Analysis of graph 2 - Height
From observing the graph, you can conclude that the most frequent height is from 156-160 cm, therefore the average height of the class is this height range. There are not a lot of people who are extremely short compared to the average but there are quite a lot of people who are taller than average. Referring back to the table of results the taller ones are usually males. The graph shows a pattern similar to a bell distribution (line on graph).
The height variations are possibly dependent on their parent’s or family’s genes. Below is another genetic cross showing the possibilities of height variations.
The ratio is 3:1, tall to short.
This explains that although both parents are tall, one in for of their children can be short. This is because they both carry heterozygous genes, which is having different alleles e.g. Tt. In this case, the tall genes are dominant over the short genes which are recessive. So when the children inherits (T,T) from both parents, they will be tall. However if they inherit (t,t) from both parents, they will be short. This will make them horeozygous, which means they carry same alleles. This may cause further generations to be short.
The height variations are continuous because it always changes and does not stay constant. There are also a few factors that could affect height, hence making it environmental as well as inherited. They might be that the person did not eat a proper diet so they have a lack of nutrients in their bodies to help growth. Broken bones can also slow down growth because the body takes time to repair it so that it can grow properly again.
Analysis of graph 3 – Eye colour
Meiosis explains why every human inherit characteristics of each of their parents or their ancestors. Graph 3 shows the number of people with 3 different eye colours. Apparently, brown eyes are the most popular. One reason for this might be because the sample was from an area where there are more people of a certain race such as Asians, who usually have brown eyes. There also seems to be very few people who have blue and green eyes, for probably the same reason; environment.
To outcome getting brown eyes, both parents must be carrying at least one dominant brown eye allele.
The diagram above shows the possibilities of inheriting brown eyes. When showing a genetic cross, the capital letter always represents the dominant allele. Therefore it is a one in four chance that the child will inherit blue eyes. But obviously, not only brown eyes can be inherited.
Depending on which allele the parents carry, determines what the child inherits.
Sometimes people might have different colour eyes to their parents or to the majority around them. We could call this mutation, which is a change in genetic material of an organism which usually causes a change in its characteristics.
Analysis of graph 4 – Tongue rolling
This graph shows how many people are capable in rolling their tongue. From the graph we can tell that many people can roll their tongue. We can also conclude that being able to roll your tongue must be inherited due to scientific explanation; if either of your parents can roll their tongue, you should be able to. As tongue rolling is inherited, there must be a very strong and dominant gene present. Furthermore, tongue rolling is discontinuous and can not be environmental because there are only two alternative choices and it is impossible to learn how to roll the tongue.
Pure breed
F1 generation
Analysis of graph 5 – Arm folding
Everyone can fold their arms since they mimic people from very young ages. Then they gradually get used to it. Therefore it is environmental, also discontinuous, similarly to the sex determination. There are only two possibilities; folding the right arm over the left or the left over the right. The graph shows that more people tend to fold their left arm over their right. This has totally nothing to do with genetics.
Analysis of graph 6 – Hair colour
By looking at the graph we can relate the hair colour to the eye colour. There is a relationship between the two because as said earlier, eye colour depends on the family’s ethnic background and which allele is more dominant. Other than that, the colour of the hair is inherited. The graph shows that more people have black hair than blonde, but more blonde to brown. This means that the black hair allele is probably the most dominant in the people with black hair and their generations. Same rule with the people with blonde and brown hair applies here.
It is very rare to find a large population with ginger hair because the ginger allele is always very weak.
Analysis of graph 7
This graph shows the number of people who fall in the same foot size variations. It also shows a bell distribution similarly to the height. Again we can see a connection. The height is usually in proportion to the foot size. So for example, the taller you are, the bigger the feet you have. This is also proven in the table of results. The person with the biggest size feet is the tallest in the sample. And one of the people with the smallest size feet is the shortest. The peak point in the bell distribution allows us to find out the average foot size of the class is, which is 6. Since height is related to foot size, we can conclude that foot size is inherited.
Conversely, it is also environmental. In certain parts of the world, such as China, women bind their feet very tight so they do not grow. They do this as a sort of tradition. Another reason why it is environmental is because they might be lacking malnutrition. This is the improper way of eating leading to a decrease in growth rates. This can affect the growth of height in the same way too.
Evaluation
If I could improve the results to make them more reliable and the analysis more clearly I would find out more about the samplers parents and family. For example, if I found out if either of their parents are able to roll their tongue I could have more evidence to prove that tongue rolling is inherited. I can also find out whether their family are tall or short to find out if more people in the group inherit dominant or recessive genes. Overall the main point would be to find out more genetic information of their family members about the factors I investigated. Furthermore, I am satisfied with the results I gained.
