State the meaning of the term variation. ....................................................................................................................................... . ....................................................................................................................................... . ................................................................................................................................. (ii) Table 6.1 shows some statements about variation. Place ticks $$$(\mathcal{\checkmark})$$$ in the boxes to show which statements describe continuous and discontinuous variation. Place one tick in each row. (iii) Fig. 6.1 shows graphs of two types of variation. On Fig. 6.1, state an example of a phenotype for each type of variation shown. example ................................................... example ................................................... Fig. 6.1

Biology

IGCSE&ALevel

CAIE

Exam No：0610_w24_qp_31 Year：2024 Question No：6(a)

Answer:

18.1.1 Define variation as differences between individuals of the same species

18.1.10 State that ionising radiation and some chemicals increase the rate of mutation

18.1.11 State that phenotypic variation is caused by both genetic and environmental factors

18.1.12 State that discontinuous variation is mostly caused by genes alone, e.g. A, B, AB and O blood groups in humans

18.1.13 Define gene mutation as a change in the base sequence of DNA

18.1.14 Describe the symptoms of sickle-cell anaemia

18.1.15 Explain how a change in the base sequence of the gene for haemoglobin results in abnormal haemoglobin and sickle-shaped red blood cells

18.1.16 Use genetic diagrams to show how sickle-cell anaemia is inherited

18.1.17 State that people who are heterozygous (HbS HbA ) for the sickle-cell allele have a resistance to malaria

18.1.18 Explain the distribution of the sickle-cell allele in human populations with reference to the distribution of malaria

18.1.19 (Teaching of human inherited conditions should be done with sensitivity at all times.)

18.1.2 Distinguish between phenotypic variation and genetic variation

18.1.3 State that continuous variation results in a range of phenotypes between two extremes, e.g. height in humans

18.1.4 State that discontinuous variation results in a limited number of phenotypes with no intermediates, e.g. tongue rolling

18.1.5 Record and present the results of investigations into continuous and discontinuous variation

18.1.6 Define mutation as genetic change

18.1.7 State that mutation is the way in which new alleles are formed

18.1.8 State that ionising radiation and some chemicals increase the rate of mutation

18.1.9 State that ionising radiation and some chemicals increase the rate of mutation