S.6 & S.5 BIOLOGY SCENARIO WITH ITS SOLUTION IN NEW CURRICULUM SETTING

追加: 2026-05-21

[00:00:00]Hello, viewers.

[00:00:02]It's Alan once again.

[00:00:05]I'm back as usual.

[00:00:09]Please inform you that the subjects were made simpler, especially chemistry and biology.

[00:00:18]This is going to be evident in this video.

[00:00:22]Um by the end of this video, you must be able to respond to items uh to do with ecology, genetics, and evolution.

[00:00:37]Uh These items are very simple, but they will usually set complex uh detailed information for you to interpret.

[00:00:51]I won't be too wordy. I'll take you through the scenario.

[00:00:55]Here's a question.

[00:00:59]It reads, "A farmer in region K report a rapid outbreak of Angoumois moth, an invasive insect that feeds on staple grain crops.

[00:01:21]The pest was absent 3 years ago.

[00:01:25]Below are the field and the laboratory data collected in this season.

[00:01:31]So, table one is this one here.

[00:01:35]So, table one has a site, where we have site A, B, and C. These are farm lands that were accounted in the following ways.

[00:01:52]Recording the number of these Angoumois larvae, recording the average crop yields per kilogram and kilo in kilograms per hectare recording the plant heights, the maximum plant heights attained the percentage of crops with pest X resistance gene and they also giving us the notes.

[00:02:21]So, they are saying for A the boiler larvae, I mean, the number of larvae of bollar per meter squared of the field is eight.

[00:02:34]So, they are getting eight bollars larvae uh uh a meter squared for farmland A.

[00:02:46]The average crop yield was 4,200 kg per hectare.

[00:02:52]With a a plant maximum height of 95.

[00:02:58]The percentage of the crops that contain a a pest X resistance gene were 15 in this field.

[00:03:10]In this farmland, no pesticide was used.

[00:03:16]There was a high natural predator population.

[00:03:22]For B the bollar larvae population is of 65 bollars per meter squared. So, these are very many compared to these ones and these ones.

[00:03:38]So, for every small piece of the farmland B, there are very many bollars.

[00:03:47]These are insects like they say.

[00:03:49]>> [clears throat] >> So, the average crop yield is reducing to this.

[00:03:56]1,800 with very short plants with whose height is at 62 cm.

[00:04:07]Um the percentage there is some crops with pest X resistance gene. So, I'm going to see this pest X uh the crops with pest What is the pest X resistance gene? I'm going to have a look at it. This farmland B has high pesticide use. They use a lot of pesticide in it.

[00:04:30]Low predator activity. Interpret the data in your low lay understanding.

[00:04:39]Cuz as you read it, if you don't understand what you're reading, if you cannot interpret what you're reading, you cannot respond to any task given.

[00:04:52]So, they are continuing that there were low predator activity. So, the natural predators in field B were very few.

[00:05:06]We are talking of predators of this bollworm.

[00:05:12]For example, there are might be some insects that feed on these bollworms.

[00:05:18]In A, there were very many.

[00:05:21]In B, there are few.

[00:05:24]In field C, the number of larvae of this bollworms per meter square is actually slightly less than this one, but bigger than A.

[00:05:38]Um giving an average crop yield of 3,500 close to that of A.

[00:05:49]Um the plant height in centimeters is at uh 88.

[00:05:58]And the percentage of the crops with pest X resistance gene is at 70%.

[00:06:07]The farmland C was using pesticides at a minimum, not too much, not too little.

[00:06:16]That's why they're saying mixed pesticide use.

[00:06:22]Uh they also introduced these crops with pest X resistance gene.

[00:06:38]Um they are continuing in the scenario saying that the normal crop yield is about this normal crop yield is about 4,000 to 5,000 kg per hectare. So, the normal for this is 4,000 to 5,000 kg per hectare. This is the normal output in in black.

[00:07:06]Then they're saying the normal plant height for healthy crops is between 90 to 100 cm. So, the normal crop height is between 90 to 100 cm.

[00:07:23]So, this case is representing the results.

[00:07:28]>> [snorts] >> Um The pesticide, I mean pest X resistance gene, they're describing it, allows plants to produce a protein a protein toxic the I mean a protein that is toxic to the borer larvae. So, this the role of this pest X resistance gene in these crops in these grain crops is to allow them produce a protein.

[00:08:05]It stimulates them to produce a protein that is toxic to these uh borer.

[00:08:15]That's what they are saying in this scenario.

