Ring Species Evolution

In a large, randomly mating population where mutations, migration, and natural selection are no longer viable, the allele and genotypic frequencies will remain at equilibrium. If any of these conditions are changed, then the allele and genotype frequencies will be unable to maintain genetic equilibrium.

Perhaps, where they coexisted, some difference prevented interbreeding or the production of hybrids between these populations and early human ancestors. Usually such differences between related species originate as adaptations to the environment, not as devices for reproductive isolation.

Gene flow: genetic additions and/or subtractions from a population resulting from the movement of gametes

This occurs when a species is separated and mate with a different species, changing their genetic composition, if then the two species were to be brought back together and mate again, it would cause what is called ‘gene migration’. This process gives so many different variations among the species, which allows more and more variation and population. This process also explains endangered species and extinction.

By using DNA sequencing software and using comparative DNA alignment programs, scientists can piece together where the differences and similarities align and the percentage of identical DNA between two species. Another method of classifying these gene-swapping organisms is to alter the method of vertical genomics and shift to a new form of lateral genomics (Koonin et al. 2001). A method using vertical, linear genomics alone will not provide enough resources to clearly assign an organism to a taxonomic group. Also, scientists can look at gene loss over time as a method to group these organisms (Koonin et al. 2001). If scientists would rather stick with similarities to define a taxonomic group, the use of genomic instruments can provide a better picture of which genes are highly conserved between organisms of the same group (Doolittle 1999). Researchers have begun to employ this method as the means for best completing a phylogenetic tree. Using alignments of single copy genes conserved in the genome allows for scientists to achieve that vertical pattern of phylogeny that can be lost when focusing on the amount of transferred genes between groups (Lang et al. 2013).

Complete the worksheet writing 100- to 200-word short answers for each question. Format your references consistent with APA guidelines.

One of its most important characteristics is its beak. The finch adapted to have a thin, long beak to probe through moss, bark and leaves in search of food (Wildscreen Arkive, N.D.). These finches have the thinnest beak out of the 13 finches; which aids them to find small insects. The Green Warbler finch are mostly found in humid highland forest where their primary food source is found. These adaptations made them more fit to survive on available food. Over the years the finch’s beak has evolved as the bird developed different taste for insects. Another famous adaptation is how they camouflage in their environment. The Green Warbler is restricted to the forest and is greener in body colouration, while the Gray Warbler is found in shrubby, dry thickets and is greyer and duller looking (Certhidea olivacea, 2010). Their coloration helps them camouflage in their own environments, and to hide from predators. Recent studies have found that there are in fact two separate species of the Warbler Finch, the Green Warbler Finch and the Grey Warbler Finch, but are considered as a single species (Wildscreen Arkive, N.D.). The Green Warbler finch mainly occupies larger, inner islands, while the Grey Warbler finch inhabits the smaller, outer islands (Green Warbler Finch,

Biodiversity loss threatens to disrupt the function of ecosystems, with the potential of consequences for humans as well. Often this loss is measured by species extinction rates, but considerations should be made to include population diversity with measures including changes in size, number, distribution and genetic composition of population and potential implications those changes may have (Luck et al., 2003). Avise (2004) goes as far as to say biodiversity is genetic

Please explain what inbreeding is and why it is important to limit this effect in conservation programs.

In the case of ring species, natural selection and sexual selection each play a role in the divergence of ring species. Selective pressures allowed one phenotype to survive better than others in a certain area; sexual selection could cause divergence because organisms choose mates based on phenotypes. In the case of salamanders, natural selection affected divergence because organisms with certain coloration survived better in coastal or inland environments. In warblers, sexual selection and natural selection seem to play a part in the divergence of the ring species, as forest density and migration distance is variable and affects survival of the species. Molecular and morphological evidence can be used to support multiple species by showing

There is another side to the biodiversity of the evolutionary field, as the population weakens the species start the inbreeding of smaller populations, thus playing a role in the extinction of a species. Inbreeding is reproduction among members of a species that are genetically similar. The genetic inbreeding is designed to bolster populations of species whose numbers are in decline. However, when only a few species or varieties of a species are cultivated or survive, the genetic diversity of the organism declines, and population is more vulnerable to being wiped out by new diseases or climate changes because of the inbreeding (Alters, 2000).

Migration is a mechanism that helps gene flow, by adding new alleles or changes in frequencies of alleles that are already present within a set population. This can happen when another organism, in the case of insects on birds, gets picked up and moved to a new location. Migration will generally unify gene frequencies among populations rapidly in evolutionary time (Ridley, 2004). If the two populations originally had different gene frequencies and if selection is not operating, migration (or, to be exact, gene flow) alone will rapidly cause the gene frequencies of the different populations to converge (Ridley, 2004). In which causes genetic variation within the population, and can cause this new population to evolve having new characteristics that better suit the populations.

In organism evolution occurs through four main mechanisms that will gradually over time shift the genetic makeup of a population. The first mechanism is called mutation and this occurs when there is an alteration in the base pair sequences of DNA. The only way that this trait can affect the population is if the mutation occurs on a sex cell that is passed to offspring. The next method of evolution is genetic drift, which occurs when there is a random shift in allele frequencies that are unrelated to reproductive success. The population bottle neck effect and the founder are two ways that genetic drift can occur in a population. The bottleneck effect occurs when a rapid environmental change causes a large proportion to be killed off. Since the change is likely to affect any member of the population, the remaining members are genetically different causing

Speciation can take place in two ways, generally (Daempfle, 2016). A single species may change over time in a way that is very different from its original form. Furthermore, it may even become a new species. This is known as anagenesis. A species may become spilt into two separate groups, and the two may not share the same gene pool. This is known as cladogenesis. In both anagenesis and cladogenesis, reproductive isolation happens. Sympatric speciation happens as populations of species that share the same habitat become reproductively isolated from one another. This phenomenon commonly happens through polyploidy, which offspring will be produced with twice the normal number of chromosomes. Organisms with two pair of normal chromosomes can not

Generally speaking, there are numerous issues related to genetic diversity which include mutations, sexual reproduction, migration, and population size.