Co Index/CIE-Revision/O-Level/O-Level-Biology-Notes Index · CIE- Revision · O- Biology O Level hohounsmolathe.cf · Biology hohounsmolathe.cf · IGCSE Biology. O Level Biology Notes. Pages · · MB O' Level Biology - Home › Gayaza High School Fundamental Biology for O Level Teaching hohounsmolathe.cf Biology-Notes for -o-levelpdf - Free download as PDF File .pdf), Text File .txt) or read online for free.
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The Best Biology O Level Notes compiled from all around the world at one place for your ease. MB. 24/02/ IGCSE Biology hohounsmolathe.cf MB. more examples of diffusion in biology. Diffusion: Diffusion always takes place down a concentration gradient, that means that the particles that diffuse try. Biology Notes for IGCSE · All Notes · 1. Classification · 2. Cells · 3. Enzymes · 4. Plant Nutrition · 5. Animal Nutrition · 6. Plant Transport · 7. Human.
The more times you revise a topic, the better you will retain the information in your mind.
Revise all your past tests, exams and assignments and understand your mistakes. Consult your teacher if you need. It's not enough to just memorize your whole textbook. You need to practise doing the questions too. So start working on your ten-years series or other good assessment books.
Once you have practised sufficiently, you will come to realize that there is only a certain number of ways they can ask questions regarding a specific chapter.
download an A4 ring-binder pad. Write the essay question at the top and then write out the essay yourself with reference to your textbook or notes given out by your teacher. It is rigid dead layer. It is fully permeable layer which protects a plant cell from bursting and maintains its shape.
Cell Membrane: It is a partially permeable membrane. Outer most boundary in animal cells. It is beneath the cell wall in a plant cell.
Prevents mixing up of the contents of various cells together. Controls the inward and outward movement of substances. Cytoplasm: It is a jelly like substance which covers the space between cell membrane and the nuclear membrane.
It is a site for chemical reactions e. Nucleus: It is densely stain region in the center of an animal cell and slightly away from the center in a plant cell. It consists of a nuclear membrane which is partially permeable. It also contains chromosomes. Chromosomes carry the hereditary materials. Nucleus controls the division of cells.
Unit-1 11 Cell Structure and Organization Chloroplast: It is found in mesophyll and guard cells in a plant cell.
It is double membrane bound cell organelle. Famine is typically induced by a human population exceeding the regional carrying capacity to provide food resources. An alternate view of famine is a failure of the poor to command sufficient resources to acquire essential food, analyses of famine that focused on the political-economic processes, an understanding of the reasons for mortality in famines, an appreciation of the extent to which famine-vulnerable communities have strategies for coping with the threat of famine, and the role of warfare and terrorism in creating famine.
Modern relief agencies categorize various gradations of famine according to a famine scale.
Causes of famine In biological terms, a population beyond its regional carrying capacity causes famine. While the operative cause of famine is an imbalance of population with respect to food supply, some famines are caused by a combination of political, economic, and biological factors.
Famines can be exacerbated by poor governance or inadequate logistics for food distribution.
In some modern cases, it is political strife, poverty, and violence that disrupts the agricultural and food distribution processes. Modern famines have often occurred in nations that, as a whole, were not initially suffering a shortage of food.
One of the largest historical famines proportional to the affected population was the Great Irish Famine , , which began in and occurred as food was being shipped from Ireland to England because the English could afford to pay higher prices. The largest famine ever in absolute terms was the Chinese famine of —61 that occurred as a result of the Great Leap Forward. In a similar manner, the famine in Ethiopia was concentrated in the Wollo region, although food was being shipped out of Wollo to the capital city of Addis Ababa where it could command higher prices.
In contrast, at the same time that the citizens of the dictatorships of Ethiopia and Sudan had massive famines in the lates and earlys, the democracies of Botswana and Zimbabwe avoided them, despite having worse drops in national food production. This was possible through the simple step of creating short-term employment for the worst-affected groups, thus ensuring a minimal amount of income to download food, for the duration of the localized food disruption and was taken under criticism from opposition political parties and intense media coverage.
The failure of a harvest or the change in conditions, such as drought , can create a situation whereby large numbers of people live where the carrying capacity of the land has dropped radically. Famine is often associated with subsistence agriculture, that is, where most farming is aimed at producing enough food energy to survive. The total absence of agriculture in an economically strong area does not cause famine; Arizona and other wealthy regions import the vast majority of their food, since such regions produce sufficient economic goods for trade.
Disasters, whether natural or man-made, have been associated with conditions of famine ever since humankind has been keeping written records. The Torah describes how "seven lean years" consumed the seven fat years, and "plagues of locusts " could eat all of the available food stuffs.
War, in particular, was associated with famine, particularly in those times and places where warfare included attacks on land, by burning or salting fields , or on those who tilled the soil.
As observed by the economist Amartya Sen, famine is sometimes a problem of food distribution and poverty. In certain cases, such as the Great Leap Forward , North Korea in the mids, or Zimbabwe in the earlys, famine can be caused as an unintentional result of government policy.