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Knowledge and Skills Statement

Science concepts--biological evolution. The student knows evolutionary theory is a scientific explanation for the unity and diversity of life that has multiple mechanisms.

Genetic drift occurs in all populations, but its effects are most visible in smaller populations. Because fewer members of the population hold any given trait, the reproduction of any member can have a large effect on the allele frequencies within the population. Some alleles may increase in frequency, or some alleles may decrease or disappear by random chance.

While students may readily relate to gene flow as migration, it is also beneficial to provide examples outside of the animal kingdom such as pollen being blown across a continent or the spread of viral lineages across the world.

Mutations can be caused by errors in DNA replication, which can substitute one nucleotide for another, and by chemicals or radiation, which change the structure of individual nucleotides.

Genetic recombination is the exchange of genetic material between organisms.  Recombination increases the genetic diversity of a population by generating different combinations of alleles in the offspring from those that were present in the parents.  Recombination occurs during meiosis in eukaryotic, sexually reproducing organisms. It can also occur in bacteria and archaea via transformation (uptake of free DNA from the environment), transduction (virus-mediated DNA transfer), or conjugation (transfer of DNA via cell-to-cell contact), and is the main method of diversification in RNA viruses. V(D)J recombination occurs in organisms with an adaptive immune system and is a type of site-specific genetic recombination that helps immune cells rapidly diversify to recognize and adapt to new pathogens. Recombination is used extensively in laboratory research, vaccine development, and genetic engineering.

the theory in biology postulating that the various types of plants, animals, and other living things on Earth have their origin in other preexisting types and that the distinguishable differences are due to modifications in successive generations

the transfer or exchange of genetic material (alleles) from one population to another through interbreeding, migration, or dispersal

the total of the genes of every reproducing individual in a population

variation in the relative frequency of different genotypes in a small population, owing to the chance disappearance of particular genes as individuals die or do not reproduce

the exchange of genetic material between chromosomes that leads to the production of offspring with a combination of traits from each parent; the product of the crossing over of chromosomes during meiosis, producing novel combinations of alleles in the gametes that did not exist in the parent

a change to a gene's DNA sequence

a natural process that results in the survival and reproductive success of individuals or groups best adjusted to their environment and that leads to the perpetuation of genetic qualities best suited to that particular environment

Research

Melicher, Dacotah, and Julia H. Bowsher. "Exploring the Evolutionary History of a Novel Trait in Sepsidae." Proceedings of the North Dakota Academy of Science 69, (April 2015): 44A.

Summary:  The novel abdominal appendage in male sepsid flies (Diptera: Sepsidae) has a complex evolutionary history of primary gain, loss, and regain which we explore using fluorescent microscopy to compare the size, volume, and number of cells in the histoblast cell nests that produce the appendage during pupation across six genera including an ancestral outgroup which describe the evolutionary history of the appendage.

Research

Yang, Shimin, Jianyu Chen, Jinjian Fu, Jiayin Huang, Ting Li, Zhenjiang Yao, and Xiaohua Ye. "Disease-Associated Streptococcus pneumoniae Genetic Variation." Emerging Infectious Diseases 30, no. 1 (January 2024): 39-49. https://doi.org/10.3201/eid3001.221927

Summary:  Streptococcus pneumoniae is an opportunistic pathogen that causes substantial illness and death among children worldwide. To determine the evolutionary mechanisms of opportunistic pathogenicity, we conducted a genomic surveillance study in China. Our findings suggest that S. pneumoniae pathogenicity is complex and multifactorial, and we provide genetic evidence for precise targeted interventions.