Chromosomes are rod-shaped. Most protists are microscopic, but several algae can grow to be several meters in length. Protists are the group of organisms that do not fit into any other category. Protists have varying ways of movement, getting food, and body plans. Most living protists contain mitochondria and some also have chloroplast.
Some of the oldest eukaryotic cells were protists. Protists arose from prokaryotic cells. Scientists hypothesize that protists and other eukaryotes arose from ancient prokaryotes that lived in larger prokaryotes. Over time, the endosymbiotic prokaryotes became organelles. Protists are categorized by traits that make them similar to animal, plant and fungi. They are quite difficult to classify due to their wide degree of variation. Some of the common ways to compare them are listed below: Unicellular and Multicellular
Most protists are unicellular, like Amoeba. Some, like Volvox, form colonies in which several cells are joined into a large body. Some colonies exhibit a division of labor. Some protists can grow to be over 60 meters in length. However, these lack the cellular differentiation found in true tissues and organs. Nutrition
Many protists are autotrophs, and make their own food through photosynthesis. They may use additional pigments with chlorophyll. Some protists are heterotrophs, engulf smaller protists and digest them. Others obtain energy the way fungi do; the enzymes break down cells or bits of food into small molecules that the protists can absorb and use. Motility
Many protists are able to move at some time during their life. Some use whiplike “tail” structures called flagella. Others move with the aid of cilia. Some protists, like amoebas, move by temporarily extending structures called pseudopodia.
Many protists reproduce asexually, performing binary fission to divide into 2 cells, and multiple fission, to divide into more than two cells. During conjugation (sexual), protists join and exchange genetic material stored in a small second nucleus. Then the cells divide.
25.1 Animal-Like Protists
Phylum Protozoa Animal like protists are called protozoa. They move independently, without cilia or flagella, instead using pseudopodia. Pseudopodia are large, rounded cytoplasmic extensions that function both in movement and feeding. Using Pseudopodia to move is called ameboid movement. Sarcodines surround their food with pseudopodia then ingest them. Some sarcodines are covered with calcium carbonate shells, or tests. After many years, these shells become limestone.
Amoeba
Phylum Ciliphora Ciliophora are protists that have cilia. Cilia are short, hairlike projections that aid in movement. The most well known ciliophora is the are those of the genus paramecium. Ciliates have the most elaborate organelles. They have a pellicle (protein layer) around the cell membrane. They have oral groves that lead to the moth pore, then the gullet, then the anal pore. They also have contractile vacuoles which pumps out excess water.
Paramecium
Phylum Sarcomastigophora All members of this phylum have flagella. An example are those of the geus Typanosoma, sleeping sickness, carried by the tsetse fly. They live in water, and the blood of animals. They usually feed on smaller organisms.
Trypanasoma
Phylum Apicomplexa These protists have no means of locomotion. These are mainly diseases and infections. They have a complex life cycle involving sexual and asexual reproduction. These are characterized by an apical complex, a group of organelles specialized for entering host cells and tissues. Many require 2 hosts to complete their life cycles. Apicomplexans have killed more people than any other grup of pathogens on earth. Plasmodium, the carrier of malaria, is an example.
25.1 Plant-Like and Fungus-Like Protists
Many plantlike protest are known as algae. Algae are autotrophic protists. Algae form gametes in single-celled gamete chambers called gametangia. By contrast plants form gametes in multicellular gametangia. Algal cells often countain pyrenoids, structures associated with algal chloroplasts that synthesize and store starch. Photoplankton are unicellular, free-living aquatic algae. Colonial algae, like Volvox, consist of groups of individual cells working in a coordinated manner. Filamentous algae, such as Spirogyra, are multicellular algae that are slender, rod shaped, and made of cells joined end to end. Multicellular algae are usually large and complex and often appear plantlike. The plantlike portion of a seaweed is called a thallus and its cells are usually haploid.
Phylum Chlorophyta (Green Algae) These protists have chlorophylls a and b. They have a wide variety of body forms. Most are aquatic. Some live in coral and others live with fungi to make lichens.
Phylum Phaephyta (Brown Algae) These protists have chlorophylls a and c. Most are marine. They include seaweed and kelp, some growing up to 60 m in length. The thallus is anchored to the bottom by the rootlike holdfast. The stemlike portion of the alga is called the stipe. The leaflike region is the blade.
Phaeophyta
Phylum Rhodophyta (Red Algae) These protists have chlorophylls a and accessory pigments called phycobilins. Most are marine. They include seaweed and kelp, some growing up to 60 m in length. They can live quite deep within the ocean.
Phylum Bacillariophyta (Diatoms) These protists have cell walls consisting of two parts that fit together like a box and lid. Each half is called a valve. Centril diatoms are circular or triangular and are abundant in marine environments. Pennate diatoms have rectangular shells and live in freshwater.
