Ms. Malonek
Biology 1/2
16 January 2015
The Mendel links are here but you will need to work on them at home if the plug in is not working on your computer. You should go through the first two columns of programs. Run the program. Take a screen shot and post it in a blog with a few sentences about what you learned (3-5) about that topic.
Mendel's Peas
Mendel picked common garden pea plants to test for his research because they can be grown easily in large numbers and their reproduction can be manipulated. Pea plants have both male and female reproductive organs, meaning they can either self-pollinate themselves or cross-pollinate with another plant. In his experiments, Mendel was able to selectively cross-pollinate purebred plants with particular traits and observe the outcome over many generations. Through the selective cross-breeding of common pea plants (Pisum sativum) over many generations, Mendel discovered that certain traits show up in offspring without any blending of parent characteristics. For instance, the pea flowers are either purple or white by crossing white and purple peas.
Crossing Over
Thomas Hunt Morgan, in the early 1900’s, used a common species of fruit fly, Drosophila melanogaster, to expand the understanding of genetics. Morgan was the first to show through experiments that genes were located on chromosomes. He also found that certain fruit fly traits (e.g., white vs. red eye color) are found on the same chromosomes that also determine their sex.
Dragon
Chromosomes are made from DNA. Genes are short sections of DNA. Alleles are different forms of a gene and can be dominant or recessive. enotype is what makes the trait - the information within a gene, or the genetic makeup of a specific organism. Genotype is determined by the makeup of something called "alleles," a word that refers to the form of a gene that produces different effects.The phenotype is the physical expression, or characteristics, of that trait.
Dragon Meiosis
Meiosis is a specialized type of cell division which reduces the chromosome number by half. This process occurs in all sexually reproducing eukaryotes (both single-celled and multicellular) including animals, plants, and fungi. Meiosis the two successive divisions of a diploid cell of a sexually reproducing organism that result in four haploid progeny cells, each with half the genetic material of the original cell.
Natural Selection
Natural selection is the gradual process by which heritable biological traits become either more or less common in a population as a function of the effect of inherited traits on the differential reproductive success of organisms interacting with their environment. It is a key mechanism of evolution.Natural selection is Darwin’s most famous theory; it states that evolutionary change comes through the production of variation in each generation and differential survival of individuals with different combinations of these variable characters. Individuals with characteristics which increase their probability of survival will have more opportunities to reproduce and their offspring will also benefit from the heritable, advantageous character. So over time these variants will spread through the population.
Incomplete Dominance & Co-dominance
Incomplete dominance is a form of intermediate inheritance in which one allele for a specific trait is not completely dominant over the other allele. For instance, incomplete dominance is seen in cross-pollination experiments between red and white snapdragon plants because dominant allele that produces the red color is not completely expressed over the recessive allele that produces the white color.Co-dominance is a relationship between two versions of a gene. Individuals receive an an allele of a gene from each parent. If the alleles are different, the dominant allele usually will be expressed, while the effect of the other allele, called recessive, is masked.
Sex Determination and Linkage
Although the sex of a human is typically determined by the particular chromosomes received (XX for female and XY for male), sex is determined in different ways in many other organisms. Sex linkage describes the pattern of heredity between traits governed by genes on the sex chromosomes and the trait of 'sex', itself. In humans, although the Y is a small chromosome besides the sry gene, the X is a large chromosome with hundreds of genes that govern a wide variety of phenotypic traits.
Genetic Counseling
Genetic counseling is the process by which the patients or relatives at risk of an inherited disorder are advised of the consequences and nature of the disorder, the probability of developing or transmitting it, and the options open to them in management and family planning.Genetic tests are done by analyzing small samples of blood or body tissues. They determine whether you, your partner, or your baby carry genes for certain inherited disorders.
Punnet Squares
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