AP Biology Quiz: Continuing Evolution

What this quiz covers

This quiz focuses on Continuing Evolution, giving you a quick way to practice the rules, question types, and explanations that matter most for AP Biology.

How to use this quiz

Try each quiz question before looking at the correct answer. Use the explanations to review missed ideas, then come back to similar questions until the pattern feels familiar.

Question 1

1. The existence of fossils of extinct organisms, which proves that life forms have changed over Earth's history.
2. The discovery of living fossils, organisms that have remained morphologically unchanged for millions of years.
3. The consistent ordering of fossils in rock strata, with simpler organisms in older layers and more complex ones in younger layers.
4. The presence of transitional fossils that show intermediate anatomical features between ancestral and more recently evolved groups of organisms. (correct answer)

Explanation: Transitional fossils, such as Archaeopteryx (linking reptiles and birds) or Tiktaalik (linking fish and amphibians), demonstrate the incremental changes that occur over time as one lineage evolves into another. This provides a snapshot of evolution in progress, supporting its continuous nature. Choice A shows that change occurs but not necessarily that it's continuous. Choice B demonstrates evolutionary stasis in some lineages, not ongoing change. Choice C shows a general pattern of change over time but doesn't illustrate the continuous, step-by-step process as well as transitional forms do.

Question 2

1. The initial antibiotic treatment acted as a selective pressure, allowing a few naturally resistant bacteria to survive and reproduce, leading to a population that is now largely resistant. (correct answer)
2. The bacteria that survived the first treatment developed an immunity to the antibiotic and passed this acquired trait on to their offspring, making the new population immune.
3. The patient's immune system was weakened by the initial infection and antibiotic use, preventing it from effectively combating the bacterial population during the second treatment.
4. The antibiotic caused specific mutations to arise in the bacterial DNA that conferred resistance, allowing the population to adapt directly to the presence of the drug.

Explanation: This is a classic example of natural selection. The antibiotic kills susceptible bacteria, but individuals with pre-existing resistance survive and reproduce. This differential survival and reproduction lead to an increase in the frequency of the resistance allele in the population over time. Choice B describes an incorrect, Lamarckian view of acquired characteristics. Choice C offers a physiological explanation for the patient's condition but not an evolutionary explanation for the bacteria's resistance. Choice D is incorrect because mutations are random events, not directed responses to environmental pressures like antibiotics.

Question 3

1. that all introduced species undergo rapid and identical changes regardless of their new environment.
2. how different environmental conditions can lead to different selective pressures and result in adaptive divergence among populations. (correct answer)
3. that the founder effect is the only mechanism driving change in introduced populations.
4. that individual sparrows can change their body size in response to temperature and pass that change to offspring.

Explanation: This is an example of local adaptation. The different climates in North America impose different selective pressures. In the north, larger body size is advantageous for heat conservation, while in the south, it is not. This has led to the measurable divergence of populations since their introduction, providing a clear example of ongoing adaptation. Choice A is incorrect, as the changes are different depending on the environment. Choice C is incorrect; while the founder effect was part of the initial introduction, natural selection is driving the subsequent divergence. Choice D is an incorrect, Lamarckian explanation.

Question 4

1. An individual plant grown in a high-CO2 chamber shows a higher rate of photosynthesis than when it was grown in normal air.
2. A survey of historical herbarium specimens shows a decrease in the density of stomata on the leaves of a particular plant species over the last century. (correct answer)
3. Many plant species are shifting their geographic ranges to higher latitudes or altitudes as global temperatures rise.
4. The total global biomass of plants has increased over the last 50 years due to the fertilizing effect of increased CO2.

Explanation: A change in the heritable traits of a population over time is evidence of evolution. A decrease in stomatal density over many generations, as documented by historical specimens, would be a morphological adaptation to high CO2 levels (as plants need fewer 'mouths' to get the same amount of CO2) and would indicate a genetic shift in the population. Choice A describes phenotypic plasticity (an individual's response), not evolution. Choice C describes an ecological response (range shift), not necessarily genetic adaptation within a population. Choice D is a large-scale ecological observation that doesn't directly show heritable change within a species.

Question 5

1. Individual pigeons developed stronger jaw muscles after eating harder seeds for several weeks.
2. Allele D increased from 0.33 to 0.58 across five breeding seasons in the park population. (correct answer)
3. Pigeons spent more time foraging near benches where visitors dropped food scraps.
4. The average seed size in the park increased when a new tree species was planted.
5. Some pigeons switched from seeds to insects during summer when insects were abundant.

