Importance Of Diversity Between Species And Species

Meiosis consists of one DNA replication and two nuclear divisions resulting in 4 daughter cells. The process which provides for genetic variation is crossing over. Crossing over occurs in the early stages when homologous chromosomes move together so that their chromatids form a tetrad. This is called synapsis and allows for the exchange of chromosome sections.

These bivalents line up along the equator during metaphase I, the arrangement of the bivalent is completely random and relative to the orientation of the other bivalents, this is known as the independent assortment of chromosomes. This is followed by anaphase I where the homologous chromosomes separate and move to the opposite poles of the cell. At telophase I the cell divides into two, each cell contains one chromosome from each homologous pair. The second stage of meiosis is similar to mitosis.

Adaptive radiation of different organisms have occurred throughout geological time through the filling of ecological niches. Organisms different from one another are capable of radiating greatly, as they evolve traits that allow them to thrive better in their environment. The Anolis lizards of the Caribbean islands are a great example of a single genus to have radiated not once, but multiple times through very similar mechanisms. Different populations of the Anolis phenotypically vary in their morphological traits to facilitate adaptation to particular niches. These phenotypic variations have evolved in convergence in more than one occasion, as recently discovered fossil specimens show similar patterns in morphology to modern Anolis.

1 by crossing over in prophase I , 2 , by indpendenent assortment and three by mutations in S phase

Define the term crossing over. (3 points) During meiosis’ prophase the homologous chromatids exchange segments.

A) Meiosis consists of two cell divisions and is broken up into Meiosis I and Meiosis II. At the beginning of the Cell Cycle, in this case there are four chromatids each from the homologous pairs being A, a, B, b. This is the Diploid number (4) meaning it is 2 times the haploid number that will be seen at the end of meiosis II. During the S phase of interphase, the chromatids replicate and reach the end of G2 phase. Now starting meiosis, during the first stage of prophase I the chromosomes condense and pair up through synapsis with their sister chromatids creating AA, aa, BB, bb. After they pair up they go through a process called crossing over, where the homologous chromosomes share a piece of their genetic material with each other. Crossing over allows for the genetic diversity of chromosomes. Now there are four homologous chromosomes Aa, Aa, Bb, Bb, each containing heterozygous alleles because the sister chromatids exchanged genetic information with their homologous pair. During late prophase I, spindle fibers being to form where they will later attach to a homologous chromosomes centromere. The next stage is Metaphase I. During metaphase I, the homologous pairs line up at the metaphase plate, also known to be the center of the cell. The homologous pairs form a tetrad which is considered a group of four homologous chromosomes. These homologous chromosomes orient themselves randomly, which is know as the process of independent

Biodiversity is life’s variety. It is the varying genetics that each species carries that makes it different and “unique”. Biodiversity is important, not only in evolution, but in survival; when sometimes those terms can mean the very same thing. Interestingly, biodiversity can mean a variance in the life itself – or within the genetics of a species. In keeping breeding habits within the same lineage, some animals risk lower biodiversity and sometimes even deformities and disease, as they are able to more easily pass on unfavorable hereditary traits. In increasing the overall biodiversity, the only risk is a

_____ In swine, when a pure-breeding red is crossed with a pure-breeding white the F1 are all red. However, the F2 shows 9 red, 1 white and 6 of a new color, sandy. The Sandy phenotype is most likely determined by

gametes during meiosis in the F generation. The F can be thought of as having been formed

Asexual reproduction only involves one parent. They split their cell in half. Sexual reproduction involves two parents and they each have one cell (either an egg of sperm) which gets put together to have an infant. The egg and sperm usually have 23 chromosomes. SO when an infant is born, it has 46 chromosomes.

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

Although genomic sequencing has advanced ten-fold throughout the 21st Century, there has been little focus on non-avian reptiles3 until A. carolinensis became the first non-avian reptile to have its entire genome sequenced and published in 2011.5,6 Native to North America,5 A. carolinensis are an incredibly abundant species of amniotic vertebrates4 and have been

In meiosis the pairs of chromosomes (that code for possible outcomes of characteristics) temporarily join and exchange information (crossing over) creating different combinations of gene types (alleles). For example; a pair of chromosomes could be a dominant allele (gene type) and a recessive allele which might code for brown hair. After crossing over it might be recessive which could be blond hair.

Today’s seminar was presented by Dr. Christian Cox of Georgia Southern university. He presented the topic of “The evolutionary drivers of diversity for coral snake mimicry. The heart of his work consists of understanding the evolution of phenotypic and genetic diversity. He has tested many questions and hypotheses: genetic diversity, color polymorphism, coral snake mimicry, mimicry and color polymorphism in ground snakes, what evolutionary forces drive the spatial and temporal pattern of color polymorphism, do morph frequencies shift with age, does selection on color polymorphism vary across space, evolutionary dyanamics of phenotypic diversity and etc. In his experiemnts, the independent variable is the mimetic snake species, while the dependent variable is the

The two alleles, one contributed by the male and the one by the female gamete remain distinct; alleles do not blend with one another or become altered in any other way