Biology Flashcards: Interpret Evolutionary Trend Data

What this deck covers

This deck focuses on Interpret Evolutionary Trend Data, giving you a quick way to review the definitions, rules, and examples that matter most for 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: If a new population has allele frequencies very different from the source population at founding, what cause fits?

Answer: Founder effect (genetic drift). Small founding group creates different frequencies.

Flashcard 2: What is the term for a change in allele frequencies due to random sampling in small populations?

Answer: Genetic drift. Random sampling effects are strongest in small populations.

Flashcard 3: What is the term for closely related species becoming more different over time?

Answer: Divergent evolution. Related species develop different characteristics.

Flashcard 4: If allele frequency changes from $p=0.40$ to $p=0.55$ across generations, what occurred?

Answer: Evolution occurred (allele frequencies changed). Allele frequency change indicates evolutionary change.

Flashcard 5: If two populations show increasing genetic divergence and decreasing hybrid fertility, what conclusion fits?

Answer: Reproductive isolation is increasing toward speciation. Genetic differences and breeding barriers are developing.

Flashcard 6: If allele frequency changes from $p=0.40$ to $p=0.55$ across generations, what occurred?

Answer: Evolution occurred (allele frequencies changed). Allele frequency change indicates evolutionary change.

Flashcard 7: If allele frequencies change rapidly after a storm drastically reduces population size, what cause fits?

Answer: Bottleneck effect (genetic drift). Sudden population reduction causes random changes.

Flashcard 8: If observed heterozygosity is lower than expected under $2pq$, which process is most indicated?

Answer: Non-random mating (inbreeding) or population structure. Reduced heterozygosity indicates non-random mating patterns.

Flashcard 9: Which type of selection favors extremes and can produce a bimodal distribution?

Answer: Disruptive selection. Both extreme phenotypes are favored over intermediates.

Flashcard 10: What is the term for a trait that is favored because it increases mating success in data trends?

Answer: Sexual selection. Traits evolve to increase reproductive opportunities.

Flashcard 11: What relationship must allele frequencies satisfy at a two-allele locus when computed from data?

Answer: $p+q=1$. Two allele frequencies must sum to one.

Flashcard 12: What is the term for long periods of little change punctuated by rapid change in the fossil record?

Answer: Punctuated equilibrium. Rapid change alternates with periods of stasis.

Flashcard 13: Which option best defines an evolutionary trend in a dataset?

Answer: A consistent change in trait or allele frequency across generations. Patterns show directional change over time in populations.

Flashcard 14: What is the term for a change in allele frequencies due to random sampling in small populations?

Answer: Genetic drift. Random sampling effects are strongest in small populations.

Flashcard 15: Which type of selection shifts a trait mean in one direction over time?

Answer: Directional selection. One extreme phenotype becomes more common over time.

Flashcard 16: What relationship must allele frequencies satisfy at a two-allele locus when computed from data?

Answer: $p+q=1$. Two allele frequencies must sum to one.

Flashcard 17: If male ornament size increases while survival decreases but mating success increases, what selection fits?

Answer: Sexual selection. Ornaments increase mating despite survival costs.

Flashcard 18: If two populations become more genetically similar after migration between them, which mechanism fits?

Answer: Gene flow. Migration makes populations more genetically similar.

Flashcard 19: What is the term for a trait that is favored because it increases mating success in data trends?

Answer: Sexual selection. Traits evolve to increase reproductive opportunities.

Flashcard 20: What is the Hardy–Weinberg equation for expected genotype frequencies from allele frequencies?

Answer: $p^2+2pq+q^2=1$. Expected frequencies from allele probabilities.

Flashcard 21: What is the term for non-random mating that increases homozygosity in data trends?

Answer: Inbreeding. Relatives mating increases homozygous genotypes.

Flashcard 22: What is the term for movement of alleles between populations that can reduce differences?

Answer: Gene flow. Migration transfers alleles between populations.

Flashcard 23: What is the Hardy–Weinberg equation for expected genotype frequencies from allele frequencies?

Answer: $p^2+2pq+q^2=1$. Expected frequencies from allele probabilities.

Flashcard 24: Which statement indicates that a population is evolving in terms of population genetics?

Answer: Allele frequencies change from one generation to the next. Evolution is defined by changing allele frequencies.

Flashcard 25: What is the term for traits evolving in unrelated lineages due to similar selection pressures?

Answer: Convergent evolution. Similar environments produce similar traits independently.

Flashcard 26: Which type of selection favors extremes and can produce a bimodal distribution?

