Question+5


 * Question five: Speciation:- **

New Zealand lies on the boundary of two continental plates and has been isolated by oceanic barriers for the last 60 – 80 million years. The Southern Alps formed as a result of the movement between these two plates over the last five million years. The rise of the Alps changed the weather patterns, resulting in the west coast of the South Island being much wetter than the east coast. The uplift of the Alps also changed the soils in the regions. Between 1.6 million years ago and 10 000 years ago New Zealand was exposed to, and affected by, cold glacial and warmer interglacial periods. These caused the sea levels to fluctuate by up to 135 metres. In the glacial periods, forests retreated from the mountains towards the coasts. //Hebe //species are found throughout the country, particularly on the banks of lowland streams and rivers and in the alpine (above the treeline) and subalpine zones of the mountains. It has been proposed that the ancestral form of the current //Hebe// species arrived as a single introduction, most likely from Australia, about five million years ago. The closest modern species to this ancestor is thought to be //H. cupressoides//. The patterns of diversifi cation of the //Hebe// species suggest a rapid radiation following establishment. The ancient founder population that gave rise to the //Hebe// complex in New Zealand was most likely small, and perhaps arose from a single seed. The initial populations were later fragmented by changing sea levels, mountain building and glaciation. The combined influences of inbreeding, genetic drift and strong selection acting on small populations have probably played a major role in the rapid diversification of the //Hebe// species. Chromosomal changes related to aneuploidy and polyploidy have also been observed. //H. cupressoides H. ochracea H. cheesemanii // Examples of whipcord forms //H. elliptica H. salicifolia // Examples of larger leaf forms **Five different species of //Hebe// showing diversity in morphology. ** of the South Island. || Whipcord plant with scale-like leaves that grows up to 2 m tall. || <span style="color: #231f20; display: block; font-family: 'Times New Roman','serif'; font-size: 13px; text-align: center;">21 || <span style="color: #231f20; font-family: 'Times New Roman','serif'; font-size: 13px; line-height: normal; margin-bottom: 0pt;">rounded shrub up to 0.6 m tall || <span style="color: #231f20; display: block; font-family: 'Times New Roman','serif'; font-size: 13px; text-align: center;">20 || <span style="color: #231f20; font-family: 'Times New Roman','serif'; font-size: 13px; line-height: normal; margin-bottom: 0pt;">both main islands. || <span style="color: #231f20; font-family: 'Times New Roman','serif'; font-size: 13px; line-height: normal; margin-bottom: 0pt;">Leaves 5 – 10 cm long; rounded shrub <span style="color: #231f20; font-family: 'Times New Roman','serif'; font-size: 13px; line-height: normal; margin-bottom: 0pt;">up to 2 m tall. || <span style="color: #231f20; display: block; font-family: 'Times New Roman','serif'; font-size: 13px; text-align: center;">20 || <span style="color: #231f20; font-family: 'Times New Roman','serif'; font-size: 13px; line-height: normal; margin-bottom: 0pt;">tall. || <span style="color: #231f20; display: block; font-family: 'Times New Roman','serif'; font-size: 13px; text-align: center;">61 || <span style="color: #231f20; font-family: 'Times New Roman','serif'; font-size: 13px; line-height: normal; margin-bottom: 0pt;">Island. || <span style="color: #231f20; font-family: 'Times New Roman','serif'; font-size: 13px; line-height: normal; margin-bottom: 0pt;">Leaves 4 – 5 cm long; woody shrub up to 4 m tall. || <span style="color: #231f20; display: block; font-family: 'Times New Roman','serif'; font-size: 13px; text-align: center;">20 || <span style="color: #231f20; font-family: 'Times New Roman','serif'; font-size: 13px; line-height: normal; margin-bottom: 0pt;">South Island. || <span style="color: #231f20; font-family: 'Times New Roman','serif'; font-size: 13px; line-height: normal; margin-bottom: 0pt;">Leaves 1 – 2.5 cm