Biological Evolution And Diversity On Earth 7th grade!:)

Evolution is caused by natural selection which is where the ones that are more adapted to surviving in the environment are more likely to survive predators and continues to breed passing on the successive gene. For example, evolution happens because of four things there is variation within a species those variations are inheritable there is limited resources in an ecosystem, and thus, competition between members of a species for those resources the members of a species with the traits best suited to acquire resources tend to leave behind more offspring than those without those traits. Genetic diversity is an important thing in the survival and adaptability of a species. When a populations habitat changes, the population may have to adapt to survive. High genetic diversity is also essential for a species to evolve. Species that have less genetic variation are at a greater risk. With very little gene variation within the species, healthy reproduction becomes increasingly difficult, and offspring are more likely to deal with problems such as inbreeding.

The genetic variation is a variation in alleles of genes, occurs both within and among populations. Genetic variation is important because it provides the genetic material for natural selection. Genetic variation is brought about by mutation, which is a permanent change in the chemical structure of a gene. Polyploidy is an example of chromosomal mutation. Polyploidy is a condition wherein organisms have three or more sets of genetic variation.

Without genetic variations there can be no evolution. Natural selection is the selection of those variations. Natural selection (the driving force of evolution) is the selection of genetic variations by how they affect the organism's chances of survival or reproduction. If they diminish it's chances, the organism or its immediate offspring die and the gene is gone.