Heredity and Variations
* The process of passing of the traits from parents to offspring is called Heredity.
* Offspring are never an exact copy of their parents. They show minor differences, which are called Variations.
* Mendel was the pioneer among Geneticists who found the inheritance of characters from parents to offspring.
* A child who inherits an X chromosome from the father will be a girl, and one who inherits a Y chromosome will be a boy.
Evolutionary Relationships I
* Evolution is defined as any genetic change in a population that is inherited over several generations.
* Changes occur in genes or colour and are inherited over generations.
* Variations are the differences among individuals of a species, caused by genetic and environmental factors.
* Mechanism of evolution includes mutation, migration, genetic drift and natural selection.
* A species is defined as a group of individuals that can interbreed.
* Speciation is splitting of populations into two independent species that cannot reproduce with each other.
* A hurricane or storm can cause a genetic drift.
Evolutionary Relationships II
* Homologous and analogous characteristics help identify an evolutionary relationship between different species.
* Fossils are an important evidence of evolution.
* Evolution of eye in different species is an example of biological convergence.
* Reptiles and birds have evolved from a common ancestor through adaptation.
* Different vegetables are descended from the wild cabbage ancestor.