Do you remember the biology lesson "Systematics and classification of living organisms"? If not, then our article is for you. We will get acquainted with the subject of study of this science and dwell in detail on plant groups and the characteristics by which they are combined.
What is systematics in biology
The variety of living organisms on the planet is simply amazing. Just imagine, in the modern period, scientists know 8.7 million species. They have mastered absolutely all habitats: from water bodies and soil to parasitic existence inside living organisms. Over time, a science arose that was able to streamline this diversity, which greatly simplified the process of studying them.
What is taxonomy? Presentations on biology and various manuals give a lot of definitions to this concept. We will focus on the most accurate. Systematics is the science of the diversity and classification of living organisms. Translated from Greek, this name translates as "ordered."
The first attempts to unite organisms on the basis of common features were made by Aristotle and Theophrastus. Therefore, what is systematics in biology was known in the ancient world.
The founder of taxonomy is considered to be the Swedish scientist Karl Linney. It was he who introduced into science double, or binary, names of plants and animals. To this day, the unit of classification is the species. For example, silver poplar, lemon balm, plantain.
Kingdoms of wildlife
Systematics is a category in biology that unites organisms into groups according to similar characteristics. They are called taxa. The smallest of these is the species, and the highest is the kingdom. Between them are intermediate taxa. For example, in plants it is a genus, family, order, class and department.
There are five kingdoms of wildlife:
- Plants are characterized by an autotrophic way of feeding, the presence of a green pigment of chlorophyll in cells, the ability to photosynthesis, attached lifestyle, unlimited growth.
- Animals by way of feeding are heterotrophs, actively move, increase in size only in a certain period.
- Mushrooms are a group of organisms that occupies an intermediate position between plants and animals. It combines the attributes of both kingdoms. For example, like plants, mushrooms lead an attached lifestyle. At the same time, they feed on prepared organic substances like animals.
- Bacteria are unicellular microscopic organisms that do not have a nucleus.
- Viruses are non-cellular life forms. They are formed by nucleic acid molecules surrounded by a protein coat.
Biology, Grade 6: plant taxonomy
And now we will dwell in more detail on the classification of representatives of the plant kingdom. We already know what systematics in biology are and what characteristic features the representatives of this kingdom differ in. What groups are allocated within it?
Biology and taxonomy of plants considers two of them to be the highest: lower and higher. Plants of the first group do not form real tissues and organs. These include all algae. These are the most primitive plants that first appeared on the planet.
As they land, plants began to form tissues and organs. Without this, their existence under the new conditions would have been simply impossible. So in the process of evolution, higher plants arose.
Lower plants
What is systematics in biology? It is also a science that distinguishes the main characteristic features of organisms. For plants in general, this is an autotrophic method of nutrition, for lower ones, the absence of specialized cells. In algae, they all have the same structure. They are combined only anatomically, but not functionally.
The body of algae is called the terms thallus, slan, or thallus. And instead of roots, they have rhizoids. They can be single and multicellular, as well as colonial. In addition to the chlorophyll pigment, algae can contain dyes of other colors in cells. Depending on this, the departments of Green, Red, Brown, Golden Algae are distinguished. But the representatives of Diatoms are surrounded by a shell of silica. through its openings the metabolic process is carried out.
Higher: characteristic features
The first landlords did not yet have real fabrics. They still had rhizoids, and the shoot was horizontal and forked. In the process of evolution, those representatives of plants whose body assumed a vertical position survived. This provided more effective conditions for photosynthesis. So in higher plants specialized cells and tissues appeared - mechanical, conductive, integumentary and basic.
The most primitive representatives of this systematic unit are the spore. Their modern species are represented by four departments: Moss, Plauno, Horsetail and Fern-shaped. Their common characteristics are the leaf-stem structure of the shoot, reproduction by spores, and alternation in the life cycle of sexual and asexual generations.
Variety of seed
More progressive structural features are seed plants. The name itself speaks of one of the ways of their reproduction. Seeds, unlike spores, have a significant supply of nutrients. They contribute to a more efficient germination and development of young plants.
Within this group of taxonomy, two departments are distinguished: Holo- and Angiosperms. Representatives of the first are spruce, pine, fir, juniper, kinkgo, velvichia. Their seeds develop on the scales of cones openly, barely. This feature defines the name of the taxon. Gymnosperms do not form flowers and fruits; most of them are evergreen.
Angiosperms, or Flowering, are a group of plants that at the present stage occupy a dominant position on the planet. What features of the building made this possible? First of all, this is the presence of a flower that acts as a generative organ in which double fertilization occurs. As a result of this process, fruits are formed within which seeds develop. Such a structure provides protection from adverse conditions, favorable development and distribution of plants.
So, in our article we examined what taxonomy is in biology. This is a science that determines the position of organisms in the organic world system based on certain structural features.