1. DNA in forensic science: DNA contains the genetic code of a person. The genetic information stored in the DNA, is coded in the form of nucleotide sequence. The nucleotide sequence is formed by four fundamental nucleotides: A, T, G, C nucleotide, that formed a polymer in a set order. A typical human DNA, has 3 billion nucleotide bases. The DNA sequence is 99.8% identical in all human beings and is only 0.2% dissimilar. This dissimilarity is the basis for identification of the suspects in forensic medicine. No two human beings can have a DNA that is 100% identical. DNA is found in all nucleated cells. It is located within the nucleus of the cell. All types of cells in the body have DNA. Most commonly, white blood cells, sperms, cells from once cheek, are a common source of DNA for forensic studies. Red blood cells do not contain DNA, as they lack a nucleus. At the site of crime, DNA can be collected from any cell that contains nucleus: blood, semen, saliva, tissue, bone, teeth, hair, maggot crops. The DNA sequence of the unknown culprit, is compared with the DNA sample of known suspects to identify the actual culprit. Blood or buccal swabs, collected from the suspect, can be used to isolate the DNA. Short tandem repeat sequence of the DNA, varies between individuals and is used for identification of individual culprit. The FBI Codi database contains the STR code of suspects. The DNA from each sample is subjected to restriction fragment length polymorphism technique to identify paternity. Children usually tend to inherit the RFLP pattern of their parents. The RFLP pattern of an individual is called the DNA fingerprint of the person. (Stark, 2011)
2. Population in genetic terms refers to the number of individuals of the same species in a given space and time. Within a population, variations are seen in the alleles that code for the same gene. These variations arise from mutation that arise in the DNA sequence. These variations contribute to differential reproductive abilities. Only individuals with gene that favor survival and reproduction in a given environment, contribute to the subsequent generate. The natural forces in the environment and the variations in the gene pool contribute to natural selection. Mutations and recombination are two mechanisms by which, variations are introduced into the population. Natural selection has played an important role in population evolution. Darwin’s theory of evolution is based on natural variation and natural selection. He used fossil to study and prove evolution. According to Darwin, species evolve with time, individuals with traits that enable survival are selected by the natural forces that acts on them. According to Darwin’s hypothesis, all forms of life originated from a single organism. With time, they evolved into a different complex organism. This origin of life theory, connects prokaryotes and eukaryotes. According to Darwin’s hypothesis, eukaryotes evolved from prokaryotes. There are a number of evidences in nature that support Darwin’s theory! Application of this theory is that, lower life forms can be used to study phenomenon happening in higher life forms. The study of human diseases in mice is an example of this. The fundamental mechanism of cellular activity is similar in all life forms. ("Welcome to Evolution 101!", 2016)
3. The variety seen in the life forms on the planet is called biodiversity. Biodiversity can be seen at three levels: diversity in the life forms, diversity in the ecosystem and diversity in the DNA. The diversity of life forms is very important for the ecosystem. When one or more organism in the ecosystem is destroyed, it affects other life forms in the ecosystem. This is because all life forms are interrelated. The application of the concept of biodiversity, can be seen in many conservation efforts. Biodiversity offer consumption value to humans. The food, medicine and fuel, which we consume from the environment are produced by other forms of life. The air we exhale is purified by plants and the biological waste generated is decomposed by other life forms called decomposers. Knowledge of biodiversity can be applied in areas like bio-productivity, cleaning of air or water, control of pest, prevention of land erosion, etc. (Fleming & Ogo, 2016)
4. According to evolution, modern day organism evolved from ancient organism. Certain plants and animals are restricted to a particular geographical location. For example, kangaroos are found only in Australia and not found in England. Certain types of plants are found in one geographical location and they are not found in another. These different species of plants and animals arise from different ancestors. Lamarck suggested the use and disuse theory to suggest how plants and animals in different habitat, evolve to adapt to their environment. The evolution of plants and animals has its application in comparative embryology and artificial selection. In artificial selection, the species are intentionally selected for a specific trait. For example, plants that carry the gene that confer resistance to certain pesticides can be selected, and the gene for this favorable trait can be incorporated into a non-resistant plant breed. (Neal, 2004)
5. Population dynamic indicates the changes seen in the population size, density and dispersion. The population size is determined by the death rate and birth rate in the population. Density on the other hand is influenced by migration and immigration of species to the area. The spacing of individuals in a given area is dealt by dispersion. Exponential growth curves are more applicable to bacteria growth rate in a culture. The human population is represented by a logistic growth curve. A number of factors like: food supply, accumulation of toxic waste, disease and predation can affect the population growth rate. The data on population dynamics is sought for many medical, agricultural, industrial and economic applications. Knowing population dynamics are important for proper resource management. Population explosion will result in scarcity of resources and poverty. Likewise, knowing the population density of an area is important for determining sampling rate from a given locality. In certain cities, people live in crowded neighborhood, while in the rural community the population is more scattered. (Fleming & Ogo, 2016)
6. Biomes unlike ecosystem are larger communities. There are classified based on certain key features like water availability, temperature, rainfall, biotic and by the abiotic component present in the region. Eight major biomes found in the world: boreal grassland, desert grassland, permanent ice, deciduous forest, temperate rainforest, tropical rainforest and tundra. Biome is also influenced by the latitude, elevation and ocean current in the area. The animal and plants in a biome undergo structural, physiologically or behaviorally adaptation to live in the environmental conditions presented by the biome. While ecosystem is used to refer to the biotic and abiotic components that affect an organism. Biome involves a larger region, with a characteristic climate and soil condition. (Landsberg & Gower, 1997)
Human activity and the associated global warming, has been causing changes in temperature and climate of certain region. This is causing changes in the biomes, causing certain biomes to become extinct or altered. Pollution and drilling for oil, releases huge volume of greenhouse gas, that contributes to global warming. As a result of global warming, the snow-capped north pole and south pole are melting, causing the level of water in the oceans to rise. The is also an alteration in the duration and time of the year when rainfall occurs. This has an important impact on the rainforest biome. Agricultural activities have also led to the alteration of biomes. Certain agricultural practices like cultivating a nonnative plant and removing native plants, so as to suit agricultural practices are ways through which the biome is altered. Intensively managed agricultural practices can hinder the survival of native wild species of plants and animal. Large scale deforestation activities and human encroachment can also cause changes in biome. (Landsberg & Gower, 1997)
References
Fleming, A. & Ogo, J. (2016). SCC GK12 Lesson Plan -- Biodiversity, Population Biology & Population Dynamics. Earthref.org. Retrieved 28 May 2016, from https://earthref.org/SCC/lessons/2011/biodiversity/
Landsberg, J. & Gower, S. (1997). Applications of physiological ecology to forest management (pp. 19-27). San Diego: Academic Press.
Neal, D. (2004). Introduction to population biology. Cambridge, UK: Cambridge University Press.
Stark, M. (2011). Clinical forensic medicine (pp. 124-130). New York: Humana Press.
Welcome to Evolution 101!. (2016). Evolution.berkeley.edu. Retrieved 28 May 2016, from http://evolution.berkeley.edu/evolibrary/article/evo_01
