Classification and Heredity (Leaving Cert Biology): Revision Notes
📚 Revision Notes
Classification and Heredity
Classification
- Classification involves placing organisms into similar groups.
- Taxonomy is the branch of science that classifies organisms/
infoNote
A species is a group of organisms that are capable of interbreeding with one another to produce fertile offspring.
- Members of a species share many features, but there are differences between individuals. These differences are called variations.
- Types of variations include:
- Acquired variations
- Inherited variations
Types of Variations:
- Acquired Variations:
- Not controlled by genes.
- Learned or developed during life.
- Examples: Speaking, riding a bike, using a computer.
- Inherited Variations:
- Controlled by genes.
- Examples: Number of fingers, production of hair and nails.
Heredity
infoNote
Heredity is the passing on of features from parents to offspring by means of genes. It is also called genetic inheritance.
Key Concepts in Heredity:
- Characteristics:
- Traits or features that are genetically inherited.
- Genes:
- A gene is a section of DNA that causes the production of a protein.
- Many proteins produced by genes are enzymes.
- Genes vary in length because the proteins they produce are of different lengths.
- Gene Expression:
- The way genetic information in a gene is decoded in the cell to produce a protein.
- Not all genes are expressed. For example, a gene for tallness may not cause tallness if the child's diet lacks proper nutrients.
infoNote
Characteristics = Heredity + Environment
Characteristics are determined by the interaction of:
- Heredity (genes inherited from parents).
- Environment (external factors like diet or climate).
infoNote
A gene is a section of DNA that causes the production of a protein.
infoNote
Gene expression is the precise way in which the genetic information in a gene is decoded in the cell and used to make a protein.