[00:08:19]Borer adults from uh develop I mean borer develops from eggs to larvae to pupa and then adults in 28 days. So, for this borer to reach their maturity they take 28 days and they undergo four stages of development.

[00:08:44]20 Sorry.

[00:08:48]They take 28 days to reach maturity.

[00:08:55]To fully develop.

[00:08:59]And at 28° so, the 28 They take 28 days to reach maturity at a temperature of 28° C.

[00:09:12]If the temperature is at 28° C this is this borer will take 28 days to reach maturity.

[00:09:21]We are analyzing the data.

[00:09:24]As also as also look at the scenario in the description of the video and on the screen.

[00:09:33]They are also adding that with warmer seasons development speed up by 15 15 to 20%.

[00:09:46]When the temperature exceed 28, this is what we are saying. When this temperature exceed 28° C, the rate of development increases by 15 to 20 what? Percent.

[00:10:03]So, we shall expect a faster rate of development of these borers to maturity or to a reproductive stage when the temperature become warmer.

[00:10:15]So, analyzing the data.

[00:10:20]The table Another table is summarizing the ecological observations made on the following.

[00:10:27]On site A, B, C for natural predator abundance, soil nitrogen levels, and recent temperature trends.

[00:10:41]This for site A, there is a high natural predator abundance.

[00:10:48]For site A, the number of predators that feed on these borers is high.

[00:10:56]There is a high soil nitrogen level.

[00:10:59]There is a lot of nitrogen in the soil in site A.

[00:11:03]The temperature is slightly increasing by 0.8° C in 5 years.

[00:11:10]You can imagine how many seasons are in 5 years.

[00:11:16]For site B, the natural predator abundance is very low.

[00:11:21]As also, the soil nitrogen is low.

[00:11:25]But, the temperature is increasing by 1.2° C in the 5 years.

[00:11:32]So, this is a slightly high increase in temperature.

[00:11:39]Um for site C, everything is moderate and also the temperature increase is slightly moderate in the 5-year in the past 5 years.

[00:11:51]So, I'm going to use this data to respond to this task, which reads, "Evaluate the genetic, ecological, and developmental factors driving the bowler the bowler outbreak, crop loss, and and crop loss across the site sites A, B, and C.

[00:12:19]Integrate inheritance, population growth, plant growth, and ecological interactions. Explain why the problem differ between sites.

[00:12:35]Develop sustainable strategies for region K that can address the invasive species and account for the ongoing changes for the ongoing changes.

[00:12:50]So, I'm now going to look at site by site. We have three sites, A, B, and C.

[00:12:57]We are going to look at them in terms of, like they are saying, in terms of the genetics, the ecology, and the developmental factors.

[00:13:10]So, this item comes from an assessment objective. That is part assessment objective uh four that sits an item in the section B part two of a yearly paper.

[00:13:29]It integrates the uh such as ecology, inheritance and evolution.

[00:13:36]So, in this we shall expect all evolution I mean genetic crosses, inheritance crosses and conditions.

[00:13:47]We shall expect gene codes there, the nucleic acids.

[00:13:54]We shall expect all the evolutionary mechanisms in this item in these kinds of items, the speciations, the melanisms.

[00:14:06]All those ones the Hardy-Weinberg equilibrium principle, all of those ones are expected in these ones.

[00:14:16]The food webs, types of population, factors affecting population growth, and so on. The population trends, or graphs, all will appear in these in this section B, part two.

[00:14:36]You always choose an item.

[00:14:41]So, to go into this one, we shall look at each site at a time.

[00:14:49]When we look at site A, we're going to first outline what what we we can see.

[00:14:55]Site A shows better results in terms of average crop yield of about this one.

[00:15:09]That is close to that is actually in the normal range.

[00:15:15]Um a plant I mean plants showing uh better growth uh, with with heights that falls in the normal range. This is 95 cm.

[00:15:31]Um, though we have less crops with pest eggs resistance genes of 15.

[00:15:47]In food A, they are using less pesticide.

[00:15:52]But we have more of the natural predators.

[00:15:57]Like we said, I'm not going to always give you responses. The responses are always are already written. They are in our item bank that was already released.

[00:16:10]Um, here I'm only giving you an overview.

[00:16:14]Getting a chance to have a look at these questions already exposes you towards you should read and how to read it.

[00:16:23]So it's better you order for a copy. You can contact us on our WhatsApp number 0703 278 271.

[00:16:37]So the information you've just seen, what does that information mean?

