3 (b) shows the variation of height in human .

State the type of variations shown in Diagram 5.3 (a) and Diagram 5.3(b) Diagram 5.3(a): Discontinuous variation Diagram 5.3(b): Continuous variation Construct graph

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The students of Form 5 Anggun carried out an experiment to investigate the Variation amongst themselves. The height and the type of ear lobe of each student Were observed and recorded. The data was compiled in Table 5.1 and Table 5.2 Height

Type of ear lube

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Based on Table 5.1 and 5.2, draw a frequency distribution histogram to show : i) 'I'he number of students against their height

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ii)

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1 iii) 4 State the example

Based on the diagram ,State the example of continuous variation and discontinuous variation continuous variation : body weight,height discontinuous variation:types of earlobe ,type of finger print

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4551/2 Chapter 6: Variation

Aspect Continuous variation

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Figure shows various type of fingerprints

Based on Figure 5, name the type of fingerprints of students X and Y below.

X - Loop ;

Y- Composite

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What is the type of variation shown in Figure 5? Continuous variation

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State two traits, other than fingerprint, which show the same type of variation as in (b)(i). The ability to roll tongue Types of hair

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Diagram shows the type of wing in the fruit flies

Referring to diagram 5.1 construct a histogram for the number of fruit flies against the type of wings

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Continuous variation

Two parents who are both thin and are able to roll their tongues have a son who is fat and is able to roll their tongue. Explain how this happens. P1- Thin parents can have a fat son even though the son inherits genes for thinness from his parents P2- Body size is affected by environmental factors P3- Continuous variation P4- Due to diet, the size of body changes P5- The ability to roll the tongue is determined by genetic factors P6- Alleles for the ability to roll the tongue can be inherited P7- Genes for this characteristic is dominant P8- Hence, the son can roll his tongue

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Discontinuous variation

Explain the type of variation shown in Figure F- Discontinuous variation E1- Contrasting features E2- No intermediate values E3- Caused by genetic factors Continuous variation and discontinuous variation are type of variation Identify the type of variation of blood group F-Discontinuous variation E1-Blood reason shows a distinctive in the characteristic//does not show intermediate characteristics/qualitative characteristic A student collected some characteristic of the garden pea plants Pisum sativum .He listed his observation and finding in table 9.1

Based on the table 9.1 draw a bar chart to show the total number of tall and short plants

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against the height pf plant on the graph paper provided in page 23 3

Based on the bar chart construct in (a)n(i) what is the type of variation shown by the plant? Explain your answer F-Discontinuous variation P1-The differences in the character is distinctive /with no intermediate characters P2-The character is qualitative /cannot be measured form one extreme to the other P3-The graph shows a discrete distribution P4-A single gene /a pair of allele determines the differences in the character/traits P5-The phenotype is controlled by a pair of allele (F + any 2P)

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Essay enhancement Corner No 1.

Marking Criteria Diagram 9.1 shows a group of boys with different height and diagram 9.2 bshows the various types of fingerprints

Based on the biology knoledge ,explain the chracteristic in doagram 9.1 and diagram 9.2 F1-Diagram 9(a)/height is a continuous variation P1-the graph is a bell-shape curve /normal distribution P2-quantitative /its feature can be measured P3-There are intermediate characteristic P4-Have no distinct categories //have complete range of measurement aomng the boys P5-influenced by enviromental condition condition //causes by enviromental and genetic factor//cannot be inheited P6-controlled by two or more genes F2-Diagram 9(b)/fingerprint pattern is a discontinuous variation P7-The graph shows discrete distribution /separate bar colunm P8-qualilatuve /characteristic cannot be measured P9-there is not intermediate pattern P10-each pattern is distinctively different P11-not be influenced by enviromental factors /caused by genetic factors only/can be inherited P12-controlled by one gene

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Diagram 7.1 and Diagram 7.2 show the variation of height in a population of pea plants and in a population of human respectively.