long; subshrub that grows up to 0.3 m tall. || <span style="color: #231f20; display: block; font-family: 'Times New Roman','serif'; font-size: 13px; text-align: center;">21 || <span style="color: #231f20; font-family: 'Times New Roman','serif'; font-size: 13px; line-height: normal; margin-bottom: 0pt;">soils of northern South Island. || <span style="color: #231f20; font-family: 'Times New Roman','serif'; font-size: 13px; line-height: normal; margin-bottom: 0pt;">Leaves 0.6 – 1.9 cm long; spreading low shrub up to 1 m tall. || <span style="color: #231f20; display: block; font-family: 'Times New Roman','serif'; font-size: 13px; text-align: center;">40 || <span style="color: #231f20; font-family: 'Times New Roman','serif'; font-size: 13px; line-height: normal; margin-bottom: 0pt;">South Island. || <span style="color: #231f20; font-family: 'Times New Roman','serif'; font-size: 13px; line-height: normal; margin-bottom: 0pt;">Leaves 1 – 2.5 cm long; subshrub that grows up to 0.3 m tall. || <span style="color: #231f20; display: block; font-family: 'Times New Roman','serif'; font-size: 13px; text-align: center;">60 ||
 * **<span style="color: #231f20; font-family: 'Times New Roman','serif'; font-size: 16px;">Species ** || **<span style="color: #231f20; font-family: 'Times New Roman','serif'; font-size: 16px;">Habitat conditions ** || **<span style="color: #231f20; font-family: 'Times New Roman','serif'; font-size: 16px;">Morphology ** || **<span style="color: #231f20; font-family: 'Times New Roman','serif'; font-size: 16px;">Chromosome number (n) ** ||
 * //<span style="color: #231f20; font-family: 'Times New Roman','serif'; font-size: 13px;">H. cupressoides // || <span style="color: #231f20; font-family: 'Times New Roman','serif'; font-size: 13px; line-height: normal; margin-bottom: 0pt;">Subalpine east of the main mountains
 * //<span style="color: #231f20; font-family: 'Times New Roman','serif'; font-size: 13px;">H. cheesemanii // || <span style="color: #231f20; font-family: 'Times New Roman','serif'; font-size: 13px; line-height: normal; margin-bottom: 0pt;">Rocks on drier mountains of the South Island. || <span style="color: #231f20; font-family: 'Times New Roman','serif'; font-size: 13px; line-height: normal; margin-bottom: 0pt;">Semi-whipcord plant; shrub up to 0.3 m tall. || <span style="color: #231f20; display: block; font-family: 'Times New Roman','serif'; font-size: 13px; text-align: center;">21 ||
 * //<span style="color: #231f20; font-family: 'Times New Roman','serif'; font-size: 13px;">H. ochracea // || <span style="color: #231f20; font-family: 'Times New Roman','serif'; font-size: 13px; line-height: normal; margin-bottom: 0pt;">Mountains of the north-west South Island. || <span style="color: #231f20; font-family: 'Times New Roman','serif'; font-size: 13px; line-height: normal; margin-bottom: 0pt;">Semi-whipcord plant; shrub up to 0.3 m tall. || <span style="color: #231f20; display: block; font-family: 'Times New Roman','serif'; font-size: 13px; text-align: center;">62 ||
 * //<span style="color: #231f20; font-family: 'Times New Roman','serif'; font-size: 13px;">H. hectorii // || <span style="color: #231f20; font-family: 'Times New Roman','serif'; font-size: 13px; line-height: normal; margin-bottom: 0pt;">Wet subalpine scrub and tussock of the South Island. || <span style="color: #231f20; font-family: 'Times New Roman','serif'; font-size: 13px; line-height: normal; margin-bottom: 0pt;">Whipcord plant; erect, rigid plant that grows up to 0.75 m tall. || <span style="color: #231f20; display: block; font-family: 'Times New Roman','serif'; font-size: 13px; text-align: center;">20 ||
 * //<span style="color: #231f20; font-family: 'Times New Roman','serif'; font-size: 13px;">H. imbricata // || <span style="color: #231f20; font-family: 'Times New Roman','serif'; font-size: 13px; line-height: normal; margin-bottom: 0pt;">Drier mountains of the South Island. || <span style="color: #231f20; font-family: 'Times New Roman','serif'; font-size: 13px; line-height: normal; margin-bottom: 0pt;">Whipcord plant; erect, much branched
