Speciation & evolution questions from VCAA Exams with answers

Speciation & Evolution Questions from VCAA Exams (includes answers)

2009

Question 11

A mutation is

A. a product of natural selection.

B. caused by immigration and emigration.

C. a change in an allele due to a change in DNA.

D. a random change in gene frequencies from one generation to the next.

77% got this correct

Question 12

The 200th anniversary of the birth of Charles Darwin is celebrated in 2009.

In the development of his ideas on evolution, Darwin proposed that

A. all members of a species have an equal chance of survival.

B. offspring look more like their parents than they do to unrelated people .

C. individuals in a population have the same chance for reproductive success.

D. environmental changes that change the structure of individuals are transmitted to the next generation.


Question 14

A small population of copper-coloured butterflies was found in Eltham in 1938. The butterfly has since been found in one location in Castlemaine and six locations at Kiata. The butterfly lays its eggs on the native shrub sweet bursaria ( Bursaria spinosa ) and the larvae shelter in the nest of the Australian ant ( Notoncus emery ). After 1956 it was thought that the butterfly was extinct, but it was found again in 1986.

Extinction of the copper butterfly from all three areas would best be prevented by

A. moving the populations to one area to give greater genetic diversity.

B. planting more sweet bursaria in reservation areas at all locations.

C. burning off local undergrowth to remove competitive weeds.

D. removing the nests of all Australian ants.


Question 15

In 2006, two separate palaeontology laboratories were set up in the Sahara desert. Laboratory 1 uncovered a burial site that contained human remains. Over 200 human remains were found and they were dated from 10 000 to 4500 years ago. Laboratory 2 discovered a 110 million-year-old plant-eating dinosaur, Nigersaurus , in a nearby area in a different sedimentary layer.

To date the fossils accurately the two groups of palaeontologists would most likely have used

A. carbon-14 dating for both the human and dinosaur remains.

B. uranium-235 dating for both the human and dinosaur remains.

C. uranium-235 dating for the human remains and carbon-14 dating for the dinosaur remains.

D. carbon-14 dating for the human remains and uranium-235 dating for the dinosaur remains.


Question 16

In 1954, copper waste in the Finniss River killed numerous fish. This caused various species in the area to die out. However, one species, the black-banded rainbow fish, increased in numbers.

The black-banded rainbow fish have modified gills that enable the fish to filter and remove the copper before it enters their body. With respect to the black-banded rainbow fish it is reasonable to conclude that

A. a mutation occurred in their population in 1954.

B. the ability of their gills to remove copper already existed in 1954.

C. the high levels of copper in the water changed the structure of their modified gills.

D. their genomes are identical with those of the other species of fish that existed in 1954.


Question 19

Convergent evolution is

A. also known as adaptive radiation.

B. responsible for the development of analogous structures.

C. the splitting of an ancestral group into two different species.

D. the independent development of similar features in related species.


Question 21

Examine the following primate evolutionary tree.

Analysis of the evolutionary tree above shows that

A. gibbons and old world monkeys are unrelated.

B. lorises is the oldest group in the evolutionary tree.

C. the most recent group to evolve separately is humans.

D. chimps and humans are more closely related than gorillas and chimps.


Question 22

Scientific opinion was once evenly divided regarding the geographical origin of the modern human. Two hypotheses were put forward – the ‘Out-of-Africa’ hypothesis and the ‘Multi-

Regional’ hypothesis. In general, researchers now accept that the Out-of-Africa hypothesis is better supported by current information. Findings from worldwide human fossil sites which would best support the Out-of-Africa hypothesis include

A. dating of fossils by radioactive uranium.

B. the degree of decomposition of remains.

C. the present-day climate of the region.

D. variations in mitochondrial DNA.


Use the following information to answer Questions 23 and 24.

A scientist took a small population of 10 flowering plants and conducted an experiment to examine the change in allele frequencies over three generations. The plants were grown in identical conditions, in a controlled environment. Within the flowering plants the presence of the

R allele allows red flowers to be produced, while white flowers can only be produced when the rr genotype is present.

Question 23

The most likely reason for the population of flowering plants having more rr genotypes and white-flowered phenotypes after only three generations is

A. genetic drift.

B. natural selection.

C. divergent evolution.

D. convergent evolution.


Question 24

The allele frequency of the r allele changed during the course of the experiment. Allele frequencies for the r allele in Generation 1 and Generation 3 are

Generation 1 Generation 3

A. 0.3 0.8

B. 0.8 0.3

C. 0.7 0.3

D. 0.3 0.7


Question 3

The endangered pygmy possum ( Burramys parvus ) lives in three restricted alpine areas, Mt

Buller, Bogong High Plains and Mt Kosciusko.

About 2000 individuals remain in the wild. Studies show that there is a lot of genetic diversity between the three populations. Due to the isolation of these populations, scientists think that each population has a separate gene pool. d. Explain what is meant by gene pool.

