| What is variation? | Variation is the difference in the characteristics of individuals in a population |
| What are the three main causes of variation? | The three main causes of variation are alleles that individuals have inherited, which are genetic causes such as hair and eye colour, the environment, such as the colour of the hydrangea bloom flowers depending on the pH of their soil, or language in humans, and other variation is caused by a combination of genes and environment such as height in humans, as some people have alleles to grow taller though they also need a sufficient amount of calcium for their bone to fully develop |
| What are mutations? | Mutations are random changes to DNA that take place all the time and have no effect on the phenotype, and rarely cause a new phenotype.
However they can influence the phenotype e.g. alleles can cause tallness if a person’s diet is calcium sufficient. |
| What is an example of new phenotypes being beneficial if environments change? | An example of phenotypes being beneficial if environments change is in 1953 the virus myxomatosis killed over 99% of wild rabbits, however, mutations occurred which made the surviving rabbits resistant to the virus, so the new mutation have them a new phenotype |
| What is the difference between evolution by natural selection and evolution? | Evolution by natural selection is the theory that all life forms evolved from simple single cells.
While evolution is the change in the inherited characteristics of a population over time through a process of natural selection. |
| What is natural selection? | Natural selection is the adaptions of organisms to survive their environments, which prevent extinction through reproduction that allows inherited alleles to become widespread. Such as rabbits who live in colder environments inheriting an allele for thicker fur. |
| What is another example of natural selection? | Another example of natural selection is in rabbits who have alleles for better eyesight and hearing to detect predators such as foxes, and therefore survive and reproduce, passing on their alleles to their offspring so these traits eventually become widespread. |
| What are four key examples of selective breeding? | Four key examples of selective breeding are domestic dogs which are selectively bred to have a gentle nature, food crops that are selectively bred to be resistant to disease, cows being selectively bred to produce more meat or milk, and plants being selectively bred to produce large or unusual flowers |
| How would a cow be selectively bred for meat? | A cow would be selectively bred for meet by taking a mixed population of cows and selecting the largest male and female and breeding them together to produce a mixture of smaller and larger cows
Then the largest female and male offspring would be selected and bred together, which is continued until all the offspring are large |
| Why is selective breeding dangerous? | Selective breeding is dangerous because breeding closely related animals or plants, can result in inbreeding causing breeds to be prone to diseases or inherited defects, e.g. inbred dog breeds like Boxer dogs and German Shepherds have inherited disorders such as joint problems, heart disease, or epilepsy |
| What are genes and what do they code for? | Genes are sections of DNA on a chromosome.
And genes code for the amino acid sequences of a specific protein. |
| What happens to genes in genetic engineering? | In genetic engineering genes from one organism e.g. a human, are cut out and transferred to cells of a different organism e.g. bacteria, making the genome of the bacteria modified to include a human gene.
An example of genetic engineering is in insulin because bacteria have been genetically modified to contain the human insulin gene that can be purified to use for type 1 diabetes. |
| What are the benefits of GMO crops? | GMO crops are beneficial because they produce a greater yield of crops, and can produce larger fruits and vegetables. GMO crops can also be made resistant to disease or insect attack, such as herbicide-resistant plants allow farmers to spray their fields with weed killer without harming the GMO crops. Although some people are against GMO crops because they question if they are harmful to insects or wildflowers, and therefore believe more research needs to be carried out on the health effects of eating GMO crops. |
| What is gene therapy? | Gene therapy is when genetic modification is used to treat inherited disorders in humans |
| What does a vector do? | A vector transfers DNA from one organism to another, such as plasmids and viruses |
| What are the steps for genetic engineering? | First, identify the gene you want to transfer such as an animal gene, and use enzymes to isolate the gene, then transfer the gene into a vector, such as a small circle of DNA called a plasmid, or a virus. Finally, transfer the desired gene into the cells or the target organism such as an animal at the earliest possible stage of the organism’s development such as the early embryo stage to ensure all the cells reservice the transferred gene so the desired characteristic is developed |