[00:16:43]It means that um, despite the low use of the pesticide, the decreasing uh, number of boa boa larvae in site A a- I I as a result of the high or the big number of natural what? Predators.

[00:17:13]This number, the high number of the natural predators, is brought about by the not all less pressure created by the pesticides.

[00:17:23]Selection pressure.

[00:17:25]So, here the factor that is bringing about the selection pressure is the pesticide.

[00:17:32]Cuz when introduced a pest I mean a pesticide will kill every insect in the field.

[00:17:41]Not even isolating this natural predator that feeds on this boll larvae.

[00:17:49]So, there are more predators that are there to check the population of the what?

[00:17:58]The the boll larvae.

[00:18:01]So, less available to eat on the tissues of the plant and therefore more developed attain a height that falls within the what?

[00:18:16]The expected range.

[00:18:20]Still the high average crop yield of this and are relatively um required plant height of the 95 is as a result is as a result of the high nitrogen levels in the soil.

[00:18:48]This makes the nitrates more nitrates available for the synthesis of proteins and chlorophyll that is required um to make more food.

[00:19:06]Not only that to make more plant tissues that contribute to this uh plant height of a 95 cm.

[00:19:19]The low number of boiler larvae indicated is due to the slight increase in temperature that allows a few boiler larvae to reach maturity or to reach the reproductive stage so that they can form less so that they form this less number of the boiler larvae per generation.

[00:19:48]So, the response is based on the values we have, but bringing in the information we have in the scenario here.

[00:19:58]Remember, as I have told you, the response is already developed. They are responses If you need them, they are there.

[00:20:08]The scenario that the question is that there are very many, over 100.

[00:20:12]And they are some of the responses.

[00:20:18]Just to guide you as you read.

[00:20:23]>> [snorts] >> Um The results I'm sorry. The results The results and the findings in the table are enough to show that ecological interactions with healthy soils This The availability of these predators and the healthy soils are enough to bring about um a high crop yield despite the low numbers of the pest X resistance gene.

[00:21:09]So, what is showing in this site A is the ecological interaction with the what? The healthy soils. Nourishing the plants well to bring about uh yields, better yields. The nitrogen also help these plants enable these plants to overcome the the damages caused by the few pests the few bollworm larvae in the field.

[00:21:42]So, the nitrogen in the soil is talking on the nutritional side.

[00:21:48]Enabling these plants to restore our tissues damaged during protein synthesis and so on.

[00:22:01]To continue, for site B, it is showing the worst worst data.

[00:22:09]A very big number of bollworm larvae.

[00:22:17]It is brought about by this elevated temperature over this [clears throat] uh five these five years.

[00:22:28]And remember we said that if the temperature increases beyond 28° C, uh more of these bollworm larvae will I mean, will develop at a rate that is increased it over about 20% such that more reach the reproductive stage to give raise to more bollworm larvae. I mean, larvae increasing them to six to a number of a 65.

[00:23:05]This implies that more of them are going to be feeding on the plant tissues.

[00:23:15]And due to the low nitrogen levels in field B, these fed on tissues of the plant are not replaced because of the unhealthy soils in field B.

[00:23:35]There is also less uh since food synthesis resulting to this abnormally low yield over this season.

[00:23:53]Hope you're seeing. So, the result of the bowler bowler's feeding on these plants and the less nitrogen in the soil resulting to reduced recovery of these plants by forming new tissues due to nitrogen uh absence is resulting to this uh poor plant heights and low yields.

[00:24:21]The big number is as a result of this high increase in temperature of over plus 1.2 degrees Celsius that is raising the temperature beyond the 28 increasing the maturity rate to over 20%.

[00:24:40]About 20% to this ratio.

[00:24:45]About 20%.

[00:24:47]Such that more of them reach maturity to reproduce uh or giving rise to these more bowler larvae.

[00:25:00]Also, the due to a lot of pesticides used in site B, it is indicated here, creates a selection pressure that removes all the predators.

[00:25:24]The natural predators we have the low active predatory activities in site C. Removing all the pre-natural predators that are at the selection disadvantage preserving uh the bowel and larvae that are invasive and at the selection advantage.

[00:25:55]Still, this the high use of these uh pesticides also bring about um resistance.

[00:26:07]Incre- increases resistance.

[00:26:10]This bowel and resistance to the chemicals in in the pesticides in the way that even if they are used, they have no effect on them.

[00:26:30]So, the population goes on increasing.

