Download 91605 Sample Assessment Schedule

NCEA Level 3 Biology 91605 (3.5) — page 1 of 4
SAMPLE ASSESSMENT SCHEDULE
Biology 91605 (3.5): Demonstrate understanding of evolutionary processes leading to
speciation
Assessment Criteria
Achievement
Demonstrate understanding involves
using biological ideas and/or scientific
evidence to describe evolutionary
processes leading to speciation.
Achievement with Merit
Demonstrate in-depth understanding
involves using biological ideas and/or
scientific evidence to explain how or
why evolutionary processes lead to
speciation.
Achievement with
Excellence
Demonstrate comprehensive
understanding involves linking
biological ideas and/or
scientific evidence about
evolutionary processes leading
to speciation. The linking of
ideas may involve justifying,
relating, evaluating, comparing
and contrasting, analysing
using evidence for evolution.
NCEA Level 3 Biology 91605 (3.5) — page 2 of 4
Evidence Statement
Question One
Expected Coverage
The pattern is punctuated equilibrium
or adaptive radiation. There are long
periods of stasis or no change
followed by a period of rapid
diversification to fill available niches
and different habitats.
In New Zealand in the past 3.5
million years there have been
geological changes involving
glaciation and mountain building,
which has caused geographical
isolation and habitat differences.
Plants that can tolerate particular
conditions, such as greywacke soils,
or alpine areas will be reproductively
isolated from other such populations,
eventually leading to the adaptive
radiation pattern shown. Substrate,
climate changes and geographical
isolation are the selection pressures
affecting survival and adaptation.
Plants with the phenotypes that
enable them to survive and
successfully compete have become
established in particular areas. Eg,
plants with leaves that can withstand
dry, cold climates can survive further
south or in alpine areas, or plants
with roots that can cope with
particular rock types such as
greywacke or schist can colonise
those areas. Leaves with reduced
surface area will compete more
successfully in drier, colder climates
than leaves with larger surface areas.
NØ
N1
No
response;
no relevant
evidence
ONE partial
idea
Achievement
Merit
Candidate:
Candidate:
 identifies the
pattern
correctly
 explains the
impact of a
geological event
(resulting in
speciation)
 describes a
relevant
geological
event
 describes a
relevant
selection
pressure
 explains the
effect of different
selection
pressures
(resulting in
pattern)
Excellence
Candidate comprehensively
discusses the geological
changes that have occurred
in the past 3.5 million years
and how they have
contributed to selection
pressures and so the pattern
of evolution
AND
links to the adaptive features
of the different species OR
the different habitats created
 identifies a
structural or
habitat
difference
between
species from
the diagram
that could
impact on
survival
 explains the
cause of
structural or
habitat
differences (due
to different
niches and so
selection
pressures)
N2
A3
A4
M5
M6
E7
E8
ONE A
point (or
TWO
partial)
TWO
A
points
THREE
A points
TWO
M
points
THREE M
points, or
TWO
clearly
using
example
E, may have
minor errors
or not use
e.g. fully
E, accurately
and specific
to example
NCEA Level 3 Biology 91605 (3.5) — page 3 of 4
Question Two
Expected Coverage
The contributing species must be closely
enough relate for them to be able to create a
hybrid.
Triticum and wild triticum have contributed 7
chromosomes each in a fertilisation that has
produced a sterile hybrid. Due to an error in
cell division or non-disjunction, where the
chromosomes fail to separate, offspring have
been produced with double sets of
chromosomes, so the plant is able to self
fertilize and produce fertile offspring of a new
species called Emmer wheat.
In a further reproductive event Emmer wheat
has combined with wild wheat, contributing a
further set of chromosomes. The offspring
are infertile hybrids, but can reproduce
asexually, until a further non-disjunction
event has occurred during meiosis, forming
modern wheat, with a phenotype that enables
it to withstand temperate climates, so that it
can be grown in a larger number of places.
