Types of Natural Selection

A type of bird, called a black-bellied seed cracker, has either small beaks (better for eating soft seeds) or large beaks (better for eating hard seeds).   A tornado has damaged many of the trees growing large seeds.   

• Directional

• Disruptive

• Stablizing

Tags

NGSS.HS-LS4-4

NGSS.HS-LS2-6

NGSS.HS-LS4-5

Small lizards have difficulty defending territories, but large lizards are more likely to be preyed upon by owls.  Medium lizards have a place to hide. 

• Directional

• Disruptive

• Stabilizing

Tags

NGSS.HS-LS4-4

NGSS.HS-LS2-6

Spotted brown-and-white butterflies blend into lichen-covered tree bark, making it difficult for predators to see them, while solid brown and solid white butterflies are easier to see and get eaten. 

• Directional

• Disruptive

• Stabilizing

Tags

NGSS.HS-LS4-4

NGSS.HS-LS4-2

An area has flowers that are deep, so long beak hummingbirds can get the pollen from the flower.  This area also has flowers that are shallow so short beak hummingbirds can get the pollen from the flower.  There aren’t any flowers for medium beak hummingbirds.

• Directional

• Disruptive

• Stabilizing

Tags

NGSS.HS-LS4-4

NGSS.HS-LS4-2

Panthers with teeth that are too short have difficulty capturing prey, while panthers with teeth that are too long have difficulty chewing their food.  Panthers with medium teeth have plenty of food.

• Directional

• Disruptive

• Stabilizing

Tags

NGSS.HS-LS4-4

NGSS.HS-LS4-2

A certain species of rabbits in a dark, dense forest come in white, light grey, and dark brown fur colors.  Hawks, soaring overhead, often eat the rabbits.  Only one species of rabbits will survive.

• Directional

• Disruptive

• Stabilizing

Tags

NGSS.HS-LS4-4

NGSS.HS-LS4-2

Limpets are marine animals that attach to rocks.  Their color varies from pure white to tan to dark brown. There are two different types of rocks in the area: rocks covered with goose barnacles (also white) and dark-colored rocks.

• Directional

• Disruptive

• Stabilizing

Tags

NGSS.HS-LS4-2

NGSS.HS-LS2-6

In flowers, short flowers have a difficult time getting sunlight; medium flowers get some sun, while tall flowers get plenty of sun.

• Directional

• Disruptive

• Stabilizing

Tags

NGSS.HS-LS4-4

NGSS.HS-LS4-2

Larger squirrels can carry larger acorns to their burrows, and they outcompete medium and smaller squirrels when acorn supplies are limited.

• Directional

• Disruptive

• Stabilizing

Tags

NGSS.HS-LS4-4

NGSS.HS-LS2-6

In a lake in South Africa, guppies are eaten by the pike fish, and the larger the guppy, the more difficulty the guppies have escaping its pike fish predator.

• Directional

• Disruptive

• Stabilizing

Tags

NGSS.HS-LS4-4

NGSS.HS-LS2-6