The sum of alleles within a given population

The term ‘gene pool’ was not well understood. It is incorrect to state that it is the genes in a population. Incorrect responses given by students included variation (this could be environmental), genotypes, allele frequency or traits in a population, or the sum of alleles in an individual, species or community.

1 mark

45% got this correct e. Explain how exchange of genetic material may be beneficial in the survival of endangered species like the pygmy possum.

Both of:

• increase in genetic diversity/variation

• the greater the variation within a species, the more likely it is able to survive a change in the environment.

Many students did reasonably well on this question; however, many did not take the consequences of genetic variation to completion, for example, ‘to help the possums survive’ was deemed too vague to be awarded the mark.

2 marks

33% got 0, 33% got 1, 34% got 2

Question 4

In 1877, German workers found a slab of stone containing the fossil of an ancient bird form.

The fossil bird was called Archaeopteryx . a. i. Describe how this fossil could have been formed.

The bird was rapidly covered by sediment, and one of:

• hidden from scavengers

• decreased rate of decomposition

• undisturbed

• long time.

This question was poorly answered. Too many students stated that the fossil was buried under rock or lava. The sediments, over time, form rock. ii. Scientists use information gained from sedimentary rock to arrange animal and plant fossils into some kind of evolutionary sequence over time. Explain how such sequencing is possible.

Both of:

• stratigraphy is where layers of sediment build up over time

• the oldest fossils are found in the lowest stratum (or the converse).

Students could also have suggested radioisotopic dating and described how the sequence could be determined. If students answered in this way it was difficult to gain marks as they did not relate their answer to the sequencing.

1 + 2 = 3 marks

32% got 0, 35% got 1, 23% got 2, 10% got 3

b. i. Name one isolation barrier involved in allopatric speciation.

Mountain range/dry ground/road/or any other suitable answer

A common incorrect answer was geographic isolation. ii. Explain how isolation may result in speciation.

All of:

• the two separated populations have different gene pools/genetic variation/mutations present

• different selection pressures/environments/natural selection acts on each population

• if the two populations, when brought together, do not produce fertile offspring, they are different species

Many students were able to gain three marks for this question. They set out clear and logical answers, taking advice from previous Assessment Reports. The question allowed for a broad range of responses. Too often students incorrectly wrote that ‘the environment caused mutations which were advantageous’. Unlike similar questions in past examinations, students were able to choose their own example of an isolation barrier and describe speciation in general terms.

1 + 3 = 4 marks

26% got 0, 18% got 1, 23% got 2, 25% got 3, 8% got 4

Question 6

The press recently reported:

‘Anthropologists have uncovered ancient fossil footprints in Kenya dating back 1.5 million years, the oldest evidence that indicates our ancestors walked like present-day humans . . .’ a. Give one significant feature of the footprints that would have led anthropologists to this conclusion.

Any of:

• big toe is arranged parallel to other toes

• big toe is not opposable

• prints indicate two feet, not four, or the use of hands/knuckles.

1 mark


The pictures below show views of skulls from Homo erectus and Homo sapiens . b. With reference to two structural features of the skull, which skull set represents Homo erectus ? Justify your choice.

Set 2 and two of:

• prominent brow ridge

• smaller cranial capacity

• face protrudes more

• foramen magnum is positioned further back.

Some students gave too much information, some of which was incorrect. It is advisable that students give their best answer first. Students should only give the number of reasons asked for in the question.

2 marks

21% got 0, 26% got 1, 52% got 2

According to one interpretation of the hominid fossil record, Homo habilis is thought to have existed about 2 million years ago. c. What kind of discoveries have been made at Homo habilis sites that have increased our understanding of the technological evolution of hominids?

Evidence of:

• tools

• use of fire.

1 mark


‘The rate of technological evolution has been increased by cultural evolution of

Homo sapiens

.’ d. i. Describe one example of the effect that cultural evolution has had on the rate of technological evolution.

Articulate speech/writing/painting/ceremonies enabled information to be passed on.

Cultural evolution depended on the development of physical capabilities of the Homo genus. ii. What physical feature has played the most important role in this advancement?

How has this feature developed over evolutionary time?

Any of:

• the brain – an increase in capacity leads to greater processing of information

• precision grip led to the ability to make tools for fine manipulation

• structures involved with speech led to communication through speech.

Arguably, modern Homo sapiens has taken the manipulation and control of the environment to its highest level in history. iii. Does this mean that our species will no longer physically evolve by the mechanism of natural selection?

Justify your answer.

• yes – medical advances or genetic manipulation mean that modern humans are interfering in their own selection to the extent that natural selection no longer operates

• no – humans still exist in many different environments and are still subjected to different selective pressures, for example, disease

Students could argue either for or against the statement; however, a mark was only awarded if a reasoned argument was presented.

1 + 1 + 1 = 3 marks

31% got 0, 33% got 1, 26% got 2, 11% got 3

2008

Question 10

The highest level of genetic variation in mitochondrial DNA in modern-day humans occurs in

African populations.

