Chapter 19 summary 2023 with complete solution

Explain what is meant by divergent,parallel and convergent evolution. convergent evolution: this is where species which are not closely related at all evolve to have similar traits or characteristics as result from adapting to similar or the same environments. Divergent evolution:the process by which a species evolves into two or more descendant or different forms; also, the process of tracing two or more species back to a common ancestor. parallel evolution: this is the development of a similar characteristic which are related from distance species which have descended from the same ancestors but are in different groups. Demonstrate an understanding of the main way that new species evolve by allopatric speciation, which involves an initial geographic isolation of populations. when species are separated from each other and it occurs for an extended period of time the alleles of the separated species will become more pronounced due to the differences with the environment, food sources and habitat which can thus lead to the formation of new species because of those differences. Explain how polyploidy can result in new species the polyploids will create gametes which have an unusual amount of chromosomes and this will generally lead to lowered fertility when they reproduce sexually and this can lead to a doubling of chromosomes which can restore fertility partially but the organism will be unable to reproduce with it's parent species this therefore creates a new species. Explain the terms background and mass extinction background extinction: this is the ongoing extinction of organisms due to environmental or ecological changes or because of competitive disadvantage with other species. mass extinction: this is when there is a sudden and sharp decrease of organisms or species because of catastrophically event such as an asteroid hitting the earth.