what does combining genes from two parents contribute to? | variation within a species |
what is discrete variation | single gene inheritance of characteristics where measurements fall into distinct groups |
How can discrete variation be displayed? | as a bar graph or pie chart |
what is continuous variation? | the polygenic inheritance of characteristics where there is a range of values from one extreme to the other |
how can continuous variation be displayed? | as a histogram
when a curve is drawn, a bell shaped normal distribution curve is formed |
what is a gene? | a section of dna on a chromosome that codes for a characteristic |
what is an allele? | different forms of the same gene |
what is meant by homozygous/ true breeding | an individual with two copies of the same allele present |
what is meant by heterozygous | an individual with two different alleles present |
what is a phenotype? | the physical characteristics of an organism |
what is a dominant allele | allele that always shows its effect as a phenotype and masks the presence of the other form |
what is a recessive allele | an allele that is masked by the dominant allele, it will only show its effect in the phenotype if both allele's are presnet |
what is a genotype | the set of alleles possessed by an individual |
what is meant by P | parent generation |
what is meant by F1 | first (filial) generation |
what is meant by F2 | second (filial) generation |
what is a monohybrid cross | the model used to show the inheritance pattern of one characteristic |
what is a punnett square used for | to predict the results of any cross where the genotypes of the parents are known |
why might predicted phenotypic ratios not match the actual result | fertilisation is a random process |
what is a phenotypic ratio | the ratio of the appearance of the offspring produced in a geneticcs cross |
what is a genotypic ratio | the ratio of genotypes of the offspring produced in a genetics cross |