 * //<span style="color: #231f20; font-family: 'Times New Roman','serif'; font-size: 13px;">H. salicifolia // || <span style="color: #231f20; font-family: 'Times New Roman','serif'; font-size: 13px; line-height: normal; margin-bottom: 0pt;">Lowland to mountains in the South Island; widespread except near the coast in Marlborough Sounds. || <span style="color: #231f20; font-family: 'Times New Roman','serif'; font-size: 13px; line-height: normal; margin-bottom: 0pt;">Leaves 5 – 15 cm long; shrub up to 5 m tall. || <span style="color: #231f20; display: block; font-family: 'Times New Roman','serif'; font-size: 13px; text-align: center;">20 ||
 * //<span style="color: #231f20; font-family: 'Times New Roman','serif'; font-size: 13px;">H. speciosa // || <span style="color: #231f20; font-family: 'Times New Roman','serif'; font-size: 13px; line-height: normal; margin-bottom: 0pt;">Exposed sea cliffs on western side of
 * //<span style="color: #231f20; font-family: 'Times New Roman','serif'; font-size: 13px;">H. cockayniana // || <span style="color: #231f20; font-family: 'Times New Roman','serif'; font-size: 13px; line-height: normal; margin-bottom: 0pt;">Wet subalpine scrubland and grasslands in south-west South Island. || <span style="color: #231f20; font-family: 'Times New Roman','serif'; font-size: 13px; line-height: normal; margin-bottom: 0pt;">Leaves 1 – 2 cm long; erect much branched shrub up to 1 m tall. || <span style="color: #231f20; display: block; font-family: 'Times New Roman','serif'; font-size: 13px; text-align: center;">20 ||
 * //<span style="color: #231f20; font-family: 'Times New Roman','serif'; font-size: 13px;">H. elliptica // || <span style="color: #231f20; font-family: 'Times New Roman','serif'; font-size: 13px; line-height: normal; margin-bottom: 0pt;">Coastal. || <span style="color: #231f20; font-family: 'Times New Roman','serif'; font-size: 13px; line-height: normal; margin-bottom: 0pt;">Leaves 1.5 – 4 cm long; bushy shrub up to 2 m tall. || <span style="color: #231f20; display: block; font-family: 'Times New Roman','serif'; font-size: 13px; text-align: center;">20 ||
 * //<span style="color: #231f20; font-family: 'Times New Roman','serif'; font-size: 13px;">H. topiaria // || <span style="color: #231f20; font-family: 'Times New Roman','serif'; font-size: 13px; line-height: normal; margin-bottom: 0pt;">Wet subalpine areas of the South Island. || <span style="color: #231f20; font-family: 'Times New Roman','serif'; font-size: 13px; line-height: normal; margin-bottom: 0pt;">Leaves about 1 cm long; compact neatly rounded bushy shrub up to 2 m
 * //<span style="color: #231f20; font-family: 'Times New Roman','serif'; font-size: 13px;">H. gracillima // || <span style="color: #231f20; font-family: 'Times New Roman','serif'; font-size: 13px; line-height: normal; margin-bottom: 0pt;">Damp swampy places in the South Island. || <span style="color: #231f20; font-family: 'Times New Roman','serif'; font-size: 13px; line-height: normal; margin-bottom: 0pt;">Leaves 1 – 2 cm long; shrub up to 2 m tall. || <span style="color: #231f20; display: block; font-family: 'Times New Roman','serif'; font-size: 13px; text-align: center;">40 ||
 * //<span style="color: #231f20; font-family: 'Times New Roman','serif'; font-size: 13px;">H. venustula // || <span style="color: #231f20; font-family: 'Times New Roman','serif'; font-size: 13px; line-height: normal; margin-bottom: 0pt;">Subalpine mostly North Island || <span style="color: #231f20; font-family: 'Times New Roman','serif'; font-size: 13px; line-height: normal; margin-bottom: 0pt;">Leaves 1 – 2 cm long; erect bushy shrub up to 1.5 m tall. || <span style="color: #231f20; display: block; font-family: 'Times New Roman','serif'; font-size: 13px; text-align: center;">60 ||
 * //<span style="color: #231f20; font-family: 'Times New Roman','serif'; font-size: 13px;">H. stricta // || <span style="color: #231f20; font-family: 'Times New Roman','serif'; font-size: 13px; line-height: normal; margin-bottom: 0pt;">Common in lowland and subalpine areas, mostly on banks in the North
