The relationship between species, populations community and the ecosystem

1. The relationship between species, populations community and the ecosystem Developed by KZN advisors

2. Carrying capacity is the maximum population size a certain environment can support for an extended period of time, for a population of a particular species. Under ideal conditions, a population naturally increases until it overshoots the carrying capacity.  At this point, the environment can no longer provide for the species, due to a number of different environmental resistances, including food, crowding, competition, etc. The population, due to lack of resources, will begin to die out, allowing the environment to recover. As the environment recovers, the species population is able to flourish once more. This leads to a fluctuation between the prosperity of the species and the prosperity of the environment (hence the fluctuations in the graph).  Developed by KZN advisors

3. Carrying capacity Developed by KZN advisors

4. If a population reaches carrying capacity it can remain stable or move up and down (fluctuate). If there is more rainfall and more food available the carrying capacity increases and the population will increase until it reaches the new carrying capacity before it levels off again. If there is habitat destruction or a draught the carrying capacity decreases and the population will decrease until it reaches the new carrying capacity and levels off again. Developed by KZN advisors

5. Carrying capacity of rabbits in a specific area 1. What does the blue line represent? What does the purple line represent? What does it mean when the purple line rises above the blue line? 2. Which of the following situations might cause the purple line to decrease below the blue line: abundant food sources, lack of competition, a young population, or plentiful roaming space? 3. Can you think of any events that would cause the purple line to stay above the blue line indefinitely? Developed by KZN advisors

6. 1.1 Suggest THREE reasons why the growth form between the period 1920 and 1935 is as it is.1.2 What is the growth phase called between 1910 and 1920? (1)1.3 During which year did the jackal enter the fenced area? Give a reason for your answer from the information supplied. (3)1.4 Between 1940 and 1950 the springbok population increased again. Mention a possible reason for this increase. (2)1.5 Mention FOUR other factors, besides the jackals, which could have caused the decline in the springbok population between 1935 and 1940? (4)1.6 What method was most probably used to determine the size of the springbok population? (1)1.7 Do you think the line representing the carrying capacity is accurate? Give a reason for your answer. (3)1.8 The population between 1965 and 1975 appears to have stabilised. Suggest how the farmer might be controlling the population. (2)1.9 What do you notice about the growth from 1915 – 1925 and 1940 – 1950? (1)(20) Question: Carrying capacity Developed by KZN advisors

7. Density dependent and factors Developed by KZN advisors

8. Geometric growth form (J- curve) Developed by KZN advisors

9. Logistic growth form (S-shaped curve) Developed by KZN advisors

10. Question : growth patterns • 4. A certain fast growing unicellular micro-organism is cultivated in a sugar solution in a closed test tube at 250 C. At regular intervals, samples were taken in order to calculate the population size. The graph below was drawn from the data obtained. Study the graph and answer the questions that follow. • 4.1 Which specific organism was most probably cultivated in the test tube? (1) • 4.2 Name the growth phases indicated by A, B and C respectively. (3) • 4.3 Give an explanation for the specific growth pattern of each of the phases A, B and C. (6) 4.4 What is phase Y called and what is the possible cause, thereof, for this specific population in particular? (3) • [ 13 ] Developed by KZN advisors

11. Comparison between geometric (J-curve) and Logistic (S-curve) Developed by KZN advisors

12. Methods to determine population size1. Direct method: census Developed by KZN advisors

13. A pitfall sampling method can also be used Developed by KZN advisors

14. Methods to determine population size2. Indirect method: simple sampling Developed by KZN advisors

15. Simple sampling can be used to determine the number of plants in an area Developed by KZN advisors

16. Quadrat sampling method for plants Developed by KZN advisors

17. In simple sampling a physical count of all the animals/plants under investigation in a small sample are of the habitat is done. The total population in the big area is calculated as follows:Estimate number of = number of individuals in sample x habitat sizeindividuals in the __________________________population sample size Developed by KZN advisors

