NCEA Level 3 Biology (91605) 2014 — page 1 of 5

Assessment Schedule – 2014

Biology: Demonstrate understanding of evolutionary processes leading to speciation (91605)
Evidence Statement
 
Q1 Evidence Achievement Merit Excellence

A reproductive isolating mechanism is a barrier that • Describes a Reproductive • Explains how RIM could have • Links ideas by explaining
prevents two organisms from differing species from Isolating Mechanism (RIM). happened in these cases. reproductive isolation in terms of
mating and producing fertile offspring / prevents Eg: Coyote and dingo probably speciation AND selection
successful interbreeding / prevents gene flow • Describes relevant RIMs for the went through allopatric pressures:
species given. speciation: Geographical
These species have gone through divergence or adaptive - Coyote and dingo probably went
Eg: geographical isolation, isolation.  differences in
radiation. Dingos would have become reproductively through allopatric speciation:
behavioural or territorial behaviour / external features /
isolated when Australia mainland broke away from Geographical isolation.  no
isolation. gene pool / different species.
Gondwana, and would have remained isolated for millions gene flow / interbreeding 
of years, an example of allopatric speciation. The coyote different selection pressures 
• Describes relevant selection • Jackal species went through
in Northern America would have become reproductively differences in behaviour /
pressures. allopatric speciation. They now
isolated from other dog species, partly by allopatric external features / gene pool /
Eg: competition for resources, occupy the same area (sympatric
speciation due to separation of landmasses and mountain different species.
environmental conditions, species). Behavioural or
building. This geographic barrier would have stopped
predators. territorial differences prevent - Jackals: Sympatric speciation:
gene flow and, as the coyote was subjected to different
interbreeding. Behavioural/niche isolation. 
selection pressures (hot, dry environment) genetic
• Describes / defines speciation. OR no gene flow / interbreeding 
differences (perhaps provided by mutations) would have
Eg: creation of a new species Another reasonable explanation. different selection pressures 
been selected for, eventually leading to speciation.
from a common ancestor / that is Eg: Sympatric speciation: named differences / different
However, it has also survived other closely related wolf
reproductively isolated. Behavioural/niche isolation  gene pool / different species.
species living within the same range, so other factors such
OR named difference / different gene OR
as behaviour, climate changes, and territory may have
Describes whether true pool / species. Random mutation: different
been factors. The coyote range does not appear to extend
speciation has occurred or not Eg: Random mutation caused appearance; no gene flow /
north into the colder northern parts of North America and
Eg. Gives a reason why not / different appearance leading to reproductive isolation; different
Europe. This may have been both allopatric and sympatric
why this is true speciation. reproductive isolation from the selection pressures; speciation /
speciation.
group. gene pool difference.
The jackal species found in the Serengeti region of Africa
appear to be reproductively isolated due to behavioural • Explains link between selection - Explains link between selection
differences. Territoriality, courtship differences and pressures and speciation: pressures and speciation:
recognition are factors that have operated to keep the three Selection pressures include Selection pressures include
species reproductively isolated. They are sympatric environmental conditions, environmental conditions,
species, but it is not clear from the information if they climate, and availability of food. climate, and availability of food.
originally became separated due to sympatric speciation. Individuals most suited to Individuals most suited to survive
survive are selected for. are selected for and therefore
As all these species have been known to reproduce with have increased reproductive
the domestic dog and produce viable offspring, they do
 NCEA Level 3 Biology (91605) 2014 — page 2 of 5

not fit with the definition of a species commonly used in • Gives reasons why these are not success / survival.
biology. However, each species is adapted to and naturally true species: • Discusses why true speciation
survives within its own preferred ecological niche and Although all these species has not occurred:
shows physical differences and presumably mating appear (and probably behave) All these species can reproduce
preferences (known to mate with the domestic dog, but not differently, they have all been with domestic dogs and produce
commonly). This example shows the complexity of the known to reproduce with fertile offspring, which suggests
concept of speciation and calls into question whether or domestic dogs and produce they are not true species / which
not these are all different species or different populations fertile offspring, which suggests does not fit with the biology
of the same species. they are not true species / which definition of a true species.
does not fit with the biology AND
definition of a true species. Hybrid dog may have less
survivability / hybrid
breakdown.
OR
Insufficient time has elapsed /
differences have accumulated for
true speciation / complete
reproductive isolation.
OR
As they can reproduce and
produce fertile offspring they
could be considered to be sub-
species.