 * //<span style="color: #231f20; font-family: 'Times New Roman','serif'; font-size: 13px;">H. odora // || <span style="color: #231f20; font-family: 'Times New Roman','serif'; font-size: 13px; line-height: normal; margin-bottom: 0pt;">Common usually in wet ground, alpine and subalpine. || <span style="color: #231f20; font-family: 'Times New Roman','serif'; font-size: 13px; line-height: normal; margin-bottom: 0pt;">Leaves 1 – 2 cm long; variable shrub up to 1.5 m tall. || <span style="color: #231f20; display: block; font-family: 'Times New Roman','serif'; font-size: 13px; text-align: center;">21 ||
 * //<span style="color: #231f20; font-family: 'Times New Roman','serif'; font-size: 13px;">H. haastii // || <span style="color: #231f20; font-family: 'Times New Roman','serif'; font-size: 13px; line-height: normal; margin-bottom: 0pt;">Drier mountains of the South Island || <span style="color: #231f20; font-family: 'Times New Roman','serif'; font-size: 13px; line-height: normal; margin-bottom: 0pt;">Leaves 0.6 – 1.3 cm long; very low growing shrub up to 0.3 m tall || <span style="color: #231f20; display: block; font-family: 'Times New Roman','serif'; font-size: 13px; text-align: center;">21 ||
 * //<span style="color: #231f20; font-family: 'Times New Roman','serif'; font-size: 13px;">H. societatis // || <span style="color: #231f20; font-family: 'Times New Roman','serif'; font-size: 13px; line-height: normal; margin-bottom: 0pt;">Subalpine small plant zone in northwest
 * //<span style="color: #231f20; font-family: 'Times New Roman','serif'; font-size: 13px;">H. crenulata // || <span style="color: #231f20; font-family: 'Times New Roman','serif'; font-size: 13px; line-height: normal; margin-bottom: 0pt;">Subalpine shrubland and tussock grassland, often in shallow or rocky
 * //<span style="color: #231f20; font-family: 'Times New Roman','serif'; font-size: 13px;">H. dilatata // || <span style="color: #231f20; font-family: 'Times New Roman','serif'; font-size: 13px; line-height: normal; margin-bottom: 0pt;">Grasslands to rocky screes of southern
 * //<span style="color: #231f20; font-family: 'Times New Roman','serif'; font-size: 13px;">H. raoulii // || <span style="color: #231f20; font-family: 'Times New Roman','serif'; font-size: 13px; line-height: normal; margin-bottom: 0pt;">Drier mountains and hills of the South Island. || <span style="color: #231f20; font-family: 'Times New Roman','serif'; font-size: 13px; line-height: normal; margin-bottom: 0pt;">Leaves 0.6 – 2.5 cm long; small low growing shrub up to 0.3 m tall. || <span style="color: #231f20; display: block; font-family: 'Times New Roman','serif'; font-size: 13px; text-align: center;">21 ||


 * <span style="color: #231f20; font-family: 'Times New Roman','serif';">Table 1 Summary of characteristics of key //Hebe// species **

<span style="color: #231f20; font-family: 'Times New Roman','serif'; font-size: 16px; line-height: normal; margin-bottom: 0pt;">Discuss the evidence for the role of each of the following in the evolution and diversifi cation of the //Hebe s//pecies in New Zealand: <span style="color: #231f20; font-family: 'Times New Roman','serif'; font-size: 16px; line-height: normal; margin-bottom: 0pt;">• selection pressures generated by environmental changes resulting from mountain building and glaciation <span style="color: #231f20; font-family: 'Times New Roman','serif'; font-size: 16px; line-height: normal; margin-bottom: 0pt;">• mutations, particularly aneuploidy and / or polyploidy <span style="color: #231f20; font-family: 'Times New Roman','serif'; font-size: 16px; line-height: normal; margin-bottom: 0pt;">• genetic drift and / or the Founder effect <span style="color: #231f20; font-family: 'Times New Roman','serif'; font-size: 16px; line-height: normal; margin-bottom: 0pt;">• adaptive radiation and / or convergence <span style="color: #231f20; font-family: 'Times New Roman','serif'; font-size: 16px; line-height: normal; margin-bottom: 0pt;">• sympatric and / or allopatric speciation. <span style="color: #231f20; font-family: 'Times New Roman','serif'; font-size: 16px; line-height: normal; margin-bottom: 0pt;">Your answer needs to address all the bullet points. Where there are two concepts for one bullet point it is not essential that both concepts are covered. Headings may be used.