Discuss the graphs shown in Diagram 7.1 and 7.2. The variation in height for humans is shown in Diagram 7.1 P1- It is continuous variation /normal distribution P2- It has many intermediate values between the highest and the shortest in the population P3- The characters are quantitative P4- The variation in height for pea plant its shown inDiagram 7.2 P5- It is a discontinuous variation / discrete distribution P6- There are only two categories of variation P7- either short or tall; there are no intermediate values in between them P8- The characters are qualitative

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Differences: No 1.

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Explain one difference between Discontinuous variation and Continuous variation variations Discontinuous variation Continuous variation 1. There is no gradual change between the two extreme characteristics//The characteristics fall into distinct categories / no intermediates

There is complete range of measurements ( for a particular characteristic) // differences between individuals are slight with intermediates/ gradual change

2. Graph consists of separate bar charts //Do not give a normal distribution

The graph has a normal distribution/ bell shaped curve

3. It is normally controlled by a single gene

A large number of genes are usually involved

4. Is described as qualitative/ characteristics can be either present or absent

Is described as quantitative/ characteristics can be measured

5. It is not influenced by environmental conditions.

It is influenced by environmental conditions.

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State two differences for both variation Aspect Continuous Discontinuous Intermediate With Intermediate Distinctive characteristic characteristic characteristic Quantitative or The characters are The characters are qualitative Quantitative qualitative Environment factors Is influenced by Is not influenced by environment factors environment factors Genes Two or more genes A single gene determines control the same the differences in the characters traits of a character Phenotype The phenotype is usually The phenotype is controlled by many pairs controlled by a pair of of alleles allele Diagram 7.1 and 7.2 shows the distribution of two type of variations in human.

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With a suitable examples, explain the type of variation for characteristic P and characteristic Q.4 F1 - Height // weight E1 - continuouse variation becouse have differences very slightly E1 – Controls by environment. F2 - Blood type E2 – discontinuouse variation / E2 - controls by genetics. Compare the variation shown in figure 9(thumb print) with the type of variation shown by

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body mass. Body mass - Continous variation - Features change gradually - Intermediate values - Caused by genetic factor and affected by environmental factors - Cannot be inherited if characteristic affected by environmental factors - Graph shows normal distribution

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Thumbprints - Discontinous variation2 - Contrasting features - No intermediate values - Caused by genetic factor

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- Can be inherited Graph distribution

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discrete

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Marking Criteria List two differences between the variation shown by the height characteristic and the type of ear lobe of the students. Height (continuous variation) Type of ear lobe (discontinuous variation) Have no distinct catogories Have distinct categories into which individuals can be into which individuals can placed be placed

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Have a range of values

No intermediate values

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Usually controlled by large number of genes (polygenes)

Usually controlled by one pair of genes

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Are significantly affected by environment factors Form a nomal distribution

Are largely unaffected by environment factors Discrete distribution

Height is a type of variation. Explain the differences between the type of variation shown by fingerprints and height Height Types of fingerprint - Shows normal distribution Shows discrete distribution - Affected by environmental Not affected by environmental factor Factors State four differences between continuous variation and discontinuous variation continuous variation discontinuous variation P1The changes of characteristic among The differences among individual individual are gradual are distinct P2Continuous variation is discontinuous variationis quantitative//caharcteristics are equal qualilative//characteristics is either present or absent P3The graph shows the normal The graph shows the discrete distribuiton curve distribuiton P4The character is determined by many The character is determine by a gene single genes P5The characteristic is influence by the The characteristic is influence by enviroment factor and genetic factor the genetic factor P6Exhibits a range of phenotype with There are no intermediate groups intermediate characters State the differences between continuous variation and discontinuous variation continuous variation discontinuous variation Has normal distribution /bell shape Has a discrete //graph drawn graph /graph drawn Quantitative //has intermediate Qualitative //no intermediate chracteristic /values characteristic/values Influenced ny genetic and enviromental Influenced by genetic factor factors Controlled by many genes/polygenes Controlled by A,AB ,B ,O gene

