- Current section: Introduction
- Learning outcomes
- 1 The pinnipeds, sirenians and cetaceans
- 2 Living in the water
- 3 The ‘diving response’
- 4 The evolution of whales
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Studying mammals: Return to the water
Some of the most unusual and versatile of all the mammals are the groups that live,...
Some of the most unusual and versatile of all the mammals are the groups that live, feed and reproduce underwater. In this unit we will see how these formerly land-based mammals adapted to a return to the water, discussing such challenges as breathing, movement and communication. This is the seventh unit in the ‘Studying mammals’ series.
By the end of this unit you should be able to:
- contrast the physical properties of air and water and describe implications of such differences for aquatic mammals;
- give examples of the adaptations displayed by aquatic mammals that enable them to hold their breath while submerged for relatively long periods;
- describe some of the biological differences between pinnipeds, sirenians and cetaceans;
- discuss the importance of communication by sound in aquatic mammals, describe the role of blubber and explain countercurrent heat exchange;
- explain the diving response and its significance in natural dives;
- explain how the evolution of whales can be described within the conceptual frameworks of natural selection and punctuated equilibria.
Studying mammals: Return to the water
The versatility of mammals is a central theme of the ‘Studying mammals’ series of units, but surely no environment has tested that versatility as much as the rivers and oceans of the world. Mammals are essentially a terrestrial group of animals, but three major groups have independently adopted an aquatic way of life. In moving to the water, aquatic mammals have had to survive, feed and reproduce using a set of biological characteristics that evolved in association with life on land. This unit will explore how these characteristics have provided challenges, and opportunities, for mammals that spend some or all of their time in the water.
This is the seventh in a series of units about studying mammals. To get the most from these units, you will need access to a copy of The Life of Mammals (2002) by David Attenborough, BBC Books (ISBN 0563534230), and The Life of Mammals (2002) on DVD, which contains the associated series of ten BBC TV programmes. OpenLearn unit S182_8 Studying mammals: life in the trees contains samples from the DVD set. You should begin each unit by watching the relevant TV programme on the DVD and reading the corresponding chapter in The Life of Mammals. You will be asked to rewatch specific sequences from the programme as you work through the unit.
This unit is from our archive and is an adapted extract from Studying mammals (S182) which is no longer taught by The Open University. If you want to study formally with us, you may wish to explore other courses we offer in.
This is an extract from an Open University course which is no longer available to new students. If you found this interesting you could explore more free Natural History course units or view the range of currently available OU Natural History courses.
Copyright & revisions
Originally published: Wednesday, 8th June 2011
- Creative-Commons: The Open University is proud to release this free course under a Creative Commons licence. However, any third-party materials featured within it are used with permission and are not ours to give away. These materials are not subject to the Creative Commons licence. See terms and conditions. Full details can be found in the Acknowledgements section.
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