Genetics

DNA DNA is a double helix molecule (twisted ladder design) DNA is a molecule that includes four different components. The arrangement of these four components within the double helix forms a chemical code. Chromosomes are individual strands of DNA.

DNA and Chromosomes

Genes Genes are sections of a chromosome that carry the code for a particular trait. The basic Laws of Mendelian Genetics can explain the transmission of some traits that can be inherited from generation to generation. Genetic engineering manipulates the genetic code to obtain a desired product. Genetic engineering has numerous practical applications in medicine, agriculture, and biology.

Gene Characteristics Every person has dominant and recessive genes that determine the characteristics of their off spring. Each environment has a population that exhibits biodiversities.. Species with varying traits (fur length, ear height, colorations) Individuals of a population exhibit a range of variations in a trait as a result of the variations in their genetic codes.

Types Phenotypes: Physical Traits (what you look like) Genotypes: Genetic make-up… the genes you got from your parents Heterozygous: an individual (or a condition in a cell or an organism) containing two different alleles for a particular trait (Aa) Homozygous: Individuals that get two copies of the same allele (AA or aa)

Mendel & the Punnett Square

Punnet Squares 1. Determine the genotypes (letters) of the parents. Bb x Bb 2. Set up the punnet square with one parent on each side. 3. Fill out the Punnet square middle 4. Analyze the number of offspring of each type.

Adaptations Adaptations are structures, functions, or behaviors that enable a species to survive. Adaptations are expressions of the organisms’ genetic information.

Mutations Mutations are inheritable changes because a mutation is a change in the DNA code. A mutation may result in a favorable change of adaptation in genetic information that improves a species’ ability to exist in its environment A mutation may result in an unfavorable change that does not improve or impedes a species’ ability to exist in its environment.

Evolution The evidence for evolution is drawn from data including the fossil record, radiometric dating, genetic information, the distribution of organisms, and anatomical and developmental similarities across species. The mechanisms through which evolution takes place are a related set of processes that include mutation, adaptation, natural selection, and extinction.

Natural Selection Natural selection is the survival and reproduction of the individuals in a population that exhibit the traits that best enable them to survive in their environment. If a species does not include traits that enable them to survive in its environment, or to survive changes in the environment, then the species may become extinct. Species: A type of organism, Scientific name for an organism

Galapagos Islands On an island east of Santa Cruz, a hybrid lizard has just recently appeared. It is a cross between a marine iguana (it is black and has a mouth like the marine iguana) and the land iguana (it has a white undercarriage). It may become a new species or it may be sterile like a mule.