The most likely explanation is that

A. Homo sapiens evolved in Africa.

B. mitochondrial DNA has a higher mutation rate in African environments.

C. gene flow occurred between Homo sapiens and other Homo species in Africa.

D. natural selection does not operate on mitochondrial DNA in African environments.


Question 11

In his theory of evolution by natural selection, Darwin

A. described the role of DNA as the material of inheritance.

B. used evidence from Mendel’s experiments on pea plants.

C. stated that favourable alleles were passed on from parents to offspring.

D. proposed that particular characteristics suit an organism to its environment.


Question 12

Two hominin (also called hominid) skull fragments were found in separate locations and each was associated with a number of artefacts. Skull X was dated and shown to be 100 000 years old, while skull Y was dated at 20 000 years old.

The artefacts most likely discovered with skull Y but not skull X would be

A. fireplace fragments.

B. stone tools for cutting.

C. pigment used in rock paintings.

D. bones from hunted animals.


The following information relates to Questions 15 and 16.

The following table shows a stratigraphic section of rock. Scientists found that fossils A and C had analogous structures.

Question 15

From the data it can be concluded that

A. fossil A is less than 5 million years old.

B. fossil D is the youngest fossil present.

C. fossils A and C are closely related.

D. fossil B is extinct.


Question 16

Fossils A and C both have limb-like appendages.

As they had analogous structures then they must have shared very similar

A. DNA sequences.

B. RNA sequences.

C. habitats.

D. selection pressures.


Question 22

Australian Eucalyptus trees characteristically have two types of leaves, a juvenile (young) form and an adult form. The juvenile leaves are held horizontally and are relatively large and broad, while the adult leaves hang vertically and are long and narrow. Typical juvenile and adult leaves are shown below.

A selection pressure which is likely to have had the greatest influence on the evolution of the juvenile leaf shape and position would be

A. competition for light.

B. unpredictable rainfall.

C. browsing by herbivores.

D. high ambient temperatures.


Question 23

Lucilia cuprina , the sheep blowfly, lays its eggs in wounds and the wet fleece of sheep. The larvae hatch and burrow into the sheep’s skin, causing distress, reduced wool production and sometimes death. Particular chemicals were used in the past to control the L. cuprina but these became less effective as sheep blowfly developed a resistance to the chemicals.

The cause of the increased resistance to the chemicals was most likely due to

A. farmers successively reducing the levels of insecticide applied to sheep.

B. the insecticide producing a change in a gene which enhanced the survival of the blowfly.

C. a chance mutation in a blowfly gene conferring a survival advantage in the chemical environment.

D. the insecticide producing a change in phenotype which enhanced reproduction of the blowfly.


Question 24

Consider the following diagram that represents one type of evolution.

It may be concluded that

A. species Q and R could be the result of parallel evolution.

B. species Q and R could be the result of convergent evolution.

C. species P would appear in the fossil record later than species R.

D. species Q and R could have arisen through a process of allopatric speciation.


Question 25

Since the introduction of the poisonous cane toad to Australia in 1935, there has been an increase in the ratio of body length to head size in two species of snakes, the Red-bellied Black Snake and the Green Tree Snake. A smaller headed snake cannot consume a large prey item, and so cannot swallow a large cane toad that has sufficient toxin to kill the snake. The rapid evolution of body dimensions in the Red-bellied Black Snake and the Green Tree Snake most likely came about because

A. cane toad toxin reduced the head size of the snakes.

B. even small cane toads contain enough toxin to kill a long-bodied snake.

C. smaller headed snakes are better at catching cane toads than large headed snakes.

D. larger headed snakes were killed by the levels of toxin ingested when they ate a large cane toad.


Question 5

Three different kinds of plants, a cactus, euphorbia and milkweed, have similar adaptations for growing in desert environments. They all have long, fleshy stems for water storage, protective spines and reduced leaves. Both the euphorbia and milkweed plants are believed to have evolved from leafy plants adapted to more temperate climates. They share a more recent ancestor than either one does to a cactus. a. Draw an evolutionary tree (also called phylogenetic tree or cladogram) to demonstrate this relationship.

1 mark

72% got this correct b. Name the process by which the ancestral leafy euphorbia plant could have given rise to the desert-adapted species described above.

Natural Selection

1 mark

58% got this correct c. What is a possible explanation for there being so few cactus fossils?

Either of:

• lack of sedimentation

• lack of hard parts.

For students to gain the mark, it was important that they named a necessary condition for fossilisation or identified that the lack of a specific condition would have prevented fossilisation.

Vague statements such as ‘incorrect conditions for fossilisation’ did not score a mark.

1 mark


Question 7

The relatively abundant Green-eyed Tree Frog ( Litoria genimaculata ) inhabits tropical rainforest in Far North ueensland. There are two main populations, a north and a south population.