Explanation: Continuing evolution refers to genetic shifts in populations adapting to new conditions, such as these pigeons facing harder seeds. The correct answer, choice B, demonstrates this as allele D for deeper beaks rose from 0.33 to 0.58 over five breeding seasons, implying better food handling led to higher survival and reproduction. This population trend reflects natural selection favoring deeper beaks in the changed food environment. Consistent sampling across seasons highlights the heritable nature of the change. Choice A tempts with muscle development from eating harder seeds, a misconception of acquired traits or plasticity rather than genetic evolution. A transferable approach is to examine allele frequency data over generations to confirm evolution, avoiding confusion with non-heritable changes.

Question 6

1. Individual rabbits shed fur earlier in warm years than in cold years.
2. The frequency of allele B increases in the population over successive years. (correct answer)
3. More predators are observed hunting in open areas during low-snow winters.
4. Some rabbits change hiding behavior by using shrubs more on snow-free days.
5. Juvenile rabbits grow more slowly when winter temperatures are above average.

Explanation: This question assesses the skill of understanding continuing evolution, which involves ongoing changes in allele frequencies within a population over generations due to selective pressures. The correct answer, choice B, demonstrates evolution because it shows the frequency of the B allele increasing from 0.12 in 2016 to 0.20 in 2018, 0.29 in 2020, and 0.33 in 2022, indicating a population trend toward brown coats as snow cover decreases. This change reflects natural selection favoring brown rabbits that are less detectable by predators on snow-free ground, enhancing survival and reproduction. Spring sampling of the same population tracks the genetic response to warmer winters. A tempting distractor is choice A, which describes individual rabbits shedding fur earlier in warm years, but this is wrong because it represents seasonal phenotypic plasticity, not genetic evolution across generations. To identify evidence of continuing evolution in similar questions, focus on data showing shifts in allele or genotype frequencies over multiple generations rather than short-term individual responses.

Question 7

1. Individual mice drink less water during drought years than during wetter years.
2. The population's allele frequency for H2 increases across multiple sampling years. (correct answer)
3. Some mice migrate from nearby hills into the lowlands during the drought.
4. Mice increase burrow use during hot days to reduce water loss.
5. Young mice weigh less at weaning during the driest years of the study.

Explanation: This question assesses the skill of understanding continuing evolution, which involves ongoing changes in allele frequencies within a population over generations due to selective pressures. The correct answer, choice B, demonstrates evolution because it shows the frequency of the H2 allele increasing from 0.10 in 2000 to 0.16 in 2002, 0.23 in 2004, and 0.24 in 2006, indicating a population trend toward better oxygen delivery during drought stress. This shift reflects natural selection favoring mice with the H2 allele that cope better with dehydration, resulting in higher survival and reproductive success. The consistent sampling during and after the drought period highlights how environmental pressure drives genetic change in the population. A tempting distractor is choice A, which describes individual mice drinking less during droughts, but this is wrong because it represents behavioral adaptation or physiological response within a lifetime, not heritable genetic evolution. To identify evidence of continuing evolution in similar questions, focus on data showing shifts in allele or genotype frequencies over multiple generations rather than short-term individual responses.

Question 8

1. Individual mosquitoes avoid entering houses with bed nets during a single night.
2. The frequency of the kdr allele increases over years in the village population. (correct answer)
3. More mosquitoes are captured during the rainy season than during the dry season.
4. Mosquito larvae develop faster in warmer puddles than in cooler puddles.
5. Some adult mosquitoes live longer when provided sugar water in laboratory cages.

Explanation: This question assesses the skill of understanding continuing evolution, which involves ongoing changes in allele frequencies within a population over generations due to selective pressures. The correct answer, choice B, demonstrates evolution because it shows the frequency of the kdr allele increasing from 0.08 in 2011 to 0.21 in 2013, 0.39 in 2016, and 0.52 in 2020, indicating a population trend toward insecticide resistance with bed net use. This change reflects natural selection favoring mosquitoes with reduced sensitivity, allowing better survival and reproduction despite exposure. Consistent sampling from the same households tracks the genetic adaptation over time. A tempting distractor is choice A, which describes individual mosquitoes avoiding houses with nets, but this is wrong because it represents behavioral avoidance or learning, not a heritable shift in allele frequencies. To identify evidence of continuing evolution in similar questions, focus on data showing shifts in allele or genotype frequencies over multiple generations rather than short-term individual responses.

