Pages 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 8777 result(s) returned

1.5.1 Juvenile survival

For organisms that are able to complete their life cycles within a year there is the possibility of spending the winter in various juvenile stages. We have already considered annual plants, the adults of which may die before the onset of winter, with seed not germinating until the spring. Surviving the winter as seeds has the advantages that the seeds are robust, and because they have a low water content they are less affected by freezing temperatures. Disadvantages of this strategy include t
Author(s): The Open University

License information
Related content

Except for third party materials and/or otherwise stated (see terms and conditions) the content in OpenLearn is released for use under the terms of the Creative Commons Attribution-NonCommercial-Share

1.4.5 Summary of Section 1.4

  1. Deciduous trees avoid the problems of winter by shedding their leaves.

  2. Plants can store nutrients over winter in a variety of structures.

  3. Amphibians have evolved behavioural responses (e.g. burying themselves) and physiological responses (e.g. different types of antifreeze in the body fluids) to winter.

  4. Hibernation occurs only in certain small mammal species and one species of bird and is accompanied by marked phy
    Author(s): The Open University

    License information
    Related content

    Except for third party materials and/or otherwise stated (see terms and conditions) the content in OpenLearn is released for use under the terms of the Creative Commons Attribution-NonCommercial-Share

1.4.4 Hibernation in mammals

Many animals become inactive for periods of varying duration during the winter and there is a diversity of terms used to describe this state, including: sleep, torpor, dormancy, lethargy and hibernation. The word hibernation is often used loosely to refer to general inactivity but, in biology, it refers to a specific phenomenon, sometimes called ‘true hibernation’. Hibernation is defined as the condition of passing the winter in a resting state of deep sleep, during which metabolic
Author(s): The Open University

License information
Related content

Except for third party materials and/or otherwise stated (see terms and conditions) the content in OpenLearn is released for use under the terms of the Creative Commons Attribution-NonCommercial-Share

1.4.3 Freeze tolerance in ectothermic vertebrates

In Britain, the vertebrate class Amphibia is represented by frogs, toads and newts. Amphibians are ectotherms, meaning that they are unable to generate large quantities of heat within their bodies, so their body temperature is close to that of their surroundings. The majority of amphibian species avoid the lethal consequences of being frozen, by digging their way under a large object, such as a rock, or deep into the soil, below the level that is penetrated by frost. There are some species, h
Author(s): The Open University

License information
Related content

Except for third party materials and/or otherwise stated (see terms and conditions) the content in OpenLearn is released for use under the terms of the Creative Commons Attribution-NonCommercial-Share

1.4.2 Winter storage in plants

Many plants that survive winter in a dormant state form storage organs below the ground which store nutrients during the winter, the rest of the plant withering away. Storage organs come in a variety of forms, including tap roots, bulbs, corms, rhizomes, root tubers and stem tubers (Figure 13). In the carrot, the root is greatly enlarged into a fleshy tap root; the bulbs of onions are modified leaves; crocus corms, iris rhizomes and dahlia tubers are modified stems, and the tubers of potatoes
Author(s): The Open University

License information
Related content

Except for third party materials and/or otherwise stated (see terms and conditions) the content in OpenLearn is released for use under the terms of the Creative Commons Attribution-NonCommercial-Share

1.4.1 Deciduous trees

During the winter months, a combination of factors, including lower temperatures, reduced light intensity and shorter days, means that plants can only photosynthesise at a slow rate and for restricted periods. As a result, photosynthesis cannot produce energy as fast as respiration expends it. In addition, water is often in short supply because of freezing, and so plants that do not have adaptations to conserve water, as conifers do, would lose water. Deciduous trees avoid these problems in w
Author(s): The Open University

License information
Related content

Except for third party materials and/or otherwise stated (see terms and conditions) the content in OpenLearn is released for use under the terms of the Creative Commons Attribution-NonCommercial-Share

1.2.5 Summary of Sections 1.1 and 1.2

  1. The majority of organisms are exposed to environmental fluctuations, including seasonal change in climate. In this unit, we focus on the effects of winter.

  2. Organisms have evolved a range of strategies to cope with winter. Thus this common environmental variable has led to a diversity of responses.

  3. The strategies for coping with winter can be considered with respect to different levels and types of explanation.

  4. Mol
    Author(s): The Open University

    License information
    Related content

    Except for third party materials and/or otherwise stated (see terms and conditions) the content in OpenLearn is released for use under the terms of the Creative Commons Attribution-NonCommercial-Share

1.2.4 The evolutionary level

Life histories and trade-offs

In this section, the emphasis switches from proximate (molecular, cellular, physiological and behavioural) types of explanation to ultimate types of explanation. In order to proceed, we need to understand two key concepts: life history and trade-off. Both of these concepts are important tools in organising thoughts about why organisms are so diverse. An organism's life history is the set of key biological events in its life, including b
Author(s): The Open University

License information
Related content

Except for third party materials and/or otherwise stated (see terms and conditions) the content in OpenLearn is released for use under the terms of the Creative Commons Attribution-NonCommercial-Share

Cover of Suffragette pamphlet

The National Archives UK posted a photo:

Cover of Suffragette pamphlet

Women's Movements. Women's Labour League, Suffrage; various material on women workers


Author(s): nobody@flickr.com (The National Archives UK)

License information
Related content

https://www.flickr.com/commons/usage/

Learning outcomes

At the end of this unit you should know that:

  • By biological evolution we mean that many of the organisms that inhabit the Earth today are different from those that inhabited it in the past.