L. genimaculata has a green crescent across its upper eye and a ridge along the back of its limbs.

It has mottled colouring and can vary from light brown and green, to grey with reddish blotches. a. State a phenotypic characteristic of L. genimaculata and suggest a possible selection pressure acting on this characteristic.

• phenotypic characteristic: colour of skin

• selection pressure: camouflaged from predators

1 mark


The critically endangered Kuranda Tree Frog, Litoria myola , is found in very small populations in isolated fragments of wet tropical rainforest near Cairns in Queensland. The two species, L. myola and L. genimaculata , are very similar in appearance, although the male L. genimaculata is larger than the male L. myola . Biologists have also found that their mating calls differ markedly.

There is some overlap between the ranges of these three frog groups.

The following diagrams show the distribution of the frogs, and the characteristics of their calls.

b. Examine the data in the graphs and describe two differences between the mating calls of L. myola and L. genimaculata .

Two of L. myola has:

• a longer mating call than L. genimaculata

• a faster note rate than L. genimaculata

• a higher pitch than L. genimaculata.

This part was well answered and most students correctly interpreted the data. Some students needed to take greater care in constructing their answers, for example, stating that ‘L. myola mates more frequently and faster than L. genimaculata’ has a completely different meaning.

2 marks

6% got 0, 13% got 1, 80% got 2

Scientists now believe that L. myola evolved from the L. genimaculata about 8000 years ago. It is proposed that a population of Green-eyed Tree Frogs became isolated due to changing climate conditions. c. Suggest how changing climate conditions could have isolated small populations of rainforest frogs.

Either of:

• pockets of rainforest may have changed and become more or less favoured by frogs

• some ponds may have dried up restricting location of frogs.

The condition that isolated the groups had to be permanent, due to climate change, and relevant. Some incorrect suggestions were flooding (not a permanent event), mountains, (not climatic) and volcanoes (not relevant).

1 mark

21% got this correct d. What is one type of evidence that biologists could use to estimate an approximate date of divergence of these two species?

Extent of differences in:

• mitochondrial DNA

• DNA

• amino acid sequence. or

A description of fossil or stratigraphic evidence, such as ‘the sequence of fossils are observed to determine when divergence occurred’.

1 mark


e. Describe how L. myola could have evolved from L. genimaculata

. (Use the terms ‘allele frequency’ and ‘gene flow’ in your answer.)

All of:

• for many generations, a small population of L genimaculata was isolated by changed geography due to climate and there was no gene flow (or allele flow) between the populations

• allele frequencies in the small population changed (particularly with respect to size and mating call) due to natural selection or genetic drift

• eventually the two groups are different enough to prevent successful reproduction.

Many students failed to recognise that this was a question on speciation. Many students wrote a sentence using the words required with no additional information.

3 marks

58% got 0, 17% got 1, 14% got 2, 11% got 3

In northern areas, where the distributions of the two species overlap, a few hybrid offspring

(1.4% of the population) have been observed, resulting from matings between the two species.

Biologists wish to establish whether or not the Green-eyed and Kuranda Tree Frogs are, in fact, distinct species. f. How could biologists determine this experimentally?

Either of:

• interbreed the two species and if they produce viable and fertile offspring, they are the same species

• interbreed the two species and if they do not produce viable or fertile offspring, they are not the same species.

To gain the mark for this question students needed to state what could be concluded from their suggestion.

1 mark


Question 8

Two paleoanthropologists each used fossil data to draw a model of the human evolutionary tree.

The two models they produced are shown below. a. Explain how it is possible that the paleoanthropologists produced different models for the human evolutionary tree.

Different palaeontologists may make different interpretations of the same data.

1 mark

25% got this correct b. i. State one feature of agreement between the models.

Either of:

• Australopithecus afarensis evolved about three million years ago

• Homo heidelbergensis evolved from Homo ergaster (about one million years ago). ii. State one feature of confl ict between the models.

Any of:

• Homo erectus evolved from Australopithecus afarensis in Model 1

• Homo erectus evolved from Homo ergaster in Model 2

• Model 2 shows linear evolution from Australopithecus afarensis.

1 + 1 = 2 marks

14% got 0, 32% got 1, 55% got 2

c. Give two structural features that would distinguish between the fossils of Homo erectus and

Australopithecus afarensis .

Homo erectus had:

• a larger brain case

• a less prominent brow ridge

• a more parabolic jaw. or

Correct statements with respect to teeth size or position of foramen magnum received one mark for each correct feature named.

Many answers were not structural, such as type of diet. Other incorrect answers included, placement of eyes, sagital crest and hair. Size of brain is incorrect as this can only be inferred; the size of the brain case is the feature.

2 marks

Evidence suggests that Homo sapiens and Homo neanderthalensis were living in the same areas some 30 000 years ago, but did not interbreed. d. Give one reason why interbreeding might not have occurred.

Any of:

• different customs and lifestyle prevented interbreeding

• different mating behaviour or rituals

• mating occurred, however, viable offspring were not produced.

