Whether they take shape as the elegant petals of a rose, the graceful blooms of the Easter lily or the strange buds of the Christmas cactus, the overwhelming majority -- more than 90 percent -- of plants have flowers. While at first glance they might seem to be nothing more than a beautiful accent or decoration, there is much, much more to these flowering plants than meets the eye.
Chlorophyll is a basic structure contained within all flowering plants, and it's necessary for their survival. This green pigment absorbs sunlight, which is needed by the plants for photosynthesis -- the process by which plants turn raw materials into the life-sustaining nutrients they need.
By extension, chlorophyll is also the lifeblood of every creature on the planet; without chlorophyll there would be no photosynthesis, and with no photosynthesis, there would be no oxygen. Given off as a waste product during the process, flowering plants are the earth's ultimate recyclers. It also serves an important function in the human bloodstream as well, helping increase circulation and speed nutrients on their way to every organ in the body.
It's also what gives plants their green color.
Flowers are the reproductive organs of their respective plants. Most contain both male and female parts of the plant; pollen comes from the male part of the flower, and must be transferred to the female part for the seed to form. Often -- not not in all cases -- the male and female parts must be in different flowers.
This process, called pollination, can take place in a number of ways -- and this is where flowers' decorative nature comes in. The bright colors and sweet smells attract insects and birds. When these creatures land on the flowers, they pick up pollen and take it with them to the next flower they land on. When birds and insects cannot always be relied upon, the wind and rain serve as pollinators.
When most people think of evolution, they think of things becoming more complicated. That's not necessarily the truth with flowering plants, though. In fact, flowering plants have, over millions of years, become less complicated. They have less parts than they used to, as parts fuse together to become less complicated and more compact.
In spite of the fact that the majority of plants are flowering, they haven't been around that long when compared to other types of plants. Fossil records show that conifers have been around for more than 400 million years, where flowering plants are fairly new -- merely about 100 million years old. Their explosive growth rate and diversity is a testament to their success -- flowering plants found something that worked, and stuck with it.
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Flowering plants are categorized based on the number of petals their flowers have.
Trimerous flowers have petals that number in multiples of 3. Tetramerous flowers have petals that number in multiples of 4, while pentamerous flowers are multiples of 5. That's no coincidence.
The numbers are linked with the Fibonacci sequence, a number sequence that turns up repeatedly in the natural world. The Fibonacci sequence -- 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, etc. -- is a series of numbers where each number is the sum of the two numbers preceding it. Without going into too much mathematical detail, the sequence is linked to the circular pattern of many flowers. Having flowers with a particular number of petals fills the available space most effectively -- a lesson that Mother Nature has learned well.
Perhaps the most unusual of all flowering plants are the carnivorous varieties. Carnivorous plants are either active or passive -- the pitcher plant consists of a long, tube-like structure that waits for insects to fall into; once they're in, a lid closes and keeps them inside until they are digested. An example of an active trap can be found in the Venus flytrap, a plant that closes its bladed leaves around an insect when it lands.
It's not only insects that these plants can consume, though. The genlisea, a member of the normally carnivorous bladderwort family, recently became the first flowering plant that was documented to trap and digest microscopic organisms. Growing in areas that are usually lacking in nutrients -- such as rocks and white sand -- the genlisea has yellow or purple flowers. It's the leaves that grow under the ground that secrete a chemical that lures the microscopic organisms to the plant, where they are trapped by tiny hairs and then digested.