5.3 Hindgut fermenters The odd-toed ungulates (comprising the order Perissodactyla), the horses, tapirs and rhinoceroses, are hindgut fermenters, as are elephants. Update Table 2 with this information. These animals have a relatively simple, small undivided stomach, but this time an even larger caecum and colon where the microbes are housed and whe
4.2 Digesting cellulose Figure 3 in this section contains a lot of information and many terms that are probably new to you. Set aside the detail for the moment, read 4.1 A brief digression about digestion There are many new scientific terms introduced in this unit. Are you making your own lists of them? If you were to encounter these terms in a fresh context (perhaps on a website, or during your own reading around these subjects), your aim should be not just to recognise the terms, but also to understand their m 2 The herbivore lifestyle – living on leaves Leaves are a much less nutritious food than most kinds of animal material, so large herbivores have to eat large quantities of plants and they have special ways to digest their food. As author David Attenborough (DA) says, ‘Leaves are extremely poor food’ [p. 89]. To find out why living on a diet of leaves is particularly difficult, we need to know something about how leaves work. Learning outcomes By the end of this unit you should be able to: describe the particular problems in digesting plant material; give examples of the ways in which teeth are modified for a herbivorous diet; explain the importance of digestive enzymes; explain the importance of microbes in digesting plant material; compare the main features of the digestive systems of ruminants and hindgut fermenters; describe some of the way 3.4 Competition In plants it is particularly obvious that many more potential offspring (seeds) are produced than can survive. To a very large extent it is a matter of chance as to which are the survivors. Some are eaten, others overlooked or stored away and forgotten. Those that survive to germinate might be on unsuitable soil, too dry or too wet, so that they shrivel or rot. The successful seedling could be in poor soil, deficient in minerals, or there may be many other plants that are already established 3.1 Introduction How evolution proceeds is obviously of central importance when studying mammals. Of fundamental importance to the way evolution works is the notion of natural selection, and in S182_3 Studying mammals: chisellers I'll be talking about what most researchers regard as this ‘single most important idea in biology’. But before that, I want to describe some of the adaptations evident in insect eaters. From your reading of LoM you'll appreciate that natural selection promotes the ev 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 7 Unit summary The law of conservation of charge applies locally at each point and time, so any variation of the total charge within a closed surface must be due to charges that flow across the surface of the region. This principle leads to the equation of continuity: 6 Appendix: a note on displacement current density This appendix is optional reading. It is included for the sake of comparison with other texts. The Ampère–Maxwell law, is sometimes expressed in the form Introduction This unit examines why water shortages are predicted as a result of the world's growing population and the importance of access to clean and safe drinking water in public health. It looks at the distribution of water throughout the world and problems with contamination, topics of wide general interest. Introducing health sciences: a case study approachI
(SDK125) 3.6.1 Radioactivity and bugs! Many natural processes involve repeated doublings or halving at regular intervals. You may have come across this already in your work, in the context of bacterial growth or radioactivity. In this section, we are going to look in more detail at bacterial growth and radioactivity and we will be using graphs to examine how the numbers of bacteria or numbers of radioactive atoms change over time. 2.6 The surface David A. Rothery Teach Yourself Planets, Chapter 6, pp. 66–75, Hodder Education, 2000, 2003. Copyright © David Rothery Look at the Moon even with the unaided eye, and you will see that it has dark patches on a paler background (Figure 2). This simple observation picks out the two distinct types of crust on the Moon. The paler areas are the lunar highlands, and the darker areas are the lunar ‘seas’ or maria (singular: mare). Both the highla 2.4 The atmosphere and polar ice David A. Rothery Teach Yourself Planets, Chapter 6, pp. 66–75, Hodder Education, 2000, 2003. Copyright © David Rothery The Moon's atmosphere is almost as insubstantial as Mercury's, and probably has much the same origin. The Clementine mission returned our first clear views of the lunar poles, showing sites in particular near the south pole that are permanently in shadow, and which could therefore be places where ice might accumulate (Figure 1). Clementine' 2.3 Missions to the Moon David A. Rothery Teach Yourself Planets, Chapter 6, pp. 66–75, Hodder Education, 2000, 2003. Copyright © David Rothery The Moon was the first extraterrestrial target for space missions. Probes have been directed towards it since almost the very dawn of the space age (see below), and it was the main focus of the 1960s–1970s ‘space race’ between the USA and the then Soviet Union. In the end, only NASA attempted to put people on the Moon, and the six suc 2.1 The Moon David A. Rothery Teach Yourself Planets, Chapter 6, pp. 66–75, Hodder Education, 2000, 2003. Copyright © David Rothery
In this chapter you will learn:
about the nearest planetary body to the Earth about the long record of impact cratering on its surface, and about the ancient eruptions that flooded many low-lying areas. 1 Observing the Moon Try to make out features on the surface of the Moon, even if you have no optical aid available. If you have the use of a pair of binoculars you will probably Learning outcomes After studying this unit you will be able to: retrieve, evaluate and interpret data and information about the Moon, so that (for example) using a close-up picture of the Moon's surface you could identify the types of feature visible and recognise the processes responsible for creating them; interpret simple tables; express, manipulate and compare very small numbers. Acknowledgements Except for third party materials and otherwise stated (see terms and conditions), this content is made available under a Creative Commons Attribution-NonCommercial-ShareAlike 2.0 Licence Grateful acknowledgement is made to the following sources for permission to reproduce material in this unit: 9 Unit summary You have learned about the following concepts in this unit: Each type of atom contains a characteristic number of protons in a central nucleus and an equal number of electrons in layers surrounding the nucleus. Elements are substances that consist of only one type of atom. Compounds contain two or more elements combined together. There are two kinds of bond between atoms: covalent and ionic. Molecules are the smallest
Activity 1
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