Life Is Fine

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  • Topic: Evolution, Paleontology, Fossil
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GRADE 12

LIFE SCIENCES (new content framework) Exemplar Assignment: Evolution - evidence MAY 2011

MARKS: 70 TIME: 1 hour 10 minutes

This assignment consists of 10 pages.

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INSTRUCTIONS AND INFORMATION Read the following instructions carefully before answering the questions. 1. 2. 3. 4. Answer ALL the questions. Write ALL the answers on your ANSWER SHEET. Start EACH question on a NEW page. Number the answers correctly according to the numbering system used in this question paper. If answers are NOT presented according to the instructions of each question, candidates will lose marks. Draw diagrams and flow charts ONLY when requested to do so. The diagrams in this question paper may NOT necessarily be drawn to scale. The use of graph paper is NOT permitted. Non-programmable calculators, protractors and compasses may be used. Write neatly and legibly.

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EVIDENCE FOR EVOLUTION

1.1

The diagrams below represent the evolution of the horse, compiled from fossil records.

Species of horse

Height

Front leg

Modern horse (Equus) 1,6 m Toe Merychippus 1,0 m Toes

Mesohippus 0,6 m Toes

Hyracotherium 0,4 m Toes

Evolution of the horse compiled from fossil records

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Life Sciences/Assignment

4 Grade 12/NSC

WCED/Exemplar 2011

1.1.1 Calculate how many times is the modern horse taller than its earliest ancestor? Show your working. 1.1.2 What happened to the appearance of the feet of the horse over time?

(2) (2)

1.1.3 Paleontologists suggest that ancient horses lived in forests, but modern horses live in open grassland. Explain TWO ways in which the modern horse is adapted to open grassland. (4) 1.1.4 Explain ONE way in which the hoof of the modern horse could be a disadvantage in the open grassland environment. (2) 1.1.5 The fossil record is one source of evidence that can be used to explain the theory of evolution. Name TWO other sources that can serve as evidence for evolution. (2) (12) 1.2 Study the passage and diagrams below and answer the questions that follow. MAMMALS FROM REPTILES Evolutionary theory proposes that all living organisms share a common ancestor at some time in the past and that new species form from existing ones. An example of a line of descent in the fossil record in South Africa is the fossil mammal-like reptiles (therapsids) who display reptilian and mammalian features. Therapsid fossils from the Karoo portray the evolutionary development of mammals from reptiles. The lower jaw of a reptile comprises seven bones, while that of a mammal has only one. A reptile has only one ear bone while a mammal has three. By studying the jaw structure of a succession of therapsids from the Karoo, palaeontologists have discovered that the extra two ear bones of mammals (hammer and anvil) developed from the two bones that form the jaw joint (quadrat and articular bones) in reptiles. This clearly indicates how the mammalian hearing system evolved. Reptiles also do not have a bony palate separating the nasal passages from the mouth cavity but mammals have a complete bony palate that enables them to chew their food without impairing their breathing. Fossil evidence indicated that the oldest and most primitive therapsids had no bony palate while the most recent therapsids in the rocks of the upper Karoo possessed a fully developed bony palate as is found in mammals. Adapted from The Story f Earth and Life – A southern African perspective on a 4.6 billion-year journey

A comparison between a therapsid and mammal skull, showing the development of the ear and jaw Copyright reserved Compiled by T. Botha & J. Goliath

Life Sciences/Assignment

5 Grade 12/NSC

WCED/Exemplar 2011

1.2.1 According to the passage evolutionary theory is based on two assumptions. Name the TWO assumptions. (2) 1.2.2 According to the passage name the transitional fossils between reptiles and mammals? 1.2.3 Give a reason for your...
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