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Table 7.1 and 7.2 show the blood group and height variation of the student in a secondary school i) Blood group

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Height

Based on table7.1 and 7.2 ,construct two different histogram on graph paper to show the number of student against blood group and the numbers against height, Explain the similarities and difference between these two type of variation 10 Graph: Height variation – continuous Blood group Variation – discontinuous Similarity – both height variation and blood group variation create varieties in population. Differences 1. Continuous variation 2. Graph shows normal distribution

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Discontinuous variation Graph shows discrete distribution

3. influence by environmental factors

Influence by genetic

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4. Traits are controlled by two or more genes 5 The phenotype is usually controlled by many pairs of gene. 6. the characters can be measured and graded// quantitative

Traits are controlled by a single gene

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The phenotypes is controlled by a pair of alleles The characters cannot be measured and graded// qualitative

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6.2 Causes of variations Aspect

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Genetic Factor

State one factor that causes variation in the fingerprints of students X and Y Genetic factor

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State the factor that cause the variation in figure 5.3 Genetic factor

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How does the factor in (b) cause the variation 2 P1-Independent assortment chromosomes during meiosis//metaphase I P2-Crossing over during meiosis/prophase II P3-Random fusion of gametes during fertilization

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State how the factor in (a)(ii) cause variation Genetic recombination during crossing over results in the formation of different Genetic factor on offspring is influenced by gnetic factors .Diagram 5.2 shows four possible gametes with different genetic combination produced which is one of the factor

Based on the diagram ,explain the genetic factor 2 F-Independent assortment P-Produces various genetic combination of gametes Figure 5.3 show two different types of fingerprint in humans

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Genetic factor

Vestiga /short wing normal wing State one factor that causes variation between the two types of wings in fruit flies genetic factor

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Describe how the factor in (b) causes variation E1-crossing over and independent on random assortment E2-Producing a different gene in it’s content

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Explain the factors causing the types of variation shown in Diagram 7.1 and 7.2 The continuous variation shown in Diagram 7.1 is P1- the result of the combined effects of many genes. P2- Environmental factors also affect the way in which the genes express themselves. The continuous variation shown in Diagram 7.2 is P4-the result of the effect of one or only a few genes. P5- It is caused by genetic factors and also by the mutation of genes and chromosomes.

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Essay

Rajah 7.4.1 shows differences among cats. Diagram 7.4.2 shows the factors affected the differences.

Diaram 7.4.1

Diagram 7.4.2 Explain how this factors in the diagram will cause the differences among the cats in Diagrams 7.4.1. F1 – meiosis P1- produce varies gamete with different genetic contents; P2- through homologous chromosomes random assortment during metaphase 1

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F2- Fertilization P3- random fertilization between sperm and ovum P4 – produce zygote with varies genetic materials.

F3 – crossing over P5 – crossing over occurs between the homologous chromosomes during prophase 1 - result recombinants gens - produce varies gamete cells

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4551/2 Chapter 6: Variation

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Diagram 8 shows the results of breeding on mice.

Based on Diagram 8 identify the different characteristics among the mouse family members. Discuss how the difference in characteristics is inherited 1. Type of tail 2. (Coat) colour 3. Type of whiskers State the cause of genetic variation C1- Phenotypes are displayed based on dominant alleles C2- During gamete formation in sexual reproduction C3- Crossing over occurs during meiosis 1 between pairs of homologous chromosomes. C4- fertilization between gametes occur C5- Recombinations of chromosomes to produce offspring Sample answer : 1. Female mouse /A has short tail Male mouse / B has long tail Mouse C has long tail 2. Female mouse / A has grey/black (coat) colour Male mouse / B has white (coat) colour Mouse C has grey/black (coat) colour 3. Female mouse / A has short whiskers Male mouse / B has long whiskers Mouse C has long whiskers Able to explain each cause of variation correctly. Explaination 1 : -Offspring display phenotypes based on dominant alleles Explaination 2 : -Gametogenesis is the production of gametes in sexual reproduction

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Explaination 3: -Crossing-over during meiosis 1 between pairs of homologous chromosomes. -Arrangement of homologous chromosomes during metaphase 1 occurs randomly -Total number of haploid chromosomes / n= 23 causes vast number of recombinations of chromosomes in gametes.