Question 9

1. Individual sunflowers wilt less on salty days because their leaves close stomata.
2. The frequency of allele T increases across years in the roadside population. (correct answer)
3. Road salt application varies between winters depending on snowfall amounts.
4. Some plants grow taller in shaded patches than in sunny patches along the road.
5. Seedlings grow more slowly when transplanted from the roadside into a greenhouse.

Explanation: This question assesses the skill of understanding continuing evolution, which involves ongoing changes in allele frequencies within a population over generations due to selective pressures. The correct answer, choice B, demonstrates evolution because it shows the frequency of the T allele increasing from 0.14 in 2012 to 0.26 in 2015, 0.37 in 2018, and 0.40 in 2021, indicating a population trend toward salt tolerance along salted roadsides. This shift reflects natural selection favoring plants with the T allele that produce more seeds in salty soils, enhancing reproductive success. Sampling from the same road stretch ensures the trend is a genetic response to de-icing salt. A tempting distractor is choice A, which describes individual sunflowers wilting less by closing stomata, but this is wrong because it represents physiological acclimation, not heritable genetic change. To identify evidence of continuing evolution in similar questions, focus on data showing shifts in allele or genotype frequencies over multiple generations rather than short-term individual responses.

Question 10

1. Allele S increased in frequency from 0.50 to 0.93 over 300 generations in the population. (correct answer)
2. Individual yeast cells increased transporter activity when placed into the sugar medium.
3. The culture's growth rate changed when the incubator temperature varied slightly between days.
4. Some yeast cells entered a dormant state when nutrients became temporarily limited in the flask.
5. Cells clustered together, reducing exposure to ethanol produced during fermentation.

Explanation: Continuing evolution illustrates genetic changes in lab populations under controlled conditions, as with this yeast in sugar medium. Choice A correctly demonstrates evolution through allele S's rise from 0.50 to 0.93 over 300 generations, indicating better sugar transport conferred advantages, increasing reproduction and shifting population genetics. Identical flasks and continuous reproduction highlight selection's role in this trend. The generational scale confirms a heritable adaptation. Choice B tempts by noting increased transporter activity upon exposure, a misconception of induced physiological changes mistaken for evolution without genetic frequency shifts. A useful strategy is to analyze long-term allele data to verify evolution, separating it from immediate cellular responses.

Question 11

1. Plants in drier years produced fewer flowers per individual because water limited growth.
2. Allele F increased from 0.27 to 0.63 across six generations in the population. (correct answer)
3. Individual plants flowered earlier when temperatures were warmer during a particular spring.
4. Pollinators visited more frequently during mornings than afternoons in the hottest months.
5. Seeds germinated later in some years because rainfall occurred later than average.

Explanation: Continuing evolution involves populations genetically adapting to climate variability, like these desert plants with shorter springs. Choice B is correct as allele F for earlier flowering increased from 0.27 to 0.63 over six generations, suggesting earlier bloomers reproduced more successfully before rains ended, altering the population's genetics. Similar population sizes and no seed introductions point to natural selection favoring this trait. The multi-generation trend reflects ongoing heritable changes. Choice C tempts with earlier flowering from warmer temperatures, confusing environmental cues and plasticity with evolutionary genetic shifts. To recognize evolution, focus on tracking allele frequencies over generations, distinguishing from phenotypic responses to conditions.

Question 12

1. Mice hid under denser vegetation more often after the predator arrived, reducing daytime activity.
2. Some mice grew thicker fur during colder winters and thinner fur during warmer winters.
3. Allele D rose in frequency from 0.22 to 0.55 across multiple sampling intervals. (correct answer)
4. Individual mice learned to freeze longer when they detected predator scent near their burrows.
5. The predator population increased in the first year and then stabilized at a similar density.

Explanation: Continuing evolution describes genetic adaptations in populations facing new selective pressures, like these field mice with a new predator. The correct answer, choice C, illustrates this through allele D's increase from 0.22 to 0.55 over 10 years, implying darker coats offered camouflage advantages, leading to higher survival and reproduction rates. Consistent habitat and migration rates indicate natural selection drove this population-level genetic shift. The decadal trend reflects ongoing heritable changes in response to predation. Choice A is a tempting distractor, portraying behavioral hiding as evolution, but this misconceptions confuses learned or plastic behaviors with genetic evolution requiring allele changes. To spot evolution, always verify shifts in genetic frequencies over generations, not just behavioral modifications.

