# data[].attributes.body
In this recording you will hear what I have learned throughout this project.

# data[].attributes.body
In this project you can hear some on the things I learned wild doing this project.

# data[].attributes.body
One thing I learned is that angiosperm are the second kind of true seed- bearing plant called spermatphytes. And that they could also we know as "flowering plants". I also learned that Even thought gymnosperms also technically have flowers, the angiosperms have a much broader diversity of more obvious flowering structures.

# data[].attributes.body
One thing that I learned they have needle like leaves. I also, learned that there are different types of trees that are called conifers, cycads, Ginkgo, and Gnetophytes. There are also female cones and male cones.

# data[].attributes.body
In the picture it shows that gymnosperms grow seeds in their plants

# data[].attributes.body
In this picture, you can see some different example of angiosperm flowers.

# data[].attributes.body
One thing that I learned about gymnosperms in this article is the definition. The definition of gymnosperms is any vascular plant that reproduces by means of an exposed seed. I also, learned that gymnosperm are reproduced asexual. One more thing that I learned is that in gymnosperms the seed coat is known as the protestant and consists of two layers.

# data[].attributes.attachment_link.readable_text
Gymnosperm, any vascular plant that reproduces by means of an exposed seed, or ovule-unlike angiosperms, or flowering plants, whose seeds are enclosed by mature ovaries, or fruits. The seeds of many gymnosperms (literally "naked seeds") are borne in cones and are not visible until maturity. Taxonomists recognize four distinct divisions of extant (nonextinct) gymnospermous plants- Coniferophyta, Cycadophyta, Ginkgophyta, and Gnetophyta -with 88 genera and more than 1,000 species distributed throughout the world.

Gymnosperms were dominant in the Mesozoic Era (about 252.2 million to 66 million years ago), during which time some of the modern families originated ( Pinaceae, Araucariaceae, Cupressaceae). Although since the Cretaceous Period (about 145 million to 66 million years ago) gymnosperms have been gradually displaced by the more recently evolved angiosperms, they are still successful in many parts of the world and occupy large areas of Earth's surface. Conifer forests, for example, cover vast regions of northern temperate lands, and gymnosperms frequently grow in more northerly latitudes than do angiosperms.

Gerald Cubitt/Bruce Coleman Ltd.

General features

In all living gymnosperm groups, the visible part of the plant body (i.e., the growing stem and branches) represents the sporophyte, or asexual, generation, rather than the gametophyte, or sexual, generation. Typically, a sporophyte has a stem with roots and leaves and bears the reproductive structures. As vascular plants, gymnosperms contain two conducting tissues, the xylem and phloem. The xylem conducts water and minerals from the roots to the rest of the plant and also provides structural support. The phloem distributes the sugars, amino acids, and organic nutrients manufactured in the leaves to the nonphotosynthetic tissues of the plant.

In most gymnosperms the male pollen cones, called microstrobili, contain reduced leaves called microsporophylls. Microsporangia, or pollen sacs, are borne on the lower surfaces of the microsporophylls. The number of microsporangia may vary from two in many conifers to hundreds in some cycads. Within the microsporangia are cells which undergo meiotic division to produce haploid microspores.

wind pollination Robert J. Erwin/Science Source

The gametophyte phase begins when the microspore, while still within the microsporangium, begins to germinate to form the male gametophyte. A single microspore nucleus divides by mitosis to produce a few cells. At this stage the male gametophyte (called a pollen grain) is shed and transported by wind or insects.

Female ovulate cones, called megastrobili, may be borne on the same plant that bears microstrobili (as in conifers) or on separate plants (as in cycads and Ginkgo). A megastrobilus contains many scales, called megasporophylls, that contain megasporangia. Within each megasporangium, a single cell undergoes meiotic division to produce four haploid megaspores, three of which typically degenerate. The remaining megaspore undergoes mitosis to form the female gametophyte. As the number of free nuclei multiplies, the megasporangium and megaspore wall expand. At this stage the ovule is ready to be fertilized.