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Explaination 4: -Fertilisation between gametes occurs randomly

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-The number of combinations between the ovum and any one sperm is very great Explaination 5: - Recombinations of chromosomes resulting in the production of an offspring with various characteristics

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4551/2 Chapter 6: Variation

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Diagram shows three variant P,Q and R of a species of fish

Describe how the variation occurs in that species of fish 10 P1-The variation take place causes by genetic factors P2-Genetic factors are crossing over,independent assormant (of chromosome),random fertilization and mutation Crossing over P3-Occurs during prophase I of meiosis P4-Segment of chromatids exchange places/segment of maternal chromatids attacheds to paternal chromatid P5-creates a new combination of genes P6-A gamete (with variuos combination of genes ) produces when chromatid separate during anapahse II Independent assortment pf chromosome P7-At metaphase I, homologous pairs of chromosome are arranged on the equator on the equatorial plate /metaphase plate at random P8-Chromosome (inherited ) from the father /mother may pass into the same /sofferent gamete P9-(some of the ) gamete may have the paternal /maternal genotype P10-(other) may have different combinations of the paternal and maternla genotype Random fertilizaiton P11-Haploid gamee fertilize/fuse randomly with another different haploid gamete P12-From diploid zygote woth a new combination of genes /different genetic composition Mutation P13-Chenges in DNA (due to tation )produce new genes P14-Two type of mutation : chromosomal mutation and gene mutation Reject: Enviroment factor because is not be inherited

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Mutation Chromosomal mutation Aspect Definition

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Diagram shows karyotype of individual M whi has experience mutation

Based on diagram ,State the meaning of mutation 3 P1-Mutation is a sudden random change P2-Due to the addition of the number of chromosome 23//extra X chromosome //XXY P3-That cause klinefelter’s syndrome Causes

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Explain the causes if mutation in the diagram P1-Exposure to mutagen /carcinogen subtances (any suitable example) P2-sex chromosomes /chromosome no. 23 fails to separate P3-during meiosis/anaphase I P4-Producing abnormal chromosamal number of sperm or ovum P5-Example :Sperm carry sex chromosome fertilise with normal ovum //sperm XY sex chromosome fertilise with abnormal ovum (carry XX sex chromosome)//(diagram accepted) P6-fertilizaiton (between sperm and ovum ) produce zygote which has XXY/47 chromosomes

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Chromosomal mutation

If the generation of Drosophilla sp.exposed to the X-ray for 2 week and then were crossed among each other ,there will be Drosophilla sp with green eyes in F2 generation Name the process in the situation given Mutation Based on your knowledge about genetic ,explain the process occurs in (d)(i) 2 P1-X-rays causes changes in the genetic composition /genotype P2-The mutated genetic composition will be inherited to the offspring

Gene mutation

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Diagram 5.3 shows errors which lead to chenges in the base sequence of the DNA that finally will cause mutation

Explain the mutation involved process M 2 F-Base substitution P-is the replacement of one more base /nucloetide with another Diagram 5.2(i) diagram (ii) shows the changesoccur in the structure chromosmw which causes mutation

State one factor which causes the mutation UV ray/gamma ray/X-ray Compare the mutation which occur in diagram 5.2 (i) and 5.2 (ii)3 E1-5.2(i) deletion and 5.2 (ii) inversion E2-Deletion is a segment of hromosome break off and lost and join up to give a shorter chromosome but the segemnt of chromosome in nversion break off and reattached in aand inverted position E3-Deletion and inversion can caused mutaiton

