Name: ________________________

B6 SPECIATION
Practice questions Class: ________________________

Date: ________________________

Time: 58 minutes

Marks: 58 marks

Comments: Biology Only

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 (a) Which of the following is the best definition of a species?
1
Tick ( ) one box.

Organisms with many features in common

Organisms that live in the same habitat and eat the same food

Organisms that reproduce together to form fertile offspring

(1)

(b) Figure 1 is a photograph of the Grand Canyon.

The layers of rock contain fossils.

© Sumikophoto/iStock/Thinkstock

Scientists found five fossils of different species of animal, P, Q, R, S and T, at the positions
shown in Figure 1.

(i) What is the evidence in Figure 1 that animals P and Q were alive at the same
time?

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(1)

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(ii) Was animal R alive at an earlier time or at a later time than animals P and Q?

Give the reason for your answer.

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(1)

(iii) Which two of the following would be evidence that animal T may have evolved
from animal S?

Tick ( ) two boxes.

The fossils of animals S and T have many features in common,

but T is more complex than S.

The fossils of animals S and T are the same size.

The fossils of animals S and T have the same skin colour.

The fossil of animal S was found in a deeper layer of rock than

the fossil of animal T.

The fossil of animal T is more similar to the fossil of animal R

than to the fossil of animal S.

(2)

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(c) Figure 2 shows two species of ground squirrel, W and X.

Squirrel W lives on the high ground to the south of the Grand Canyon.

Squirrel X lives on the high ground to the north of the Grand Canyon.

The land to the north of the Grand Canyon is about 300 metres higher than the land on the
south side. The north side also has lower winter temperatures and has more rain and snow
than the south side.

(i) The two species of squirrel are very similar.

Describe one way, which you can see in Figure 2, in which squirrel X is different from
squirrel W.

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(1)

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 (ii) The Grand Canyon was formed about 6 million years ago.

Explain how the two different species of squirrel could have developed from a
common ancestor.

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(6)

(iii) Squirrels W and X are separate species, but they are still very similar.

Suggest why the two species have not become more different over time.

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(2)
(Total 14 marks)

Darwin’s theory of evolution states that all species of living things have evolved from simple life
2 forms.

Darwin’s theory was published in 1859.

(a) Give two reasons why Darwin’s theory was only slowly accepted.

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(2)

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(b) Darwin observed birds called finches on the Galapagos Islands, 1000 km from the coast of
South America.

He saw that the birds were similar to, but not the same as, birds he had seen on the
mainland of South America.

Recent evidence suggests that 13 different species of finch on the islands evolved from 1
species of finch that arrived from the mainland about 1 million years ago.

Describe how a new finch species may have evolved from the original species of finch that
arrived from the mainland.

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(4)

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(c) The diagram below shows the evolutionary tree for some Galapagos finches.

(i) Which type of present-day finch is least closely related to all the others?

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(1)

(ii) Which branching point, P, Q, R or S, on the diagram above shows the most recent
common ancestor of all the tree finches?

Write the correct answer in the box.

(1)

(iii) Which two finches have the most recent common ancestor?

1. ____________________________________________________________

2. ____________________________________________________________
(1)
(Total 9 marks)

Page 7 of 21
 Howea forsteriana and Howea belmoreana are two species of palm tree.
3
The two species grow together on a small island in the South Pacific.

(a) What is meant by the term species ?

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(2)

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(b) The table gives some information about these two species of palm tree.

Howea forsteriana Howea belmoreana

Optimum pH of the soil for

pH 8 pH 6
growth of the palm tree

Height above sea level of

30 to 60 metres above 120 metres
most common habitat

Month when most palm trees

October December
flower

Method of pollination Wind carries pollen Wind carries pollen

Scientists believe that these two species of palm tree began to evolve from a single
species over 2 million years ago.

Suggest how these two different species developed.

In your answer you should use information from the table and your own knowledge.

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(5)
(Total 7 marks)

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 Figure 1 is a map showing a group of islands in the Pacific Ocean, near the coast of California,
4 USA.

