2. A. INTRODUCTION
In five kingdom classification system designed by Whittaker.
Protist are put in a sepparate kingdom. Protozoa, the animal like
protist, are also put in this kingdom and separated from its usual place
in the animal kingdom. The same goes for plant like protist. The term
Protist was first used by Ernest Haeckel.
3. B. PROTIST CHARACTERISTIC
Protist are a group of eukaryotic organism, either unicelluler or
multicellular and have not yet shown real tissue differentiation.
The characteristics of protists are :
1. Most are one-celled, but some have many cells.
2. Cells have a membrane arround the nucleus (eukaryotic).
3. Some get nutrients and energy by eating other organisms.
4. Some get energy from the sun, and nutrients from the water.
5. Most reproduce by splitting in two
6. Examples are paramecium, amoeba, and kelp
4. C. THE MEMBER OF PROTIST
The members differ from one another in morphology and how they live.
There are those with fungi , animal, or plant characteristic.
1. Fungus-like Protists
Fungus like protist consist of water molds and slime molds.
Fungus-like protist characteristics have structure to produce spore,
heterotrophic.
Characteristic Fungus-like Protist :
Live in water or moist environments
Look like tini threads with a fuzzy covering
Attack food such as potatoes, cabbage, and corn and can destroy
whole crops
Live in moist soil and on decaying plants and trees
Very colorful
Move by forming pseudopods
5. Fungus-like protists are heterotrophic, they cannot make their own food, and
thus they must be able to move at some point in their lives. These protists contain
long hyphae-like strands thus they contain the physical appearance of fungi. The
difference lies in that the hyphae of fungi are white while the hyphae of protists are
usually bright in color.
The fungus-like protists can act as decomposers. They break down dead
organisms by releasing digestive enzymes into the dead organism. In the end
materials useful to other living organisms are released into the surrounding
environment.
Water Molds (oomycota)
Water molds are fungus-like protists that live in moist environments. They look
like tiny threads with a hazy covering (when in a damp environment). Most water
molds are decomposers, breaking down dead organisms; few water molds are
parasites, living in or on other organisms.
6. Water molds attack foods such as potatoes, cabbage, and corn. They are capable of
completely destroying crops. An example of the devastation a water mold is capable of
doing happened between the years of 1845 and 1860. The growing seasons at this time
was a cold and damp one; these are conditions that encourage the spread of the water
mold Phytophthora infestans. This water mold is the cause of rotting potato plants (late
blight). It infested all of the potato crops in Ireland. During this period one third of
Irelands population died; they either starved to death or were killed by the infested
potatoes.
7. Slime molds (Myxomycota)
Gb. Dictyostellium discoideum
Slime molds are a fungus-like protist that lives in moist soil, decaying plants, and
trees. They have a very bright appearance.
Slime molds are single celled organisms. When conditions become unfavorable
the single celled organisms join together and act like a "multi-cellular"
organism. The protists will then form a sporangia-a cluster of cells on top of a
stalk. The sporangia consist of living cells in a dormant stage, while the stalk
consists of dead cells that act as a foot and push the cells to favorable conditions.
When conditions become favorable the "multi-cellular" organism separates itself
back into the single celled organisms.
8. The new communal structure produces a slimy covering and is called a slug because
it so closely resembles the animal you sometimes see gliding across sidewalks. The
slug oozes toward light. When the communal cells sense that they've come across
more food or better conditions, the slug stops. An example : Dictyostellium
discoideum
3. Animal-like protist
Animal-like protists are called protozoans ("first animals") because it is thought
that they are the evolutionary history of animals. They share many common traits
with animals. All of the animal-like protists are heterotrophs; they are unable to
make their own food. But unlike animals, they are unicellular. Since they can’t make
their own food they must be able to move through their environment and catch
their food.
The animal-like protists are divided into four groups based upon their means of
mobility and manners for catching their food. They are divided into: protists with
pseudopods, protists with cilia, protists with flagella, and parasitic protists.
