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Life Sciences Grade 12 2 July 2016

EVOLUTION

1. THEORIES OF EVOLUTION

1.1 Describe how Lamarck and Darwin explained evolution, and compare Darwin’s ideas to the ideas of Punctuated Equilibrium.

Content:Synthesis:

NOTE: NO marks will be awarded for answers in the form of flow charts, diagrams or tables.

(DBE Feb-Mar 2015)

(17)(3)

1.2 An ancestor of the elephant, Phiomia, had a long nose-like structure called a proboscis which evolved into the trunk of the elephant. The proboscis of Phiomia and the trunk of the elephant are shown below. The diagrams have been drawn to scale.

Explain the evolution of the elephant’s trunk in terms of Lamarckism and Darwinism as well as the way in which an increase in the length of the trunk of the elephant could be achieved through artificial selection.

Content:Synthesis:

(17)(3)

(20)(DBE Feb-Mar 2016)

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Evolution is a theory. Evolution is change over time. Diversity is the RESULT of this change over time. If a trait is good, the organism survives and is able to reproduce, thereby passing this good trait to the offspring. If the trait is not good/bad, then the organism dies and, therefore, does not reproduce.


2. Speciation (FORMING OF NEW SPECIES)

Remember: a species is a group of organisms that are similar in appearance, share the same DNA sequences, perform the same mating rituals and interbreed to produce viable offspring.

A population is a group of organisms of different ages that belong to the same species, live in the same area and interbreed.

Speciation is the evolutionary process so that new biological species develops, due to the splitting of the lineage.

You must know the general account on speciation through geographic isolation as you find it in the examination guidelines on p 16. You must however also be able to apply this knowledge to a specific situation, like the questions below or any unfamiliar scenario.

2.1 Study the diagram below and answer the questions that follow.

2.1.1 Define a population. (4)

2.1.2 Describe how sub-population B could form a new species. (6)

2.1.3 Tabulate THREE differences between natural selection and artificial selection. (7)

(17)(DBE Preparatory Examination Feb-Mar 2008)



2.2 The diagram below shows five closely related species of finches found on the mainland and on four nearby islands.

Describe how the different species on the four islands evolved over many generations from the original ancestor on the mainland. (8)(DBE Feb-Mar 2013)



2.3 Many species of cichlid fish are found in Lake Malawi in Africa. All these species have evolved from a single ancestral species. The diagrams below show the mouths of three different cichlid fish species formed through sympatric speciation in the same lake in Malawi. It also gives information about their feeding methods.

(DBE Feb-Mar 2014)

2.3.1 State ONE advantage of the three cichlid species being specialised feeders, eating different types of food. (2)

2.3.2 Describe the process that led to the formation of the three species shown above. (6)

(8)

2.4 The formation of new species contributes to an increase in biodiversity.

Describe how speciation occurs through geographic isolation, and describe FOUR reproductive isolating mechanisms that keep species separate.

Content: (17)(DBE Nov 2015)



2.5 Three populations of butterflies, A, B and C live separately on three oceanic islands. The butterflies on Island 2 and Island 3 originated from Island 1.

The islands experience strong prevailing winds from the north-west throughout the year.

Populations A and B can interbreed and produce fertile offspring. Population B can mate with Population C, but the offspring are infertile. Mating does not occur between Populations A and C at all.

2.5.1 How many species are represented by the three populations? (1)

2.5.2 Explain your answer to QUESTION 2.5.1. (2)

2.5.3 Use the information provided to explain how speciation might have taken place in the above example. (5)

(8)(DBE Nov 2014)



2.6 The diagrams below represent the process of speciation in tortoises.

Over a period of time species B and C evolved from species A.

(DBE Nov 2015)2.6.1 Explain why species A continued to exists on Island 1. (2)

2.6.2 Describe how species B and C evolved from species A. (6)(8)

3. Darwin’s theory of evolution by NATURAL SELECTION

You must know the general account on the process of natural selection as you find it in the examination guidelines p 15. You must however also be able to apply this knowledge to a specific situation, like the question below.

3.1 The photographs of two butterflies are provided below. Both butterflies live in the same habitat and are preyed on by predators. Although these butterflies are very similar in appearance they are two separate biological species.

Amauris ochlea has an unpleasant taste while Hypolimnas deceptor does not have an unpleasant taste.

(DBE/SCE/2015)



3.1.1 Explain why most predators are less likely to feed on Hypolimnas deceptor. (3)

3.1.2 Use Darwin theory of evolution through natural selection to explain the evolution of the Hypolimnas deceptor butterfly. (6)

3.1.3 State ONE way in which natural selection differs from artificial selection. (2)

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3.2 The extract and the diagram below provide information about a type of antelope called Bongo.

