classification

Question 1

A small population of Iberian lynx, Lynx pardinus, exists in parts of Spain. The Iberian lynx is critically endangered and, with around 100 individuals left, it is the world’s most endangered species of cat.The Iberian lynx and Eurasian lynx were once classified within the same species, based on their observable features.In the last 10 years, the Iberian lynx has been re-classified as a separate species within the genus Lynx, on the basis of its phylogeny.

Define the term phylogeny and explain how phylogeny is related to classification. Use the two lynx species as examples.

Answer 1

(phylogeny is) the evolutionary , relationship between /
history of , organisms / species ;
phylogeny is the basis of classification ;
example of molecular evidence used to classify ;
species / organisms , within the same group have
shared , phylogeny / evolutionary history /
common ancestor ; ora
idea that phylogeny of L. lynx and L. pardinus are
sufficiently , different to have been placed in
separate species / similar to have been placed
in same genus ;

Question 2

Suggest why it is only in the last 10 years that the Iberian lynx has been classified as a separate species.

Answer 2

modern / new / better , technology (to distinguish between
closely related species) ;
more , molecular / biochemical / DNA / genetic , evidence ;

Question 3

Outline three reasons why it is important to conserve the Iberian lynx.

Answer 3

idea of impact on food chain(s) ;
idea of right to exist / duty of humans to care for other
species / ethical reason / preserving species for
future generations ;
idea of aesthetic reason ;
economic reason / tourism / might provide useful
resource ;

Question 4

Explain how the selective breeding that led to this increased yield could have been done.

Answer 4

crossbreed / breed / interbreed , high-yielding , wheat
plants / individuals ;
assess / test / measure , yield / AW ;
crossbreed / AW , selected / best / high-yielding ,
offspring ;
over generations ;
marker assisted selection / prevent self-pollination /
genetic screening / prevent unwanted (cross)
pollination ;

Question 5

State two developments, other than selective breeding, that could account for the total increase in wheat yield per hectare.

Answer 5

(use of) fertiliser ;
(use of) pesticide / fungicide / insecticide ;
improved technology ;

Question 6

Tiktaalik roseae is a member of the kingdom Animalia. The structure of its individual cells has not been preserved by fossilisation.
State two features of cells of an organism from the kingdom Plantaethat would not have been present in the cells of T. roseae.

Answer 6

1 (cellulose) cell wall ;
2 chloroplast(s) ;
3 (large / permanent) vacuole ;
4 starch granules ;

Question 7

Fossils provide strong evidence that organisms have evolved over time.
Describe other types of evidence that support the theory of evolution.
In your answer you should describe some different types of evidence.

Answer 7

(similarities / differences in) genes / genetics / DNA /
RNA / molecules / biochemistry ;
(similarities / differences in) nucleotide / base ,
sequence / order ;
(similarities / differences in) cytochrome c /
haemoglobin / ATP synthase / RNA polymerase;
(similarities / differences in) sequence / order , of
amino acids (in proteins) ;
idea that similarities between any of the above implies
(close) relationship ; ora
dea of evolution within human history ;
similarities in / differences in / comparison of ,
embryology / morphology / anatomy / physiology /
behaviour ;

Question 8

Darwin made the following observation:
‘offspring generally appear similar to their parents‛ State the conclusion that Darwin drew from this observation.

Answer 8

characteristics / features / AW , are passed on to / inherited
(by the next generation) ;

Question 9

Why is natural selection now more widely accepted by scientists than it was in the 19th Century?

Answer 9

fits evidence ;
idea of more , evidence / research
(since nineteenth century) ;

Question 10

State the name given to the evolution of a new species.

Answer 10

speciation ;

Question 11

Suggest why a higher number of species have evolved in the Galapagos Islands, compared with an area of the same size on the South American mainland.

Answer 11

idea that different islands have different , selection
pressures / habitats / environments / vacant niches ; ora
idea of isolation ; ora

Question 12

Suggest one feature of the Chillingham cow that is likely to have changed during selective breeding to increase productivity.