32% got 0, 35% got 1, 33% got 2

A common incorrect answer was that the two species were geographically isolated, yet the stem of the question stated that the two species ‘were living in the same area’.

1 mark


Scientists have recently discovered a tiny fossil skull in Indonesia. It has been named Homo floresiensis (the hobbit) and dated to the time our own ancestors were colonising the world.

Some scientists believe Homo floresiensis evolved from Homo erectus . Fossils of Homo erectus have also been discovered in Indonesia. e. Modify one of the models below to include Homo floresiensis .

1 mark


There is still some debate about what the hobbit is. Two explanations have been proposed.

Explanation 1

– The hobbit belongs to a species of small-brained dwarf humans.

Explanation 2 – The hobbit is a Stone Age Homo sapiens with a disease that stunts brain development. f. i. Suggest one piece of evidence that would support explanation 1.

If adult and child fossils of Homo floresiensis were found that had skulls indicating all had the same small brain characteristic. ii. Suggest one piece of evidence that would support explanation 2.

If fossils were found in the same area and had normal sized skulls.

If adult and child fossils of Homo sapiens were found in the same area and had skulls indicating child brain size much larger than that of the fossil called Homo floresiensis.

1 + 1 = 2 marks

89% got 0, 9% got 1, 1% got 2

2007

Question 5

Biologists have suggested for a long time that reptiles evolved from fish-like ancestors. Recently, a 375 million year-old fossil fish ( Tiktaalik roseae ) was found in Canada. This fossil had fins, scales and a lower jaw like those of a fish but had a crocodile-like skull, a mobile neck and forelimb bones resembling those of early reptiles.

Relative to fish and crocodiles, this rare Tiktaalik fossil represents an example of

A. a transitional form.

B. an index fossil.

C. convergent evolution.

D. coevolution.


Question 6

According to modern evolutionary theory, changes to genetic material in mammals can only be inherited by the next generation if

A. they occur in somatic tissue.

B. they occur in reproductive tissue.

C. they make the species Þ tter.

D. they make the individual Þ tter.


Question 7

Comparison of sequences in mitochondrial DNA is often used to establish the degree of relatedness between organisms and thus to suggest evolutionary relationships, particularly in complex, higher-level organisms.

Mitochondrial DNA is used because it

A. is only inherited in males.

B. has more genes than nuclear DNA.

C. mutates more slowly than nuclear DNA.

D. contains different nitrogen bases from those found in nuclear DNA.


Question 11

The relationship between genome and organism is equivalent to the relationship between

_________ and population.

A. species

B. gene pool

C. gene

D. allele


Question 16

For allele frequencies to remain constant in a population it is essential that

A. mutations occur.

B. genetic drift occurs.

C. mating occurs at random in the population.

D. there is regular migration into the population.


Question 17

Lactase is an enzyme in humans which breaks down lactose, one of the sugars in milk. Milk is a safe and nutritious food which is readily available year-round. Although most adults around the world lose the ability to produce lactase as they mature, more than 90% of Europeans have a lactase-producing allele which remains active into adulthood.

Scientists analysed DNA in bone samples from a number of Neolithic Europeans (dated between

5840 BC and 5000 BC) and found that none of them had the adult lactase allele. The most likely explanation for this data is that

A. the adult lactase-producing allele which remains active into adulthood arose millions of years ago in ancestors of modern humans.

B. possession of the adult lactase-producing allele which remains active into adulthood confers a significant evolutionary advantage.

C. the adult lactase-producing allele which remains active into adulthood did not arise in Europe.

D. modern Europeans are not descended from the Neolithic Europeans tested.


Question 18

Excavations at a fossil site uncovered a layer of ancient flood debris. The layer consisted of stones and sand, mixed with fossilised plant and animal remains. The debris had been deposited in a rocky river valley and then covered with fine sandy sediment which was dated to approximately 10 million years ago.

In this situation it is true that

A. the fossils are less than 10 million years old.

B. the rocks of the valley walls are younger than the fossils.

C. the plants and animals lived in the same habitat.

D. the stones mixed with the fossils cannot be younger than the fossils.


Question 19

Traces of starch from wild barley ( Hordem ) and wheat ( Triticum ) species were found on a 2300year-old seed-grinding stone used by ancient humans in Israel.

The method which would have been used to date these ancient starch grains is

A. radioactive carbon-14 dating.

B. radioactive uranium-235 dating.

C. relative dating by comparing rock strata.

D. the use of a molecular clock.


Question 21

Cytochrome-c is a protein found in most organisms. The amino acid sequence of this protein varies between species. The numbers of differences in the amino acid sequences in the protein of cytochrome-c between three species of chordate A, B and C are shown in the table below.

Based on this evidence, the phylogenetic tree that best represents the possible evolutionary relationships between the three species is


The answer is B.

Question 22

This diagram illustrates one interpretation of the origin of humans. The dotted lines indicate possible evolutionary relationships, and the vertical bars show the period from which fossils are known for each species.

