Biology Unit 4: Evolving Pathogens and Species Evolution

Flashcards covering pathogen evolution, antibiotic resistance, genetic mechanisms, mutation types, selection pressures, and speciation based on the lecture notes.

Antibiotic Resistance

A form of natural selection where bacterial populations evolve to no longer be affected by antibiotics due to random mutations and selective advantages.

Antigenic Drift

Small and gradual changes in genes that code for viral surface antigens; memory cells may still recognize the virus if only a few changes have occurred.

Antigenic Shift

Sudden and significant changes to genes that code for viral surface antigens, often through viral recombination, resulting in a new subtype that the immune system typically does not recognize.

Virulence

The potential of a pathogen to cause harm to its host.

Gene Pool

The total of all the genes and alleles within a particular population or species.

Gene

A section of $DNA$ that creates a protein.

Allele

An alternate form of a gene.

Population

A group of individuals of the same species living in the same location.

Genotype

The genetic makeup at a particular gene.

Phenotype

The physical or biochemical characteristics resulting from gene expression and the environment.

Allele Frequencies

The proportion of a particular allele amongst all other alleles for that gene within a population.

Micro-evolution

A change in allele frequencies that indicates a population is undergoing change.

Germline Cell Mutation

A mutation occurring in a sperm or egg cell that may be passed down to the next generation.

Somatic Cell Mutation

A mutation occurring in a body cell that is unlikely to be passed down to the next generation.

Deletion (Block Mutation)

A type of mutation where a section of $DNA$ is removed, making the chromosome shorter.

Duplication (Block Mutation)

A type of mutation where a section of $DNA$ is doubled, making the chromosome longer.

Inversion (Block Mutation)

A type of mutation where a section of $DNA$ is reversed, causing the code to be read backwards.

Translocation (Block Mutation)

A type of mutation where sections of $DNA$ on different chromosomes swap places.

Selective Breeding

Also known as artificial selection, it is where humans choose to mate individuals with the most desirable phenotypes to influence allele frequencies.

Deleterious Recessive Alleles

Traits that can have a negative impact on an individual, which may become more prevalent due to inbreeding in selective breeding programs.

Environmental Selection Pressures

Factors from within the environment, such as predation, disease, and climate change, that influence the survivability and reproductive success of individuals.

Silent Mutation

A point mutation where a base substitution results in the same amino acid, causing no change in the protein.

Missense Mutation

A point mutation where an amino acid change alters the shape and function of a protein.

Nonsense Mutation

A point mutation where a base substitution results in a stop codon, cutting the polypeptide short.

Frameshift Mutation

A mutation involving the addition or deletion of $1$ or $2$ nucleotides, shifting all subsequent codons and changing the amino acids in the polypeptide.

Genetic Drift

Random chance events that occur in a population, resulting in the random removal of alleles and a loss of genetic diversity.

Founder Effect

A type of genetic drift where a small group of individuals colonizes a new population, creating a gene pool that is unrepresentative of the original population.

Bottleneck Effect

A type of genetic drift where a large portion of a population is wiped out by a random event like a natural disaster, severely altering allele frequencies.

Gene Flow

The movement of alleles into or out of a population via interbreeding, which tends to reduce differences between populations.

Speciation

The process where genetic differences accumulate until individuals can no longer breed to form viable and fertile offspring.

Allopatric Speciation

Speciation resulting from a geographic barrier that isolates populations and exposes them to different selective pressures.

Sympatric Speciation

The formation of a new species within the same geographical location, often due to different selection pressures acting on phenotypes or genetic abnormalities like polyploidy.

Antimicrobial Agent

An agent that kills or slows the growth of microorganisms, including antiseptics, disinfectants, antifungals, and antivirals.

Bacterial Conjugation

The process through which bacteria share $DNA$, allowing selected resistance alleles to spread through a population.