Not Achieved Achievement Merit Excellence

NØ = no response or N1 = 1 partial point, N2 = 1 point from A3 = 2 points A4 = 3 points M5 = 1 point M6 = 2 points E7 = 1 point E8 = 2 points
no relevant evidence eg one definition Achievement
 NCEA Level 3 Biology (91605) 2014 — page 3 of 5

Q2 Evidence Achievement Merit Excellence

The evolutionary relationship between the monarch butterfly • Describes co-evolution • Explains how co-evolutionary • Links ideas to give a comprehensive
and the milkweed plant is an example of co-evolution, where - Changes in one species relationships develop. explanation of how co-evolutionary
the species have exerted selection pressures on each other over leads to reciprocal - Two species may have an relationship develops.
time. The monarch butterfly is adapted to survive the toxicity of changes in the other – existing relationship and - A co-evolutionary relationship depends
the milkweed, which normally poisons most other animal they evolve and change changes in one cause on the ability of each species involved to
species. The milkweed is adapting to the damage caused by the together / exert selection reciprocal changes in the adapt to changes that occur in the other.
monarch caterpillar feeding on its leaves by undergoing rapid pressures on each other. other. As one changes over In this case, the monarch’s survival
regrowth of damaged tissue. time due to selection depends on its feeding on milkweed, and
A co-evolution relationship develops where over time two • Describes how this type of pressures, the other changes gaining an advantage from protection
species develop specific adaptations to enable their existence in relationship develops. too. due to high levels of toxicity keeping
the presence of the other organism. This might be, for example, potential predators away; leading to
predator-prey, parasitic, mutualistic or herbivory relationships, • Describes selection reproductive success / increased survival.
so that both are able to survive the impact of one upon the other. pressures working for or • Explains selection pressures.
against: (max. 2 points). • Evaluation of selection pressures.
In the case of the monarch butterfly and the milkweed plant, the − Milkweeds can be badly
- Monarchs can tolerate damaged by monarchs. - Milkweeds are responding to increased
monarch caterpillar has developed immunity to the milkweed’s
toxic, sticky alkaloids Rapid repair is a selective pressure due to monarch caterpillar
poisonous alkaloids. This gives the monarch a virtual monopoly
given out by milkweeds. advantage. Plants that can grazing by increasing their ability to
over milkweed both as a food supply for its larvae and a safe
- Monarchs have rapidly self-repair will repair damaged plant material instead of
place for laying its eggs, as the poisonous nature of the plant
developed the ability to survive the monarch grazing increasing their defence (becoming more
keeps other animals from eating it. Potential predators of the
chew around the base of / go on to reproduce. toxic) OR by reducing levels of toxins
monarch butterfly when they, in turn, become poisonous to
milkweed leaves to which results in increased survival /
many animals, will be reduced. The milkweed, in response to
reduce intake of toxins. reproductive success.
the caterpillar herbivory, have developed the ability to rapidly − Monarchs feeding on
regenerate and replace damaged tissues. There would be - Milkweeds have milkweed provides selective - Monarchs feeding on milkweed provides
pressure for this to happen where monarch caterpillar developed the ability to advantage as monarch is selective advantage as monarch is toxic to
populations are high and the resulting damage to milkweed rapidly self-repair toxic to most other animals
plants due to caterpillar feeding is also high. The high levels of most other animals and therefore
damage by monarchs. and therefore protected and
herbivory could threaten the co-evolutionary relationship if protected and better survival chances /
- Monarch caterpillars are better survival chances / reproductive success. Less toxic
plants became too heavily grazed and the monarchs lost their now toxic so avoid reproductive success. milkweed plants will probably lead to
food and egg-laying preference and the protection it offers. predation. reduced toxicity in monarchs, opening
them up to increased predation.
OR
Discusses advantages to the milkweed.

Not Achieved Achievement Merit Excellence

NØ = no evidence or no relevant N1 = 1 partial N2 = 1 point from A3 = 2 points A4 = 3 M5 = 1 point M6 = 2 E7 = 1 point E8 = 2 points

evidence point, eg one Achievement points points
definition
 NCEA Level 3 Biology (91605) 2014 — page 4 of 5