9. 1. Protists with Pseudopods :
A pseudopod is a "false foot" that slowly moves the protist. These protists
move towards their food or prey by extending their cytoplasm into a "false foot". The
"false foot" extends from the cytoplasm, attaches to the ground, and pulls the rest of the
body toward the food. The pseudopods are not only for the means of locomotion; they
also capture the food. They capture the food by wrapping the "false foot" around the
prey and bringing it into their bodies. One example of an animal-like protist with
pseudopods is the Amoeba (see picture above).
Gb. Amoeba Proteus
amoebas are single celled animal-like protists that live in moist soil, freshwater, and salt
water. There are different types of Amoeba but they all use pseudopods as means of
locomotion and capturing food. Most of the Amoebas are free-living and eat things like
other protozoans and bacteria; few Amoebas are parasitic and live on or in other
organisms, where they obtain nutrients.
10. An example of an Amoeba is Entamueba histolytica. This Amoeba is the cause of
amoebic dysentery, which is a deadly infectious disease found mostly in tropical
areas and usually in areas where sanitation is poor. This disease is the leading cause
of death for infants and toddlers; their immune systems are not yet developed,
therefore they cannot destroy the disease.
11. 2. Protists with Cilia
Cilia are tiny hair-like structures that surround some protists. The cilia beat back and
forth. This movement enables the animal-like protist to move through its aquatic
environment. The cilia also help the organism capture food. When the cilia beat, the
prey (food) is moved into its body.
Cilia are composed of ten pairs of microtubules. The microtubules are arranged in
what is known as the 9+2 configuration. Of the ten pairs of microtubules nine pairs
form a circle. Inside the circle lies the tenth pair; this is how it got the name 9+2
configuration.
12. One example of an animal-like protist with cilia is the Paramecium.
Paramecium is one known ciliated protist. The cilia help the Paramecium push the
food and water into the cell body. The food then becomes enclosed in a vesicle filled
with enzymes. In this vesicle the enzymes help the organism to digest the food.
The cilia can also helps the protist move towards the food/prey by beating the
organism through the aquatic environment. The cilia can become leg-like structures
under the Paramecium allowing it to "run.“
13.
14. 3. Protists with Flagella :
Flagella are long whip-like structures that move back and forth allowing the animal-like
protist to move. Protists with flagella beat the long whip-like structure to move through
their aquatic environments. These organisms can be free-living; some are parasitic,
living in moist tissues of plants and animals. Sometimes the parasitic protists help their
host, but others are harmful.
Flagella, like cilia, are composed of microtubules. They are arranged in a 9+2
configuration. Nine of the pairs of microtubules form a circle around the tenth pair.
One example of an animal-like protist with flagella is Giardia lamblia.
15. Parasitic Protists
The parasitic protists are animal-like protists that live in or on another organism,
obtaining all its nutrients from that host organism. Many of these protists are disease
causing. These protists go in and out of the active stage and the dormant stage. When
conditions are good for them they are active; when conditions are bad they become
dormant. One example of this parasitic animal-like protist is Plasmodium, which causes
malaria.
Plasmodium
Plasmodium is a parasitic animal-like protist. It is the cause of malaria. Plasmodium is
transported through mosquitoes. While in the mosquito the Plasmodium is in a dormant
stage. When it is transported into the human it becomes active. It is mostly found in the
red blood cells of humans. The Plasmodium asexually reproduces inside the liver and
then enters the red blood cells. The red blood cells are destroyed in massive amounts.
Merozoites are produced in some of the red blood cells. These merozoites develop into
the male and female gametophytes. The infected gametophytes are taken in through a
mosquito and the process begins all over again.
17. 3. Plants-like Protist
plant-like protists are autotrophic; they can make their own foods. They live in soil, on
the barks of trees, in fresh water, and in salt water. Plant-like protists are very important
to the earth because they produce an abundant amount of oxygen. They are the basis
for the aquatic food chain.
