Genetic Variation and Mutation | 9-1 GCSE Science Biology | OCR, AQA, Edexcel

They key points covered in this video include:
1. Variation
2. Genetic Variation
3. Environmental Variation
4. Discontinuous and continuous variation
5. Mutations

Variation

Different organisms in the same species are not exactly unique - there are differences between them. These differences are called variation. For example, people might have different hair colour or heights. Different species have even larger differences between them - the differences between them are easier to see. For example, a human looks different to a dog. Variation within a species is caused by genetic variation and environmental variation.

Genetic Variation

Genetic variation is due to the genetic material you inherit from your parents. For example, you might inherit genes that determine your eye colour and blood group. Genetic variation arises from mutations and sexual reproduction. Sexual reproduction causes alleles to be combined in new ways. Most characteristics are not caused by one gene but rather multiple genes interacting.

Mutations

Genetic variation can be caused by mutations. Mutations are random changes in the DNA base sequence. Mutations mean that the gene is altered producing an allele (different versions of the same gene). Genes code for sequences of amino acids that determine the structure of a protein, a change in the gene could lead to changes in the protein. However, most have no effect on the characteristic (phenotype), some influence the phenotype and few determine the phenotype.

Environmental Variation

Where you live and the events that happen to you can have a huge effect on the way you look. Environmental variation covers any characteristics you gain from the environment and not from your genes (in other words, they are acquired characteristics). Examples of environmental variation include scars or injuries, tanned skin or plants having yellow, wilted leaves. Some characteristics are a mixture of genetic and environmental variation. For example, your state of health is a mixture of your inherited susceptibility to certain diseases (such as heart attacks) and your lifestyle (how much exercise you do and how balanced your diet is).

Continuous and Discontinuous Variation

Variation of the phenotype can be divided into two groups: Continuous variation is present in characteristics that can vary along a range of values. Examples of this include height, weight or hair length. This type of variation is usually caused by both genetic and environmental change and is controlled by multiple genes. You can display continuous variation using a standard line graph. Discontinuous variation is present in characteristics that can be sorted into distinct groups. Examples of this include eye colour or blood type. This type of variation is usually caused solely by genetic variation and is controlled by a few or even a single gene. You can display discontinuous variation using a bar chart.

Summary

1. Variation is the differences between organisms of the same species
2. Variation can be caused by genes or by the environment
3. Genetic variation is caused by one or multiple genes interacting and is produced by mutations or sexual reproduction
4. Some genetic variation is produced by mutations, in which the DNA sequence randomly changes, causing new allele of a gene to be created
5. The new allele may create a different amino acid, leading to a change in the protein created, but most mutations do nothing
6. Environmental variation encompasses any changes to your characteristics caused by the place you live or things that happen to you
7. Some characteristics are caused by a mixture of genetic and environmental variation (such as susceptibility for disease)
8. Variation can be either continuous or discontinuous

[kaijss]

Must admit you did better than free science lessons at explaining variation

[McMwalshy]

Hello last minute studyers aka PROOCRASTORRRRNATORRS!!!!

[maypapa]

ill be using your video in science grade 3 from rochepol jane academy, january 7, 2021, thank you for your explanation and sharing your knowledge

[abrikmohadg]

Wow I am surprised how quickly I understood