Evolution Review Chapters 15-19

Historical Context

Darwin’s Theory Curriculum Guide: competition with limited resources results in differential survival. Individuals with more favorable phenotypes are more likely to survive and produce more offspring, thus passing traits to subsequent generations.

Evidence for Evolution Curriculum Guide: Fossils can be dated by a variety of methods, including the age of rocks where a fossil is found, C14 radioactive dating, relationships through phylogenetic trees, and biochemical or geographical data. The details of these methods are beyond the scope of this course and the AP exam.

Evidence for Evolution A B

Evidence for Evolution Curriculum Guide: biochemical and genetic similarities such as: DNA and RNA are carriers of genetic information through replication, transcription, and translation Major features of the genetic code are shared by all modern living systems. Metabolic pathways are conserved across all currently recognized domains.

Evidence for Evolution

Evidence for Evolution

Micro vs. Macroevolution B

Causes of Evolution

Types of Selection

Hardy-Weinberg Conditions needed to be in equilibrium: large population size no migration no mutations random mating no selection

Hardy-Weinberg Practice Problems There are 100 students in a class. Ninety-six did well in the course whereas four blew it totally and received a grade of F. Sorry. In the highly unlikely event that these traits are genetic rather than environmental, if these traits involve dominant and recessive alleles, and if the four (4%) represent the frequency of the homozygous recessive condition, please calculate the following: The frequency of the recessive allele. The frequency of the dominant allele. The frequency of heterozygous individuals. Within a population of butterflies, the color brown (B) is dominant over the color white (b). And, 40% of all butterflies are white. Given this simple information, which is something that is very likely to be on an exam, calculate the following: The percentage of butterflies in the population that are heterozygous. The frequency of homozygous dominant individuals.

Illustrative Examples Curriculum Guide Environments change and act as selective mechanism on populations. Phenotypic variations are not directed BY the environment but occur through random changes in the DNA and through new gene combinations. Some phenotypic variations significantly increase or decrease fitness of the organism and population. sickle cell anemia peppered moth rock pocket mice Illustrative Examples

Heterozygote Advantage

Peppered Moth and Rock Pocket Mice

Speciation A B C

Evolution

Illustrative Examples Curriculum Guide Phylogenetic trees or cladograms can represent traits that are either derived or lost due to evolution. They illustrate speciation that occurred, in that relatedness of any two groups is shown by how recently two groups share a common ancestor. They can be constructed from morphological similarities or DNA and protein sequence similarities. They are dynamic, based on current data, and can be revised as needed. Number of heart chambers Opposable thumbs Absence of legs in some marine animals Illustrative Examples

Phylogenetic Trees

Curriculum Guide Primitive Earth provided inorganic precursors from which organic molecules could form due to free energy available and absence of oxygen. Monomers formed polymers with ability to replicate, store, and transfer information. RNA World hypothesis proposes that RNA could have been the earliest genetic material.

Origin of Life

Geologic Timeline Earth formed 4.6 BYA and the environment was too hostile for life until 3.9 BYA, while the earliest fossil evidence dates life to 3.5 BYA. Species extinction rates are rapid at times of ecological stress. The names and dates of the five major extinctions are beyond the scope of this course and the AP exam.