3 Measuring the Sun Section 2 referred to observations that can only be made using sophisticated telescopes, but this section turns to an observation you can do yourself. There are two reasons for this: one is to give you experience in scientific measuring and the other is to introduce some terminology that astronomers use frequently.
2 Inside the Sun To account for its brightness and activity, the Sun must contain a power source. However, the nature of that power source was a great puzzle in the nineteenth and early twentieth centuries. Fossil records and ideas about evolution were beginning to provide firm evidence that the Earth must be at least hundreds of millions of years old, rather than thousands of years as was previously thought, and the Sun must be at least as old as the Earth. The only fuels known at the time were coal, wood, o
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3 Introducing the primates One group of accomplished tree dwellers are the primates – a term you perhaps think of as synonymous with monkeys and apes. Monkeys and some apes display some of the most striking adaptations to tree-living. 250 or so species of primate exist today; most taxonomists group them into 13 families. All share a lengthy list of defining features, mostly related to the following broad categories: Limbs and locomotion. The hands (and often the
2.5 Tree squirrels Coevolution also underpins the relationship between many tree squirrels and the trees that house them. The creation of food caches as a ‘winter-larder’ is mutually beneficial, partly because squirrels are sufficiently profligate in their habits to ensure that many stores are overlooked. Stealing by neighbours is so common that such over-provision may be essential – it's not through forgetfulness or lack of skill; grey squirrels appear able to detect nuts buried as deep as 30 cm below th
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6 The good family Procyonidae As DA comments, this family is such an odd and varied collection that it doesn't have a common name [p. 170]. Its most familiar member (after which the family is named) is the raccoon, but the 19 species that comprise the family include mammals as diverse in habits and feeding preferences as the raccoon dog, the kinkajou and the red panda. There is considerable taxonomic controversy about the members of the raccoon family – including the status of the red panda. With the kinkajou, ear
4.2 Other members of the bear family Other omnivorous species of bear include the Asian black bear, the North American black bear and the Andean spectacled bear. Although polar bears spend their winters hunting seals out on the Arctic sea-ice, they have to come ashore when the ice melts in spring and find other sources of food. Senses Being an effective predator requires efficient sense organs. Prey often has to be located from a considerable distance and good spatial awareness comes into play during the moments of capture. The precise mix of sensory inputs used varies a good deal, just as it does in other animal groups; many rely on good eyesight for hunting; for others, smell and/or hearing are especially important. And you'll know from the TV programme (for example, in what was said about the importance of smell in brow 10 Living in herds Wildebeest are only one of the species of plant predator that live in herds. Many others do too. Watch the the TV programme from 30.48–47.32 and read LoM p. 109. Identify and write down (a) a couple of advantages and 5.2 Pseudo-ruminants Animals in the third suborder of the Artiodactlya, the pigs, peccaries and (according to most authorities) the hippopotamuses (suborder Suina), use a slight variant on the ruminant method, and are often referred to as pseudo-ruminants. You might like to add this information to your version of Table 2. These animals do have st 3 Herbivore teeth Tables are a useful way of recording key information. The headings for Tables 1 and 2 have been prepared for you, and you can copy and complete the tables in your notebook. If you need to find any of this information again later, then it is very useful to have it summarised in a table. I 1 The herbivores As you work through this unit you will come across boxes, like this one, which give you advice about the study skills that you will be developing as you progress through the unit. To avoid breaking up the flow of the text, they will usually appear at the start or end of the sections. As well as the unit t Acknowledgements The content acknowledged below is Proprietary (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: The content acknowledged be Learning outcomes By the end of this unit you should be able to: explain the implications of a seed/nut-eating habit; suggest why rodents are a successful order of mammals; describe adaptation, based on knowledge of the theory of biological evolution by natural selection; explain how altruistic characteristics can be understood in terms of kin selection and inclusive fitness; give examples of the fitness costs and benefits associated wit 6.2 Opting out This last section of the unit contains, I think, some of the most challenging science that you have met so far. Take it slowly, translating all the abbreviations in your head as you come to them (read BAT as ‘brown adipose tissue’, for example) and looking carefully at the graph in Author(s): 5.3 Body size and surface area You will be using some more maths in this section. Remember that areas are measured in units such as m2, which is read as metres squared or, more usually, square metres. Volumes are measured in units such as m3, which you should read as metres cubed or, more usually, cubic metres. Most mea 1 Meeting the insect eaters As you work through this unit you will come across boxes, like this one, which give you advice about the study skills that you will be developing as you progress through the unit. To avoid breaking up the flow of the text, they will usually appear at the start or end of the sections. As well as the unit t 6.3 Anisotropies in the Universe itself Having subtracted the dipolar anisotropy due to the motion of the Earth relative to the 3 K radiation, we are left with radiation that is exceedingly isotropic. So, we have to ask whether there are any residual variations that would point to a departure from isotropy of the radiation itself? This is a crucial question. Although it was gratifying to have the radiation so isotropic that there could be little doubt of its cosmic origins, nevertheless a completely isotropic distribu 5.1.4 Getting agreement with the no-monopole law Substituting Equation 7.23 into the no-monopole law gives immediate agreement because The no-monopole law is analogous to Gauss's law in empty space, and it leads to a similar conclusion: the magnetic wave must be transverse. This has already been established using Farada
Activity 2
Activity 7
