On completion of this unit the student should be able to analyse evidence for evolutionary change, explain how relatedness between species is determined, and elaborate on the consequences of biological change in human evolution
Outcome 1 Analyse evidence for evolutionary change, explain how relatedness between species is determined, and elaborate on the consequences of biological change in human evolution. A report using primary or secondary data. The assessment task may be written or multimodal. (approximately 50 minutes or not exceeding 1000 words) 30 Marks
Outcome Summary
This outcome will relate to information provided of fossil evidence of human remains. Questions on this assessment will relate to the information and incorporate molecular biology techniques to help interpret the meaning of the fossil evidence. General assessment questions relating to the topics of evolution, relatedness between species and molecular biology will also form part of this assessment. This exam styled assessment will be a 50 min task with 10 mins reading time and be worth 30 marks.
Tracing human history has been reliant on the discoveries of fossils, largely incomplete, found all over the world. Scientists then use the pieces of fossil evidence to compare to other fossils that have been previously studied to build theories as to human ancestry and its timeline. Fossils can be dated via radiometric techniques or through comparisons made to fossils found in similar locations or strata.
In an area in and around the Neander Valley in Germany, a number of human-like fossils have been discovered. Two fossils have included skulls that have been labelled CA-734 and another found 20 kms away called DG-166. Scientists have concluded that one of the skulls is from the species Homo erectus and the other skull from Homo neanderthalensis. Animators have also created diagrams using the parts of the fossils that were discovered and these can be found in Fig. 1 below. Fig. 1 also includes a human skull that scientists included for comparative reasons.
Photos of the recreated skulls can be seen below.
Fig. 1
Diagram representation of fossil skulls found in Neander Valley and including human skull diagram
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QUESTION 1:
It is widely regarded that Homo erectus were the ancestors of Homo neanderthalensis. Using evidence from the skulls in Fig. 1, which of the skulls are Homo erectus and therefore the more primitive of the fossils that were discovered in Germany? (2 marks)
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QUESTION 2:
The site where the Homo neanderthalensis was discovered also contained evidence of cultural evolution. What is cultural evolution and what type of evidence might have been found at the Homo neanderthalensis site that would not have been found at the Homo erectus site? (2 marks)
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QUESTION 3:
So far Homo neanaderthalensis fossils have been widely found in Europe, the Middle East and parts of Asia. No Homo neanderthalensis fossils have been found in Africa yet. Is it likely that Homo neanderthalensis fossils will be found in Africa? Explain (2 marks)
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QUESTION 4:
Further fossils were found at the sites in Germany, from different parts on the skeleton other than the skull. These parts included hip bones, vertebrae, foot bones, radius and ulna from the arm and tibia and fibula from the legs of various species. All of the fossils that were found strongly suggested that the species that they came from were bipedal.
4a) What does the term bipedal mean? (1 mark)
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4b) What are four features that scientists could have used from the fossils that were discovered that would provide evidence for bipedalism? (4 marks)
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QUESTION 5:
Using the human skull diagram provided in Fig 1. Explain what feature has enabled modern-day humans to be more advanced in their cultural and technological evolution than the other two species that were discovered at the sites. (2 marks)
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QUESTION 6:
DNA preserved in fossils found at the sites were able to be obtained from the Homo neanderthalensis specimens. DNA from the Homo erectus fossils could not be obtained. The DNA from a particular gene was coded and compared to the Homo sapiens DNA from the same gene. DNA from another species, the Denisovans, was found in specimens found in Northern Asia, and also analysed. The analysis results from the DNA coding, of the gene, is supplied below:
Fig 2: DNA analysis from various Homo species.
6) How many differences exist between:
6ai)Homo neanderthalensis & Homo sapiens (1 mark)
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6aii)Homo neanderthalensis & Denisovan (1 mark)
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6aiii)Homo sapiens & Denisovan (1 mark)
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6b) Draw a labelled cladogram/family tree connecting the three species above. In the family tree include the species Homo heidelbergensis which is considered the common ancestor of all of the above species (2 marks)
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6c) Why might DNA samples from Homo erectus been unable to be obtained? (1 mark)
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6d)Homo erectus are believed to have originated in Africa. Groups of the species left Africa, filling in a variety of different niches in other locations around the world. What evidence has been used to support this theory? Explain (2 marks)
QUESTION 7:
The fossil record indicates that Mammoths existed at around the same time as Homo neanderthalensis. A small population of Mammoths that lived isolated on Wrangel Island off the coast of Siberia was thought to be still in existence 2000 years ago. At that time there was a significant shift in the climate. Another population, that lived in Germany at the same time as Homo species, such as Homo neanderthalensis, likely died out approximately 10000 years ago. Fossils of the German population have been found in clumps, often in caves. Evidence of Humans and Neanderthals using fires in caves has been found throughout Europe. Whilst the Wrangel Island population was separated from the mainland of Siberia, a fossil tusk that was found contained traces of human DNA on it. The tusk was dated at approximately 2000 years old.
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7a) Are the Wrangel Island Mammoths and the German Mammoths likely to be the same species of Mammoths? Discuss (2 marks)
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7b) Using the information provided, why might have the German Mammoth population died out 10000 years ago but the Wrangel Island population survived until 2000 years ago (3 marks)
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7c) Using the information provided, what may have been the cause of the eventual die out of the Wrangel Island population? (2 marks)
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7d) How might human DNA come to be found on the Wrangel Island tusk? (1 mark)