This diagram suggests that

A. Homo habilis is an ancestor of modern humans.

B. Homo sapiens is descended from Paranthropus aethiopicus .

C. Homo erectus became extinct before modern humans appeared.

D. Australopithecus species may have given rise to modern humans.


Question 24

Complex social activities require articulate speech. Evidence found with early Homo fossils suggests that this genus was the first to use articulate speech.

This suggestion would be best supported by evidence of

A. burial ceremonies.

B. use of stone tools.

C. living in groups.

D. organised hunting of prey.


Question 5

Eastern tiger snakes ( Notechi scutatus ) living on desolate islands off mainland Australia have longer jaws than the mainland populations of snakes. The diet of island snakes includes large prey, such as seagull chicks, while the diet of the mainland snakes consists of small prey, such as frogs and mice.

Researchers set up experiments using baby snakes from both locations. Snakes were fed either large or small mice over several months, until they reached maturity. The method and results are indicated in the table below. a. What were the researchers investigating in these experiments?

The effect of the diet on the size of the jaw.

1 mark

65% got this correct b. What was the independent variable in experiment 1?

The size of the prey given.

‘The type of prey’ was deemed too vague, as other types of prey were listed in the stem of the question.

1 mark

38% got this correct c. What evidence from the results suggests that the size of eastern tiger snakes’ jaws is i. a genetically inherited trait

Mainland snakes (groups C and D) had normal jaw length at maturity.

ii. affected by environmental factors?

Island snakes’ (groups A and B) jaw length increased in size when large prey was eaten.

1 + 1 = 2 marks

31% got 0, 19% got 1, 22% got 2, 27% got 3

At present the island and mainland populations are both classfied as the same species. It has been proposed that the two populations of snakes may eventually evolve into two separate species. d. Outline the steps involved in the process of speciation, with particular reference to the snakes in the two populations. You may use a labelled diagram or flow chart to illustrate your answer.

Students needed to make the following points in their responses:

• the island and mainland snakes were geographically isolated or no gene flow

• each population experienced different selection pressures

• populations, if reintroduced, were unable to produce viable fertile offspring.

This question was well answered and many students set out their answers in a clear and concise way. They also related the information to the snakes and a few students included diagrams to assist their explanation (although a diagram was not required to achieve full marks). Incorrect terms that were used included ‘geologically separated’ and ‘environmental pressure’. It is important to note that not all environmental pressures act as selective pressures.

3 marks

31% got 0, 32% got 1, 37% got 2

Question 7

A complete skeleton of Thylacoleo carnifex , a huge marsupial ‘lion’, was found in a cave in the

Nullarbor Plain. Further exploration uncovered more specimens of Thylacoleo as well as other extinct mammals, some previously unknown to science. The specimens of Thylacoleo were dated to be between 100 000 and 200 000 years old. In attempting to date the other mammal specimens, scientists had a range of methods available. a. Describe a relative dating technique which could be used to date the extinct mammals.

Stratigraphy could be used, where the relative age of a fossil can be determined by the position of that stratum.

This question was very poorly answered as many students did not understand the term ‘relative dating’ and described absolute dating, using an element with a known half life.

1 mark


Thylacoleo had powerful jaws with only two types of teeth, one type for killing and one type for slicing meat. It had short, strong limbs and opposable thumbs with prominent claws. It has been compared with large placental carnivores such as lions. b. What kind of evolution has produced similar characteristics in Thylacoleo and lions?

Convergent evolution

Some students incorrectly used the term ‘co-evolution’ and a number of sudents used the term

‘parallel evolution’.

1 mark

59% got this correct c. Describe two methods by which Thylacoleo is likely to have obtained its food, and state the evidence that supports your answers.

2 marks

12% got 0, 19% got 1, 70% got 2

Question 8

Pseudogenes are the remains of broken genes which are unable to function and can be considered to be genetic fossils. Some are relics of genes lost through evolution while others reflect an earlier version of a present functional gene. Pseudogenes are able to accumulate all kinds of mutations.

The gene G in mice makes an enzyme that helps synthesise vitamin C, but this gene became faulty in primates more than 40 million years ago and is now a pseudogene in humans. a. What is one possible consequence of the loss of gene G in primates?

Inability to synthesise Vitamin C so it must be obtained from the diet.

1 mark


In mammals, more than one thousand genes coding for smell receptors have been identified.

Individual species vary in the proportion of these genes that have become pseudogenes, and humans have fewer than 500 functional genes coding for smell receptors. The majority of these genes are still functional genes in rats and mice.

b. From the graph, what can be concluded about the importance of smell to the survival of these four groups?

Smell is most important to dogs and mice and least important to apes and humans.

Students were required to use the names of the specific examples given rather than making general statements.

1 mark

59% got this correct c. Mice and dogs can only distinguish shades of grey, while some apes and monkeys are able to distinguish colours. Would you expect to find any change in the numbers of smell pseudogenes in apes and monkeys able to distinguish colours? Explain why.

