15.1
15.2
15.3
16.1
16.2
16.3
16.4
100
A population of rabbits living in snowy environments gradually became mostly white over many generations. Explain why this change occurred.
White rabbits had better camouflage in the snow, allowing them to survive and reproduce more successfully. Over time, the allele for white fur became more common through natural selection.
100
A bacterial population becomes resistant to antibiotics after repeated exposure. Explain how mutations contributed to this change.
Random mutations created antibiotic-resistant bacteria. Antibiotics killed non-resistant bacteria, while resistant bacteria survived and reproduced.
100
A hurricane randomly kills most members of a lizard population. The remaining survivors have reduced genetic diversity. Identify this evolutionary mechanism.
Genetic drift.
100
Two frog species reproduce during different seasons even though they live in the same habitat. Identify this type of reproductive isolation.
Temporal isolation
100
A species disappears permanently after all individuals die. Identify this process.
Extinction
100
Large amounts of fertilizer enter a lake, causing algae growth and fish deaths. Identify this type of pollution.
Water pollution caused by nutrient runoff.
100
A bridge is built over a highway to allow animals to safely cross between habitats. Identify this conservation strategy.
Wildlife Corridor
200
Farmers selectively breed corn plants that produce larger kernels. Explain why this process is considered artificial selection rather than natural selection.
Humans are intentionally choosing which organisms reproduce based on desirable traits, instead of the environment determining survival and reproduction.
200
A graph shows that birds with medium-sized beaks survive less successfully than birds with either very small or very large beaks. Identify the type of selection occurring.
Disruptive selection.
200
A small group of birds migrates to an island and starts a new population with different allele frequencies than the mainland population. Identify this process.
Founder Effect
200
A mountain range separates a squirrel population into two groups. Over time, the populations become different species. Identify this process.
Allopatric speciation.
200
A highway divides a forest into smaller isolated habitats, reducing animal movement between populations. Identify this environmental issue.
Habitat fragmentation.
200
Explain how deforestation contributes to climate change.
Trees remove carbon dioxide through photosynthesis. Removing forests increases atmospheric carbon dioxide levels and reduces carbon storage.
200
Explain why recycling is considered a sustainable practice.
Recycling reduces waste and conserves natural resources by reusing materials instead of constantly extracting new resources.
300
Two bird populations of the same species live in different environments. One population develops thick beaks while the other develops narrow beaks. Identify one environmental factor that could explain this difference.
Different food sources could select for different beak shapes. Hard seeds favor thick crushing beaks, while insects favor narrow pointed beaks.
300
During a drought, plants producing larger seeds become more common. Over time, birds with larger beaks dominate the population. Explain why.
Birds with larger beaks could eat the larger seeds more efficiently, improving survival and reproduction. Their alleles became more common through directional selection.
300
Explain why small populations are more affected by genetic drift than large populations.
Small populations contain fewer individuals and fewer alleles, so random events have a greater impact on allele frequencies and genetic diversity.
300
Explain how adaptive radiation increases biodiversity.
One ancestral species evolves into many species adapted to different niches, increasing the number of species and ecological roles.
300
Explain why invasive species often reduce biodiversity in ecosystems.
Invasive species compete with native species for resources and often lack predators, allowing them to overpopulate and disrupt ecosystems.
300
A graph shows human population growth increasing exponentially over time. Explain how this trend affects natural resources.
Growing populations increase demand for food, water, energy, and land, causing faster depletion of natural resources.
300
Wetlands naturally filter pollutants from water before the water enters rivers and lakes. Identify this type of ecosystem service.
Regulating service.
400
Explain why adaptations are considered evidence for evolution.
Adaptations develop over generations as populations respond to environmental pressures. The presence of specialized traits suggests populations changed over time through natural selection.
400
Explain why the Hardy-Weinberg principle rarely occurs in natural populations.
Natural populations experience mutations, migration, natural selection, non-random mating, and changing population sizes, which all cause evolution to occur.
400
A population of flowers receives pollen from a nearby population with different alleles. Explain how gene flow affects genetic diversity.
Gene flow introduces new alleles into the population, increasing genetic diversity.
400
Hummingbirds evolved long beaks while flowers evolved deeper tubes containing nectar. Explain how this is an example of coevolution.
Each species influenced the evolution of the other. Flower shape favored birds with long beaks, while birds favored flowers matching their feeding structures.
400
After a mass extinction event, biodiversity eventually increases. Explain why.
Surviving organisms diversify to occupy empty ecological niches left by extinct species through adaptive radiation.
400
Factories release sulfur dioxide into the atmosphere. Explain one environmental consequence of this pollution.
Sulfur dioxide contributes to acid rain, which damages forests, aquatic ecosystems, and soil quality.
400
Explain how reforestation helps reduce environmental degradation.
Planting trees restores habitats, reduces erosion, absorbs carbon dioxide, and increases biodiversity.
500
Scientists discovered two species with similar bone structures but different functions. Explain how this observation supports the theory of evolution.
Similar structures suggest common ancestry. The organisms likely evolved from the same ancestor but adapted differently due to different environmental pressures.
500
A population contains 80 red flower alleles and 20 white flower alleles. Calculate the frequency of the white allele.
Total alleles = 100
White allele frequency = 20/100 = 0.20 or 20%
500
Male peacocks with large colorful tails are more successful at attracting mates despite being more visible to predators. Explain why this trait remains common.
The trait increases reproductive success through sexual selection, allowing those alleles to be passed on more frequently.
500
Explain how reproductive isolation can eventually lead to speciation.
When populations stop interbreeding, mutations and natural selection cause genetic differences to accumulate over time until they can no longer produce fertile offspring.
500
Northern white rhinos are critically endangered due to habitat loss and poaching. Explain two ways this decline can negatively affect ecosystems.
Loss of biodiversity can disrupt food webs and reduce ecosystem stability. The loss of large herbivores may also alter plant populations and nutrient cycling.
500
Explain how ocean acidification can threaten marine biodiversity.
Increased carbon dioxide lowers ocean pH, making it difficult for shell-building organisms like coral and shellfish to survive, disrupting marine food webs.
500
A city replaces fossil fuel energy with solar and wind power. Explain two environmental benefits of this change.
Air pollution and greenhouse gas emissions decrease, helping slow climate change and reducing damage to ecosystems and human health.