These protists are similar to plants. Most are photosynthetic. Some have stem-like
structures called stipes and anchoring structures called holdfasts, while plants have
actual stems and roots. Many of these protists release their eggs into the environment
where the sperm will fertilize the egg. Plants on the other hand will retain the egg in
the "parent" plant where it will fertilize.
Some examples of plant-like protists are: Euglenoids, Dinoflagellates, Chrysophytes,
Green Algae, Red Algae, and Brown Algae.
18. 1. Euglenoids
Euglenoids are plant-like protists that are usually found in fresh water. During the
day these protists are autotrophic; they can make their own foods. When night falls
they become heterotrophic; they are unable to make their own foods, and thus they
must be able to find it. Some Euglenoids have flagella to help them move during the
heterotrophic stage.
The Eugleoid is a single celled organism with an abundance of organelles. They
have an "eye spot" which covers a light-sensitive receptor. The cell will move to
places where the light suits it best.
19. 2. Dinoflagellates
Dinoflagellates are plant-like protists found in salt water. They are unicellular and
have flagella to help them move through the water. The Dinoflagellates are capable
of glowing in the dark. They are the cause of Red Tide, when there is an outburst in
population and in turn water becomes red/brown in color.
The Dinoflagellates can produce toxins. If a human eats seafood contaminated
with the toxins he/she will have memory loss and other impaired brain functions.
One dinoflagellate that has gotten out of control is Pfiesteria. Pfiesteria grows in
fertilizer and raw sewage. It has killed a billion fish along the costs of North
Carolina, Maryland, and Virginia since 1991.
gb. Pfiesteria piscicida.
20. 3. Chrysophytes
Chrysophytes are plant-like protists found in toothpaste, scouring products, and
filters. Chrysophytes have a glasslike cell wall. The Chrysophytes are free-living,
photosynthetic, unicellular protists. They consist of diatoms, golden algae, and
yellow-green algae. Many Chrysophytes form colonies.
The diatoms are photosynthetic. They contain a shell that is made of silica. The cell
has two parts that overlap. Over millions of years the shells become crushed and form
the sand found on the bottom of oceans and lakes.
Golden algae have no cell wall. They do have scales made of silica. They also contain
chloroplast and they do photosynthesize.
Yellow-green algae also have no cell wall. They are unable to move, but some do
have flagella to help assist movement when conditions become harsh. This algae is
common in nearly all aquatic environments.
21. 4. Green Algae
Green algae are plant-like protists that are structurally closest to plants. The green algae
can be seen in many forms. Most are unicellular, some live in colonies, and few are
milticellular. Green algae grows at the surface of the ocean, in marine waters, below the
surface of the soil, and in rocks, tree bark, in other organisms, and in snow.
22. 5. Red Algae
Red algae is a plant-like protist that can be found in aquatic areas; most live in marine
waters, but some are found in fresh waters as well. Not all red algae appear red. The
color depends on the pigmentation and chlorophyll abundance in the protist. They can
appear green, purple, and black. The cell walls of red algae are composed of agar, which
gives it a slimy/slippery feeling.
Humans use red algae every day. The red algae Eucheuma is used as thickening
agents in such things as paints, dairy products, and hair conditioners.
23. 6. Brown Algae
Brown algae is a plant-like protist found in cool temperature marine waters. They
range in colors from dark brown to golden, depending on the amount and
arrangement of certain pigments. They range in size from thirty meters, such as giant
kelp, to microscopic organisms.
Macrocyctis is giant kelp. It is one of the most complex of all protistans. They are
multicellualr and contain stipes (stem-like structures), blades (leaf-like structures),
and holdfasts (anchoring structures). Kelp often live in giant colonies, creating a kelp
bed. These giant kelp beds act like underwater "forests". Many fish, bacteria, and
other protistans live their lives with in the giant kelp "forests."
Brown algae are found in many products such as: ice cream, pudding, jelly beans,
salad dressing, canned foods, frozen foods, beer, cough syrup, toothpaste, floor
polish, cosmetics, and paper. Many people harvest kelp for food, mineral salt, and
fertilizer for crops.