Plants and Animals - Sample Essay
Breeding in Plants and Animals Selective Breeding in Plants Desired Characteristics plants are bred for: Decorative plants are selectively bred for colour. Food plants are selectively bred for better yield. Most plants are selectively bred to be hardier. Most plants are selectively bred for resistance against disease. Some plants are selectively bred for fragrance. Some plants are selectively bred for texture and taste. Breeding for Characteristics The definition of selective breeding is: The act of breeding two adult organisms to get offspring with desired characteristics.
The breeder would breed two adults that have the desired characteristic, then he would keep on breeding the younger generations, choosing the offspring with the strongest sense of that characteristic and thus as the generations get further and further the characteristic being breed for would become stronger. Selective breeding can also allow the combination of two adults feature for example if you wanted an orange coloured plant you could breed a red and a yellow coloured plant to get the genes to have a co – dominant relationship. Selective Breeding in Plants (notes)
In farming the farmers need to make the most profit that is possible so they breed the plants to get offspring that give a very high yield. To breed the plants they must put them in controlled conditions to stop any contamination from any other pollen. Then the plants are pollinated by the farmers using a brush to ensure that the right plants are pollinated. The ways they can increase the yield is by selectively breeding the plant so that the piece we eat for example the carrot will grow very big.
We could decrease the size of the part we don’t eat so more growth happens in the part we eat,Breed it so it grows faster and lastly improve the looks of the crop so it is more desirable. Selective plant breeding can cause problems as when selectively breeding it can also create different characteristic that are undesired for example like a miracle rice it may need lots of nutrients to grow thus is impossible for some to grow thus useless. B5b. 1a The process of selective breeding Parent organisms are chosen that show the closest variation to the required characteristics Sexual reproduction of the parent organisms produces offspring that show variety.
Offspring with the closest variation to the required characteristics are selected ad grown to adulthood. When the offspring are fully grown, they are bred with each other to produce more offspring. The stage is repeated again and again with each generation of offspring, each time with individuals whose characteristics are closer to the required characteristics After many generations, individuals that match the required characteristics are produced in the offspring These individuals then form the new variety (plants) or breed (animals)
Questions (pg. 337) TOP Some characteristics can be breed for in selective breeding as they are coded for by genes thus can be manipulated. So characteristics don’t depend on genes so won’t be effected by selective breeding. To increase crop yield we can either, increase the part we eat so that it has more weight and thus can be sold for more, reduce the part we don’t eat so that the energy that would of gone into that it used for the part we do eat and also make the crop faster growing so that we get more mass in a short period of time.
If we increase eth part we eat of the crop in size it will increase the crop yield as when growing the crop we would get more mass for one seed thus the yield would be much higher. By reducing the part we don’t eat in size it will increase the part we do eat in size thus it will give more mass per drop thus more yield. If it grows faster in a period of time we can grow more crops after harvesting the first set thus the crops will be higher in number so higher yield.
The reason plants are grown in horticulture is because they are trying to get more attractive plants as plants can get boring so to keep people interest they produce more types and shapes BOTTOM When you sexually reproduce something for selective breeding there are only the alleles of the specific mother and father so there are only limited characteristics that can be inherited as they have the desired traits, while in the wild there is any chance of a plant fertilising another plant so the possibilities are endless about the alleles.
It is useful as it means that there is more chance of the desired trait to be passed down as there is little genetic variation so it doesn’t get any other variation due to other alleles. The problem with the narrow selective breeding as there may be a mutual problem that at first isn’t noticed by the scientists such a reduced resistant to a specific disease and by narrowly breeding you are making the allele more dominant so if the crop is released it could be a flop due to this.
Yes these plants should be kept as they may have desired characteristics that we will need later in time for example there may be a disease that is killing all of the plants and one of the older crops that aren’t as efficient in growing have that specific resistance thus are able to be grown and selectively breed with the plants so they get the resilience from the specific disease. Selective breeding in animals Desired characteristic for animals are: High yield for example a sheep that produces a lot of wool and a cow that creates lots of milk.