NCEA Level 3 Biology (91605) 2015 — Page 1 of 5

NCEA Level 3 Biology (91605) 2015 — page 1 of 5

Assessment Schedule – 2015

Biology: Demonstrate understanding of evolutionary processes leading to speciation (91605) Evidence

Q Evidence Achievement Merit Excellence

ONE Convergent evolution is the evolution of similar • Describes convergent evolution Explains how each pattern could arise: Discusses the evolutionary patterns phenotypes by species from different lineages. – evolution of similar AND selection pressures: • Explains convergent evolution in phenotypes from different Divergent evolution is the diversification of a common terms of similar selection pressures Discusses convergent evolution of land lineages/no common ancestor ancestral species into two or more species. in similar island environment / lobsters: /unrelated Convergent evolution in land lobsters resulted in ground dwelling niche. • Similarity in body form (and • Describes divergent evolution – similarity in body form (and behaviour) and likely • Explains analogous structures are behaviour) is likely the product of diversification of a common resulted from similar selective pressure associated with associated with convergent similar selective pressures associated ancestral species into two or adaptations to ground-dwelling life. Such phenotypic evolution. Ovipositor / powerful with named adaptations to ground- more species similarity between unrelated species is likely to have hind legs / stocky body form dwelling life. been generated by extrinsic selective pressure, e.g. the (Similar selection pressure = ground • Explains divergent evolution (or greatly enlarged and armed hind legs of males probably dwelling / island habitat) • Homologous structures are adaptive radiation) in terms of evolved as a response to ground-hunting predators which associated with divergent different selection pressures may have found land lobsters easier to find due to their Discusses divergent evolution of evolution / Metrosideros associated with ice age / climate size compared to the smaller arboreal stick insects. The Metrosideros: OR analogous structures with change, e.g. warmer in north / colder elongated ovipositor is also an adaptation that evolved convergent evolution / Land in south. Divergent evolution in Metrosideros independently in response to ground-dwelling life. lobsters resulted from different selection • Explains homologous structures are Depositing eggs in the soil increased reproductive pressures associated with ice age. • Land lobsters in different areas associated with divergent evolution. success by improving the survival chances of the eggs This resulted in (named adaptations) were subjected to similar Must explain homologous structure compared to being deposited on the soil surface. differences in trunk shape / salt selection pressures. as trunk / salt tolerance / frost Divergent evolution in Metrosideros resulted from tolerance / frost tolerance • Metrosideros were subjected to tolerance. different selection pressures associated with the ice age. different selection pressures. Ice ages 1 – 2 Mya caused sea level to drop and Discuss the formation of homologous Zealandia became one island at peak of ice age. At the and analogous structures end of the ice age, warmer temperatures melted ice • Discusses a named analogous feature sheets, causing sea levels to rise, which separated of land lobsters and link this to Aotearoa’s single land mass into many islands. This convergent evolution. increased the range of habitat types, and the different selection pressures in each location would have AND stimulated divergent evolution by reproductive isolation. • Discusses a named homologous The morphology of the different land lobster species is feature of Metrosideros and link this similar but not the same. Therefore, these relatively to divergent evolution. inconspicuous but significant anatomical differences between the different land lobster lineages mirror their NCEA Level 3 Biology (91605) 2015 — page 2 of 5

separate origins, which is indicative of analogous structures typical of convergent evolution. Metrosideros share certain basic structures such as shoot system (e.g. stem / trunk) but diversification has led to a variety of forms (e.g. multiple branches in M. excelsa, hemi-epiphytic in M. robusta, single stem in M. umbellata), which are indicative of homologous structures typical in divergent evolution.

Not Achieved Achievement Merit Excellence

NØ = no response; no N1 = partial point(s) N2 = 1 points A3 = 2 points from A4 = 3 points M5 = 1 point from Merit. M6 = 2 points E7 = 1 point from E8 = 2 points from relevant evidence. from Achievement. from from Merit. Excellence. Excellence. Achievement. Achievement.

NCEA Level 3 Biology (91605) 2015 — page 3 of 5

Q Evidence Achievement Merit Excellence

TWO Variation of alleles / phenotypes exists in populations. • Describes natural selection – Individuals with • Explains natural selection – Evaluates the impact of competition Individuals with better adapted phenotypes (larger toe better adapted phenotypes / characteristics are “A” plus favourable E.g.: pad area and more lamellae) will have increased fitness more likely to survive and reproduce alleles will increase in • Competitive interactions (for a compared to less suited individuals, so are more likely frequency within the • Identifies directional selection named resource) with A. sagrei to reproduce and pass on their favourable alleles. population / in next • Phenotype at one end of range is favoured / drive an increase in A. carolinensis Favourable alleles will increase in frequency within the generation. selected for OR perch height, which selects for population. accept suitable diagram – see below. • Explains directional increased toe pad area / lamella A. carolinensis showed significant perch height increase selection – “A” plus • Describes trend in perch height – green anole number. Larger toe pads with more relative to controls and, in response, adaptively evolved causing the allele frequency lizard has increased perch height when brown lamella improve clinging/climbing larger toe pads and more lamellae. to shift over time. anole is present ability. Directional selection occurs when a phenotype towards • Explains that moving to • Describes trend in toe pad area OR lamella • As a result of competition between one end of the range is favoured over other phenotypes, higher perches selected for number when brown anole is present. green anole and brown anole there causing the allele frequency to shift over time in the larger toe pads / more will be an increase in the

