AP Biology Flashcards: Speciation

What this deck covers

This deck focuses on Speciation, giving you a quick way to review the definitions, rules, and examples that matter most for AP Biology.

How to use these flashcards

Work through these flashcards in short sessions. Try to answer each prompt before flipping the card, then revisit any cards you miss until the explanation feels automatic.

Flashcard 1: Identify a type of postzygotic barrier.

Answer: Hybrid sterility. Hybrids are viable but cannot reproduce successfully.

Flashcard 2: Define allopolyploidy.

Answer: Polyploidy resulting from two different species interbreeding. Hybrid polyploids from different parent species.

Flashcard 3: What is polyploidy?

Answer: The condition of having more than two complete sets of chromosomes. Common mechanism of instant speciation in plants.

Flashcard 4: Identify a factor that can initiate speciation.

Answer: Geographic isolation. Physical separation initiates independent evolutionary paths.

Flashcard 5: What is hybrid breakdown?

Answer: Hybrids are viable and fertile but their offspring are inviable or sterile. Second-generation hybrids show reduced fitness.

Flashcard 6: Define behavioral isolation.

Answer: When species have different mating behaviors. Courtship differences prevent recognition and mating.

Flashcard 7: Define habitat isolation.

Answer: When two species live in the same area but different habitats. Microhabitat differences reduce encounter rates.

Flashcard 8: Define allopatric speciation.

Answer: Speciation that occurs when biological populations are geographically isolated. Geographic barriers prevent gene flow between populations.

Flashcard 9: What is speciation?

Answer: The formation of new and distinct species in the course of evolution. The evolutionary process creating reproductively isolated lineages.

Flashcard 10: What is the biological species concept?

Answer: Species are groups of interbreeding natural populations that are reproductively isolated. Defines species by reproductive compatibility and gene flow.

Flashcard 11: What is adaptive radiation?

Answer: The diversification of a group of organisms into forms filling different niches. Rapid evolution into multiple specialized forms.

Flashcard 12: What is stability in hybrid zones?

Answer: When hybrids continue to be produced. Balanced selection maintains hybrid zone over time.

Flashcard 13: How does gene flow affect speciation?

Answer: Gene flow can counteract speciation by homogenizing populations. Genetic exchange prevents population divergence and speciation.

Flashcard 14: What is the morphological species concept?

Answer: Species are defined by structural features. Based on physical characteristics and anatomy.

Flashcard 15: Define ecological speciation.

Answer: Speciation driven by adaptation to different ecological niches. Natural selection drives adaptation to different environments.

Flashcard 16: What is the phylogenetic species concept?

Answer: Species are the smallest group of individuals sharing a common ancestor. Uses evolutionary relationships to define species boundaries.

Flashcard 17: What is genetic drift?

Answer: Random changes in allele frequencies within a population. Stronger effects in smaller populations due to sampling.

Flashcard 18: Define sympatric speciation.

Answer: Speciation that occurs without physical separation of the population. Occurs through polyploidy or behavioral changes within populations.

Flashcard 19: Define gametic isolation.

Answer: When sperm cannot fertilize the eggs of another species. Biochemical incompatibility prevents sperm-egg fusion.

Flashcard 20: What is prezygotic isolation?

Answer: A mechanism that prevents fertilization from occurring. Acts before zygote formation to prevent mating or fertilization.

Flashcard 21: What is temporal isolation?

Answer: When two species breed at different times. Different breeding seasons prevent mating opportunities.

Flashcard 22: What is reinforcement in speciation?

Answer: Strengthening of reproductive barriers to reduce hybrid formation. Selection against hybrids increases reproductive isolation.

Flashcard 23: What is postzygotic isolation?

Answer: A mechanism that reduces the viability or reproductive capacity of hybrids. Acts after fertilization to reduce hybrid fitness.

Flashcard 24: What is a reproductive barrier?

Answer: Any factor that prevents interbreeding between different species. Maintains species integrity by preventing hybridization.

Flashcard 25: What is the phylogenetic species concept?

Answer: Species are the smallest group of individuals sharing a common ancestor. Uses evolutionary relationships to define species boundaries.

Flashcard 26: What is the founder effect?

Answer: Reduced genetic diversity when a population is descended from a small number of ancestors. Small founding populations carry limited genetic variation.

Flashcard 27: What is mechanical isolation?

Answer: When physical differences prevent successful mating. Structural incompatibility prevents successful copulation.

Flashcard 28: What is fusion in hybrid zones?

Answer: When reproductive barriers weaken and populations merge. Gene flow overcomes reproductive barriers between species.

Flashcard 29: Identify an outcome of hybrid zones.

Answer: Reinforcement. Selection against hybrids strengthens reproductive barriers.

Flashcard 30: Identify a factor that can initiate speciation.

Answer: Geographic isolation. Physical separation initiates independent evolutionary paths.

Flashcard 31: Define peripatric speciation.

Answer: A form of allopatric speciation where a new species forms in isolated peripheral populations. Occurs at population margins with limited gene flow.

Flashcard 32: Define autopolyploidy.

Answer: Polyploidy from duplication of chromosomes within a single species. Chromosome doubling within one species creates polyploids.

Flashcard 33: What is incipient speciation?

Answer: The initial stage of species formation where populations are diverging. Early stages before complete reproductive isolation develops.

Flashcard 34: Identify a mechanism of sympatric speciation.

Answer: Polyploidy. Chromosome multiplication creates instant reproductive isolation.

Flashcard 35: Identify a type of prezygotic barrier.

Answer: Temporal isolation. Prevents mating due to different breeding seasons or times.

Flashcard 36: What is a hybrid zone?

Answer: A geographic region where members of different species meet and mate. Contact zone where incomplete reproductive isolation exists.

Flashcard 37: What is hybrid inviability?

Answer: Hybrids fail to develop or reach maturity. Genetic incompatibilities cause developmental failures.

Flashcard 38: What is divergence in the context of speciation?

Answer: Accumulation of differences between groups leading to speciation. Genetic and phenotypic differences accumulate over time.

Flashcard 39: What is a ring species?

Answer: A connected series of neighboring populations that can interbreed, but the end populations cannot. Demonstrates how geographic variation can lead to speciation.