Phylogenetic relationships of a group of organisms Essay

Phylogenetic relationships of a group of organisms - Essay Example Phylogenetic analysis by means of cladistics uses shared and derived characteristics as the only criteria for grouping within a genus or species. A shared character is the common feature for all the species being evaluated and a derived character is a feature that evolved only within the group being studied. The hypothetical cladistic analysis will include an organism which is distantly related to the organisms within the group being studied. In the example, this organism is known as the out-group and serves as the starting point for comparison with the other organisms being evaluated. In our example, the earthworm represents this out-group. The other organisms in the group are an eel, a salmon fish, a Lizard, a Turtle and a Lion. In the character table, the organisms are placed sequentially in a row and their characteristics are listed in a column on the left (Table). A character lacking in an organism is scored as ‘0’ and the presence of a particular trait is scored as ‘1’ as shown in the Table. When the characters or traits are displayed in the form of a tree, it represents the cladistic hypothesis of the evolutionary relationship between the organisms under study. The tree showing the above cladistic analysis is as follows: Although a cladogram does not indicate the strength of a derived character or even its evolutionary importance, it does emphasize the sequence in which the derived characters arise from a central phylogenetic tree. In the above example, the earthworm lacks all the listed characteristics while the lion which is at the top of the evolutionary ladder in this analysis possesses

Reseach methods Essay Example | Topics and Well Written Essays - 500 words

Reseach methods - Essay Example Multiple form reliability refers to the application of equivalent forms of measure and correlation. This measurement tool is similar to test-retest reliability, but in this, subjects are given both forms of measure concurrently. Split half reliability reflects the correlation between the two halves in a set of items but the coefficient varies, depending on how the scale is split. Sometimes when more than one scale, dimension or factor is evaluated then split half reliability is used to check the consistency (Sekaran, 2006). Ans. Crime seriousness scales are the severity scales that judges the seriousness of the crime on the basis of weights assigned to them. There are two types of crime seriousness scales, simple rating scales and magnitude scales. Simple rating scales determine the rate of the crime on the basis of scales ranging from 1(not serious) to 9 (extremely serious). But this rating scale is unable to determine the magnitude difference between the scale scores. While magnitude scale measures the degree of seriousness of various crimes by public ranking. Selling-wolf gang index and national survey of crime severity are the two examples of magnitude scales in crime seriousness. Both these crime seriousness scales are used in criminal justice research to determine and analyze the seriousness of the crime. Crime seriousness scales not only judges the crime level but it also helps in controlling (Wilmot, 2002). Ans. Least square regression line is known as the best fitted line, least square line, regression line and least square prediction equation. It represents a mathematical model for a group of data. Generally, linear regression consists of finding the best-fitted line through the points in the scatter diagram. This line identifies the relationship between a single predictor variable X and the response variable Y, while the other predictor variables are held fixed. This