gymnosperm+and+angiosperm

=Plant Kingdom - Slideshow=



Let's take a few minutes to look at plants of the world. What do plants have in common? They have cell walls made of **cellulose** and **chlorophyll** in their cells. That chlorophyll is the key compound involved in **photosynthesis**. Beyond those facts, plants come in a variety of sizes from tiny mosses to redwood trees that are over one hundred feet tall. The giant sequoias are the largest living organisms on Earth while one species of **angiosperm** (flowering plant) can fit into the eye of a needle.

The greatest variation among plants is found in the way they reproduce. Flowers come in thousands of varieties and even simpler **gymnosperms** have thousands of cone types. The most important contribution of plants is their ability to convert carbon dioxide into oxygen through photosynthesis. Not only do animals need the oxygen they produce, but plants also use the oxygen when they perform cellular respiration.

With the exception of a few areas of the planet, you will find plants everywhere. They were colonizing the planet long before the first animals. Through the process of natural selection, plant species adapted to every climate type. They are now able to thrive in areas from under the surface of the ocean to the tops of mountains

=Fern Structures - Plants Slideshow=

Let's take a look at this image of specialized fern structures. The top image should be easy to identify. It's a fully developed **frond** showing the true leaves. The deep green color comes from the chlorophyll in the chloroplasts. Fern leaves and branches are usually called fronds. You will find two types of fern fronds, those that make spores and those that don't. The top example shows no **spores** while the bottom one shows developing spores.

The center image shows a frond unfurling. This structure is called a **fiddlehead**. As the hairy fiddlehead unrolls, the leaves fan out and begin conducting **photosynthesis**.

The bottom image shows a frond that has developed spores. Even though these fronds are reproductive structures, they look almost identical to the true fronds of ferns. Sperms and eggs are released on the leaves. The sperm swim (through a moist surface) and meet up with eggs. The resulting **zygote** can then develop into a new fern. One of the results of this type of fertilization is a clumping of ferns. Plants that might use the wind to spread seeds can release seeds over a greater area. Fern spores tend to land close to the parent plant.