 
Q3 Evidence Achievement Merit Excellence

Allopatric speciation describes the formation of a new Describes allopatric speciation as • Explains allopatric speciation • Discusses allopatric speciation, using
species as a result of physical separation of populations of the formation of a new species / using the example of the kea / the kea and kākā divergence from
the same species, which over time, become reproductively speciation as a result of kākā divergence from proto- proto- kākā.
isolated and diverge into different species, adapted to a geographical or physical isolation / kākā (3 mya). Eg: Kea and kākā diverged from the
particular niche or environment. In this example the proto- separation of populations of same OR proto-kaka species by * separation by
kākā diverged into kea, adapted to alpine conditions, and species. The separation of North Island geographic features (Southern Alps); *
kākā, adapted to lowland forests, approximately 3 mya. and South Island kākā different selection pressures in the
This divergence coincided with the formation of the Describes sympatric species as subspecies (0.4 mya) different areas led to changes (genetic,
Southern Alps and available alpine niches. The kākā occupying the same geographical Eg: Kea and kākā diverged phenotypic); * changes accumulated
survived in the warmer northern forest niches. and migrated range / area. from the proto-kaka species by; until reproductive isolation / different
to off-shore islands, becoming isolated. separation by geographic species.
Sympatric species are species, which previously diverged Describes sympatric species as features (Southern Alps);
from a common ancestor, and now exist in the same area being reproductively isolated. different selection pressures • Kākā migrated back to the South Island
but remain reproductively isolated. The kākā returned to in the different areas and (as well as inhabiting the North Island),
the South Island when it became warmer after the last Describes South Island kākā and evolved differently. but were at this stage reproductively
glaciation and now exists alongside the kea, occupying kea as sympatric species. OR isolated from their kea relatives,
different niches and remaining reproductively isolated. Rising levels of Cook Strait existing as sympatric species in
Describes North Island and South separated kākā populations different habitats within the same
When sea levels rose about 0.4 mya, the North and South
Island kākā as becoming (geographic isolation); geographical area – the South Island.
Island became separated by Cook Strait (rising sea levels)
reproductively isolated due to different selection pressures
so the South Island and North Island kākā populations
allopatric speciation or led to changes (genetic, • Discusses the events leading to the
became isolated. They are now considered to be subspecies
geographical separation. phenotypic). formation of North and South Island
as they do not reproduce with each other, probably due to
kāā subspecies
differences in size, behaviour, and markings. Their • Explains South Island kākā and
Identifies a recent impact on kākā OR
isolation (0.4 mya) is not long enough for complete kea as sympatric species
speciation, such as loss of genetic The 4 different groups of kākā.
speciation to occur. The Norfolk Island and Chatham Island because they are reproductively
diversity / loss of genetic variation / Eg: Geographic isolation (water)
species remained reproductively isolated, however, and isolated as a consequence of
have now become extinct. genetic drift / endangered due to selection pressures. separated kākā populations; different
female losses / at risk of extinction. selection pressures led to changes. This
The loss of female nesting birds over several generations • Explains the impact of a recent has resulted in the North & South
will severely impact on the size of the kākā gene pool and event on kākā species. Island kākā populations / sub-species
Describes the geographical
reduce allele frequencies. This will lead to a decline in Eg: The loss of female breeding (NOT species).
barriers - between North Island
overall numbers and a loss of genetic diversity (genetic kākā will reduce diversity OR
and South Island kākā as the Cook
drift). The populations will become vulnerable to .This will leave the current Kākā diverged into four separate areas;
Strait.
environmental changes and risk the possibility of species vulnerable to separation by geographical feature
extinction. Speciation between the two subspecies of kākā OR
environmental change / at risk (water); different selection pressures
may not continue if hybridisation happens due to - between kea and kākā as the
of extinction. in the different areas led to changes;
conservation measures, although this may not even be Southern Alps.
changes accumulated until reproductive
possible. isolation / different species /
subspecies.

Two  ‘E’  points  on  next  page  

 NCEA Level 3 Biology (91605) 2014 — page 5 of 5

• Kākā migrated to the two offshore

islands / Norfolk & Chatham Islands
due to competition on the mainland.
Because of the founder effect / genetic
drift / not having suitable alleles, and
were vulnerable to environmental
change, which lead to their extinction.

• Discusses the impact of a recent event

on kākā species.
Eg: The loss of as many as three
generations of female breeding kākā
will reduce genetic diversity and leave
the population vulnerable to the effects
of a reduced gene pool.
AND
Conservation measures will not be able
to increase the gene pool.
OR
the reduced gene pool increases
susceptibility to environmental effects
such as disease (OR alternative
argument based on why at risk).

Not Achieved Achievement Merit Excellence

NØ = no response or no N1 = 1 partial point, N2 = 1 point A3 = 2 points A4 = 3 M5 = 1 point M6 = 2 E7 = 1 point E8 = 2 points

relevant evidence eg one definition from points points
Achievement

 
 

Cut Scores
Not Achieved Achievement Achievement with Merit Achievement with Excellence

Score range 0–7 8 – 13 14 – 18 19 – 24