2.2 Size and shape

The shape of the head is determined mainly by the relative sizes of the jaws and the nose and the back of the skull containing the brain, eyes, ears and, in artiodactyls, the horns or antlers. All these structures may differ greatly between otherwise similar species.

SAQ 7


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5.3.3 Ring-tailed lemurs

LoM p. 239 describes the life and habits of the ring-tailed lemur, drawing attention to what are commonly called their ‘stink-fights’ – a further example of the importance of smell in lemur society. But here the habit is prevalent in a species that is active by day and can spend as much as 40 per cent of its waking time on the ground. In fact, these animals seem equally at home on the ground and in the trees. Over time, some populations in Madagascar have become more ground-based than o
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7 The threat of extinction

DA ends his book by writing eloquently of the dangers of extinction faced by mammals, from habitat loss as we exploit our environment to produce more and more food, for our growing population. However bleak the picture, there is still time and opportunity to save mammal species from extinction. Although bison in the USA and Canada were reduced to barely 1000 individuals in 1900, their numbers have now risen to well over 150 000 thanks to the efforts of First Nation indigenous peoples, and ran
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Introduction

In this unit, we will explore the fascinating question of who our ancestors were. I'll be looking at living species of apes in order to pick up clues about social structure and lifestyle in our ancestors and gain some understanding about why we humans behave as we do. I'll discuss tool use and culture in both ape and human societies, and look at two ancient species known only from their fossils – an australopithecine and Homo erectus.

This is the tenth in a series of units abou
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4.1 The advantages

On the basis of LoM and the TV programme, and hearing so much about African hunting dogs and lions, you might be tempted to believe that carnivores generally live in groups.

Question: Do you think this generalisation is true? Can you think of
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2.1 Introducing the Carnivora

Table 1 in this section lists the scientific names of the families of the Carnivora, as well as their common names. You are not expected to recall
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Learning outcomes

By the end of this unit you should be able to:

  • describe the characteristics of light emitted by stars, and hence the information of cosmological interest that can be deduced from it;

  • distinguish between true and false statements relevant to the distribution and motion of stars within galaxies, and of galaxies within clusters and superclusters;

  • outline the methods used for estimating the distances to stars and to galaxies;

  • explain and
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7.4 Summary of Section 7

Fibres of the cochlear nerve synapse on the cells of the cochlear nuclear complex which is the first station of the central auditory pathway. From here signals are sent to the superior olivary complex, the inferior colliculus, lateral lemniscus, medial geniculate nucleus and finally the auditory cortex. The central role of the auditory cortex is the processing of complex sounds.

Each cochlear nuclear complex receives input from only one ear. In the cochlear nuclear complex are several d
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4 Suggestions for further reading

If you wish to pursue some of the topics discussed in this unit in greater detail you might like to start with one or another of the following works.

General

John D. Barrow (1988), The World Within the World, Oxford.

Richard P. Feynman (1992), The Character of Physical Law, Penguin Books.

Brian Greene (1999), The Elegant Universe, W. W. Norton.

Werner Heisenberg (1990), Physics and Philosophy, Penguin Books.

Jan Hilgevoor
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2.1.1 Science and regularity

‘Our experience shows that only a small part of the physical Universe needs to be studied in order to elucidate its underlying themes and patterns of behaviour. At root this is what it means for there to exist laws of Nature, and it is why they are invaluable to us. They may allow an understanding of the whole Universe to be built up from the study of small selected parts of it.”

John D. Barrow (1988), The Worl
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3.1 Introduction

In mammals and birds, homeostasis, the provision of a stable internal environment, includes keeping certain physiological variables, T b, cellular and extracellular water and blood glucose at near constant levels. T b of reptiles varies with T a, but reptiles can only function over a limited range of T b. Nevertheless, vertebrate species live successfully in deserts, which are arid, have low productivity and extremes of <
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2.1 Introduction

The unique climate and topography of each desert links to the unique and characteristic flora and fauna found there. From the brief description of deserts provided in Section 1, you can appreciate that a desert provides a variety of niches for animals and plants. The term ‘niche’ applied to animals describes its role in a particular environment, and includes a number of characteristics such as habitat range, how the animal feeds, its diet, its environmental requirements and also its preda
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5.3 Mitochondrial adaptations

During the winter months, whilst hibernating vertebrates maintain a very low metabolic rate, major reorganization of mitochondrial metabolism occurs. The phenomenon has been studied in some detail in frogs which, although not hibernators in the true sense, can endure very low water temperatures under the conditions of profound hypoxia that exist when they lie dormant for long periods below the surface. In contrast to normoxic conditions, the muscle mitochondria of dormant frogs depress their
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References

Blakemore, C. and Cooper, A. (1970) Development of the brain depends on visual environment, Nature, 228, pp. 477–8.
Caspi, A., McClay, J., Moffitt, T. E., Mill, J., Martin, J., Craig, I. W., Taylor, A. and Poulton, R. (2002) Role of genotype in the cycle of violence in maltreated children, Science, 297, pp. 851–4.
Caspi, A., Sugden, K., Moffitt, T. E., Taylor
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5.2 Sexually dimorphic nucleus of the preoptic area (SDN-POA)

As well as affecting behaviour (Section 3.4) neonatal testosterone also affects the physical characteristics of some areas of the brain. One of these is a small area of the hypothalamus, the medial preoptic area, which, although small, is much larger in males than in females. This size difference is mediated by testosterone.

<
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1.5.3 Sedimentary strata

We've seen that the detective work of piecing together a part of Earth's history from sedimentary rocks involves detailed investigation of rock samples, but this can give only a partial picture. On the larger scale of a rock exposure, there can be plenty for us to see and to interpret. Sedimentary rocks are usually found as layers referred to as strata (Author(s): The Open University

1.5.2 Sedimentary processes

Sedimentary grains are formed when the rocks at the Earth's surface are slowly broken up physically by exposure to wind and frost, and decomposed (chemically) by rainwater or biological action. These processes are collectively termed weathering. Once a rock has been broken up by weathering, the small rock fragments and individual mineral grains can be eroded from their place of origin by water, wind or glaciers and transported to be deposited elsewhere as roughly horizontal layers of sediment
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1.6.5 RSS

RSS (‘Really Simple Syndication’ or ‘Rich Site Summary’) newsfeeds supply headlines, links, and article summaries from various websites. By using RSS ‘feedreader’ software you can gather together a range of feeds and read them in one place: they come to you, rather than you having to go out and look for breaking news. The range of RSS feeds on offer is growing daily. There is probably a feed to cover all aspects of your life where you might need the latest information, and you may
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1.4.4 O is for Objectivity

One of the characteristics of ‘good’ information is that it should be balanced and present both sides of an argument or issue. This way the reader is left to weigh up the evidence and make a decision. In reality, we recognise that no information is truly objective.

This means that the onus is on you, the reader, to develop a critical awareness of the positions represented in what you read, and to take account of this when you interpret the information. In some cases, authors may be
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