Біржасушалы эукариоттың тіршілік циклі презентациясы

Makhambet Utemisov West Kazakhstan State University

Natural – g eographical faculty

Department of biology and ecology

Subject: Systematics of plants

Theme: Life cycle of the Unicellular Eukaryote

Uralsk - 2018

A unicellular organism, also known as a single-celled organism, is an organism that consists of only one cell, unlike a multicellular organism that consists of more than one cell.

Unicellular organisms fall into two general categories:

prokaryotic organisms

eukaryotic organisms.

In prokaryotes and most species of unicellular eukaryotes life cycles are simple. They, as well as ontogenesis, begin with formation of new cell and end with its division. However, in some groups of parasitic unicellular, particularly in Sporozoa , or Apicomplexa (diagram 95), and in many of unicellular algae, such as Chlamydomonas , life cycle passes with alternation of generations. At a certain stage of successive mitotic divisions the cells mutate and turn into gametes that merge (copulate) and form a diploid zygote, immediately passing meiosis (meiosis at the stage of zygote is called zygotic). As a result, four haploid cells are produced that grow into new haploid organisms.

Diagram 95. The life cycle of malaria parasite Plasmodium: 1-2 — the development of Plasmodium in the first stage of the life cycle; 3 — reproduction in liver cells; 4-6 — development in red blood cells; 7- reproduction in red blood cells; 8-9 — development of gametes; 10 — maturation of gametes; 11 — copulation; 12 — zygote; 13-15 — reproduction after fertilization

The word protist is a historical term that is now used informally to refer to a diverse group of microscopic eukaryotic organisms. It is not considered a formal taxonomic term because the organisms it describes do not have a shared evolutionary origin. Historically, the protists were informally grouped into the “animal-like” protozoans, the “plant-like” algae, and the “fungus-like” protists such as water molds. These three groups of protists differ greatly in terms of their basic characteristics. For example, algae are photosynthetic organisms that can be unicellular or multicellular. Protozoa, on the other hand, are nonphotosynthetic , motile organisms that are always unicellular. Other informal terms may also be used to describe various groups of protists . For example, microorganisms that drift or float in water, moved by currents, are referred to as…