Natural Selection and Classification

Xylem is a plant tissue made up of elongated cells stacked end to end the length of the plant’s stem. Which function is xylem specifically adapted to perform in plants?

• Help prevent water loss

• Exchange gases with the atmosphere

• Capture sunlight for photosynthesis

• Transport water from roots to leaves

Leopard seals are animals adapted to survive in the freezing conditions of Antarctica. Individual leopard seals vary in their different traits. Which of the following variations would give a leopard seal the greatest chance of surviving in its harsh environment?

• More spots on its coat

• Thicker layer of blubber

• More elongated head

• Wider, flatter teeth

Peppered moths often hide on white-colored birch trees because they are similarly colored. Which of the following environmental changes would lead to the enhanced survival of darker moths?

• Warm weather causes the birch trees to grow their leaves back early.

• Birch trees become covered in black ash from nearby factories.

• Heavy rainfall causes birch trees to grow taller than normal.

• Disease kills off more than half of the birch tree population.

Several years of drought affect a population of plants in southwest Texas. Which of the following characteristics would you expect to see more frequently in the plants over the next several generations?

• Abundant broad leaves to capture more energy

• Waxy coating on leaves to prevent water loss

• Flowers blooming regularly to increase to seed production

• Tall, narrow stems which are damage easily in high winds

When Charles Darwin visited the Galapagos Islands in the 1800s, he observed many types of organisms that were similar but lived on different islands. The four species of mockingbirds found on the Galapagos Islands are shown. Each species lives on a different island.

These species are very similar, but the Hood mockingbird has a longer beak than the other three species. Which of the following best explains this difference?

• The Hood mockingbird needs a longer beak for defense against predators.

• The Hood mockingbird originated from a different type of bird than the other species.

• The Hood mockingbird’s longer beak is an adaptation to the food available in the bird’s habitat.

• The Hood mockingbird’s beak stretched to reach its food, and the longer beak was passed down to its offspring.

A farmer wants to increase the amount of food produced by corn crops. If the farmer selectively breeds the plants, for which trait should the farmer select?

• Taller stems

• Deeper roots

• Resistance to pesticides

• More cobs on plant

A table of physical traits of chickens is provided. A breeder records the average data on three generations of a chicken population that has been bred. For which trait is the breeder most likely selectively breeding?

• Heavier bodies

• Longer beaks

• More white feathers

• More abundant tail feathers

Some dairy farmers want to increase the amount of milk produced by their cows. How can the farmers use selective breeding to increase milk production?

• By increasing the age of the cows that are bred

• By choosing cows that are high milk producers

• By limiting the number of offspring per cow

• By choosing cows that can produce milk after eating the most food

A chameleon’s camouflage is an example of

• Structural Adaptation

• Behavioral Variation

• Organism Interaction

• Sustainability

All of the following are considered behavioral adaptations EXCEPT –

• Gills on a fish

• Caribou migrating for food sources

• A bear hibernating

• Plant bulbs going into dormancy