[00:26:36]The absence of despite the I mean despite the big num- I mean the the moderate number of the crops with pest X resistance gene, We are seeing that still the yields are less.

[00:26:59]Meaning that this number of the resistance gene it this this indicates that the genetic cuz this is genetic uh this is a genetic pressure that is put on this population of the bollards.

[00:27:17]It indicates that um despite the use of the pesticides the population of the pest the bollards is increasing just because the decrease or the low numbers of the predators in the field makes more of these bollards reach maturity unchecked.

[00:27:57]With limited pressure no predators are attacking them. So they are safe.

[00:28:11]In the way that they can even resist these crops with the pest X resistance gene.

[00:28:21]So what is hindering uh the numbers to get to extremes is just because of the presence of the pest X resistance gene.

[00:28:37]It is the one that is stopping the outbreak.

[00:28:42]But the soil health and the natural predator abundance are not affecting the population in this case at all.

[00:28:54]To continue with population C, everything is moderate.

[00:29:00]The slight increase or the moderate increase in temperature by 1.0° C in 5 years in 5 years brings about a slight increase in the population of the larvae.

[00:29:18]This is because more of these larvae, I mean more of these Boala reach maturity, I mean a slight number of these Boalas reach maturity to give raise to some or to a moderate number of the Boala larvae.

[00:29:36]But per per season or per generation.

[00:29:42]So the moderate number of the larvae in field C are contributing um to the low yields since they moderately feed on the tissues of these plants.

[00:29:58]But since there is some nitrogen in the soil, a little I mean some of these plants overcome the stress of these Boalas.

[00:30:17]And the presence of a big number of crops with pest pest ex-resistance gene creates a pressure that checks these what?

[00:30:35]Um the Boala larvae.

[00:30:39]So this relatively high yield of young 3,500 kg per hectare are coming from these crops with the resistance X I mean with the pest X resistance gene that are not attacked by the borers.

[00:31:03]So the results in C indicate that the genetic uh the genetic pressure created by the pest X resistance gene is not sufficient alone to result into the expected yields and plant growth rates unless uh if healthy sales are availed with some predators in the field.

[00:31:43]So the item is bringing about the interaction between evolution genetics and ecological changes undergone by plants or organisms such as plants and insects for survival and it is or directing the learners to talk about food security.

[00:32:08]The emergence of all these environmental factors How should these farmers ensure that food is availed season after season despite of these pressures created by the environment by their mistakes made.

[00:32:32]So the strategies made should be in this line.

[00:32:37]You may advise these farmers to make to use composite composite or to add composite composite manure uh and legume intercropping to field such as field B cuz uh farms such as with the same conditions such as field B.

[00:33:03]This make more of the nitrogen available to be used by the plants to form structures. They used overcome stresses caused by pesticides. I mean pests.

[00:33:19]Two, you may advise the farmers to grow more plants, more crops with pest X resistance strains.

[00:33:33]Mixed with those plants that do that lack the this resistance gene.

[00:33:42]Just allow some susceptible bowal larvae larvae to survive interbreed with the other ones that are invasive that are to the select that are at the selective sexual advantage.

[00:34:00]This is an advantage because whenever you force something get extinct, it also looks for ways of surviving. So, when you let some survive, they will interbreed with those ones that are resistant and it will reduce the effects of resistance or the emergence of resistance by these bowal larvae.

[00:34:33]Three, you can advise these farmers to reduce use of broad-spectrum herbicides.

[00:34:42]Just because these kinds of pesticides also kill the natural predators that check the populations of these of these borers, the invasive borers.

[00:35:00]You can also advise the farmers to use uh cultured farm farming spaces such as greenhouses where the temperature is regulated.

[00:35:13]All factors can be regulated.

[00:35:19]To reduce the effects of the borer population increasing as a result of temperature increase.

[00:35:31]Remember, so these kinds of items needs you sitting down.

[00:35:38]Try out very many of them.

[00:35:42]Remember, the more steps you take, the more experience you get.

[00:35:51]The more number of items you try out, the better you become.

[00:35:56]They get your mind exposed. The mind gets experience over challenges.

[00:36:03]You find yourself better in what was difficult for you.

[00:36:10]Remember, we said what we propose is not final. It is an It is >> [laughter] >> a suggestion from which you can start on to make your own.

[00:36:20]However, we have written responses that you may need to see and try out.

[00:36:27]You have more scenarios of that kind.

[00:36:30]more scenarios of that kind.

[00:36:34]And I'm told always read it out.