Difference Between Gymnosperm and Angiosperm

Gymnosperm seeds are literally naked. They are carried in cones and are not visible till maturity. There are 4 divisions of non-extinct plants of gymnosperm:

• Pinophyta
• Cycadophyta
• Ginkgophyta
• Gnetophyta 

More than 1000 species of gymnosperms are scattered all over the world with 88 genera. In the Mesozoic era, about 252 to 66 million years ago, gymnosperms were quite abundant on Earth. But, with evolution, some 145 to 66 million years ago, gymnosperms were replaced by highly developed angiosperms. 

Angiosperms are commonly called flowering plants. It is the most diverse and largest group of the Plant Kingdom. There are about 30,000 species of flowering plants on Earth. From the living plants on Earth, angiosperms comprise almost 80 per cent. 

Angiosperms are vascular seeds which contain ovules that would be fertilised and cultivated into a seed. The seed is enclosed inside the ovary which ultimately develops into a fruit. The ovary contains the male or female reproductive organs, or both. Angiosperms are further divided into monocots and dicots.

Difference between gymnosperms and angiosperms

Both gymnosperms and angiosperms are vital groups of vascular plants. The main difference between gymnosperms and angiosperms is how their seeds cultivate. The angiosperm seed is developed inside the ovary which is surrounded by the fruit. In angiosperms, the flowers can be bisexual (containing both male and female parts) or unisexual (flowers with either male or female parts). In gymnosperm, there is no fruit nor flower and their seeds are naked. To carry out pollination, both the angiosperm and the gymnosperm use pollens. Angiosperms have an extraordinary variety of pollination strategies.   

Plants of gymnosperms are mostly shrubs and wood trees. In contrast, angiosperms have a wide variety of plants that include massive trees, climbing vines, annual herbs, etc. Both gymnosperms and angiosperms possess vascular bundles which are xylem and phloem. Angiosperms have well-developed vascular systems as compared to gymnosperms. The only gymnosperm with the climbing vine is Gnetum. Humans consume a vast variety of angiosperm plants. Pine nuts and ginkgo, which are gymnosperms, are of regional significance in some territories. 

Life cycle of a gymnosperm 

The seeds of gymnosperms are partially covered by modified leaves known as sporophylls. A stalk is surrounded by a dense cluster of sporophylls which refers to strobilus. The sporophytic tissue has a layer called integument that consists of megasporangium and embryo.

Gymnosperms possess cone-shaped seeds. In the life cycle of the gymnosperm, the sporophytic phase is dominant. On the sporophytic plant, the gametophyte and young sporophyte develop. It has a haplodiplontic life cycle which means alternation-of-generation. The sporophyte is a diploid phase. Gametophytic generation is relatively short of the sporophytic generation. Megasporangium undergoes meiosis and generates four haploid spores. From these four only one spore exists and represents a megaspore. This megaspore undergoes mitosis to generate a female gametophyte. A spongy and leaf-like organ, called a male cone, possesses a microsporangium. The microsporangium possesses male microspores which undergo meiosis to develop the male gametophyte, pollen. Pollen contains generative cells and pollen tubes.

• Cones develop on a mature sporophyte plant. Inside male cones, there is a male gametophyte which produces male spores. Each gametophyte has various cells containing pollen
• Likewise, female cones possess female gametophytes which have female spores. The female gametophyte has an ovule
• During pollination, pollen is transferred from male cones to female cones. When pollen travels and reaches the egg, fertilisation occurs. This leads to zygote formation
• Inside a seed, this zygote develops further into an embryo
• Next, this seed germinates and develops into a sporophyte tree, hence continuing the life cycle
• On a mature sporophyte plant, the life cycle begin

Examples of gymnosperms

• Conifers: They are the most abundant gymnosperms found under the division Pinophyta. Many species are adapted to cold climatic conditions. Examples include redwood, spruces, pines
• Cycads: They possess compound leaves with a woody trunk. The leaves grow in a rosette manner. They are diecious. Examples include cycadales, cycadopsida
• Ginkgo: These are huge and long trees with fan-shaped leaves. Ginkgo biloba is a living fossil

Example of angiosperms

Conclusion

Angiosperms are the most predominant plants in the world. Angiosperms have seeds, while gymnosperms lack fruit and flowers. Angiosperms are classified as monocots and dicots. Gymnosperms have no further classifications.