Variation and Evolution: Identification and Classification of Living Things

All organisms on Earth are classified into a hierarchical system, based on their similarities and differences.
The classification system, from broadest to narrowest, includes: Kingdom, Phylum, Class, Order, Family, Genus, Species. This system helps scientists understand and study the complexity of life on Earth.
An organism’s scientific name comprises two parts: its genus and species. This binomial system of naming was developed by Carl Linnaeus. For example, Homo sapiens is the scientific name for human beings.
Living organisms share certain characteristics: they all respire, move, grow, reproduce, excrete wastes, sense their environments, and consume nutrients.
Variation refers to the differences in physical or genetic characteristics between different organisms of the same species. Organisms may vary due to genetics or environmental influences.
Evolution is a gradual process of changes in organisms over long periods. It is driven by natural selection, where the organisms best adapted to the environment are more likely to survive and reproduce.
Variation is critical for evolution, as it gives a population the genetic diversity required to adapt to changing environments.
DNA plays a crucial role in classifying organisms and understanding their evolutionary relationships. Similarities in DNA can suggest a common ancestor and indicate how closely related species may be.
Evolution creates biodiversity, which refers to the variety of life on Earth. Biodiversity can be measured on several levels: ecosystem diversity, species diversity, and genetic diversity.
Fossil records provide evidence of evolution. Fossils demonstrate how species have changed and evolved over time.
Charles Darwin is a key figure in the study of evolution. His theory of evolution by natural selection proposes that species with characteristics that give them an advantage are more likely to survive and pass on these traits to their offspring.
Artificial selection is a process where humans selectively breed animals and plants for desirable traits. This differs from natural selection as it is guided by human preference rather than survival and adaptation.
Genetic engineering is another method of creating variation in species, wherein the DNA of an organism is directly manipulated. This approach can result in organisms with entirely new traits.