Near Manchester, tree bark was blackened by soot. Records of one moth species show the dark form was about 2% of the population in 1848 and about 98% by 1895. Birds hunt these moths by sight on bark. What do the data show?

A farm baited rats with warfarin for 12 years. Of the rats trapped and given a standard dose, 5% survived in year 1, 34% in year 6 and 71% in year 12. What do the data show?

On one mountain, rams with the largest horns were shot by trophy hunters for 30 years. Mean horn length of 4-year-old rams fell from 68 cm to 55 cm over that time. Horn length is inherited. What do the data show?

During 15 years of heavy ivory poaching in one African park, the share of female elephants born without tusks rose from about 19% to about 51%. Tusklessness is an inherited trait. What do the data show?

Myxoma virus was released to control rabbits. Of rabbits infected under test conditions, 1% survived in the first year, 40% five years later and 74% after ten years. What do the data show?

A student grows one bacterial culture on plates holding a low dose of an antibiotic. From equal samples, the drug plate carried 3 colonies at transfer 1, 40 at transfer 5 and 210 at transfer 10. What do the data show?

Hawks and shrikes hunt this lizard by sight from above, on the pale gravel it lives on. Which inherited skin coloring is expected to become more common in the population?

The stem surface shown belongs to a plant of the Sonoran Desert, where rain falls on only a few days a year. Which inherited stem feature does that environment favor?

This small fox lives in the Sahara. Its large thin ears carry many blood vessels close to the surface. Which pressure favored the foxes with the largest ears?

In this habitat the only rich nectar sits at the base of deep tubular flowers. Which inherited bill shape is expected to become more common in the hummingbird population?

These trees grow in soft tidal mud that is waterlogged and low in oxygen, and the tide pushes against them twice a day. Which inherited root feature does this environment favor?

This mouse population lives on pale sand, and owls hunt it by sight. A lava flow leaves part of the range covered in near-black rock, and some mice spread onto it. What is expected in the mice living on the dark rock over many generations?

A farmer sprays the same weedkiller on this field every year. A very small number of the weeds carry an inherited variant that lets them survive the spray. What is expected in the weed population over the next several years?

A fishery's nets keep every cod above a set length and let smaller fish slip through. Age and size at first spawning are inherited. What is expected in the cod population after many generations of this fishing?

After a severe winter storm, the sparrows found dead were mostly the largest and the smallest birds, while the survivors were close to average body size. Body size is inherited. What is expected in this population?

Swallows killed by vehicles have longer wings than the colony average, and shorter-winged birds turn more sharply. Wing length is inherited. What is expected in this bridge-nesting colony over many generations?

This herd's mean coat thickness is greater today than it was 40 generations ago, and the arctic winters across that time were severe. Which statement describes what happened?

Grass now grows on ground left by an old metal mine, where the soil holds metal levels that kill grass from the pasture next door. Which statement describes how the mine population came to tolerate the metal?

Where these newts carry a strong toxin in their skin, the local garter snakes can eat them and survive, while snakes from toxin-free areas cannot. Which statement describes how the local snakes came to tolerate the toxin?

Fish in this cave pool have no working eyes, while fish of the same species in the river above have normal eyes. Which statement describes what happened in the cave population?