Need help for this essay. Questions 1–4: Answer the following essay questions in

Question

Need help for this essay. Questions 1–4: Answer the following essay questions in 1–2 short paragraphs. 1. Compare and contrast directional selection and disruptive selection and provide an example of each. 2. Many pathogenic bacteria species are becoming resistant to antibiotics. Explain how such adaptations can develop through the process of natural selection. (Hint: Relate this example to the conditions that are necessary for natural selection to occur.) 3. What are the major evolutionary trends that developed among major vertebrate groups, specifically those that allowed for the transition from aquatic to terrestrial life? 4. Providing examples, explain how sexual reproduction in plants has evolved to become less dependent on water.

Explanation / Answer

In directional selection the one phenotype changes over the advantage of new phenotype within the species. For example the white moth was using the bark of tree which was in white in color to hide them from the predator. After the industrial evolution the production of smoke increased because of that the bark color changes from white to darken. To save from predator the color of moth changed from white to dark color. To favor this condition allele frequency changes over time in direction of phenotype. This type of selection is known as direction selection.

In case of disruptive selection the extreme trait combination helps in the surviving. The trait variation increases the chances of survival. Suppose there is trait of color. One is Black and other is white. Alleles for these colors are BB (Black) and bb (white). But in case of third allele Bb (Grey) the complete new different trait will arrive. Black can save themselves under black background and white can same themselves from predator behind white rocks. But Grey will be able to hide behind both color rocks. So the survival number of Grey will high in comparison to the White and Black.

2. Many pathogenic bacteria species are becoming resistant to antibiotics. Explain how such adaptations can develop through the process of natural selection. (Hint: Relate this example to the conditions that are necessary for natural selection to occur.)

Antibiotics used to care against the pathogenic bacteria because bacteria will not able to grow in presence of antibiotic. But after some time they get resistant by modification in there expression system of gene. This makes them able to grow under the antibiotic presence. After long time period this character passes into colonies of similar bacteria and bacteria become adaptive to such change. This change selected by the natural selection in nature will help them to survive. Change in Nature it is important to adapt and survive under stress condition. As per natural selection the fittest will survive.

3. What are the major evolutionary trends that developed among major vertebrate groups, specifically those that allowed for the transition from aquatic to terrestrial life?

There were the trends of evolution includes improved protective and respiration covering of body. Change in organism from water to land includes the effective reproductive method for example placenta of some animals and egg layer for other animals. Morphology of the organism is different in between land and aquatic animals. They will have paired and muscular appendages.

4. Providing examples, explain how sexual reproduction in plants has evolved to become less dependent on water

It involves the adaption of seed and pollen in low level of moisture to avoid desiccation. The seed and pollen will have covering around them which will keep the moisture content inside them. Some pollen attaches with animals and move from one place to other. Majority of cases the pollen transport from one place to other using the wind.

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