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Ever Wondered? Episode 9


Uncovering New Zealand's biological past

In Episode 9 of Ever Wondered?, Dr John Watt engages with scientists involved in the fields of palaeontology and archaeology. By studying fossils (palaeontology) and human history (archaeology), these scientists are uncovering New Zealand's biological past.

Digging deep

John meets Dr James Crampton, a palaeontologist with GNS in Wellington, whose speciality is shellfish fossils. James explains that New Zealand's geographical isolation allied with long periods of being almost totally submerged has led to a unique fossil record to explore. Each fossil discovery is recorded on a database developed by GNS and known as FRED (Fossil Record Electronic Database).

John then heads to the University of Otago to meet Dr Ewan Fordyce, a palaeontologist with an interest in ancient whales, dolphins and penguins. In particular, Ewan is interested in how physical changes in the world might have triggered the evolution of whales and dolphins. Ewan invites John to help him with his fieldwork, which is based in a limestone quarry in South Canterbury. Whilst wielding a pickaxe and shovel, John remarks on the strangeness of uncovering marine animal fossils so far inland, which serves as compelling evidence for our submerged past.

Studying our distant past allows us to better understand the forces still at work on the Earth today and help us to predict the changes that are still to come.

Relics of early human settlement

Shifting from palaeontology to archaeology, John visits a dig at the Tapu Tikitiki P? excavation in Waiuku, South Auckland. Here, archaeologist Dr Marianne Turner is looking at the relics of an early human settlement to better understand human interaction with the environment. Back at the lab at Auckland University, Marianne uses an X-ray fluorescence machine to match the geochemical signature of a small piece of excavated argillite with those from other sites. From this data, inferences can be made about how people from different regions interacted. She explains that where we have come from may help to understand our present and where we are heading in the future.

Next, John heads back to Otago to meet with another archaeologist, Dr Ian Smith, whose main research interest is in finding out what animals people exploited in the past. In particular, Ian is interested in the way humans have impacted on the marine environment and the changes that have occurred over time. His research has shown that, as a result of human exploitation, not only were moa forced into extinction, but also fur seal numbers in the North Island were reduced to virtually zero.

John helps Ian to sift through a pile of small bones and shells excavated from an ancient M?ori p? site midden. Ian picks out a crayfish mandible, and as he measures its size, he explains that over time the average mandible size has reduced, indicating that human exploitation of crayfish has impacted not only on their numbers but also on their size.

We know in the past human exploitation has impacted the marine environment, but how does that compare to the impacts we have created today? Archaeology is really important in how we understand the world we live in today.

Delving deep into the secrets of our past

Cutting-edge technology using a fossil's own DNA is helping to delve deep into the secrets of our past, and John takes a trip to Massey University in Palmerston North to visit Professor David Penny, PhD student Lara Shepherd and Dr Lesley Collins. David discusses his research into moa and kiwi DNA and its link to other types of flightless ratites as well as a South American flying ratite called the tinamou. DNA sequencing highlights the fact that flying was actually the normal ability of both the kiwi's and moa's common ancestors. It was New Zealand's isolation and predator-free environment that led these species down the evolutionary path to flightlessness.

Next, John accompanies PhD student Lara Shepherd to one of the DNA labs at Massey University. Here, she explains how DNA samples can be extracted from ancient kiwi bones and how the sequencing of the DNA can provide information about the past levels of diversity and distribution of kiwi. Lara shows John a map of New Zealand highlighting where kiwis are presently located and where remains have been found. She explains that there are now large areas of New Zealand where kiwis are no longer found and how the distribution of various kiwi species has been greatly reduced.

Still at Massey, John meets Dr Lesley Collins whose research looks at the very distant past, beyond the ancestors of ancient animals some 800 million years ago. Lesley's work is based on the premise that the DNA and RNA currently in organisms alive today carries with it relics of their past. All life hangs onto its successful genes, and those that are common across all life today are effectively molecular fossils. By comparing the genes present in humans with those of a microscopic organism known as Giardia lamblia, Lesley is able to identify very, very ancient genes - the so-called molecular fossils. The process for doing this comparison involves state-of-the-art DNA sequencing techniques along with very sophisticated computer software to handle the huge amount of data generated. The information gained from this work will lead to a better understanding of how life has evolved from ancient unicellular life forms.

John summarises the episode: "Due to both our isolation and the brilliant work being done by New Zealand scientists, we have a unique place in the fields of palaeontology and archaeology."

Activity idea

In conjunction with this episode of Ever Wondered?, your students may enjoy these activities.

In this activity, students investigate middens - a historic form of rubbish dump - and what rubbish can tell about people's daily lives. This activity links into Dr Ian Smith's research.
Middens
 
DNA sequencing is now routinely undertaken in a huge range of research projects, like Professor David Penny's research into kiwi and moa and Dr Lesley Collins's research into ancient animals. In this animation, students can watch a step-by-step guide to sequencing DNA in the lab.
www.biotechlearn.org.nz/themes/dna_lab/sequencing_revealing_the_dna_code

Context links

To further investigate the ideas explored in uncovering New Zealand's biological past, check out these Science Learning Hub contexts and science stories.

Conserving Native Birds: New Zealand is world famous for its unique birdlife. In this science story, we look at the issues surrounding the conservation of some of our threatened bird species.
www.sciencelearn.org.nz/Science-Stories/Conserving-Native-Birds

Future Fuels: By looking at fossils, Adam Vonk can determine two things. He can work out how old the rocks are and he can work out the rocks' paleoenvironment - the ancient environment that the fossil formed in.
www.sciencelearn.org.nz/Contexts/Future-Fuels/Sci-Media/Video/Ancient-environments

Adam Vonk explains how it is possible that we can find a marine fossil - remnants of an organism that lived in the sea - on the top of a hill.
www.sciencelearn.org.nz/Contexts/Future-Fuels/Sci-Media/Video/Marine-fossils-on-hilltops

Hidden Taonga: New Zealand has many endemic species - species that are unique to a particular place and not found anywhere else.
www.sciencelearn.org.nz/Contexts/Hidden-Taonga/Looking-Closer/Protecting-New-Zealand-s-treasures

Just Elemental: Dr Fiona Petchey's main research interest is in marine shell dating - one of the main ways of tracking the movement of people through the Pacific region, since shellfish formed part of the diet of these people. Fiona is an archaeologist at heart - she is constantly fascinated by the challenge of trying to trace human movement through the Pacific and into New Zealand.
www.sciencelearn.org.nz/Contexts/Just-Elemental/Sci-Media/Video/Dr-Fiona-Petchey-s-research

Historical artefacts like moa bones can be dated using a technique that measures the activity of the radioisotope carbon-14 still present in the sample. By comparing this with a modern standard, an estimate of the calendar age of the artefact can be made.
www.sciencelearn.org.nz/Contexts/Just-Elemental/Sci-Media/Animations-and-Interactives/C-14-carbon-dating-process

Life in the Sea: Throughout human existence, we have relied on the oceans - for food, as a waste dump, for recreation, for economic opportunities and so on.
www.sciencelearn.org.nz/Contexts/Life-in-the-Sea/Science-Ideas-and-Concepts/Human-impacts-on-marine-environments
 
Saving Reptiles and Amphibians: The International Union for the Conservation of Nature (IUCN) ranks a species as extinct when there is no reasonable doubt that the last individual has died.
www.sciencelearn.org.nz/Contexts/Saving-Reptiles-and-Amphibians/Science-Ideas-and-Concepts/Extinction


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