The resulting polyploidy phenotype has
greater hybrid vigour, improved qualities
(such as bigger seeds), improved crop
potential and is more likely to be selected for
(by humans).
Modern wheat contains double sets of three
different lots of chromosomes, originally
seven from each contributing plant. Through
meiotic error (non disjunction of chromatids)
and self fertilisation, gametes with n=21 have
produced fertile modern wheat plants with 2n
= 42.
Achievement
Merit
Excellence
Candidate:
Candidate:
Candidate:
 describes that they
must be closely
related species
 explains why
species must be
closely related
 describes
polyploidy as a
doubling /multiple of
chromosome sets
 explains why
hybrids are
infertile
 comprehensive
ly explains the
role of meiotic
error and selffertilisation in
creating a
fertile species
 describes effect of
polyploidy on wheat
phenotype, e.g.
hybrid vigour
 gives a basic
reason for sterile
hybrid (can’t form
gametes /uneven
chromosome no /
different species)
 describes
polyploidy as
instant speciation/
type of sympatric
speciation
 identifies that
hybrids can
reproduce
vegetatively/
asexually
 explains the role
of meiotic error/
double chrom #/
non-disjunction/
amphiploidy in
polyploidy
 explains the role
of self
fertilisation in
polyploidy
 links the
changes in
genotype to the
changes in
phenotype in
modern wheat
development
 comprehensive
ly explains the
link between
the genotype
and phenotype
changes in the
bread wheat
and how they
would be
selected for
 explains instant
speciation or
sympatric in
terms of
reproductive
isolation
NØ
N1
N2
A3
A4
M5
M6
E7
E8
No response;
no relevant
evidence
ONE partial
idea
ONE A point
(or TWO
partial)
TWO A
points
THREE A
points
TWO M
points
THREE
M points
ONE E
TWO E
NCEA Level 3 Biology 91605 (3.5) — page 4 of 4
Expected Coverage
Achievement
Merit
Disruptive selection. Something has
affected the middle size populations
of the second instars, possibly
predating them (or they live in
different places, e.g. logs vs.
grasses), leaving behind two
distinct groups in the ancestral
population. Those 2nd instars with
smaller body size have become L.
atritus; the larger ones have
become L. katipo.
Candidate:
Candidate:
 identifies pattern as
disruptive selection
OR the result of
natural selection
 explains how
disruptive selection /
natural selection
could occur
Speciation is due to reproductive
isolation caused by physical,
behavioural or genetic differences.
In this case the difference in size
between the two species may be
the isolating factor. Genetic
incompatibility will show that it is
happening.
 describes the
speciation process
(e.g. repro iso/ allo
or sympatric)
 explains speciation
process (niche
differences) or
evidence for
speciation (no
reproduction)
Mitochondrial DNA is used to
investigate speciation because it is
only passed on via one parent and
is not subject to recombination, like
nuclear DNA. It also gathers
mutations, which can be used to
estimate how long two populations
have been separated. In this case
the fact that there is very little
difference between the mtDNA of
one mitochondrial gene of NZ
spiders and the Australian spiders
suggests that speciation has been
very recent and the Australian and
NZ populations have not long been
separated. However, the nuclear
DNA (that is selected for) may be
quite different.
 gives a basic
relevant reason for
using the mt gene
 makes a relevant
general statement
about the evolution /
speciation of the
spider populations
(very recent/ may
still be the same
species)
Excellence
Candidate:
 explains reason for
using mt genes to
investigate speciation
 explains what the
evidence shows
about spider
evolution (because
there is so little
difference)
 comprehensively
explains speciation
in terms of the
selection pressures
on the spider
populations
 comprehensively
evaluates the
mtDNA studies and
makes an accurate
conclusion about
the evolution of the
species
NØ
N1
N2
A3
A4
M5
M6
E7
E8
No
response;
no relevant
evidence
ONE
partial
idea
ONE A
point (or
TWO
partial)
TWO A
points
THREE A
points
TWO M
points
THREE M
points
ONE E
TWO E