Diatoms
Phylum Dinoflagellata (Dinoflagellates) These protists have two unequal length flagella that are perpendicular to each other. These protists have chlorophylls a and c. These glow in the dark, producing bioluminescence, and are responsible for the red tide, a flood of fish killing toxins.
Red Tide
Phylum Chrysophyta (Golden Algae) These protists have highly resistant cysts that enable them to survive beneath frozen and dry surfaces. These protists have chlorophylls a and c. These live in fresh water, but some are found in marine environments. These store their surplus energy as oil and played a role in the formation of petroleum deposits. Phylum Euglenophyta (Euglenoids) These protists are unicellular flagellated algae called euglenoids. Many are autotrophic but they lack a cell wall and are highly motile. These protists have chlorophylls a and b. They also have eyespots that sense light and can trigger a trophism change. Euglenoids brought up in the light develop chloroplasts, while those in the dark develop mitochondria.
Euglena
There are two groups of funguslike protists: slime molds and water molds. Slime molds are found on decaying matter. They have a stationary reproductive stage in which they produce a funguslike spore bearing structure called a fruiting body. A water mold is a funguslike protist composed of branching filaments of cells.
Phylum Myxomycota (Slime Molds)
This phylum includes about 700 species of plasmodial slime molds. These are masses of cytoplasm while feeding, each containing many nuclei. It travels by cytoplasmic streaming. When food or water is scarce, the plasmodium reproduces, it makes spores, which crack open and give rise to haploid cells that then fuse.
Phylum Dictyostelida (Slime Molds)
This phylum includes cellular slime molds, which live as invidivual hapload cells that move about like amoebas. When food or water is scarce, the cells clump together in a group called pseudoplasmodium. It resembles a slug and also uses fruiting bodies.
Phylum Oomycota (Water Molds)
This phylum contains many parasitic organisms. They reproduce asexually, with zoospores, and sexually, through fertilization tubes that grow between special egg-containing and sperm-containing. This creates a zygote which grows into a mass of filaments.
Phylum Chytridiomycota (Water Molds)
These chtrids are mainly aquatic protists characterized by gametes and zoospores with a single flagellum. Most are unicellular and parasitic. They have funguslike ways of obtaining nutrients, similar cell walls, filamentous bodies, and similar enzymes and biochemical pathways.
*For the protist unit Drije said not to study info on individual phylems like habitat, growth pattern, etc.*
25.1 Characteristics of Protists
Chromosomes are rod-shaped. Most protists are microscopic, but several algae can grow to be several meters in length. Protists are the group of organisms that do not fit into any other category. Protists have varying ways of movement, getting food, and body plans. Most living protists contain mitochondria and some also have chloroplast.
Some of the oldest eukaryotic cells were protists. Protists arose from prokaryotic cells. Scientists hypothesize that protists and other eukaryotes arose from ancient prokaryotes that lived in larger prokaryotes. Over time, the endosymbiotic prokaryotes became organelles. Protists are categorized by traits that make them similar to animal, plant and fungi. They are quite difficult to classify due to their wide degree of variation. Some of the common ways to compare them are listed below:
Unicellular and Multicellular
Most protists are unicellular, like Amoeba. Some, like Volvox, form colonies in which several cells are joined into a large body. Some colonies exhibit a division of labor. Some protists can grow to be over 60 meters in length. However, these lack the cellular differentiation found in true tissues and organs.
Nutrition
Many protists are autotrophs, and make their own food through photosynthesis. They may use additional pigments with chlorophyll. Some protists are heterotrophs, engulf smaller protists and digest them. Others obtain energy the way fungi do; the enzymes break down cells or bits of food into small molecules that the protists can absorb and use.
Motility
Many protists are able to move at some time during their life. Some use whiplike “tail” structures called flagella. Others move with the aid of cilia. Some protists, like amoebas, move by temporarily extending structures called pseudopodia.
Many protists reproduce asexually, performing binary fission to divide into 2 cells, and multiple fission, to divide into more than two cells. During conjugation (sexual), protists join and exchange genetic material stored in a small second nucleus. Then the cells divide.
25.1 Animal-Like Protists
Phylum Protozoa
Animal like protists are called protozoa. They move independently, without cilia or flagella, instead using pseudopodia. Pseudopodia are large, rounded cytoplasmic extensions that function both in movement and feeding. Using Pseudopodia to move is called ameboid movement. Sarcodines surround their food with pseudopodia then ingest them. Some sarcodines are covered with calcium carbonate shells, or tests. After many years, these shells become limestone.
Phylum Ciliphora
Ciliophora are protists that have cilia. Cilia are short, hairlike projections that aid in movement. The most well known ciliophora is the are those of the genus paramecium. Ciliates have the most elaborate organelles. They have a pellicle (protein layer) around the cell membrane. They have oral groves that lead to the moth pore, then the gullet, then the anal pore. They also have contractile vacuoles which pumps out excess water.