(DBE Nov 2015)3.2.1 State TWO characteristics that help the Bongo to camouflage

themselves in the dense jungle. (2)

3.2.2 Use your knowledge of natural selection and explain how the Bongo’s ability to lay its horns along its back could have developed over the years. (5)

(7)



4. HUMAN EVOLUTION

4.1 The diagram below represents the fossilised skulls of three different species of primates. They were either bipedal or quadrupedal (organisms that habitually walk on all four limbs).

4.1.1 Label part X and the type of teeth at Y. (2)

4.1.2 Explain the significance of the location of structure X in organism C.(3)

4.1.3 Which of the skulls (A, B or C) belongs to:

(a) An Australopithecine

(b) A quadrupedal primate

(1)

(1)


The term ‘Homo’ refers to the genus and means ‘human’. Studies of human evolution must include hominids such as the Australopithecines, as it is theorized that the Homo genus diverged (split) from them about four million years ago in Africa. Scientist have estimated that humans branched from there common ancestor with the chimpanzee about five to six millions years ago. Other species of Homo like Homo erectus and Homo neanderthalus have all become extinct.


4.1.4 Explain how the change in the skull form B to C could indicate a change in intelligence. (3)

4.1.5 Tabulate TWO observable differences, other than those mentioned in QUESTION 3.4.2 and 3.4.4, between skulls B and C that represents trends in human evolution. (5)

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4.2 The diagrams below represents parts of the skeletons of an African ape and a human. Diagrams A and B are drawn to scale.

(DBE/SCE/2015)4.2.1 Write down the LETTERS only of the diagrams (A–D) that represent

bipedal organisms. (2)

4.2.2 Explain how the shape of the pelvis contributes to bipedalism. (2)

4.2.3 Explain the significance of the position of the foramen magnum in the skulls in diagram A and diagram B. (4)

4.2.4 Tabulate THREE visible difference between the jaws/teeth of the skulls labelled A and B that indicate trends in human evolution. (7)

4.2.5 State THREE physical characteristics of the forelimb/upper limb that humans share with African apes. (3)

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5. PHYLOGENETIC TREES

5.1 Study the phylogenetic tree below showing a possible representation of human evolution and answer the question which follow.

(DBE/Nov 2014)5.1.1 According to the phylogenetic tree, which organism, Paranthropus

boisei of Homo habilis, appeared first on Earth? (1)

5.1.2 Name TWO species whose existence on Earth overlapped with that of Homo erectus. (2)

5.1.3 Which organisms was the direct ancestor Homo habilis? (1)

5.1.4 List FIVE characteristics that are shared by all organisms in the above phylogenetic tree. (5)


A phylogenetic tree is a schematic form that shows the evolutionary relationship within a set of organisms or groups of organisms. Phylo = organism’s phylum group and genetic = from the genes/relationship between the genes.

(See tips on how to interpret a phylogenetic tree in Mind the Gap p 78.)


5.1.5 How long did Australopthecus africanus exist on Earth? (1)(10)

5.2 The diagram below shows possible relationships between members of the family Hominidae.

5.2.1 What is the name given to the type of diagram above? (1)

5.2.2 How many of each of the following are represented in the diagram?

(a) Genera

(b) Species

(1)

(1)

5.2.3 Explain why A. robustus and A. boisei are more closely related than A. boisei and A. afarensis. (2)

5.2.4 Which of the hominids in the diagram above is considered to have been the first to use tools? (1)

5.2.5 Name TWO Australopithecus fossils found in South Africa. (2)

5.2.6 Explain how the location and the age of Homo fossils are used as evidence for the ‘Out of Africa’ hypothesis. (3)

(11)(DBE/SCE/2015)



5.3 Scientists estimated the brain sizes of Australopithecus, Homo habilis, Homo erectus and Homo sapiens by using the cranial capacity of fossil specimens. They then compared their results to the time that each hominid existed on earth.

The graph below represents the range of brain size and the time period that the hominid existed according to fossil evidence.

The results of the investigation are shown on the graph below.

5.3.1 According to the graph:

(a) When did the first Australopithecus appear?

(b) Which of the species shows the greatest variation in brain size?

(2)

(1)

5.3.1 Give the size (in cm3) of the:

(a) Largest brain of Australopithecus

(b) Smallest brain of Homo sapiens

(1)

(1)

5.3.3 State TWO types of evidence, other than fossils, that support the idea that all hominids evolved from a common ancestor. (2)

(7)(DBE/Nov 2015)



5.4 The diagram below represents the possible evolution of humans, as well as the time period for the development of bipedalism, the use of fire and the use of tools.

(DBE/Feb-Mar 2015)

5.4.1 Use the diagram above and identify TWO bipedal organisms that did not use stone tools of fire. (2)

5.4.2 How long after developing the ability to walk on two feet did pre-humans develop the ability to use stone tools? Show ALL working. (3)

5.4.3 Explain the significance of the characteristic of the skull which allowed for the development of the ability to use tool in die Homo species. (2)

5.4.4 Explain the relationship between the use of fire and changes in dentition in the Homo species. (2)

(9)


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