Helpful hawks leave more offspring than clumsy hawks.

VHD — Vampire Hippos Dance.

A flock has hawks with slightly different wing shapes. In windy cliffs, the sharper-winged birds catch more prey and raise more chicks. Over generations, that wing shape becomes more common.

Which statement best describes natural selection?

A. Random changes in traits always increase fitness in every environment.

B. Individuals with heritable traits that improve reproductive success leave more offspring.

C. Populations change because organisms need traits and then pass them on.

D. All individuals in a species gradually become identical to the best-adapted type.

Helpful hawks leave more offspring than clumsy hawks.

VHD — Vampire Hippos Dance.

A flock has hawks with slightly different wing shapes. In windy cliffs, the sharper-winged birds catch more prey and raise more chicks. Over generations, that wing shape becomes more common.

Which statement best describes natural selection?

A. Random changes in traits always increase fitness in every environment.

B. Individuals with heritable traits that improve reproductive success leave more offspring.

C. Populations change because organisms need traits and then pass them on.

D. All individuals in a species gradually become identical to the best-adapted type.

Helpful hawks leave more offspring than clumsy hawks.

VHD — Vampire Hippos Dance.

A flock has hawks with slightly different wing shapes. In windy cliffs, the sharper-winged birds catch more prey and raise more chicks. Over generations, that wing shape becomes more common.

Which statement best describes natural selection?

A. Random changes in traits always increase fitness in every environment.

B. Individuals with heritable traits that improve reproductive success leave more offspring.

C. Populations change because organisms need traits and then pass them on.

D. All individuals in a species gradually become identical to the best-adapted type.

Helpful hawks leave more offspring than clumsy hawks.

VHD — Vampire Hippos Dance.

A flock has hawks with slightly different wing shapes. In windy cliffs, the sharper-winged birds catch more prey and raise more chicks. Over generations, that wing shape becomes more common.

Which statement best describes natural selection?

A. Random changes in traits always increase fitness in every environment.

B. Individuals with heritable traits that improve reproductive success leave more offspring.

C. Populations change because organisms need traits and then pass them on.

D. All individuals in a species gradually become identical to the best-adapted type.