DNA (Deoxyribonucleic acid) is what carries out genetic information that is used for the development and functioning of living things and acts as a biological hard drive, storing 10 trillion GB of genetic information in a cup. There are four types of repeating nucleotide bases in DNA that connect specifically with the matching base. This is called the “complementary base pairing rule”: A (adenine) always pairs with T (thymine), C (cytosine) always pairs with G (guanine). Genes are a section of the DNA that codes for a particular trait and acts as the blueprint for it. A trait is a feature inherited from the parents of living things, like eye colour, hair type, and whether you can roll your tongue or not. An allele is a different version of the same gene because you inherit one allele from each parent, meaning you have two alleles for one gene. We can find out the chances of a living thing inheriting these traits by using something called a Punnett square. A Punnett square is used to show the chances of a specific trait being more likely to be passed on, with the distinction of dominant and recessive traits. The genotypes, which are the internal appearance of the traits passed, can be expressed in two different ways: dominant and recessive in the Punnett square. A dominant trait is shown as the capital letter, while the recessive trait is the small letter. By using the Punnett square, we can figure out the chances of the specific trait being passed on by seeing how many times the allele would match to make the specific trait with the determing factor is having a captital letter with itself or the small letter its the one getting passed on while on the other hand having the small letter paired wiith each other meaning that trait getting passed on instead. Homozygous is when the same type of allele is paired, while Heterozygous is when two different types of allele are paired in the Punnett square.
Phenotypes, the physical/outward appearance of the traits, are sometimes naturally selected by nature more for the species to better fit and survive the environment they’re in. This process is called natural selection. Natural selection happens when a specific trait lets a creature fill a specific niche that benefits it in some way, and then the species with that trait survives longer and can reproduce more than the one that doesn’t, which leads to a gradual increase of the trait being seen because it gets passed on more. These changes in the frequency of alleles in a population over generations are called evolution. These changes that let the species survive and be better suited to their environment are called adaptations. There are three types of adaptation: structural, the physical features of the organism like fur, scales, and height; behavioral, things that the organism does like hiding, hunting, jumping; and lastly physiological, which is the internal features of the organism like venom, body fluids, and temperature. Sometimes changes can occur to the base sequences; these changes are called mutations, it can be good (leading to natural selection), bad, or neutral to the effects it has to the species. Mutations are how new alleles/traits are made. There are three different types of mutation: substitution, which is the replacement of a base with a different base, deletion, the removal of a base, and lastly insertion, a new base added.