Answer 12

udder size / milk production / meat production / growth rate

/ muscle (as proportion of body mass) ;

Question 13

Describe how modern cattle have been produced from less productive wild cattle ancestors.

Answer 13

artificial selection ;
(selection of) named desired feature (linked to
productivity) ;
(cross)breed , selected / AW , cattle ;
(cross)breed, best / selected / AW, offspring ;
over (many) generations ;

Question 14

State the meaning of the term phylogenyand explain how phylogeny is related to classification.

Answer 14

(phylogeny is) evolutionary relationships
(between organisms) ;
(phylogeny is study of) closeness of
(evolutionary) relationships ;
phylogeny is basis of / used in , natural /
scientific / modern, classification ;
idea that the closer the (evolutionary or
genetic) relationship the closer the
(taxonomic) grouping ;
correct use of example ;

Question 15

Water bears are extremely common in many habitats, including household gardens. However, they were not discovered until approximately 300 years ago.Suggest reasons why they were not known before this time.

Answer 15

too small to see ;
(unable to see them) until invention of microscope /
development of suitable viewing apparatus / AW ;
only 0.3mm in length ;

Question 16

Why is the key in Table 1.1 described as a dichotomous key?

Answer 16

(each question has) two options / AW ;

each question has yes or no option / AW ;

Question 17

Suggest an adaptation shown by at least one of the insects in Fig. 1.1 that allows them to survive in an aquatic habitat.

Answer 17

1 gills ;
2 streamlined (shape) / absence of wings ;
3 flattened shape ;
4 tail(s) / hind legs , for , propulsion / swimming
/ moving ;
5 blood pigment for storing oxygen ;

Question 18

An unknown species is discovered. Its cells contain many nuclei scattered throughout the cytoplasm of thread-like structures.
Suggest the kingdom to which this species belongs.

Answer 18

fungi

Question 19

Living organisms can also be classified into three groups called domains.Outline the features of this system of classification compared with the five kingdom system.

Answer 19

Assume answers refer to 3 domain classification unless
otherwise stated
based on (differences in) , DNA / RNA / nucleic acids /
polynucleotides ;
idea that more accurately reflects origins (of,
prokaryotes / eukaryotes) ;
(domain) divides / AW , prokaryotes ; ora
idea that domain reflects differences / AW , between
(eu)bacteria and archaea ;
example of two differences to support point 3 or 4 ;
(domain) groups / AW , eukaryotes together ; ora
idea that domain reflects the fact that there are
similarities between eukaryotic kingdoms ;
example of two or more similarities to support point 6 or
7 ;

Question 20

Suggest how the ability to use echolocation may have evolved from an ancestor that did not have that ability

Answer 20

natural / directional , selection ;
mutation ;
(mutation / genetic variation, is) random / due to
chance / spontaneous / pre-existing ;
selection pressure is lack of / competition for , food /
prey ;
individuals with mutation(s) / allele(s) / gene(s) (for
echolocation) , survive ; ora
(echolocation) allele(s) / gene(s) / mutation(s) ,
passed on ( to next generation) ;
over many generations frequency of , echolocation /
allele / characteristic , increases ;

Question 21

State two pieces of molecular evidence that can be used to identify organisms as belonging to different species.

Answer 21

genetics / genes / DNA ;
RNA ;
amino acid sequences ;
cytochrome C / fibrinopeptide ;

Question 22

Describe how it is possible to confirm, over a longer period of time, whether two organisms belong to different species or the same species.

Answer 22

(inter)breed / AW ;
determine if offspring are fertile ;
if offspring are infertile / no offspring produced,
 then different species ; ora
genetics / genes / DNA ;
RNA ;
amino acid sequences ;
cytochrome C / fibrinopeptide ;

Question 23

The soprano pipistrelle has an echolocation call that is ‘high pitched’ (between 52 and 60 kHz). The common pipistrelle has an echolocation call that is ‘low pitched’ (between 42 and 47 kHz).Variation within and between species can be as a result of genetic or environmental factors. Whatever the causes of variation, the type of variation displayed can occur in two different forms.
Using the pipistrelle as an example, describe the key features of both forms of variation.
In your answer you should make it clear how genes and environment relate to each form of variation.

