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Higher Biology

Higher Biology. Monitoring Populations. Monitoring Populations. By the end of this lesson you should be able to:. Give four reasons for monitoring populations. Introduction. Wild plant and animal populations are regularly monitored to detect any changes in their population numbers.

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Higher Biology

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  1. Higher Biology Monitoring Populations

  2. Monitoring Populations By the end of this lesson you should be able to: • Give four reasons for monitoring populations.

  3. Introduction • Wild plant and animal populations are regularly monitored to detect any changes in their population numbers.

  4. Managing species used for food and raw materials • Humans make use of many species for: Food Raw materials Fuel Medicines Housing Furniture

  5. Managing a Species • In order for a population to survive, the death rate must not exceed the birth rate. • When hunting or farming, it is important to ensure that there is enough of the population left to replenish their numbers. • The Maximum Sustainable Yield (MSY) is the numbers of individuals that can be removed from a population without affecting its productivity in the future.

  6. Managing a Species- example • Fish stocks in the North Sea have been depleted due to over-fishing. • Governments set fishing quotas-stating how many fish can be harvested per year.

  7. Controlling Pest Species • A pest is a species that is harmful to humans, animals or crops. • Examples- insects, rodents, fungi • Monitoring the population of pest species, provides information needed to keep them under control. • They are controlled by either • Chemical means- pesticides • Biological means- introducing the pest’s predator.

  8. Controlling Pest Species-example • Controlling • Aphid (greenfly) numbers • Locust numbers- by monitoring weather patterns and locust swarms- early warnings can be issued to areas likely to be affected. • Rats- numbers monitored to limit the spread of disease.

  9. Monitoring levels of Pollution • Indicator Species- indicate pollution levels in an environment, by their presence or absence. e.g. Freshwater Invertebrates Lichens Birds of Prey

  10. Protecting Endangered Species • Population numbers need to be monitored to reveal those in danger of extinction. e.g. • Currently there are only about 1100 pandas living in the wild and about 40 in captivity (Chinese zoos)

  11. Protecting Endangered Species • In the 1930-1940s there were estimated to be 3 to 5 million elephants in Africa. • In 2002 there was less than 500, 000. • Reason? • Poaching and illegal ivory trade.

  12. Protecting Endangered Species • In 2002 there was 600 mountain gorillas left in the wild- with none in zoos. • It is highly possible that this species will be extinct in your lifetime. • Many wild plants are also in danger of extinction.

  13. Practice Questions • Torrance • TYK page 302 Q1-3a • TYK page 306 Q1&2 • AYK page 310 Q7

  14. Monitoring Populations Can you do it? • Give four reasons for monitoring populations.

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