Question 13

1. Some snails repaired shell damage faster after crab attacks during a single growing season.
2. Allele T increased in frequency from 0.40 to 0.79 across seven generations in the lake. (correct answer)
3. Snails spent more time under rocks during the day when crabs were most active.
4. Crabs preferred shallow water, causing snails to shift deeper during hot months.
5. Individual snails produced thicker shells when calcium levels were higher in the water.

Explanation: Continuing evolution highlights genetic changes in populations over generations, evident in these snails adapting to an invasive crab. Choice B is correct as allele T for thicker shells rose from 0.40 to 0.79 over seven generations, suggesting snails with thicker shells survived crab predation better and reproduced more, altering the population's genetics. The lack of stocking and continued reproduction in the lake point to natural selection favoring this trait. This generational trend demonstrates heritable adaptations spreading through the population. Choice E tempts by noting thicker shells from higher calcium, a misconception of environmental influence on phenotype without genetic change, confusing plasticity with evolution. A key strategy is to seek evidence of allele frequency shifts across generations to confirm evolutionary dynamics.

Question 14

1. Male frogs called louder on nights with heavy traffic and quieter on nights with less traffic.
2. Allele N increased in frequency from 0.15 to 0.44 across many breeding seasons. (correct answer)
3. Frogs moved closer to vegetation during the day to reduce desiccation in warmer months.
4. Traffic volume increased over the first few years and then remained relatively constant.
5. Individual tadpoles grew faster in ponds with higher algae levels after spring rains.

Explanation: Continuing evolution encompasses genetic adaptations to ongoing environmental challenges, like noise in this frog population. Choice B is correct because allele N for noise-tolerant calls increased from 0.15 to 0.44 over 12 years, suggesting frogs with this allele communicated better amid traffic, leading to more successful breeding. Stable breeding adult numbers and no translocations indicate selection drove this genetic shift. The long-term trend shows heritable changes propagating in the population. Choice A is a tempting distractor, describing variable call volumes based on traffic, but this misconceptions equates behavioral flexibility with evolutionary genetic change. To detect evolution, always check for allele frequency alterations across multiple generations, not situational adjustments.

Question 15

1. Individual weeds produce thicker leaves when grown in sunny parts of the field.
2. The frequency of allele r increases across years in the same field population. (correct answer)
3. Farmers apply herbicide Y at the same time each year during early spring.
4. Some weeds avoid herbicide contact because spray coverage is uneven.
5. Resistant and susceptible weeds can both germinate after heavy rainfall events.

Explanation: This question assesses the skill of understanding continuing evolution, which involves ongoing changes in allele frequencies within a population over generations due to selective pressures. The correct answer, choice B, demonstrates evolution because it shows the frequency of the r allele increasing from 0.05 in 2014 to 0.19 in 2016 and 0.41 in 2019, indicating a population trend toward herbicide resistance under annual applications. This shift reflects natural selection favoring resistant weeds that survive and reproduce more successfully despite herbicide use. Consistent field surveys using the same methods ensure the trend represents genetic change in the population. A tempting distractor is choice A, which describes individual weeds producing thicker leaves in sunny areas, but this is wrong because it represents environmental-induced phenotypic variation, not heritable evolution. To identify evidence of continuing evolution in similar questions, focus on data showing shifts in allele or genotype frequencies over multiple generations rather than short-term individual responses.

Question 16

1. More individual fish express higher detox-enzyme activity after short‑term PCB exposure.
2. The frequency of the D allele increases across years in the same population samples. (correct answer)
3. Some fish move away from the outflow and avoid PCBs during their lifetime.
4. Juvenile fish grow more slowly when raised in PCB-contaminated water.
5. Adult fish develop enlarged livers after living in contaminated water for months.