Phylum Sarcomastigophora
All members of this phylum have flagella. An example are those of the geus Typanosoma, sleeping sickness, carried by the tsetse fly. They live in water, and the blood of animals. They usually feed on smaller organisms.
Phylum Apicomplexa
These protists have no means of locomotion. These are mainly diseases and infections. They have a complex life cycle involving sexual and asexual reproduction. These are characterized by an apical complex, a group of organelles specialized for entering host cells and tissues. Many require 2 hosts to complete their life cycles. Apicomplexans have killed more people than any other grup of pathogens on earth. Plasmodium, the carrier of malaria, is an example.
25.1 Plant-Like and Fungus-Like Protists
Many plantlike protest are known as algae. Algae are autotrophic protists. Algae form gametes in single-celled gamete chambers called gametangia. By contrast plants form gametes in multicellular gametangia. Algal cells often countain pyrenoids, structures associated with algal chloroplasts that synthesize and store starch. Photoplankton are unicellular, free-living aquatic algae. Colonial algae, like Volvox, consist of groups of individual cells working in a coordinated manner. Filamentous algae, such as Spirogyra, are multicellular algae that are slender, rod shaped, and made of cells joined end to end. Multicellular algae are usually large and complex and often appear plantlike. The plantlike portion of a seaweed is called a thallus and its cells are usually haploid.Phylum Chlorophyta (Green Algae)
These protists have chlorophylls a and b. They have a wide variety of body forms. Most are aquatic. Some live in coral and others live with fungi to make lichens.
Phylum Phaephyta (Brown Algae)
These protists have chlorophylls a and c. Most are marine. They include seaweed and kelp, some growing up to 60 m in length. The thallus is anchored to the bottom by the rootlike holdfast. The stemlike portion of the alga is called the stipe. The leaflike region is the blade.
Phylum Rhodophyta (Red Algae)
These protists have chlorophylls a and accessory pigments called phycobilins. Most are marine. They include seaweed and kelp, some growing up to 60 m in length. They can live quite deep within the ocean.
Phylum Bacillariophyta (Diatoms)
These protists have cell walls consisting of two parts that fit together like a box and lid. Each half is called a valve. Centril diatoms are circular or triangular and are abundant in marine environments. Pennate diatoms have rectangular shells and live in freshwater.
Phylum Dinoflagellata (Dinoflagellates)
These protists have two unequal length flagella that are perpendicular to each other. These protists have chlorophylls a and c. These glow in the dark, producing bioluminescence, and are responsible for the red tide, a flood of fish killing toxins.
Phylum Chrysophyta (Golden Algae)
These protists have highly resistant cysts that enable them to survive beneath frozen and dry surfaces. These protists have chlorophylls a and c. These live in fresh water, but some are found in marine environments. These store their surplus energy as oil and played a role in the formation of petroleum deposits.
Phylum Euglenophyta (Euglenoids)
These protists are unicellular flagellated algae called euglenoids. Many are autotrophic but they lack a cell wall and are highly motile. These protists have chlorophylls a and b. They also have eyespots that sense light and can trigger a trophism change. Euglenoids brought up in the light develop chloroplasts, while those in the dark develop mitochondria.
There are two groups of funguslike protists: slime molds and water molds. Slime molds are found on decaying matter. They have a stationary reproductive stage in which they produce a funguslike spore bearing structure called a fruiting body. A water mold is a funguslike protist composed of branching filaments of cells.
Phylum Myxomycota (Slime Molds)
This phylum includes about 700 species of plasmodial slime molds. These are masses of cytoplasm while feeding, each containing many nuclei. It travels by cytoplasmic streaming. When food or water is scarce, the plasmodium reproduces, it makes spores, which crack open and give rise to haploid cells that then fuse.
Phylum Dictyostelida (Slime Molds)
This phylum includes cellular slime molds, which live as invidivual hapload cells that move about like amoebas. When food or water is scarce, the cells clump together in a group called pseudoplasmodium. It resembles a slug and also uses fruiting bodies.
Phylum Oomycota (Water Molds)
This phylum contains many parasitic organisms. They reproduce asexually, with zoospores, and sexually, through fertilization tubes that grow between special egg-containing and sperm-containing. This creates a zygote which grows into a mass of filaments.
Phylum Chytridiomycota (Water Molds)
These chtrids are mainly aquatic protists characterized by gametes and zoospores with a single flagellum. Most are unicellular and parasitic. They have funguslike ways of obtaining nutrients, similar cell walls, filamentous bodies, and similar enzymes and biochemical pathways.
*For the protist unit Drije said not to study info on individual phylems like habitat, growth pattern, etc.*