Resources created or licensed by the Utah Education Network
Vestigial structures are structures or remnants of structures that do not have a function. Whales and pythons have vestigial hind leg bones embedded in their bodies, illustrating that they evolved from four-legged ancestors.
Vestigial structures are structures or remnants of structures that do not have a function. The coccyx, also known as tailbone, is an example of a vestigial structure in humans.
Ancient fossils Darwin found in South America suggested that ancient animals might be related to present-day living organisms.
Animation depicts the route Darwin traveled as he returned home to England in 1836, five years after departing on his trip. The information he gathered on this trip led to the theory of natural selection.
Deserts cover about one-fifth of Earth's surface. Most deserts are located between about 30 degrees north and 30 degrees south latitude.
A lunar eclipse occurs when Earth is directly between the moon and sun. In a lunar eclipse the Earth casts a shadow on the moon, causing part or all of the moon to darken to an orange-red color.
It takes the moon approximately 28 days to revolve around the sun. The moon has four primary phases: new moon, first quarter phase, full moon, and 3rd quarter phase.
A solar eclipse occurs when the moon passes between Earth and then sun, causing the sun's light to be totally or partially blocked by the moon, casting a shadow on a portion of Earth.
As Earth rotates, the moon's strong gravitational force pulls toward it water on Earth's surface that is closest to the moon. The portion pulled toward the moon causes a high tide, which simultaneously occurs on the opposite side of Earth.
If a plant or animal is buried by sediments, two types of fossils may be formed - a mold or a cast.
This map illustrates the huge area covered by the Mississippi watershed.
African savannas are home to huge herds of grazing animials including giraffes and zebras.
Every continent except Antarctica has grasslands. Grasslands vary widely in their appearance, plants, and animals.
When a pollen grain lands on the sticky stigma, it forms a pollen tube through the thin style to the ovary. Once in the ovary, the pollen tube enters the ovule. Two haploid sperm nuclei then enter the embryo sac.
In most bryophytes, the haploid gametophyte phase is dominant. It's what we commonly recognize. Bryophytes tend to produce separate male and female gametophytes.
When a mature spore is released and lands in a suitable location, it develops into a tiny, heart-shaped haploid gametophyte form called a "prothallus."
Pollen is transferred via the wind or by other means from the male pollen cone to the female seed cone. Of the millions of pollen grains released from sporangia, some land on the scales of female cones near an opening called the "micropyle."
Female cones, seen here, possess ovules that produce egg cells.
Gametophytes are quite small in angiosperms and develop in the flower of the sporophyte plant. Female eggs form in ovules inside the ovary of the flower.
In the male reproductive part of the flower, haploid spores called "microspores" are produced in a structure called the "anther." The microspores consist of two-celled male gametophytes that together make up a pollen grain.