Before fertilization can take place, however, the mature male gametophyte (the pollen grain) must be transported to the female gametophyte-the process of pollination. In many gymnosperms, a sticky "pollination droplet" oozes from a tiny hole in the female megasporangium to catch pollen grains. The droplet is then resorbed into the megasporangium for fertilization. In other species, the pollen grain settles on the surface of the megasporangium, where the male gametophyte develops further. A pollen tube emerges from the grain and grows through the megasporangium toward the multicellular egg-containing structure called the archegonium. The egg and sperm continue to mature, the nucleus of the latter undergoing additional divisions resulting in two male gametes, or sperm. Interestingly, cycads and Ginkgo are the only seed plants with flagellated sperm. By the time the pollen tube reaches the archegonium, both the egg and sperm are fully mature, and the egg is ready to be fertilized.

In gymnosperms, when the nuclei of the two sperm meet the egg cell, one nucleus dies and the other unites with the egg nucleus to form a diploid zygote. The fertilized egg undergoes mitosis to begin the development of a new sporophyte generation-the multicellular embryo of the seed. Food for the developing embryo is provided by the massive starch-filled female gametophyte that surrounds it. The time interval between pollination and maturation of the embryo into a new sporophyte generation varies among different groups, ranging from a few months to over one year (in pine, for example).

In gymnosperms such as cycads and Ginkgo, the seed coat is known as the sarcotesta and consists of two layers. The sarcotesta is often brightly coloured in cycads and the sarcotesta of Ginkgo seeds is foul-smelling when ripe. The seeds of some conifers have a thin winglike structure that may assist in the distribution of the seed. Others, such as yews, have a fleshy structure, known as an aril, surrounding the seed. The cones of juniper are fleshy and commonly eaten by birds.

aril MPF

At maturity, a gymnosperm embryo has two or more seed leaves, known as cotyledons. Cycads, Ginkgo, and gnetophytes have two cotyledons in the embryo; pine and other conifers may have several (eight is common; some have as many as 18). In cycads and Ginkgo the cotyledons remain within the seed and serve to digest the food in the female gametophyte and absorb it into the developing embryo. Conifer cotyledons typically emerge from the seed and become photosynthetic.

key people

related topics

# data[].attributes.attachment_link.description
Gymnosperm, any vascular plant that reproduces by means of an exposed seed, or ovule-unlike angiosperms, or flowering plants, whose seeds are enclosed by mature ovaries, or fruits. The seeds of many gymnosperms (literally "naked seeds") are borne in cones and are not visible until maturity.

# data[].attributes.body
There are a lot of things that I learned in this article. One of them is that angiosperms reproduce sexually. Another that I learned dis that thee are about 300,000 species of flowering plants. They are the largest and most diverse group within the kingdom Plantae. One more thing that I learned is that angiosperms have evolved specialized cells and tissues that carry out every day functions.

# data[].attributes.attachment_link.readable_text
angiosperm, any of about 300,000 species of flowering plants, the largest and most diverse group within the kingdom Plantae. Angiosperms represent approximately 80 percent of all the known green plants now living. The angiosperms are vascular seed plants in which the ovule (egg) is fertilized and develops into a seed in an enclosed hollow ovary. The ovary itself is usually enclosed in a flower, that part of the angiospermous plant that contains the male or female reproductive organs or both. Fruits are derived from the maturing floral organs of the angiospermous plant and are therefore characteristic of angiosperms. By contrast, in gymnosperms (e.g., conifers and cycads), the other large group of vascular seed plants, the seeds do not develop enclosed within an ovary but are usually borne exposed on the surfaces of reproductive structures, such as cones.

Unlike such nonvascular plants as the bryophytes, in which all cells in the plant body participate in every function necessary to support, nourish, and extend the plant body (e.g., nutrition, photosynthesis, and cell division), angiosperms have evolved specialized cells and tissues that carry out these functions and have further evolved specialized vascular tissues ( xylem and phloem) that translocate the water and nutrients to all areas of the plant body. The specialization of the plant body, which has evolved as an adaptation to a principally terrestrial habitat, includes extensive root systems that anchor the plant and absorb water and minerals from the soil; a stem that supports the growing plant body; and leaves, which are the principal sites of photosynthesis for most angiospermous plants. Another significant evolutionary advancement over the nonvascular and the more primitive vascular plants is the presence of localized regions for plant growth, called meristems and cambia, which extend the length and width of the plant body, respectively. Except under certain conditions, these regions are the only areas in which mitotic cell division takes place in the plant body, although cell differentiation continues to occur over the life of the plant.

