AP Bio Unit 7 Review: Natural Selection, Hardy-Weinberg, and Phylogeny

Flashcards covering key vocabulary and concepts related to natural selection, Hardy-Weinberg equilibrium, phylogeny, and speciation, as discussed in an AP Biology review session.

Charles Darwin

Developed the theory of natural selection, observing similarities between organisms in South America, the Galapagos Islands, and Europe.

Descent with modification

The idea that descendants exhibit slight modifications due to more favorable traits, increasing survival and reproduction.

Natural selection

Organisms with favorable traits are more likely to survive and reproduce, increasing the frequency of those alleles in the gene pool.

Evolution

The change in the inherited characteristics of biological populations over successive generations.

Peppered Moths Example

The individuals that are able to blend in with their environment are more likely to survive.

Antibiotic Resistance

Bacteria that have resistance to antibiotics; when antibiotics are taken, the non-resistant bacteria are killed, increasing the prevalence of resistant bacteria.

Lamarckian statements

The false theory that traits acquired during an organism's lifetime can be passed on to offspring; traits must have a genetic component in the gametes to be inherited.

Artificial selection

When organisms with specific, desirable traits are bred to enhance those traits in offspring.

Disruptive selection

Selection against the intermediate phenotype, favoring the two extreme phenotypes.

Stabilizing selection

Selection for the intermediate phenotype, reducing variation in the population.

Directional selection

Selection that favors one extreme phenotype, causing a shift in the population's trait distribution.

Hardy-Weinberg equilibrium

A principle stating that a population will not evolve if five conditions are met: large population size, random mating, no mutations, no gene flow, and no natural selection.

Genetic drift

A random change in allele frequency, especially significant in small populations.

Founder's effect

A small group that gets isolated from a larger group.This small population is not representative of the original allele frequency and will see a major change in allele frequencies in the new population

Bottleneck effect

A drastic reduction in population size due to a random event (natural disaster), resulting in a non-representative allele frequency in the new population.

P

The dominant allele in the Hardy-Weinberg equation.

Q

The recessive allele in the Hardy-Weinberg equation.

P^2

The frequency of homozygous dominant individuals (RR).

2PQ

The frequency of heterozygous individuals (Rr).

Q^2

The frequency of homozygous recessive individuals (rr).

Biochemical evidence

Using DNA or proteins to determine whether evolution is occurring.

Morphological evidence

Looking for similarity in traits to determine whether evolution is occurring.

Ancestral traits

Traits that come from the ancestors.

Derived traits

The traits are the ones that come from descendants.

Analogous structures

Structures that look similar but have no common descent.

Phylogenetic Tree

Diagrams that depicts the lines of evolutionary descent of different species, organisms, or genes from a common ancestor.

Speciation

The creation of new species.

Biological Species Concept

Concept that two organisms are of the same species if they can interbreed with fertile viable offspring.

Reproductive barriers/isolation mechanisms

Mechanisms that prevent mating (prezygotic) or the formation of fertile offspring (postzygotic).

Behavioral isolation

Occurs when two species have different mating rituals that prevent interbreeding.

Temporal isolation

Occurs when two species mate at different times of day or year.

Geographic isolation

Occurs when two species are separated by a geographical barrier that prevents interbreeding.

Habitat or ecological isolation

Occurs when two species live in different habitats and do not interact, even if there is no physical barrier.

Mechanical isolation

Occurs when two species are anatomically incompatible and cannot mate.

Gametic isolation

Occurs when the gametes of two species cannot fuse, preventing fertilization.

Reduced hybrid viability

Occurs when the hybrid offspring is not viable or healthy and cannot survive.

Reduced hybrid fertility

Occurs when the hybrid offspring is infertile and cannot reproduce.

Hybrid breakdown

Occurs when the first generation of hybrid offspring is viable and fertile, but subsequent generations are not.

Sympatric speciation

The formation of new species in the same geographic area, usually due to absence of gene flow.

Allopatric speciation

The formation of a new species due to a geographic barrier that prevents gene flow between populations.