Answer: Disruptive selection. Both extreme phenotypes are favored over intermediates.

Flashcard 27: Which equation gives allele frequency $q$ for allele $a$ from genotype counts $AA, Aa, aa$?

Answer: $q=\frac{2aa+Aa}{2N}$. Counts both homozygotes and half the heterozygotes.

Flashcard 28: What is the term for similarity in traits due to similar function, not shared ancestry?

Answer: Analogy. Similar function evolved independently, not inheritance.

Flashcard 29: What is the term for speciation caused by geographic isolation, often inferred from range data?

Answer: Allopatric speciation. Geographic barriers separate populations, preventing gene flow.

Flashcard 30: What is the term for speciation caused by geographic isolation, often inferred from range data?

Answer: Allopatric speciation. Geographic barriers separate populations, preventing gene flow.

Flashcard 31: If genotype counts are $AA=36$, $Aa=48$, $aa=16$, what is $q$ for allele $a$?

Answer: $q=0.40$. Calculate from $(32+24)/200 = 0.40$.

Flashcard 32: What is the definition of fitness when interpreting selection from survival or reproduction data?

Answer: Relative reproductive success in a specific environment. Measured by survival and reproductive output.

Flashcard 33: If $p=0.70$ and $q=0.30$, what is the expected heterozygote frequency under equilibrium?

Answer: $2pq=0.42$. Two times the product of allele frequencies.

Flashcard 34: What is the term for evolution of similar traits due to shared ancestry, not similar pressures?

Answer: Homology. Similarities arise from common evolutionary origin.

Flashcard 35: What is the term for a gradual change within a lineage over time as seen in fossil sequences?

Answer: Anagenesis. Single lineage changes gradually over time.

Flashcard 36: Which option lists the five Hardy–Weinberg conditions used to interpret equilibrium from data?

Answer: Large population, random mating, no mutation, no migration, no selection. Requirements for stable allele frequencies over time.

Flashcard 37: What is the term for allele frequency change when a small group colonizes a new area?

Answer: Founder effect. Small founding groups carry limited genetic diversity.

Flashcard 38: If fossil morphology stays stable for long intervals with abrupt shifts at boundaries, what pattern fits?

Answer: Punctuated equilibrium. Stasis interrupted by rapid morphological change.

Flashcard 39: What is the term for a split in one lineage into two or more lineages shown in phylogenetic data?

Answer: Speciation. One lineage splits into multiple separate lineages.

Flashcard 40: What is the term for selection that favors different phenotypes in different environments?

Answer: Diversifying selection. Different environments select for different traits.

Flashcard 41: What is the term for random change in allele frequencies that is strongest in small populations?

Answer: Genetic drift. Random sampling effects vary inversely with population size.

Flashcard 42: What is the definition of allele frequency used when interpreting evolutionary data?

Answer: Proportion of a specific allele among all alleles at a locus. Calculated from total alleles in the population.

Flashcard 43: What is the term for a gradual change within a lineage over time as seen in fossil sequences?

Answer: Anagenesis. Single lineage changes gradually over time.

Flashcard 44: If two populations become more genetically similar after migration between them, which mechanism fits?

Answer: Gene flow. Migration makes populations more genetically similar.

Flashcard 45: Which statement indicates that a population is evolving in terms of population genetics?

Answer: Allele frequencies change from one generation to the next. Evolution is defined by changing allele frequencies.

Flashcard 46: Which option best interprets a consistent increase in antibiotic-resistant bacteria after treatment?

Answer: Natural selection increased resistance allele frequency. Antibiotic creates selective pressure favoring resistance.

Flashcard 47: If intermediate phenotypes decline and both extremes increase over generations, which selection fits?

Answer: Disruptive selection. Extremes increase while intermediates decrease.

Flashcard 48: What is the term for movement of alleles between populations that can reduce differences?

Answer: Gene flow. Migration transfers alleles between populations.

Flashcard 49: Which option best defines reproductive isolation when interpreting speciation evidence?

Answer: Barriers prevent gene flow between populations. Populations cannot successfully interbreed and exchange genes.

Flashcard 50: If observed heterozygosity is higher than expected under $2pq$, what pattern is indicated?

Answer: Negative assortative mating or heterozygote advantage. Excess heterozygotes suggest outcrossing or advantage.

Flashcard 51: What is the definition of adaptation as inferred from evolutionary trend data?

Answer: Heritable trait that increases fitness in a given environment. Inherited traits that improve survival or reproduction.

Flashcard 52: What is the term for evolution of similar traits due to shared ancestry, not similar pressures?