18. Activity 1: simple sampling Method Mix an unknown number of tiny beads with sea sand thoroughly to fill a 500 ml jar. Remove a level teaspoon (5 ml) of the mixture from the jar. Spread the mixture on a saucer and count the number of beads. Use the formula below to estimate the total number of beads in the bottle :  Total nr. of beads = nr. of beads in sample x total volume of mixture (500 ml) ____________________________ volume of teaspoon (5ml) Place the bead and sea sand mixture back into the jar. Mix thoroughly and repeat the exercise a few more times. Obtain an average estimate of the number of beads in the jar Results Complete the table :- Questions Why is it necessary to repeat the investigation a number of times? 2. How is this investigation limited? Developed by KZN advisors

19. Simple sampling can be used to determine the number of micro organisms on a slide Developed by KZN advisors

20. A leading Kwa-Zulu entomologist ( a person that studies insects ) decided to work out the number of worms that occurred in Kwa-Mashu. The total area in Kwa Mashu where the worms occurred was 2000 m2. He chose five 10 m2 plots and found 120, 100, 150, 130 and 100 worms in each plot respectively. (i) Estimate the total number of worms in the Kwa-Mashu area. (Show ALL calculations). (5) (ii) Describe two ways how the entomologist could improve the reliability of these results. (2)(7) Question : Simple sampling Developed by KZN advisors

21. Answer : Simple sampling Ave. number of worms in a plot = 120+100+150+130+100 = = 120 worms/plotEstimate number of = number of individuals in sample x habitat sizeindividuals in the __________________________population sample size = = 24 000 worms Developed by KZN advisors

22. Methods to determine population size2. Indirect method: mark recapture A number of animals are caught and marked Developed by KZN advisors

23. In theory, mark / recapture techniques involve sampling a population of animals and then marking all of the individuals captured in a recognizable way. The marked animals are then released back into the population and left to mingle for a suitable period of time. Once they have become thoroughly mixed into the population again, the population is re-sampled.The assumption is then made that the proportion of marked animals in the second sample is the same as the proportion of marked animals to non-marked within the whole population. Enough time must be allowed to elapse for complete mixing to have occurred. Developed by KZN advisors

24. The same method are used with fish Developed by KZN advisors

25. The fish are marked – but don’t take them out of water for too long! Developed by KZN advisors

26. The following should be taken into account when animals are caught and marked 1. The animal usually needs to be captured to be marked, the animal should not be injured and its behaviour pattern should not be altered. 2. The mark used should not harm the animal - for example a dot of a particular paint may turn out to be toxic to the animal. Trials therefore need to be done to ensure that the animal is not harmed in any way. 3. Take random samples from the population. If you take samples from only one place each time, they you are likely to catch the same animals that you released. 4. Once you have released the first sample, give the animals enough time to mix randomly with the rest of the population before you take the second sample. 5. Ensure that animals do not become 'trap-shy' and avoid the traps after the first capture. This can be reduced as far as possible by choosing a method which will not distress the animal unduly. Some animals may become 'trap-happy', particularly if the traps are baited. This can be overcome by setting out the baited traps, without actually trapping, for some time before the first sample is taken. This allows all animals in the population to become equally trap- happy before you start. Trap-shyness results in population overestimates, while trap-happiness results in population underestimation Developed by KZN advisors

27. They are released back into the water and some are caught again after a period of time Developed by KZN advisors

28. The mark-recapture method can also be used on frogs Developed by KZN advisors

29. The mark-recapture method can also be used on crabs Developed by KZN advisors

30. Activity 2: Mark -recapture Method: Get into groups of 4. Tear old papers (newspaper/unused notes) into small pieces and throw into a container. The container will represent a dam and the paper pieces fish. You should have ± 100 - 200 fish in your dam. Mark 30 of your fish with a pen. Discuss how you should mark real fish. Put the marked fish back into your dam and mix them up with the rest of the fish. Take a handful of the mixed fish out of the dam. Count the marked and the unmarked fish. Estimate the size of your fish population by using the formula: Repeat your estimate at least 5 times and calculate the estimated average fish in your dam. Tabulate your results. List possible shortcomings of your investigation Developed by KZN advisors

31. It is evident from the graph that :-1. the human population is increasing rapidly and shows a geometric (J-shaped) growth form2. the population is doubling in shorter periods3. the next doubling period (8 000 million) has been calculated to be in the year 2010 – a doubling period of 35 years4. this increase in population CANNOT go on indefinitely – as environmental resistance (shortage of food, O2 and living space) increases – something has to give – unless we are able to stabilise the population at the carrying capacity of the world Trend in the human population growth up to 1650 and from 1650 to the present moment Developed by KZN advisors