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Gene mutation Diagram 3.2 shows the sequence of nitrogenous bases in the strand of DNA which lead to the formation of erythrocyte with normal shape Diagram 3.2 (b ) Shows the sequence of nitrogenous bases in the strand DNA which lead to the formation of erythrocytes with abnormal shape due to mutation

Based on diagram 3.2 (a) and 3.2 (b): State the type of mutation Explain how the mutation lead to the formation of abnormal of shaped erythrocytes3 F1-Gene mutation E1-Adnine is replaced with thymine E2-Change the sequence of nitrogenous base ( in the DNA chain )//changes the sequence of amino acid (which is the building block /monomer of protein )

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Sickle –cell anemia

Mutation may occur on a recessive or dominant gene.Diagram 5.4 shows blood smear with different condition of red blood cells because of a disease .Explain the disease F-Sickle –cell anemia P1-Mutated (recessive )allele causes the production of abnormal haemoglobin which crystalizes P2-causing the red blood cells to become sickle shped /s-shaped Albinism

Albinism is genetic disorder. Explain the cause of this genetic disorder2 F: cause by gene mutation E: fail to produce an enzyme for production of melanin

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4551/2 Chapter 6: Variation

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Importance of variation Aspect Importance

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Explain how variation can ensure the survival of a species. P1- Can differentiate from one individual to another / no one is the same P2- Able to adapt to a new environment P3- Able to camourflage to run away from any predators

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Diagram 5.1 shows a phenomenon that occurs during meiosis.

Explain the significance of the phenomenon shown in diagram 5.1 F 1 : Creation of genetic variation amongst individuals of the same Species F2: provide a valid stock of individuals for natural selection in the process of evolution E 1 : crossing over between the non sister chromatids of homologou )chromosomes produce new combination of genes in the gametes Interaction between environment factors and genetic factors

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Kelantan 2008 Diagram shows the colour variation in a species of moth BIston Betularia in polluted environment. Due to natural selection ,the white moths become extinct as time goes by

Based on the diagram ,explain the meaning of “natural selection “4 P1- Over the time, one species better adapted to the environmental changing. P2- Example : camouflage of colour protect themselves from predator P3- That particular (white/ black) species increase their population while the others cannot. P4- White species / black species becomes dominant in their community

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Interaction between environment factors and genetic factors

Explain one different characteristics between Lepus alleni and Lepus articus on how to help them to survive in thier respective habitat Lepus alleni P1- has bigger ear, to increase the ratio of TSA/V P2- to increase the rate of the heat loss from the body P3- to bring down the body temperature in the hot environment/ habitat Lepus articus P4- has smaller ear, to reduce the ratio of TSA/V P5- to slow down the rate of the heat loss from the body, P6- to maintain body temperature in the cold environment / habitat. If we were to plant some cloned banana plants, they will grow into adult banana plants with some physical variation like height and number of fruits eventhough they have the same genotype. Explain how that variation occurs amongst the cloned banana plants3 F: Effects of environmental factors on the cloned banana plants El : Plants / clones received different amount of light intensity / mineral nutrients /water/ fertilizers E2: Plants exposed to different soil type /soil pH E3: Plants exposed to pests of parasites

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Figure 5.4 shows two type of biston betularia can be found in city W.M is grey coloured and N is dark melanic

Based on figure 5.4,which one is able to survive in an unpolluted environment Grey coloured biston betularia State a reason for (a) (i) P1-the grey coloured biston betularia is well camouflaged against lichen-covered tree trunk in unpolluted environment P2-Giving them protection form predators//avoid being eaten by predator If the air quality I the city W declined ,predict and explain what would happen to the number of dark Biston betularia P1-Dark mellanic Biston betularia increase P2-And well camouflaged in polluted environment P3-giving them protection from predators

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