Answer 23

continuous ;
(continuous / AW , is) effect of , many genes / polygenic /
genes and environment / genetic and environmental /
environment ;
quantitative ;
there is a range / any value is possible / intermediate values /
no distinct groups / AW ;
example to illustrate any C marking point ;
discontinuous ;
(effect of) one / few, genes ;
little / no, environmental effect ;
discrete categories / no intermediates / AW ;
example to illustrate any D marking point ;

Question 24

State two features of the malarial parasite that indicate that it is not a prokaryote.

Answer 24

nucleus / nuclei ;
other named organelle /
membrane bound organelles ;
linear chromosomes ;
DNA, associated with / AW, histones / protein ;
80S / 22nm / large, ribosomes ;
large cells / AW ;
no cell wall ;

Question 25

n a piece of word-processed homework, a student stated that one species of parasite that causes malaria is called:Plasmodium Vivax
State one error made by the student.

Answer 25

capital letter on, specific name / Vivax ;

not italicised / not underlined ;

Question 26

State two characteristics that birds, such as parrots, share with other members of the animal kingdom.

Answer 26

1 (cells have) no cell wall ;
2 heterotrophic ;
3 eukaryotic ;
4 multicellular ;
5 (fertilized eggs develop into), blastula / ball of cells ;
6 high degree of mobility / AW ;

Question 27

Name the domain to which the parrot belongs.

Answer 27

Eukaryota(e) / Eukarya / eukaryote(s) ;

Question 28

Using the information provided, suggest the likely genetic relationship between the three parrot species.

Answer 28

1 all are in same family as all, are closely related ;
2 kea and kaka are both, same genus / Nestor ; ora for kakapo
3 kea and kaka, are more closely related /
share more recent common ancestor,
(than with kakapo) ;
4 kea and kaka have more genes in common / AW
(than with kakapo) ;
5 example of genetic similarity (between kaka and kea) evident
from Fig 4.1 ;
6 differences between, kea and kaka / all three,
are great enough for each to be described as a
different species ;

Question 29

How does fossil evidence support the idea that evolution has taken place?

Answer 29

fossils show that organisms have changed over time ;
idea that fossils or rocks can be dated ;
idea of fossils showing intermediate forms / sequences ;

Question 30

Aphids can be killed using an insecticide. However, over a period of time, an increasing concentration of insecticide is required to control the aphid population. Explain why this is the case.

Answer 30

natural selection ;
insecticide is the , selective agent / selection pressure ;
idea of mutation / (genetic) variation ;
random / naturally occurring ;
resistant survive / non-resistant die ;
(resistants will) pass on , allele / mutation , for
resistance (to offspring) ;
higher proportion of / more , resistant individuals in
population ;
idea that resistance allele confers resistance only to a
small dose of insecticide ;

Question 31

Explain how fossils provide evidence for the theory of evolution.

Answer 31

idea of fossils show changes over time ;
idea that there are methods to date fossils ;
idea of simplest / most different from modern , species /
AW , in oldest rocks ;
idea of showing , links / relationships , between , groups /
species / organisms / taxa ;
many fossils organisms no longer exist ;
idea of compare DNA extracted from some fossils ;

Question 32

Suggest how the information obtained by DNA analysis can be useful to taxonomists.

Answer 32

(information used to) decide which, group / taxon, organism
/ species / named example, fits in ;
compare the proportion of (different) bases ;
compare the DNA / genes / sequence of bases ;
idea of: the more similar the, DNA / genes, the closer the
relationship / AW ;

Question 33

State two types of evidence, other than biochemical evidence, that are used by taxonomists when classifying organisms.

Answer 33

fossil record ;
anatomy / physiology / behaviour ;
embryology / AW

Question 34

Suggest why the findings from the museum specimens may not relate closely to the current pine marten population of the United Kingdom.

Answer 34

no DNA from living specimens in Wales analysed ;
population (may have) evolved / mutations have occurred /
genetic variation, (since 1948) ;