Answer: Homology. Similarities arise from common evolutionary origin.

Flashcard 53: Which option lists the five Hardy–Weinberg conditions used to interpret equilibrium from data?

Answer: Large population, random mating, no mutation, no migration, no selection. Requirements for stable allele frequencies over time.

Flashcard 54: What is the term for speciation without geographic separation, inferred from within-range divergence?

Answer: Sympatric speciation. Populations diverge in the same geographic area.

Flashcard 55: If fossil morphology stays stable for long intervals with abrupt shifts at boundaries, what pattern fits?

Answer: Punctuated equilibrium. Stasis interrupted by rapid morphological change.

Flashcard 56: If $q=0.20$ at a Hardy–Weinberg locus, what is the expected frequency of $aa$?

Answer: $q^2=0.04$. $q$ squared gives homozygous recessive frequency.

Flashcard 57: If a trait mean steadily increases across time points, which selection pattern is most consistent?

Answer: Directional selection. Consistent shift in one direction indicates selection.

Flashcard 58: What is the term for long periods of little change punctuated by rapid change in the fossil record?

Answer: Punctuated equilibrium. Rapid change alternates with periods of stasis.

Flashcard 59: If observed heterozygosity is higher than expected under $2pq$, what pattern is indicated?

Answer: Negative assortative mating or heterozygote advantage. Excess heterozygotes suggest outcrossing or advantage.

Flashcard 60: If observed heterozygosity is lower than expected under $2pq$, which process is most indicated?

Answer: Non-random mating (inbreeding) or population structure. Reduced heterozygosity indicates non-random mating patterns.

Flashcard 61: If intermediate phenotypes decline and both extremes increase over generations, which selection fits?

Answer: Disruptive selection. Extremes increase while intermediates decrease.

Flashcard 62: If male ornament size increases while survival decreases but mating success increases, what selection fits?

Answer: Sexual selection. Ornaments increase mating despite survival costs.

Flashcard 63: What is the term for a DNA sequence difference used to track evolutionary change in populations?

Answer: Genetic marker. DNA variations help track population changes.

Flashcard 64: If a harmful recessive allele persists because heterozygotes have highest fitness, what mechanism is shown?

Answer: Heterozygote advantage (balancing selection). Mixed genotype has highest fitness, maintaining both alleles.

Flashcard 65: If genotype counts are $AA=36$, $Aa=48$, $aa=16$, what is $q$ for allele $a$?

Answer: $q=0.40$. Calculate from $(32+24)/200 = 0.40$.

Flashcard 66: What is the term for closely related species becoming more different over time?

Answer: Divergent evolution. Related species develop different characteristics.

Flashcard 67: If allele frequency changes are larger in a small population than a large one, what trend does this show?

Answer: Stronger genetic drift in smaller populations. Smaller populations show larger random fluctuations.

Flashcard 68: What is the term for a split in one lineage into two or more lineages shown in phylogenetic data?

Answer: Speciation. One lineage splits into multiple separate lineages.

Flashcard 69: Which type of selection favors intermediate phenotypes and reduces variation?

Answer: Stabilizing selection. Middle values are favored, reducing trait variance.

Flashcard 70: What is the term for a DNA sequence difference used to track evolutionary change in populations?

Answer: Genetic marker. DNA variations help track population changes.

Flashcard 71: If allele frequency changes are larger in a small population than a large one, what trend does this show?

Answer: Stronger genetic drift in smaller populations. Smaller populations show larger random fluctuations.

Flashcard 72: What is the definition of allele frequency used when interpreting evolutionary data?

Answer: Proportion of a specific allele among all alleles at a locus. Calculated from total alleles in the population.

Flashcard 73: Which option best interprets a molecular clock where sequence differences increase with time?

Answer: Mutations accumulate over time at an approximately constant rate. Genetic differences accumulate steadily over time.

Flashcard 74: What is the term for selection that favors different phenotypes in different environments?

Answer: Diversifying selection. Different environments select for different traits.

Flashcard 75: Which option best interprets a molecular clock where sequence differences increase with time?

Answer: Mutations accumulate over time at an approximately constant rate. Genetic differences accumulate steadily over time.

Flashcard 76: If $p=0.60$ and $q=0.40$, what are expected genotype frequencies $AA, Aa, aa$?

Answer: $AA=0.36$, $Aa=0.48$, $aa=0.16$. Use $p^2$, $2pq$, and $q^2$ formulas.

Flashcard 77: If a harmful recessive allele persists because heterozygotes have highest fitness, what mechanism is shown?

