Science Assessment – Term 1

Biology – Key Topics

Over many years, scientists have discovered more and more about the living beings on the planet. Because there are no other known living beings in the world, people are curious as to how we continue to survive on Earth. In order to understand this, scientists have researched from the ground up on how an organism is created and how it functions.

DNA, stands for Deoxyribonucleic acid, carries genetic information used for development and the functioning of living things. This is important for every single organism on the planet. DNA is why individuals around you seems so unique despite being the same species. We can differentiate individuals from their eye colors, the type of hair they have, and down to even their facial structure. This is all thanks to genes. Genes are the traits, or characteristics, inherited from the parents of an offspring. which is why some individuals sometimes not only looks the same as their parent, but also with how they act. In order for us to know what traits an organism can inherit, biologists tend to use something called a ‘Punnet Square’. A punnet Square’ is a square shape broken down into nine tiles. A punnet square can help us figure out the probability of a trait being passed onto an offspring. To use this, we need to take the two alleles from each parents. One allele will be received from each parent by the offspring, giving it two alleles in total for one gene. The most dominant allele will be what the offspring receives.

Though, inheriting traits aren’t just for humans. This can also apply to other organisms like animals. Animals in the wild survive based on the traits they inherit. An example of this is when a giraffe has a long neck. They inherited this trait from their parents in order for them to eat leaves from high up like trees. Another example are animals that are carnivores. Ever wondered why these animals have such long, strong teeth? This is because of the traits they inherited from their parents in order for them to chew on meat. This is all thanks to something called ‘Natural Selection’. When animal can survive long enough to reproduce, it typically passes down the most useful traits down to their offspring. It then goes on to do the same as their parents. Live long enough with their inherited trait in order to reproduce, then pass on the useful traits to their offspring. When done for a long period of time, a change in frequency of alleles in a population will happen due to the act of natural selection. This is called evolution. Because of evolution, organisms continue to thrive and live for generations.