Students needed to make both of the following points:

• apes and monkeys are less dependent on smell or more dependent on vision

• they would therefore have more pseudogenes or less smell genes.

This question was poorly answered as many students did not make the link that, as smell is less important to these animals, mutations are possible in genes responsible for smell as these will not affect the organism’s chance of survival. These mutated genes are classed as pseudogenes.

Students who gained both marks clearly explained the outcome for both types of genes. Many students used the pronoun ‘they’ and it was not possible to interpret which gene was being discussed.

1 mark

20% got this correct d. Why are pseudogenes able to accumulate mutations that do not exist in functional genes?

Students needed to make both the following points:

 pseudogenes are not expressed and any mutation in them does not harm the offspring when passed on

 functional genes become inoperative or produce a different protein which could affect the survival of offspring.

2 marks

76% got 0, 16% got 1, 8% got 2

Question 9

There are two varieties of lice which live on humans: body lice which only live in clothing but feed on the body, and head lice which only live in hair and feed on the scalp. It is not known when humans began wearing clothes. It is difficult to find evidence of cultural evolution in early humans as changes in behaviour are rarely reflected in physical changes visible in fossils.

However, indirect evidence can be found.

A scientist used DNA hybridisation to measure differences between the DNA of head lice and body lice. He estimated that the two groups diverged about 72 000 years ago. a. Explain how DNA hybridisation can be used to determine evolutionary relationships.

Students needed to make both of the following points:

• DNA hybridisation involves the dissociation of different samples of DNA and their reassociation, providing a measure of similarity

• the greater the similarity of the DNA (determined by melting temperature), the more closely related the two organisms are from which the samples were taken.

Many students demonstrated a sound understanding of the process of DNA hybridisation, which was pleasing. The inference of close relationship due to the degree of hybridisation was not clearly made by many.

2 marks

55% got 0, 23% got 1, 22% got 2 b. A scientist claimed to have found other evidence showing the time at which humans began wearing clothes. What might this evidence have been?

Any one of:

• artefacts associated with the production of clothing, such as bone needles

• fossilised remains of clothing

• cave paintings showing humans wearing clothes.

Common incorrect answers involved the presence of fossilised lice or of preserved humans showing less hair.

1 mark


c. Explain a possible advantage for lice of living in clothing.

Living in clothing provided the lice with:

• a warm environment

• close contact to the whole body

• more places to hide

• an easier way to transfer between hosts.

A common error was that many students stated that the lice ate the clothes, whereas the stem stated ‘the lice live in the clothing but feed on the body’.

1 mark


2006

Question 16

The founder effect and bottleneck are examples of

A. gene flow.

B. speciation.

C. genetic drift.

D. selection pressures.


Question 17

The shark (a fish) and the dolphin (a mammal) are an example of

A. convergent evolution.

B. allopatric speciation.

C. divergent evolution.

D. species radiation.


Question 18

During a volcanic eruption molten material called magma comes out of the volcano, cools and solidifies on the surface of the earth forming basalt. Volcanic ash, also from the eruption, is deposited near the basalt and may contain well-preserved fossils.

The surrounding basalt can be useful to date fossils in the strata formed by the ash because

A. eruption dates of volcanoes are known from historical data.

B. organic remains are baked and preserved in the basalt.

C. radioactive elements within the basalt can be accurately dated.

D. the basalt may contain an index fossil.


Question 19

There is little fossil evidence of the earliest forms of life because the organisms

A. decayed quickly in the oxygen-rich atmosphere.

B. did not have hard parts which would fossilise easily.

C. evolved so quickly that they left few remains.

D. lived in water and were not preserved.


Question 21

Hominids are believed to have evolved in Africa because

A. the oldest hominid fossils have been found in Africa.

B. the most hominid fossils have been found in Africa.

C. monkey fossils were found in Africa.

D. Africa is the oldest continent.


Question 22

Consider the following diagrams of skulls.

The skull most likely to be that of a chimpanzee is

A. W

B. X

C. Y

D. Z


Question 23

There is evidence that Homo sapiens and Homo neanderthalensis coexisted in Europe more than

30 000 years ago. Both of these species left signs of cultural evolution from this period. An example of evidence which would show that cultural evolution was occurring in these groups at this time is

A. drawings and carvings on rocks.

B. animal remains close to a Homo skeleton.

C. male and female skeletons in the same area.

D. Homo sapiens and Homo neanderthalensis skeletons in the same area.


Question 24

The following statements (not in correct order) summarise the steps in natural selection.

1. Some individuals are better suited to a particular environment.

2. Over time there is an increase in particular characteristics in the population.

3. There is variation within a population, some of which is genetic.

4. Individuals better suited to the environment are more successful at survival and reproduction.

The order of statements which best describe natural selection are

A. 1, 3, 2, 4

B. 3, 1, 4, 2

C. 2, 3, 1, 4

D. 1, 2, 4, 3


Question 25

Comparisons of the amino acid sequences of the α-globin polypeptide have been made between humans and a number of other vertebrates. The number of differences is shown in the table below.

