Gymnosperms (lat. Gymnospérmae) and angiosperms, or flowering (lat. Magnoliophyta) are two different groups of the plant kingdom (sub-kingdom Higher plants), which appeared 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 have existed on Earth since the Devonian period (Paleozoic era), which is about 370 million years ago. It is believed that they were descendants of seed ferns (lat. Pteridospermae) -completely extinct plants, numerous imprints 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.
Diversity of species and forms of life
Gymnosperms number approximately 1,000 species currently existing in nature. Other representatives of this group are completely extinct and are often found by paleontologists in fossil form. Life forms - evergreen trees and shrubs, as well as rare creepers. Gymnosperms are represented by several classes:
- Cycads: drooping cycad, woolly stangeria, bovenia, etc.
- Bennettites: Williamsonia, Nilsoniopteris (completely extinct class).
- Gnetovye: ephedra horsetail, Velichia mirabilis.
- Ginkgo: Ginkgo biloba.
- Conifers: spruce, fir, pine, juniper, cedar, etc.
Significantly greater species diversity is what distinguishes angiosperms from gymnosperms. There are about 300 thousand species of angiosperms - this is more than half of all plants on the planet. They exist in the form of trees, shrubs, perennial and annual herbs, vines. Their classification is different.great variety and complexity, namely:
Class Monocots:
Families:
Grains: rye, oats, wheat, etc.
Lilies: lily, tulip, garlic, onion, etc.
Class Dipartite:
Families:
Solanaceae: potatoes, tobacco, nightshade, dope, henbane, etc.
Asteraceae: sunflower, wormwood, dandelion, Jerusalem artichoke, etc.
Beans: soybeans, chickpeas, peas, beans, etc.
Cruciferous: cabbage, radish, radish, turnip, etc.
Rosaceae: rose, wild rose, rowan, 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, pistil - female genital organ (the fruit will develop from it), corolla with petals, receptacle and pedicel. 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, as can be easily judged by its size. It is on its scales that the ovules develop, and subsequently the seed is formed.
Fertilization
The process of fertilization is the key difference between gymnosperms and angiosperms. In gymnosperms, it is quite simple. In pollen bagsthere is a gradual maturation of pollen grains, 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.
Flowers are different. Double fertilization takes place here, this is how angiosperms differ from gymnosperms. Briefly, this process was described by the domestic scientist S. G. Navashin in 1898. It happens as follows: two sperm germinate from the pollen grain inside the ovary, one of them fertilizes the egg from which the seed develops, the second - the central cell that gives rise to the endosperm - the supply of nutrients for the embryo.
Fetal formation
After fertilization, flowering plants form fruits - what distinguishes angiosperms from gymnosperms. The formation of a fetus with a seed inside occurs by modifying the walls of the ovary. But sometimes the 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 towards the fetus, which can deplete other tissues. Fruits, like 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 scale of the cone and are not protected by anything. However, they have special devices that allow them to extend tolong distances.
Distribution
The method of seed dispersal is an important circumstance that distinguishes gymnosperms from angiosperms. In the first group, this happens in the only way - with the help of the wind. Therefore, the seeds are equipped with outgrowths, wing-shaped appendages and a membranous structure. Air movements are able to spread such seeds over considerable distances, which ensures the expansion of the range of a particular plant.
In angiosperms, seed dispersal methods are more diverse. This happens with the participation of wind, insects, birds, mammals, people. Some seeds have attachments and outgrowths that can cling to clothing or animal hair and thus travel long distances. Many fruits have a sweet, juicy pulp that is edible for humans and animals, which also enables seed dispersal.
Structure of conductive tissues
The structure of the conducting system is what distinguishes gymnosperms from angiosperms. In older plants, the movement of water and nutrients in 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 the roots to the leaves. Tracheids are clearly visible when viewed under a microscope.
Conducting systemangiosperms is more perfect. In these plants, tracheids were transformed into vessels. These are very long tubes (in some vines they reach tens of meters), through which an enhanced flow of fluid and nutrients is carried out. This feature of the structure contributes to a more active flow of many important physiological processes in the plant: the formation of chlorophyll, photosynthesis, respiration.
Evolutionary advantages
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. How do angiosperms differ from gymnosperms? What advantages allowed them to occupy a dominant position in the plant world of the planet? There are several points that determined this, namely:
- The appearance of a flower attractive to insects has increased the plant's chances of pollination;
- variety of pollination options;
- ovary protects the ovule from possible damage;
- double fertilization allows the germ of the seed to receive enough nutrition for its development;
- juicy fruit keeps the seed inside;
- increasing ways to distribute seeds;
- diversity of life forms (trees, grasses, shrubs) allows you to populate more ecological niches;
- the conductive system is strengthened by blood vessels, which activates many necessary physiological processes of the plant organism.
Main differences. 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.
| Sign | Gymnosperms | Angiosperms |
| Origin | Paleozoic era | Mesozoic era |
| Historical age | About 370 Ma | 125-150 Ma |
| Species diversity | About 1000 kinds | Approximately 300 thousand species |
| Diversity of life forms | Mainly trees and shrubs | Trees, shrubs, herbs |
| Seed position | Open, unprotected | Located inside the fruit |
| Pollination | Wind-blown | Wind, insects, birds, self-pollination |
| Fertilization | Simple | Double |
| Presence of fetus | No | Yes |
| Movement of water in tissues | By tracheids (slow upward current) | Through the vessels (amplified upward current) |
Evolutionarily evolved adaptations such as seed protection, double fertilization, insect pollination, and an improved vascular system have allowed angiosperms to dominate the planet's flora.
