Simply put, biology involves the study of living organisms, from single-celled organisms to multiple-celled plants, animals and humans. Some basic biology class topics might include cellular structure and functions, evolution and natural selection, heredity and genetics and ecosystems. The study of this life science changes and evolves as ongoing research reveals new discoveries about how living organisms work and interact, down to the smallest possible detail. Since the subject is much too broad to cover in only one class, many high schools also offer advanced biology classes as well as more specialized courses such as anatomy.
Advanced high school biology topics may include such subjects as:
- Central nervous systems and brain functions
- Energy and chemistry of life
- Plant systems and ecology
- Evolution, ecology and diversity
- Cell structure and specialization
Cellular Structure and Function
Though microscopic, cells consist of complicated structures capable of growing and dividing. They provide the foundation for all living things. Students learn what a cell is and how cells differ from each other. They diagram single-celled organisms and learn about the hierarchical structure of multi-cellular organisms. Lessons include the basic structure and function of cells as well as how they combine and work together. Students learn how cellular processes enable life, through means such as photosynthesis, chemosynthesis, cellular respiration and cell division and differentiation.
Evolution and Natural Selection
Fossil and genetic evidence supports the idea that Earth evolved over time, with many changes occurring in its surface and the organisms that dwell on it. Organisms often experience physical changes over time to adapt to changing living conditions. Mutations such as distinct colorations sometimes occur and in some cases enhance the ability of a species to survive -- like white fur in the Arctic. In natural selection, the population of organisms not possessing these new traits is reduced, while those that do possess the advantageous traits increase in number, until few to none of the species exhibit the original traits.
Heredity and Genetics
Hereditary traits are easily seen in families in areas such as eye and hair color. Outliers where a child resembles a grandparent rather than a parent are easily explained in this manner. Scientists have learned that each person has a unique DNA code. Genes are segments of these DNA molecules. Each organism has a genome that contains all of the information needed to create and maintain that organism.
The study of DNA sequencing allows scientists to determine how physical traits and certain health issues are passed on. Any change in the sequence of these molecules results in a change to the gene. Students learn about genetic traits commonly passed down from parent to child as well as about gene mutations and chromosomal abnormalities which can cause visible changes to the body.
Ecosystems and Interdependence
Students learn about ecosystems and how all living organisms support each other. All living organisms depend on others to a certain degree. Lessons explore how lower level life forms such as plants and algae are consumed by more complex organisms, which may then be consumed by even higher life forms. Ultimately, the higher life form dies and is returned to provide food for the lowest level organisms. Lessons address the importance of maintaining this system. When this natural cycle is broken, organisms may undergo biological changes to adapt or in more severe situations, the survival of the species may be threatened.