Kingdom Protista Flashcards
The term ‘Protista’ is derived from the Greek word “_____”, meaning “the very first”.
• Protists are simple eukaryotic organisms that are neither plants nor animals or fungi.
• Scientists speculate that protists form a link between plants, animals and fungi as these three kingdoms diverged from a common protist-like ancestor, billions of years ago
These are usually aquatic, present in the soil or in areas with moisture.
• Most protist species are unicellular organisms, however, there are a few multicellular protists.
• Just like any other eukaryote, the cells of these species have a nucleus and membrane bound organelles.
Protistos
NUTRITIONAL
CLASS OF PROTISTS
Autotrophic
Heterotrophic
Mexotrophic
TYPES OF PROTIST
Animal-like:
Protists
Heterotrophs and motile
Plant-like:
Protists
Autotrophs with the capability to carry out photosynthesis
Fungi-like Protists:
Heterotrophs and characteristically have cell walls in the cells and spores formation is the
reproduction method
In this mode, the organisms prepare their food from CO2 and water by utilizing sunlight with the help of
photosynthetic pigments like chlorophyll. The process is called photosynthesis.
Examples are din flagellates, diatoms and euglenoids.
Photosynthetic (Holophytic)
In this mode, the individual captures and ingests the food like animals. It is found in many protozoans like
Amoeba and Paramecium.
Holozoic or
Zoo-Trophic (Ingestive, Phagotrophic)
In this mode, the organism releases enzymes into the surroundings where the enzymes convert organic matter into simpler products.
These products are then absorbed through body surface of the organism.
Saprobic nutrition is found in
slime moulds.
Saprobic or
Saprotrophic
Some protists get their food from the body of other organisms. The individual which obtains its food is called parasite and the organism from which parasite gets food is called host.
Trypanosoma, Giardia, Entamoeba, Plasmodium are some examples of parasites.
Parasitic
It is a mixed type in which the organism can perform two kinds of nutrition. For example, in Euglena nutrition is both holophytic and saprobic.
Mixotrophic
Zoo flagellates, Trichonympha, and Lophomonas live as a symbiont in the intestine of termites and wood roaches respectively. Both Trichonympha and Lophomonas secrete cellulose digesting enzymes which convert cellulose into glucose. The digested food (glucose) is shared by both zoo
flagellates
d the hosts.
Symbiotic
Soluble organic substances and salts are known to be absorbed in Amoeba and others through pinocytosis.
Pinocytosis
ASEXUAL
MODE
Binary Fission- The parent body divides into two equal daughter cells by undergoing mitosis. Examples: Amoeba, Euglena, and Paramecium.
Multiple Fission-Here, the parent cell divides into a number of daughter cells.
Examples: Amoeba and
Plasmodium.
Plasmotomy-This mode of asexual reproduction is seen in the multinucleate protists.
In this mode, the multinucleate parent cell undergoes division to form two or more multinucleate offspring. However, in this process, only the division of the cytoplasm occurs There is no division of the nucleus. Example: Opalina.
Spore Formation- Some protists form spores by asexual reproduction in order to withstand unfavorable or undesirable environmental conditions. Once spores are exposed to the optimum conditions, they germinate and form new progeny. Example: slime molds.
BUDDING- A small outgrowth or protrusion develops on the body of the parent cell which eventually pinches off to form a new organism. Example:
Arcella (a sarcodine).
SEXUAL
MODE
Meiosis- It is the essential part of the sexual mode of reproduction, wherein the number of chromosomes is reduced from 2n (diploid) to n (haploid). This step of reduction of the number of chromosomes is essential to keep the number of chromosomes constant in the progeny of a species.
Fertilization-also known as generative fertilisation, syngamy and impregnation, is the fusion of gametes to give rise to a zygote and initiate its development into a new individual organism or offspring
ECOLOGICAL
IMPORTANCE OF PROTISTS
KINGDOM
Protists form the foundation of the food chain.
The protist feeds upon the bacteria and microbes and thus controls the population of bacteria and microbes.
The autotrophic protists carry out almost 40% of the world’s total photosynthesis and help in reducing global carbon dioxide and fixing carbon.
The molds are primary decomposers in soil, especially in forests, and feed upon bacteria, fungi, etc.
EXAMPLES OF
PROTISTS
KINGDOM
PROTISTA
АМОЕВА
Amoeba is an animal-like protist that can be found in soil as well as in freshwater and marine environment.
Amoeba is unicellular and lack flagella.
Amoeba move by forming specialised cytoplasmic projections called pseudopodio.
PARAMECIUM
Paramoecium is also an animal-like protist that belong to Ciliate class of protozoa.
Paramoecium is a unicellular eukaryote.
In Paramecium the surface of the cell is covered with several fine, short, hair like structures called Cilia which help paramecium in motility and also in ingesting their tood.
ALGAE
Algae are plant like photosynthetic protists carrying out probably 50→60% of all photosynthesis on earth. Algae exhibit a remarkable rate of growth forms. Some are unicellular other are filamentous.
Almost all the algae are aquatic but when actively growing, algae are restricted to damp environments.
