Seed plant

Some plants make seeds.

These seeds grow into new plants. Many land plants use seeds. This includes most plants you see.

Some plants have seeds in fruit. These are the flowering plants. Other plants have naked seeds.

These are called gymnosperms. You might see a ginkgo tree. You might see a conifer tree. These plants are very special. They help our world grow.

Seed plants are a large group of land plants.

These plants make seeds to grow new life. Most plants you see on land are seed plants. This group does not include mosses or ferns.

Scientists divide these plants into two main groups. The first group is called gymnosperms. These plants have naked seeds. This means the seeds are not inside a fruit.

You can see gymnosperms in many forms. Cycads are one kind. Ginkgo trees are another. Conifers are also gymnosperms. These are trees or shrubs that grow cones.

The second group is called angiosperms. These are the flowering plants. They are the largest group of seed plants. Angiosperms keep their seeds inside a fruit. Long ago, different plants lived on Earth. Some were called seed ferns. They were one of the first successful land plants. Many of these plants are now extinct. They are no longer living today.

Seed plants are a huge group of land plants. These plants are special because they make seeds. Most of the plants you see on land belong to this group. This category does not include mosses or ferns. Scientists use the name spermatophytes for these plants. They also use the name phanerogams. This word comes from Ancient Greek. It means "visible." This is because their sexual organs are easy to see. This is different from plants with hidden parts.

There are two main ways these plants work. One group is called gymnosperms. These plants have "naked seeds." This means the seeds are not inside a fruit. You can find them in five different divisions. Cycads are one group of these plants. Ginkgo trees are another group with just one living species. Conifers are cone-bearing trees or shrubs. There are also gnetophytes, which include woody plants like Welwitschia. The other group is called angiosperms. These are the flowering plants. They are the largest and most diverse group. They keep their seeds enclosed inside a fruit.

Seed plants have a very long history. A big change happened in their ancestors about 360 million years ago. This was a whole genome duplication event. Scientists found a precursor plant in Belgium. This plant lived about 385 million years ago. It lived 20 million years before the first true seed plants. A plant called Runcaria is a very important find. It had most seed plant qualities but lacked a solid seed coat. It also lacked a way to guide pollen to the seed. Scientists think its shape helped with wind pollination.

Many different types of seed plants lived in the past. One group was called seed ferns. They were very successful land plants in the late Paleozoic. A tree genus named Glossopteris lived in the ancient land of Gondwana. This happened during the Permian period. By the Triassic period, seed ferns were not as important. Gymnosperms became the most common plants after that. They stayed dominant until the end of the Cretaceous period. Then, the flowering plants began to spread quickly. Other extinct groups include the Bennettitales and the Cordaitales.

Learning about seed plants helps us understand nature. You can see these plants in your own backyard. You might see a pine tree with cones. Those are gymnosperms. You might see a bright flower in a garden. Those are angiosperms. Even the trees in a park follow these rules. They use seeds to make sure new life grows. This process has been happening for millions of years. It is how the world stays green and full of life.

Seed plants, also known as spermatophytes, are a major group of land plants. These plants are defined by their ability to produce seeds. This characteristic makes them different from other land plants like mosses, ferns, or algae. Scientists also call them phanerogams, a term from Ancient Greek meaning "visible." This name refers to the fact that their sexual organs are visible. This is the opposite of cryptogams, which have hidden sexual organs.

There are two primary ways these plants organize their seeds. The first group is called gymnosperms, which means "naked seeds." These plants do not enclose their seeds within a fruit. The second group is the angiosperms, also known as flowering plants. Angiosperms are the largest and most diverse group of spermatophytes. Unlike gymnosperms, angiosperms possess seeds that are enclosed inside a fruit.

Gymnosperms are divided into four living groups. The first is Cycadophyta, which contains the cycads. These are typically subtropical or tropical plants.

The second group is Ginkgophyta. This group is unique because it includes only a single living tree species in the genus Ginkgo.

The third group is Pinophyta, known as the conifers. These are mostly cone-bearing trees and shrubs. The fourth group is Gnetophyta. This includes various woody plants like Ephedra, Gnetum, and Welwitschia.

The history of seed plants involves massive evolutionary changes. About 360 million years ago, a whole genome duplication event occurred in a seed plant ancestor. Scientists have identified a precursor to seed plants in Belgium. This plant lived during the middle Devonian period, about 385 million years ago. This was 20 million years before the first true seed plants appeared. One important fossil is Runcaria. It was a small, radially symmetrical plant. It had an integumented megasporangium surrounded by a cupule.

Runcaria provides clues about how seeds first formed. It possessed many seed plant qualities but lacked a solid seed coat. It also lacked a system to guide pollen to the seed. Scientists suspect its shape helped with anemophilous pollination, which is pollination by wind. After Runcaria, plants with more condensed cupules appeared, such as Spermasporites and Moresnetia. By the end of the Devonian period, seed-bearing plants had diversified greatly. Many different types, such as Elkinsia and Warsteinia, existed during this time.

The fossil record shows many extinct seed plant groups. One famous group was the Pteridospermae, or "seed ferns." These were among the earliest successful land plants. They were very common during the late Paleozoic era. A specific tree genus called Glossopteris was very prominent in Gondwana. This was an ancient southern supercontinent during the Permian period. By the Triassic period, seed ferns began to lose their ecological importance. Gymnosperms then became the dominant plants through the end of the Cretaceous period.

During the Cretaceous period, a major shift occurred when angiosperms radiated. This means they spread and increased in variety. Scientists study the relationships between these groups using different methods. Traditional studies used morphology, which is the study of physical shapes. Older studies suggested a close link between gnetophytes and angiosperms due to vessel elements. However, modern molecular studies often show a different relationship. Most current evidence suggests gnetophytes belong in or near the conifers.

Understanding seed plants helps us see how life on Earth changed over millions of years. We can see the results of these ancient shifts in modern forests. The difference between a pine cone and a fruit is a result of these long evolutionary paths. From the ancient seed ferns of the Paleozoic to the diverse flowers of today, seed plants have shaped the land. They represent a successful lineage of vascular plants that continue to dominate our world.