Answer: Heterozygote advantage (balancing selection). Mixed genotype has highest fitness, maintaining both alleles.

Flashcard 78: If genotype frequencies match $p^2:2pq:q^2$ and remain constant, what is the conclusion?

Answer: Population is in Hardy–Weinberg equilibrium at that locus. Genotype frequencies match predictions and stay constant.

Flashcard 79: What is the term for non-random mating that increases homozygosity in data trends?

Answer: Inbreeding. Relatives mating increases homozygous genotypes.

Flashcard 80: What is the term for similarity in traits due to similar function, not shared ancestry?

Answer: Analogy. Similar function evolved independently, not inheritance.

Flashcard 81: What is the term for random change in allele frequencies that is strongest in small populations?

Answer: Genetic drift. Random sampling effects vary inversely with population size.

Flashcard 82: If a trait mean steadily increases across time points, which selection pattern is most consistent?

Answer: Directional selection. Consistent shift in one direction indicates selection.

Flashcard 83: If trait variance decreases while the mean stays similar over time, which selection is most consistent?

Answer: Stabilizing selection. Reduced variance with stable mean indicates stabilizing.

Flashcard 84: If allele frequencies cycle because rare phenotypes have higher fitness, what mechanism is indicated?

Answer: Negative frequency-dependent selection. Rare types have advantage, preventing fixation.

Flashcard 85: What is the term for a sharp reduction in population size that changes allele frequencies by chance?

Answer: Bottleneck effect. Dramatic population reduction causes random allele loss.

Flashcard 86: What is the definition of phenotype frequency in a population dataset?

Answer: Proportion of individuals expressing a particular phenotype. Observable traits expressed by individuals in a dataset.

Flashcard 87: If allele frequencies cycle because rare phenotypes have higher fitness, what mechanism is indicated?

Answer: Negative frequency-dependent selection. Rare types have advantage, preventing fixation.

Flashcard 88: If genotype counts are $AA=36$, $Aa=48$, $aa=16$, what is $p$ for allele $A$?

Answer: $p=0.60$. Calculate from $(72+24)/200 = 0.60$.

Flashcard 89: If $p=0.60$ and $q=0.40$, what are expected genotype frequencies $AA, Aa, aa$?

Answer: $AA=0.36$, $Aa=0.48$, $aa=0.16$. Use $p^2$, $2pq$, and $q^2$ formulas.

Flashcard 90: If a new population has allele frequencies very different from the source population at founding, what cause fits?

Answer: Founder effect (genetic drift). Small founding group creates different frequencies.

Flashcard 91: If allele frequencies change rapidly after a storm drastically reduces population size, what cause fits?

Answer: Bottleneck effect (genetic drift). Sudden population reduction causes random changes.

Flashcard 92: If $q=0.20$ at a Hardy–Weinberg locus, what is the expected frequency of $aa$?

Answer: $q^2=0.04$. $q$ squared gives homozygous recessive frequency.

Flashcard 93: If genotype counts are $AA=36$, $Aa=48$, $aa=16$, what is $p$ for allele $A$?

Answer: $p=0.60$. Calculate from $(72+24)/200 = 0.60$.

Flashcard 94: What is the term for a sharp reduction in population size that changes allele frequencies by chance?

Answer: Bottleneck effect. Dramatic population reduction causes random allele loss.

Flashcard 95: Which option best defines reproductive isolation when interpreting speciation evidence?

Answer: Barriers prevent gene flow between populations. Populations cannot successfully interbreed and exchange genes.

Flashcard 96: Which equation gives allele frequency $p$ for allele $A$ from genotype counts $AA, Aa, aa$?

Answer: $p=\frac{2AA+Aa}{2N}$. Counts both homozygotes and half the heterozygotes.

Flashcard 97: Which option best defines an evolutionary trend in a dataset?

Answer: A consistent change in trait or allele frequency across generations. Patterns show directional change over time in populations.

Flashcard 98: What is the definition of phenotype frequency in a population dataset?

Answer: Proportion of individuals expressing a particular phenotype. Observable traits expressed by individuals in a dataset.

Flashcard 99: Which equation gives allele frequency $q$ for allele $a$ from genotype counts $AA, Aa, aa$?

Answer: $q=\frac{2aa+Aa}{2N}$. Counts both homozygotes and half the heterozygotes.

Flashcard 100: Which equation gives allele frequency $p$ for allele $A$ from genotype counts $AA, Aa, aa$?

Answer: $p=\frac{2AA+Aa}{2N}$. Counts both homozygotes and half the heterozygotes.