Evolution Questions

Unit C Evolution
Written Answers

1. A chromosme can be described as two U shaped chromatids attached together to create a bow tie type figure. A chromatid being only half of the chromosome, is referred to as a single DNA molecule.

2. Firstly a genome contains all of the genetic information that gives it the ability to reproduce itself. Secondly, a gene pool is the ratio of all the allelles (a variation of a particular gene) and all the genes of a species. It is referred to a “pool” because the allelles and the genes are pooled together. A gene pool is important to recognise because when reproduction or death occurs, the ratio in the gene pool is affected.

3. How much would a DNA cell from a dog differ from a cat cell?
In many ways a DNA cell from a dog would differ from a cats. As all DNA, it varies on every living organisms, it is a genetic code that determines your characterisitcs. After some research, I have concluded that the cats and dogs DNA when compared is very different. For example, in 1998, scientists at the Kyungpook National University in Korea compared the DNA nucleotide sequences of dogs, cats and seals, and determined that “there is a closer relationship between the dog and the seal than there is between either of these species and the cat.”


4. In artificial selection there are many pros and cons. The pros being:
- You can interbreed different species to combine the benefits of both animals into one super species.
- breeders commonly mate together animals which are closely realted and which share desireable characterstics.
- Dogs can be interbred for human benefit to be “cute” and have benefits that other truebreeds may not have.
- horse racers crossbreed horses to make the fastest racehorse they can create

Cons:
- Messing with crossbreeding species can result in disasterious outcomes. For example true breeds may be lost forever.
- Animals created may be sterile. For example the mule, a combination of the horse and the donkey.

5. Genetic Drift woud occur more rapidly in a smaller population because, it is easiest to recognise a change due to smaller number of mating partners. The more offspring an individual has, the more that indivual’s allelles will become represented in the gene pool. selective pressures

6. Contrast:
a. Accidental Selection vs. Natural selection
Since natural selection is when living organisms are not allways equally suited for survival and these unfortunate disadvantage as only affected by nature. Accidental selection is when living organisms evolve due to human interfearance. This can become a problem when human activity results in accidental selection, in the sense that since we are such a huge speicies that don’t exactly work with other living organisms, the survival of certain species can be put in jeopardy unintentionally.
b. Gradual Change vs. Puntuated Equilibrium
Gradual Change is when any signifigant evoltuionary changes occur very slowly. Puntuated Equilibrium is when natures steady flow in suddenly disturbed. For example, earthquakes or forestfires can effect ecosytems and disrupt gradual change. Also, mass extinction is an example of puntuacted equilibrium because a large number of organism and sometimes species can be wiped out for various reasons, which as you could guess. would completely disrupt the ecosytems natural balance.


7. Describe how our knowledge and understanding of evolution has evolved.
Our ideas about evolution has evolved because the more we can investigate cells and plants, beginnings and changes and genetic modification, we learn about how they have evolved. As technology becomes more modern and advanced, so does our knowledge on the endless world of evolution.


8. What is the relationship between a gene pool and evoltuion.
The gene pool is essentially the ratio of all the variations of a particular gene. In relation to evolution, this plays a role in the sense that, as soon as the ratio of genes in the gene pool starts to change and become uneven, evolution occurs.

9. What is Biston betularia? Describe the details of its evoltuion in the 19th century.
Biston betularia is latin for the peppered moth and if often used as a erfect example of natural selection. They are seen as a direct example of natural selection because over the past 200 years, they have been closely monitored and studied. Originally, the peppered moth had a very light colouration that successfully camouflaged them to the light coloured trees and lichened they landed on. However, due to widespread polution from the industrial revolution in England, many of the lichens died out and the trees which peppered moths would rest on were covered with soot. Since the polution were coating all of England with soot, the light coloured peppered moths died off due to predation. At the same time, the dark-coloured, or melanic moths flourished because of their ability to hide on the darkened trees. Since then, with improved environmental standards, light-colored peppered moths have again become common, but the dramatic change in the peppered moth's population has remained a subject that has been studied in great detail. Peppered moths are a perfect example of natural selection, and an example of evolution in action!