Biology@beechencliff - Home



|Question number|Answer |Marks |Guidance |

|1 a |classification / taxonomy ( |B1 | |

|1 b |phylogeny ( |B1 | |

|1 c |intraspecific variation ( |B1 | |

|1 d |selection pressure ( |B1 | |

|1 e |(pesticide) resistance / resistant ( |B1 | |

|2 a |1 domain ( |B7 | |

| |2 Animalia ( | | |

| |3 phylum ( | | |

| |4 class ( | | |

| |5 family ( | | |

| |6 genus ( | | |

| |7 species ( | | |

|2 b |anatomical: A and C ( |B3 |allow B |

| |behavioural: D and E ( | |allow F |

| |physiological: B and F ( | | |

|3 a |four from: |B4 | |

| |pre-existing genetic variation ( | | |

| |mutations occur ( | | |

| |different selection pressures / different (environmental) conditions (in each pool) | | |

| |( | | |

| |best-adapted (in each pool) survive / differential survival ( | | |

| |best-adapted (in each pool) reproduce / differential reproduction ( | | |

| |frequency of some / advantageous alleles increases ( | | |

|3 b |three from: |B3 | |

| |count base changes ( | | |

| |larger number of differences = less closely related (or related answer) ( | | |

| |larger number of differences = diverged / separated a longer time ago (or related | | |

| |answer) ( | | |

| |make cladogram / tree of species based on numbers of differences ( | | |

| |to show phylogeny / closeness of relationships ( | | |

|3 c |anatomical / named example, e.g. shiny or light colour to reflect sun’s rays ( |B3 | |

| |physiological / named example, e.g. special kidneys to excrete more salt or retain | | |

| |more water ( | | |

| |behavioural / named example, e.g. stay in shade / rest at hottest time of day / swim| | |

| |at night ( | | |

|4 a i |red panda and raccoon ( |B2 | |

| |polar bear and brown bear ( | | |

|4 a ii |polar bear and brown bear ( |B2 | |

| |because they are more, physically / phenotypically, similar to each other ( | |ACCEPT descriptions, e.g., bears |

| | | |only differ in colour or more |

| | | |differences between raccoon and red |

| | | |panda, e.g., shape of face, colour, |

| | | |ear shape |

|4 a iii |time elapsed ( |B2 | |

| |since speciation / separation from, common ancestor / each other ( | | |

|4 a iv |geographical distribution / ranges overlap / both from Asia ( |B1 | |

|4 a v |two from: |B4 | |

| |red panda and raccoon both have | | |

| |long / striped, tails ( | | |

| |distinctive face stripes / ‘masks’ ( | | |

| |small size ( | | |

| |and two from: | | |

| |but in contrast bears have | | |

| |short / plain, tails ( | | |

| |plain face or other pattern (not a true ‘mask’) ( | | |

| |large size ( | | |

|4 a vi |fossil evidence ( |B1 | |

|4 b i |DNA 93.3% ( |M2 | |

| |protein 98.3 ( | | |

|4 b ii |more similarity / less change, in protein because, it has to function effectively / |B2 | |

| |structure is conserved ( | | |

| |less similarity / more change, in DNA because, silent mutations occur / genetic code| | |

| |is degenerate / several codons code for same amino acid ( | | |

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10 Classification and evolution

Exam-style mark scheme

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