direction of that phenotype. Under directional selection, lamellae. differences in perch height AND the advantageous allele increases in frequency as a • Explains that moving to toe pad area / lamellae number, consequence of differences in fitness among different higher perches reduces thus ensuring that both obtain phenotypes and over time may become fixed. competition for named sufficient named resources to Competitive interactions with A. sagrei drive an resources, e.g. food. survive. Over time this will lead to increase in A. carolinensis perch height, which selects greater divergence / evolution of for increased toe pad area and lamella number. Larger the green anole. toe pads with more lamella improve clinging ability, allowing them to climb higher. A shift to this habitat reduces competition for resources such as food. • Divergence between these sympatric species is due to character displacement in which resource competition is the selection pressure. A behavioural change with regards to perch height reduces competition for similar food sources. A. carolinensis has increased its http://img.sparknotes.com/figures/A/ perch height, and this character displacement may a3aa6bb95c7d70781cc0089d17f9160f/direct.gif lead to greater divergence / evolution.

Not Achieved Achievement Merit Excellence

NØ = no response; no N1 = partial point(s). N2 = 1 points A3 = 2 points from A4 = 3 points M5 = 1 point from Merit. M6 = 2 points E7 = 1 point from E8 = 2 points from relevant evidence. from Achievement. from from Merit. Excellence. Excellence. Achievement. Achievement. NCEA Level 3 Biology (91605) 2015 — page 4 of 5

Q Evidence Achievement Merit Excellence

THREE Polyploidy is where an organism has more than two • Describes polyploidy as having • Explains non-disjunction – Discuss a likely polyploid process. homologous sets of chromosomes in their somatic cells. more than two sets of chromosome pairs are not • Chromosome pairs are not pulled The polyploids are fertile because they have homologous chromosomes pulled apart correctly resulting apart correctly giving diploid / pairs / even number of chromosomes so can form viable • Identifies or describes non- in diploid gametes multiploid gametes which may lead gametes. disjunction. • Explains how tetraploid OR to a new polyploid species (at Polyploidy can be caused by the spindle pulling an • Why polyploids fertile hexaploid forms - fertilisation). incorrect number of chromosomes to one end. This non- described – because they have Tetraploid – two diploid Discuss the adaptive advantage of disjunction may result in 2n gametes. If two 2n gametes pair of / even number of gametes fuse polyploidy. fuse, a tetraploid (4n) may result. Hexaploid – a diploid and a chromosomes • Polyploids have a unique named tetraploid gamete fuse Postzygotic RIMs such as hybrid infertility / hybrid • Describes speciation feature and link this to survival sterility may keep polyploids isolated. E.g. tetraploid with (formation of a new species) • Polyploids have resulted in a advantage and reproductive success. 18 chromosomes in gametes + hexaploid with 27 new named feature (Guard cell OR species (a population that Discusses how change in structures chromosomes in gametes results in hybrid with 45 density/thickness of epidermal can interbreed and produce may lead to speciation. chromosomes, which cannot form viable gametes because fertile offspring) layer/xylem width) • Named changes in phenotype the chromosomes cannot pair at meiosis because some • Explains likely postzygotic • Identifies polyploidy as an resulting from polyploidy contribute have no homologues. RIM, e.g. hybrid sterility due to example of instant speciation / to niche differentiation by giving Changes in morphology resulting from polyploidy odd number of chromosomes in in one generation adaptive advantages in named contribute to habitat / niche differentiation. These new the new hybrid. • Identifies polyploidy as an habitat. Different habitats have physiological tolerances allow them to exploit novel example of sympatric • Explain that polyploids can different selection pressures such as niches. Different habitats / niches have different selection speciation result in hybrid vigour giving water availability, which may lead to pressures such as water availability which may lead to them an increased survival • Identifies that polyploidy can speciation. (sympatric) speciation. For example, polyploids have advantage. lower stomata density and thicker epidermis which result in hybrid vigour. Discusses that this is an example of

reduces water loss / transpiration and maintains turgor. sympatric speciation. The wider xylem reduces the chances of air blockage in • Formation of two different species in drought conditions, which gives an adaptive advantage in the same area due to polyploidy these conditions and allows photosynthesis to be (instant speciation). This results in maintained. named different phenotypes. Discusses a likely post-zygotic process.

• E.g. tetraploid (18 chromosomes in gametes) + hexaploid (27 chr in gametes) results in hybrid with 45 chromosomes, which cannot form viable gametes because the chromosomes cannot pair at meiosis because some have no pair.

NCEA Level 3 Biology (91605) 2015 — page 5 of 5

Not Achieved Achievement Merit Excellence

Cut Scores

Not Achieved Achievement Achievement with Merit Achievement with Excellence

0 – 7 8 – 13 14 – 18 19 – 24