An evolutionary relationship between these vertebrates was determined and illustrated in the figure below.

Based on the information provided, the correct placement of each animal on the figure to show the evolutionary relationship is

A. V = cow, W = kangaroo, X = newt, Y = carp, Z = shark

B. V = shark, W = carp, X = newt, Y = kangaroo, Z = cow

C. V = carp, W = shark, X = kangaroo , Y = newt, Z = cow

D. V = kangaroo, W = cow, X = newt, Y = shark, Z = carp


Question 6

Selective breeding has been used to improve the milk yield of cattle herds in Australia. e. Identify a key difference between selective breeding and random mating in a herd of cattle.

In selective breeding humans choose organisms with a desirable trait and breed them. In random mating each bull and cow have an equal chance of mating.

It was important here that students made a comparison between the two.

1 mark

56% got this correct f. What is the impact of selective breeding on genetic variability in a herd of cattle?

Selective breeding reduces genetic variability.

This part was well answered, however many students did not gain the mark as they made further incorrect statements, such as that the number of genes were reduced. Students must realise that all members of the same species have the same genes, it is the alleles which may be different.

1 mark


The quality and yield of milk in cattle has been improved by artificial insemination in which semen from a selected bull is used. g. Explain how the use of artificial insemination may intervene in the evolutionary process.

Artificial insemination will influence the frequency of alleles in the next generation by one bull contributing more frequently to the population.

This part was poorly answered. Many incorrect answers were seen, such as ‘there would be less chance of mutation occurring’ and ‘evolution would stop’. A new word appeared, evolutionise, which was novel but incorrect.

1 mark


Question 8

The Isthmus of Panama is a narrow strip of land that joins North and South America.

The land bridge formed approximately 3 million years ago.

Snapping shrimps, genus Alpheus , can be found on either side of the land bridge. The two groups are phenotypically similar. However when the males and females from either side of the land bridge were brought together they snapped aggressively at each other and would not mate. They are now considered to be two different species. a. Why is the inability to mate insufficient evidence to call the two groups different species?

Inability to mate is not enough evidence; it is the inability to produce viable offspring which is important.

1 mark b. What type of speciation has occurred in the snapping shrimp?

Allopatric speciation

Incorrect answers included divergent evolution and founder effect.

1 mark c. Explain how the differences between the shrimp on either side of the land bridge could have arisen.

• There were different selection pressures in the two environments, which allowed differences in allele frequencies to develop.

• Over time there is an accumulation of genetic differences which changes a trait, such as mating behaviour.

This question was poorly answered and was generally not recognised as a ‘natural selection’ question. Students needed to provide both of the above points for two marks.

2 marks

8a-c: 33% got 0, 26% got 1, 21% got 2, 15% got 3, 5% got 4

Thylacinus cyanocephalus (Tasmanian tiger) was the largest living marsupial carnivore in

Australia at the time of European settlement. The thylacine is believed to have become extinct on

7 September 1936 when the last captive thylacine died in the Hobart Zoo. There are thylacine fossils found in Tasmania and mainland Australia, but when Europeans arrived in Australia living thylacines were only found in Tasmania. d. Suggest why thylacines were not found in mainland Australia at the time of European settlement.

Either of

• thylacines were hunted to extinction by indigenous Australians

• thylacines were out-competed by another predator, for example, the dingo.

Too many students made vague statements such as ‘unsuitable environment’ or ‘hunted’. It was also disappointing the number of students who made some statement about Europeans having an input into their demise. The question clearly asked why the thylacines were not found at the time of European settlement.

1 mark


Since 1936 there have been many reported sightings of thylacines in Tasmania and along the southern coast of Victoria. e. Explain why scientists still believe thylacines are extinct.

Either of

• no thylacines have been captured or found alive

• there is no specific, named evidence such as scats, recent remains or tracks.

Again the answers provided here were vague or incorrect, such as ‘no evidence found’, ‘the thylacines had evolved into a different species’ or other answers which restated the stem of the question.

1 mark


The dingo is a eutherian mammal and the thylacine is a marsupial mammal. Scientists regard these two carnivores as an example of convergent evolution. f. Explain why scientists would regard the thylacine and the dingo as an example of convergent evolution.

Convergent evolution is when two species, which do not share a recent common ancestor, independently develop similar feature due to similar selection pressures.

This question required a definition. Students should be able to correctly define terms/concepts as specified in the study design .

1 mark


Speciation & evolution questions from VCAA Exams with answers

Speciation & Evolution Questions from VCAA Exams (includes answers)

Related documents

Products

Support

Speciation & evolution questions from VCAA Exams with answers

Speciation & Evolution Questions from VCAA Exams (includes answers)

Related documents

Add this document to collection(s)

Add this document to saved

Suggest us how to improve StudyLib