32. Worldwide human population growth from 1750 to 2000 Developed by KZN advisors

33. Human population growth according to History Developed by KZN advisors

34. Human population growth in SA from 1947 to 2011 Developed by KZN advisors

35. Human population age and gender distribution in:1. an increasing populationA population pyramid with a small number of old people indicates a population with a high birth rate, a high death rate and a short life expectancy. This pattern is typical of less economically developed countries (LDC) like South Africa, South America and Asia (excluding Japan)2. a stable populationThere is approximately the same number of young people and old people. About the same number of children is born each year compared to the number of people who die each year. Economical developed countries like Ireland have this kind of pyramid3. a decreasing populationThere are more old people than young people. Each year more people die than are born. Developed countries like Germany have this kind of pyramid. Some southern African countries, like Botswana (experiencing the effects of HIV/AIDS) are also starting to show this kind of age-gender pyramid. Developed by KZN advisors

36. Population sizes in different parts of the world Developed by KZN advisors

37. The graph is divided into 2 groups:1. The less developed countries (LDC) like Latin America, Africa and Asia (excluding Japan). Population growth is expanding rapidly and the majority of people live in poverty. Medical care and technological advances are not readily available, food is scarce and levels of education are low. A high social value is placed on large families.2. The more developed countries (MDC) like North America, Australia and Europe. Population growth is low and people enjoy a good standard of living. Medical care and technology is readily available. Food and technology are available, level of education is high. A comparison of less developed countries with more developed countries Developed by KZN advisors

38. Discuss the differences between the gender-age pyramids for Japan & Zimbabwe. Developed by KZN advisors

39. Use these graphs to discuss the changing trends in the SA population. Indicate the working group (20 – 60 years), mention how their economical contributions will support the non-economical groups (children and old people). Take the % of jobless people into consideration and the fact that only 5.6% of the population pays tax Developed by KZN advisors

40. The effect of high population growth on the environment Developed by KZN advisors

41. The effect of high population growth on the environment (depletion of resources and increased pollution) Developed by KZN advisors

42. The effect of a growing population on resources, pollution, industrial output and the availability of food Developed by KZN advisors

43. Ecological footprint: the impact of a person, city, or country on the ecology of a local area or the whole planet. It is a measure of how much land and water a person, city or country needs and the wastes that are produced. Developed by KZN advisors

44. We do not know what the carrying capacity of the world is. The United Nations has predicted a global human population of over 10 billion people by 2050 – therefore an estimated 4 billion people will be added to the population in the next 40 years. One approach to estimate the carrying capacity of the earth is to look at the ecological footprint of different groups of humans. Developed by KZN advisors

45. According to the Global Footprint Network, humanity uses the equivalent of 1.3 planets to provide the amount of resources we consume and absorb the waste we produce. This means it now takes the Earth one year and four months to regenerate what we deplete in a year. Developed by KZN advisors

46. To calculate the ecological footprint of a population all their needs need to be taken into account, e.g. food, water, fuel, building materials, clothing and medical care. The impact, to produce the needs, on the environment is then calculated. An ecological footprint represents the area of land and water utilised by a particular nation. It takes into account the resources used by wastes produced by that country. It measures how much land an water a human population requires to produce what it consumes, and to absorb its wastes using current technology. It compares human demand with the earth’s capacity to regenerate Developed by KZN advisors

47. In 2006, the global ecological footprint outpaced the Earth’s biological capacity by 30 percent. This trend is increasing. In fact, on September 23rd of this year, we passed “Overshoot Day,” the day the human ecological footprint exceeded the Earth’s biocapacity and began living beyond its ecological means. Since then, we have been engaged in the ecological equivalent of deficit spending: our rate of resource consumption is exceeding the rate at which those resources can be naturally replenished. Developed by KZN advisors

48. What are we doing? Developed by KZN advisors

49. Activity 3:Use the next two slide to complete the table: Developed by KZN advisors

50. The effect of high population growth on the environment. The darker the colour, the greater the ecological footprints. Developed by KZN advisors