Genetic Material:
- Each species has a unique set of genetic information encoded in its DNA. This genetic material contains instructions for the development and functioning of organisms within that species.
Chromosomes:
- Genetic information is organized and stored in structures called chromosomes. Chromosomes are thread-like structures found in the nucleus of cells.
Genes:
- Genes are segments of DNA located on chromosomes. Each gene carries instructions for a specific trait or characteristic.
Inheritance:
- During reproduction, organisms pass on copies of their chromosomes and genes to their offspring. This is known as inheritance.
Mendelian Laws:
- The patterns of inheritance were first described by Gregor Mendel, an Austrian monk, in the mid-1800s. His principles, known as Mendelian laws, explain how specific traits are passed down through generations.
- Law of Segregation: During gamete formation (egg and sperm), the alleles for each gene separate (segregate) and end up in different gametes.
- Law of Independent Assortment: The inheritance of one gene does not affect the inheritance of another gene.
Variation:
- Species heredity also involves genetic variation. Genetic variation arises due to mutations, gene flow, genetic recombination, and other mechanisms.
- Mutations: Changes in the DNA sequence, known as mutations, introduce new genetic variations within a species.
- Gene Flow: The exchange of genetic material between populations of the same species is called gene flow.
Evolution:
- Species heredity is the foundation of evolution. Over time, the accumulation of genetic variations can lead to significant changes in populations.
- Natural Selection: Certain traits or characteristics can provide a survival advantage in a given environment. Individuals with these advantageous traits have a higher chance of surviving and reproducing, leading to the gradual increase of those traits in the population.
In summary, species heredity involves the passing on of genetic material from one generation to the next within a species, resulting in the continuity and evolution of that species over time.