Explanation: This question assesses the skill of understanding continuing evolution, which involves ongoing changes in allele frequencies within a population over generations due to selective pressures. The correct answer, choice B, demonstrates evolution because it shows the frequency of the D allele increasing from 0.18 in 2005 to 0.31 in 2010 and 0.44 in 2015, indicating a population trend toward higher prevalence of the detox-enzyme variant associated with PCB survival. This shift in allele frequency across years reflects natural selection favoring individuals with the D allele in the contaminated environment, leading to more of them surviving and reproducing. Consistent sampling from the same breeding area ensures this trend represents a genetic change in the population rather than sampling artifacts. A tempting distractor is choice A, which describes individual fish expressing higher enzyme activity after exposure, but this is wrong because it represents phenotypic plasticity or acclimation within an individual's lifetime, not heritable genetic change across generations. To identify evidence of continuing evolution in similar questions, focus on data showing shifts in allele or genotype frequencies over multiple generations rather than short-term individual responses.

Question 17

1. Some lizards darkened slightly after sun exposure each summer, then lightened during cooler months.
2. Predators hunted more actively on darker ground immediately after the fire than before the fire.
3. Allele B increased from 0.30 to 0.67 across multiple breeding seasons in the island population. (correct answer)
4. Individual lizards selected darker basking sites during the day after the wildfire.
5. Lizards grew faster in warm years because higher temperatures increased metabolism.

Explanation: Continuing evolution captures how populations adapt genetically to environmental changes, such as the lizards on this island post-wildfire. Choice C is correct because allele B, linked to brown coloration that likely provides better camouflage on darkened ground, increased from 0.30 to 0.67 over five breeding seasons, showing selective advantage and higher reproduction for brown lizards. Stable census sizes suggest this shift resulted from differential survival and breeding success in the altered habitat. The multi-season trend underscores a genetic response to predation pressure after the fire. Choice A tempts by describing seasonal color changes due to sun exposure, a misconception of phenotypic plasticity mistaken for evolution, as it does not involve heritable genetic alterations. For similar questions, focus on tracking allele frequency changes across generations to confirm evolutionary processes.

Question 18

1. The beetle populations are declining due to the accumulation of harmful mutations caused by long-term pesticide exposure.
2. Individual beetles can change their physiology within their lifetimes to detoxify the pesticides and become permanently resistant.
3. The pesticides act as a selective agent, causing a shift in the allele frequencies of beetle populations toward genotypes that confer resistance. (correct answer)
4. The beetles have reached a state of evolutionary equilibrium where they are no longer affected by environmental changes like pesticide application.

Explanation: The continued application of pesticides creates a strong selective pressure on the beetle population. Beetles with pre-existing genetic variations that confer resistance are more likely to survive and reproduce, passing these traits to their offspring. This leads to a change in the genetic makeup of the population over generations, which is the definition of evolution. Choice A is incorrect; the populations are thriving due to resistance, not declining. Choice B is Lamarckian. Choice D is incorrect as the development of resistance is clear evidence that the population is not in equilibrium and is actively evolving.

Question 19

1. The virus intentionally alters its genetic material to perfectly match the host's cell receptors, ensuring a successful infection.
2. Genomic changes, such as point mutations and reassortment of genetic segments, create new variants that can evade previously acquired immunity in the host population. (correct answer)
3. The virus's evolution slows down once it has successfully adapted to the human host, leading to less virulent strains over time.
4. The annual vaccine development process forces the virus to evolve in a predictable, linear direction towards a single, ultimate form.

Explanation: Influenza's rapid evolution is due to its error-prone replication (causing mutations) and the ability of different strains to swap genetic segments (antigenic shift). These genomic changes create new surface protein structures that are not recognized by the immune systems of people who were previously infected or vaccinated, demonstrating ongoing evolution. Choice A incorrectly implies intent. Choice C is not necessarily true; virulence can fluctuate. Choice D is incorrect because evolution is not directed or linear; it is a response to selective pressures, which can be complex and unpredictable.

Question 20

1. a single species can split into two separate species when a competitor is introduced.
2. populations can exhibit rapid, observable adaptive changes in response to new selective pressures. (correct answer)
3. individual green anoles chose to move to higher perches and grew larger toe pads to survive.
4. the introduced species will eventually cause the complete extinction of the native species.

Explanation: The presence of the brown anole created a new selective pressure (competition for lower perches). In response, the green anole population evolved measurable morphological changes (larger toe pads) in a relatively short time frame, demonstrating that evolution is an ongoing process of adaptation. Choice A describes speciation, which hasn't necessarily occurred here. Choice C is a Lamarckian explanation of acquired traits. Choice D is a possible outcome of competition, but it is not what the evidence provided illustrates about the anoles' evolution.