Figure 1

A species of fox, called the Island Fox, lives on each of the six islands shown in Figure 1.

Figure 2 shows an Island Fox.

Figure 2

© GaryKavanagh/iStock

The foxes on each island are slightly different from those on the other islands.

The Island Foxes are similar to another species of fox, called the Grey Fox.

The Grey Fox lives in mainland California.

(a) Suggest how scientists could prove that the six types of Island Fox belong to the same
species.
Page 10 of 21
 ___________________________________________________________________

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(2)

(b) Scientists believe that ancestors of the modern Island Fox first colonised what is now Santa
Cruz Island during the last Ice Age, approximately 16 000 years ago. At that time, lowered
sea levels made the three northernmost islands into a single island and the distance
between this island and the mainland was reduced to about 8 km.

(i) How could the Island Fox have developed into a completely different species from the
mainland Grey Fox?

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(5)

(ii) Suggest why the Island Foxes have developed into different varieties of the same
species instead of six different species.

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(1)
(Total 8 marks)

Page 11 of 21
 (a) Fossils provide evidence for what early life forms were like. From the evidence, scientists
5 think that life began on Earth more than 3 billion years ago.

Many early life forms were soft-bodied.

Explain why this makes it difficult for scientists to be certain about what these early life
forms were like.

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(2)

(b) The illustration below shows two types of pistol shrimp.

The shrimps live in shallow, tropical seas on opposite sides of Panama.

Panama

Not to scale

Scientists put one Type A shrimp and one Type B shrimp together in a tank of seawater.
The two types of shrimp snapped their claws aggressively at each other.
They did not mate.

The scientists said that this was evidence for the Type A and Type B shrimps being
classified as two different species.

(i) Give one reason why the scientists’ opinion may be correct.

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(1)

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 (ii) Suggest two reasons why the scientists’ opinion may not be correct.

1. ____________________________________________________________

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2. ____________________________________________________________

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(2)

(c) Panama is a narrow strip of land which today joins North America and South America.
It was formed by land moving up from beneath the sea. Panama has separated the Pacific
Ocean and the Caribbean Sea for the past 3 million years.

Explain how two different species of pistol shrimp could have developed from an ancestral
species of shrimp.

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(6)
(Total 11 marks)

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 (a) How do fossils provide evidence that species alive today have evolved from simpler
6 organisms?

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(3)

(b) The photographs show two species of gull.

Herring gull (Larus argentatus) Lesser black-backed gull (Larus fuscus)

By Ken Billington (Own work) [CC-BY-SA-3.0],

By Andreas Trepte (Own work) [CC-BY-SA-2.5],
via Wikimedia Commons
via Wikimedia Commons

Both species are now found in the UK but the two species cannot interbreed with each
other. Scientists believe that these two species have evolved from a common ancestor.

The map on the next page shows a view of the Earth from above the North Pole.
The map also shows where these two species are found.

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Page 15 of 21
Suggest an explanation for the development of these different species.

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(6)
(Total 9 marks)

Page 16 of 21
Mark schemes
(a) organisms that reproduce together to form fertile offspring
1 1

(b) (i) fossils of P and Q in same stratum / layer / level / height

1

(ii) earlier − fossil in deeper layer / further down

1

(iii) the fossils of animals S and T have many features in common, but T is more
complex that S
1

the fossil of animal S was found in a deeper layer of rock than the fossil of
animal T
1

(c) (i) X has white tail / shorter tail

allow other points eg X has furrier tail / smaller feet / is furrier
or
W has sharper claws / W has larger claws
1

(ii) two (ancestral) populations separated / isolated (by geographical barrier / by

canyon / river)
1

genetic variation (in each population) / different alleles / different genotypes /

(different) mutation(s)
1

different environmental conditions / example described

allow abiotic or biotic example
1

the better adapted survive / natural selection occurs

allow survival of the fittest
ignore they adapt to the environment
1

so (different / favourable) alleles / genes passed on (in each population)

