Plant-like
protists are autotrophic. They can live
in soil, on the bark of trees, in fresh water, and in salt water. These protists are very important to the
Earth because they produce a lot of oxygen. These plant-like protists can be
unicellular, multicellular, or live in colonies. The plant-like protists are divided into four
basic groups: euglenoids, dinoflagellates, diatoms and algae.
Euglenoids: These protists are autotrophs when its sunny and heterotrophs when its dark. They are unicellular organisms and are mostly found in freshwater. Some may have a flagellum that helps them move. Ex.The euglena protist has three methods of nutrition. The first is holozoic, which is obtaining nutrition from other organisms or organic matter. The second is saprophytic, which is the feeding, absorbing or growing upon decaying organic matter. The last method is holophytic, which uses chemical elements to synthesize complex organic compounds by photosynthesis.
Dinoflagellates: These protists have two flagella and are unicellular. They are found in the ocean and are covered by stiff plates. They also may glow in the dark. Dinoflagellates can reproduce asexually or sexually. Dinoflagellates have a life-cycle that usually involves asexual reproduction by binary fission. Sexual reproduction also occurs and is only known in a small percentage of dinoflagellates.This takes place by fusion of two individuals to form a zygote. This zygote may later form a resting stage that is called a dinoflagellate cyst.
Diatoms: These protists are unicellular, although they can exist as colonies. Diatoms are producers within the food chain. A unique feature of diatom cells is that they are enclosed within a cell wall made of silica called a frustule. These are the glass-like cell walls. Diatoms live in the water and require light for photosynthesis. Perhaps the most studied group of diatoms belong to the phytoplankton. Phytoplanktonic diatoms rely on ocean currents and wind to keep them in the upper oceanic levels as their cell wall is denser than water around them. They would naturally sink otherwise. The frustule has small pores that allows the diatoms to dispose of their waste. This helps them maintain homeostasis because the removal of waste allows them to have a normal pH level.
Euglenoids: These protists are autotrophs when its sunny and heterotrophs when its dark. They are unicellular organisms and are mostly found in freshwater. Some may have a flagellum that helps them move. Ex.The euglena protist has three methods of nutrition. The first is holozoic, which is obtaining nutrition from other organisms or organic matter. The second is saprophytic, which is the feeding, absorbing or growing upon decaying organic matter. The last method is holophytic, which uses chemical elements to synthesize complex organic compounds by photosynthesis.
Dinoflagellates: These protists have two flagella and are unicellular. They are found in the ocean and are covered by stiff plates. They also may glow in the dark. Dinoflagellates can reproduce asexually or sexually. Dinoflagellates have a life-cycle that usually involves asexual reproduction by binary fission. Sexual reproduction also occurs and is only known in a small percentage of dinoflagellates.This takes place by fusion of two individuals to form a zygote. This zygote may later form a resting stage that is called a dinoflagellate cyst.
Diatoms: These protists are unicellular, although they can exist as colonies. Diatoms are producers within the food chain. A unique feature of diatom cells is that they are enclosed within a cell wall made of silica called a frustule. These are the glass-like cell walls. Diatoms live in the water and require light for photosynthesis. Perhaps the most studied group of diatoms belong to the phytoplankton. Phytoplanktonic diatoms rely on ocean currents and wind to keep them in the upper oceanic levels as their cell wall is denser than water around them. They would naturally sink otherwise. The frustule has small pores that allows the diatoms to dispose of their waste. This helps them maintain homeostasis because the removal of waste allows them to have a normal pH level.