  • Natural selection is one of several processes that can bring about evolution, although it can also promote stability rather than change.

  • The four propositions underlying Darwin's theory of evolution through natural selection are: (1) more individuals are produced
    Author(s): The Open University

    License information
    Related content

    Except for third party materials and/or otherwise stated (see terms and conditions) the content in OpenLearn is released for use under the terms of the Creative Commons Attribution-NonCommercial-Share

1.6.4 Blogs

The founder of Technorati  claims that the number of ‘blogs’ doubles every five months and that the creation rate is approaching two per second. One estimate I read in July 2010 put the number at 400 million blogs. Because these online diaries offer instant publishing opportunities, you potentially have access to a wealth of knowledge from commentators and experts (if they blog) in a wide ra
Author(s): The Open University

License information
Related content

Except for third party materials and/or otherwise stated (see terms and conditions) the content in OpenLearn is released for use under the terms of the Creative Commons Attribution-NonCommercial-Share

1.6.2 Alerts

Online bookshops and some of the major search engines offer ‘Alerts’ services. These work by allowing you to set up a profile once you have registered on their site, and when there are items meeting your criteria you receive an email. The good thing about alerts is that you don’t have to do anything once you have set up your profile. The downside, particularly with alerts services from the search engines, is that given the extent to which internet traffic is on the increase whether new
Author(s): The Open University

License information
Related content

Except for third party materials and/or otherwise stated (see terms and conditions) the content in OpenLearn is released for use under the terms of the Creative Commons Attribution-NonCommercial-Share

1.6.1 Introduction

The process of keeping up-to-date in your chosen subject area is useful for your studies and afterwards, for your own personal satisfaction, or perhaps in your career as part of your continuing professional development.

There are a great many tools available that make it quite easy to keep yourself up to date. You can set them up so that the information comes to you, rather than you having to go out on the web looking for it. Over the next few pages, you will be experimenting with some
Author(s): The Open University

License information
Related content

Except for third party materials and/or otherwise stated (see terms and conditions) the content in OpenLearn is released for use under the terms of the Creative Commons Attribution-NonCommercial-Share

1.5.8 Bibliographic software

If you are considering taking your studies further you might like to consider using bibliographic software. Bibliographic software can be used to sort references, annotate them, manage quotations or create reading lists.

There are several software packages on the market. Some are listed below.

1.5.7 Referencing

We mentioned above that we need to reference sources to ensure we abide by copyright legislation. But there is another reason we need to give accurate references to items we use – so we can share it.

Consider this scenario. A friend says they’ve just read an interesting article where Joshua Schachter, founder of Delicious has spoken about why it isn’t a faceted search system, and you should read it. How would you go about finding it? Would you start looking in a news database, a s
Author(s): The Open University

License information
Related content

Except for third party materials and/or otherwise stated (see terms and conditions) the content in OpenLearn is released for use under the terms of the Creative Commons Attribution-NonCommercial-Share

1.3.2 Search Engines and Subject Gateways

Although both search engines and subject gateways will help you find the resources that you need, the types of information that you find will differ.

Search engines such as Google and Yahoo! search the internet for keywords or phrases, and then show you the results. These results are not mediated by the search engines, and therefore you need to use your own judgement on the reliability of the results. You may, for example, find websites written by experts, alongside websites written by
Author(s): The Open University

License information
Related content

Except for third party materials and/or otherwise stated (see terms and conditions) the content in OpenLearn is released for use under the terms of the Creative Commons Attribution-NonCommercial-Share

1.1.6 Keeping Up-to-date

How familiar are you with the following different ways of keeping up to date with information; alerts, mailing lists, newsgroups, blogs, RSS, professional bodies and societies?

  • 5 - Very familiar

  • 4 - Familiar

  • 3 - Fairly familiar

  • 2 - Not very familiar

  • 1 - Not familiar at all


Author(s): The Open University

License information
Related content

Except for third party materials and/or otherwise stated (see terms and conditions) the content in OpenLearn is released for use under the terms of the Creative Commons Attribution-NonCommercial-Share

1.1.1 Assessing your current level of knowledge

If you explore all the resources and activities in this unit, you might need to allow between two and nine hours to complete it.

Before you read this guide, why not use the self-assessment questions on the next screen to rate your current level of knowledge?

Print or save these questions and for each question, mark the most appropriate number on the scale. When you have finished, you can review your answers. A score of three or less might indicate a gap in your knowledge
Author(s): The Open University

License information
Related content

Except for third party materials and/or otherwise stated (see terms and conditions) the content in OpenLearn is released for use under the terms of the Creative Commons Attribution-NonCommercial-Share

3.5 Common law

This may be a familiar term that you have encountered in newspaper reports or on the television or radio. Common law has its roots in history. In 1066, William the Conqueror began to establish a strong central government and to standardise the law in England. Representatives of the King were sent
Author(s): The Open University

License information
Related content

Except for third party materials and/or otherwise stated (see terms and conditions) the content in OpenLearn is released for use under the terms of the Creative Commons Attribution-NonCommercial-Share

4.13.3 Scrutiny

Again, connected to the accountability issue is the problem of adequate scrutiny. The detailed, technical and specific nature of much-delegated legislation means that, on the whole, Members of Parliament (the elected representatives) do not have the expertise to consider proposed legislation effectively. In addition, you have already noted that the scrutiny committees themselves only have limited powers.


Author(s): The Open University

License information
Related content

Except for third party materials and/or otherwise stated (see terms and conditions) the content in OpenLearn is released for use under the terms of the Creative Commons Attribution-NonCommercial-Share

Pages 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439