Specific Immune Response T-Helper cells (a type of lymphocyte that responds to specific antigens) and mature B cells (another type of lymphocyte) have specific receptors located on their cell surfa...
Antigens Every organism has cells with unique molecules on the cell surface membrane which act as markers to identify it These unique markers are macromolecules and they allow cell-to-cell recognit...
Populations & their Allele Frequencies Comparison of allele frequencies of geographically isolated populations Allele frequency is a term that assigns a relative frequency of an allele at a par...
Polyploidy & Speciation NOS: Looking for patterns, trends and discrepancies—patterns of chromosome number in some genera can be explained by speciation due to polyploidy When patterns and trend...
Gradualism & Speciation Speciation can be defined as the emergence of new and distinct species that are reproductively isolated from other separate species Two theories exist to explain the eme...
The Process of Evolution by Natural Selection Evolution requires that allele frequencies change with time in populations Evolution is defined as the cumulative change in the heritable characteristi...
Gene Pools A gene pool consists of all the genes and their different alleles, present in an interbreeding population Some populations of the same species are geographically isolated from each other...
Types of Variation The ways in which organisms differ from one another is called variation Variation occurs between species In fact, species are classified based on differences between their respec...
Chi-squared Test and Dihybrid Crosses Use of a chi-squared test on data from dihybrid crosses The difference between expected and observed results in experiments can be statistically significant or...