The angiosperms dominate Earth's surface and vegetation in more environments, particularly terrestrial habitats, than any other group of plants. As a result, angiosperms are the most important ultimate source of food for birds and mammals, including humans. In addition, the flowering plants are the most economically important group of green plants, serving as a source of pharmaceuticals, fibre products, timber, ornamentals, and other commercial products.

Although the taxonomy of the angiosperms is still incompletely known, the latest classification system incorporates a large body of comparative data derived from studies of DNA sequences. It is known as the Angiosperm Phylogeny Group IV (APG IV) botanical classification system. The angiosperms came to be considered a group at the division level (comparable to the phylum level in animal classification systems) called Anthophyta, though the APG system recognizes only informal groups above the level of order.

Throughout this article the orders or families are given, usually parenthetically, following the vernacular or scientific name of a plant. Following taxonomic conventions, genera and species are italicized. The higher taxa are readily identified by their suffixes: families end in -aceae and orders in -ales.

For a comparison of angiosperms with the other major groups of plants, see plant, bryophyte, fern, lower vascular plant, and gymnosperm.

# data[].attributes.attachment_link.title
Angiosperm | Definition, Reproduction, Examples, Characteristics, Life Cycle, Taxonomy, & Facts

# data[].attributes.attachment_link.description
Angiosperm, any of about 300,000 species of flowering plants, the largest and most diverse group in the plant kingdom. Angiosperms are vascular seed plants in which the ovule is fertilized and develops into a seed in an enclosed ovary. Learn about angiosperm characteristics, evolution, and importance.

# data[].attributes.headline
The Difference between Angiosperms and  Gymnosperms articles #3

# data[].attributes.subject
The Difference between Angiosperms and  Gymnosperms articles #3

# data[].attributes.body
One thing I learned we learn from this article is that angiosperms and gymnosperms are the two major groups of vascular seed plants. Another thing I learn is that the key difference between angiosperms and gymnosperms is how their seeds are developed. I also learned that Gymnosperm seeds are usually formed in unisexual cones, known as strobili, and the plants lack fruits and flowers.

# data[].attributes.attachment_link.readable_text
© Harald Biebel/Fotolia

Angiosperms and gymnosperms are the two major groups of vascular seed plants. Angiosperms, which are flowering plants, are the largest and most diverse group within the kingdom Plantae. With around 300,000 species, they represent approximately 80 percent of all the known green plants now living. Gymnosperms are a smaller, more ancient group, and it consists of plants that produce "naked seeds" (seeds that are not protected by a fruit). There are more than 1,000 species of gymnosperms still found on Earth.

The key difference between angiosperms and gymnosperms is how their seeds are developed. The seeds of angiosperms develop in the ovaries of flowers and are surrounded by a protective fruit. Flowers can be unisexual (e.g., male flowers and female flowers) or bisexual (the flower has both male and female parts). Gymnosperm seeds are usually formed in unisexual cones, known as strobili, and the plants lack fruits and flowers. Both groups use pollen to facilitate fertilization, though angiosperms have an incredible diversity of pollination strategies that are not found among the gymnosperms.

While angiosperms have an enormous variety of body types and forms, ranging from annual herbs to climbing vines to massive trees, gymnosperms are largely woody trees and shrubs. is the only gymnosperm genus with climbing vines. As vascular plants, both groups contain xylem and phloem. All but the most ancient angiosperms contain conducting tissues known as vessels, while gymnosperms (with the exception of Gnetum) do not.

Many ecological niches are filled only by angiosperms. For example, carnivorous plants, submerged aquatic plants, and parasitic plants (with one possible exception) are all flowering plants. Additionally, the vast majority of plants consumed by humans for food are angiosperms, though the seeds of some gymnosperms, such as ginkgo and pine nuts, are of local importance in some places.

# data[].attributes.attachment_link.title
What's the Difference Between Angiosperms and Gymnosperms?

# data[].attributes.attachment_link.description
Angiosperms and gymnosperms are the two major groups of vascular seed plants. Angiosperms, which are flowering plants, are the largest and most diverse group within the kingdom Plantae. With around 300,000 species, they represent approximately 80 percent of all the known green plants now living.

# data[].attributes.headline
The Life Cycle Of An Angiosperms drawing 

# data[].attributes.subject
The Life Cycle Of An Angiosperms drawing 

# data[].attributes.body
Page 153

# data[].attributes.body
Page 156