1

eventually two types cannot interbreed successfully

allow to produce fertile offspring
1

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 (iii) any two from:
• environments similar / described
allow example, e.g. similar predator(s) / food / climate
• therefore similar adaptations / features / phenotypes suit
accept suitable named feature
• original ancestor already well adapted
ignore reference to not enough time for evolution.
2
[14]

(a) any two from:

2
• most people still believed that God made all the animals / plants on Earth
allow against their ‘religion’
• insufficient evidence
do not allow no proof / evidence
ignore ‘fossil’
• the mechanism of inheritance / genes unknown (at the time)
2

(b) any four from:

• finches separated / isolated

• genetic variation / mutation (in finch population(s))
• finches with alleles / genes best suited to their environment survive
Do not allow ‘characteristics’
• advantageous alleles / genes passed on (to offspring)
• after many generations / a long time, the populations can no longer successfully
interbreed
Ignore ‘speciation’
4

(c) (i) vegetarian finch

1

(ii) R
1

(iii) mangrove and woodpecker finches

1
[9]

(a) organisms that can breed together

3
accept converse points re. 2 different species
1

successfully
accept produces fertile offspring
1

Page 18 of 21
 (b) any two from:
(live at)

• different pH of soil

• different height above sea level

• different flowering times

2

AND

genetic variation / mutation / different alleles (produced in isolated populations)

1

natural selection acts differently on the two populations

or different characteristics in the two populations survive

or different alleles passed on in the two groups

1

eventually resulting in interbreeding no longer possible

1
[7]

(a) reference to interbreeding

4 1
successfully between Island types
allow ref. to production of fertile offspring
allow ref. to DNA analysis / comparison for 1 mark
ignore ref. to grey fox
1

(b) (i) (two ancestral populations) separated / isolated (by geographical barrier / sea)
1
and genetic variation (in each population) or different / new alleles or mutations occur
1
under different environment / conditions
allow abiotic or biotic example
allow different selection pressures
1
natural selection occurs or better adapted survived to reproduce
1
so (favourable) alleles / genes / mutations passed on (in each population)

ignore they adapt to their environment

1

(ii) any one from:

• continued to mate with one another
• few beneficial mutations (between island varieties)
• similar conditions on each island so similar adaptations/features fit
1
[8]
Page 19 of 21
 (a) lack of fossils / fossils destroyed
5
allow lack of evidence
1

(due to soft parts) decaying / geological activity

allow an example – eg vulcanism or earth movements or erosion
allow converse points re skeletons, shells, hard parts
1

(b) (i) A and B did not mate successfully

‘ A and B did not mate’ insufficient
allow did not produce fertile offspring
1

(ii) any two from:

• may not be mating season

• A and B may not find each other attractive
• this is just a one-off attempt / an anomaly / need repeats
• may be juvenile / immature
• may be the same sex
allow other sensible suggestion eg were put in unfavourable
environment or one / both could be infertile
2

(c) 1. (two ancestral populations) separated (by geographical barrier / by land) / were
isolated
1

2. genetic variation (in each population) or different / new alleles or mutations

occur
1

3. different environment / conditions

allow abiotic or biotic example
1

4. natural selection occurs or some phenotypes survived or some genotypes

survived
1

5. (favourable) alleles / genes / mutations passed on (in each population)

1

6. eventually two types cannot interbreed successfully

allow eventually cannot produce fertile offspring
1
[11]

(a) fossil is (remains / impression of) organism that lived a long time ago
6
if numbers, ≥ 1000s years
1

Page 20 of 21
 fossils show changes over time or older fossils simpler or fossils simpler than present-day
species
1

fossils have similar features to present-day species

allow fossils allow us to compare old species with present-day
species
1

(b) isolation / separation / splitting

1

by geographical barrier / sea

ignore other examples
1

there was variation (in these isolated populations) / different alleles

accept mutation
1

different environmental conditions or example eg climate / predators / food

1

natural selection acted on the isolated populations

accept became adapted in each area
1

OR

only certain allele(s) passed on to offspring / different alleles passed on in different

environments
allow genes

so differences lead to inability to interbreed

allow differences described – eg mismatch of genitalia / different
courtship displays / different breeding seasons
1
[9]

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