Gymnosperms (lat. Gymnospérmae ) and angiosperms, or flowering (lat. Magnoliophyta ) are two different groups of the plant kingdom (sub-kingdom Higher plants), appearing sequentially in the evolutionary development of nature. They play an important role in the life support of the planet, making up its green cover.
Some representatives of these groups are now completely extinct and belong to the category of fossil deposits. Now on Earth there are both holo- and angiosperms. There are major differences that characterize both groups.
Origin
Origin and age - this is the main difference between gymnosperms and angiosperms. Gymnosperms are a very ancient group of plant organisms. They exist on Earth from the Devonian period (Paleozoic era), it is about 370 million years ago. It is believed that they were descendants of seed ferns (lat. Pteridospermae ) - completely extinct plants, numerous prints of which are often found in deposits of the Late Devonian and Early Cretaceous.
Flowering or angiosperms appeared 120-150 million years ago on the border of the Jurassic and Cretaceous period (Mesozoic era) and quickly occupied a dominant position on the planet. It is believed that their ancestors were ancient gymnosperms.
Variety of species and life forms
Gymnosperms include about 1,000 species that currently exist in nature. Other representatives of this group are completely extinct and are often found by fossil fossils. Life forms are evergreen trees and shrubs, as well as rare vines. The gymnosperm department is represented by several classes:
- Cygnus: Cycas, drooping, stangeria woolly, beating, etc.
- Bennettites: Williamson, Nielsoniopteris (completely extinct class).
- Oppressive: ephedra horsetail, velivicia mirabilis.
- Ginkgo: Ginkgo biloba.
- Conifers: spruce, fir, pine, juniper, cedar, etc.
Significantly greater species diversity is what distinguishes angiosperms from gymnosperms. Angiosperms, there are about 300 thousand species - this is more than half of all plants on the planet. They exist in the form of trees, shrubs, perennial and annual grasses, vines. Their classification is very diverse and complex, namely:
Families:
Cereals: rye, oats, wheat, etc.
Liliaceae: lily, tulip, garlic, onions, etc.
Families:
Solanaceous: potatoes, tobacco, nightshade, dope, belena, etc.
Asters: sunflower, wormwood, dandelion, Jerusalem artichoke, etc.
Legumes: soy, chickpeas, peas, beans, etc.
Cruciferous: cabbage, radish, radish, turnip, etc.
Rosaceae: rose, rosehip, mountain ash, cherry etc.
Reproductive organs
The main difference between angiosperms and gymnosperms is the organ of sexual reproduction. In the first group, this is a flower, in the ovary of which seeds (fruit) are formed after fertilization. It consists of stamens - male genital organs, pestle - female genital organ (the fetus will develop from it), corolla with petals, receptacle and peduncle. The flower varies in shape, color and color depending on the type of plant.
In gymnosperms, this function is performed by a modified shoot - a cone, which can be male or female, which can easily be judged by its size. It is on its scales that the ovules develop, and subsequently a seed is formed.
Fertilization
The process of fertilization is the key that distinguishes gymnosperms from angiosperms. In gymnosperms, it is quite simple. In pollen bags, pollen grains gradually mature, which are then transferred to the female gametophyte. One sperm (male gamete) fertilizes only one egg, after which a seed is formed. The process takes place in the ovules or megasporangia.
In flowering, it happens differently. Here, double fertilization takes place, this is how angiosperms differ from gymnosperms. Briefly, this process was described by the domestic scientist S.G. Navashin in 1898. It occurs as follows: two sperm germinate from the pollen grain into the ovary, one fertilizes the egg, from which the seed develops, the second - the central cell, which gives rise to the endosperm - the supply of nutrients for the embryo.
Fetal education
After fertilization, flowering plants form fruits - what is the difference between angiosperms and gymnosperms. The formation of a fetus with a seed inside occurs by modifying the walls of the ovary. But sometimes perianth, stamens and calyx take part in its formation, it all depends on the type of plant. At this time, the movement of mineral and organic substances in the plant is directed toward the fetus, which can deplete other tissues. Fruits, as well as the species composition of angiosperms, are characterized by a variety of forms.
Gymnosperms differ from angiosperms in the absence of fruits. Their seeds are located openly on the cone scale and are not protected by anything. However, they have special devices that allow them to spread over long distances.
Spread
The method of seed distribution is an important circumstance in which gymnosperms differ from angiosperms. In the first group, this happens in the only way - using the wind. Therefore, the seeds are equipped with outgrowths, appendages of the pterygoid shape and membranous structure. Air movements can spread such seeds over considerable distances, which ensures the expansion of the range of a plant.
In angiosperms, seed distribution methods are more diverse. This occurs with the participation of wind, insects, birds, mammals, people. Some seeds have trailers and outgrowths that can cling to clothing or animal hair and so travel long distances. Many fruits have a sweet, juicy pulp, edible for humans and animals, which also ensures the distribution of seeds.
The structure of conductive tissues
The device of the conductive system is what distinguishes gymnosperms from angiosperms. In older plants, the movement of water and nutrients in the tissues is not intense. The fluid moves slowly along the tracheids - hollow tubes with thick lignified walls and perforated partitions. They are part of the xylem and provide an upward flow of fluid - from roots to leaves. Tracheids are clearly visible when viewed under a microscope.
The angiosperms conduction system is more advanced. In these plants, tracheids were transformed into vessels. These are very long tubes (in some lianas they reach tens of meters), along which an enhanced flow of fluid and nutrients is carried out. This structural feature contributes to a more active course of many important physiological processes in the plant: the formation of chlorophyll, photosynthesis, respiration.
Evolutionary benefits
Gymnosperms exist on Earth much longer than angiosperms. But, despite this, they did not reach the diversity of species and forms characteristic of younger flowering plants. What is the difference between angiosperms and gymnosperms? What advantages allowed them to take a dominant position in the plant world of the planet? There are several points that have determined this, namely:
- the appearance of a flower attractive to insects has increased the plant's chance of pollination;
- variety of pollination options;
- the ovary protects the ovule from possible damage;
- double fertilization allows the seed germ to receive enough nutrition for its development;
- juicy fruit ensures the safety of the seed inside it;
- an increase in seed distribution;
- a variety of life forms (trees, grasses, shrubs) allows you to populate more ecological niches;
- the conducting system is strengthened by vessels, which activates many of the necessary physiological processes of the plant organism.
The main differences. Brief summary
So, what is the difference between gymnosperms and angiosperms? Briefly, the main differences between the representatives of both groups are presented in the table.
Comparative characteristics of bare and angiosperms| Sign | Gymnosperms | Angiosperms |
| Origin | Palaeozoic | Mesozoic era |
| Historical age | About 370 million years | 125-150 Ma |
| Species diversity | About 1000 species | Approximately 300 thousand species |
| Variety of life forms | Mostly trees and shrubs | Trees, Shrubs, Grasses |
| Seed location | Located openly, not protected by anything | Located inside the fetus |
| Pollination | By the wind | Wind, insects, birds, self-pollination |
| Fertilization | Simple | Double |
| The presence of the fetus | Not | there is |
| The movement of water in tissues | By tracheids (slow upward current) | In vessels (enhanced upward current) |
Arisen in an evolutionary way, such devices as seed protection, double fertilization, pollination by insects, as well as a more advanced conductive system, allowed angiosperms to occupy a dominant position on the planet in the world of flora.