" The Big Picture!" by Mr C

Protist:          A new bunch of organisms…

 

Some questions to ponder:

 

1. How do these animal eat?
2. How do they regulate water balance?
3. How do they reproduce?
4. What are some characteristics that can be used for classification?
5. How are different types of protists both unique and different?
6. What is the advantages and disadvantages of living in fresh water?
7. What is the difference between a zooplankton and a phytoplankton?
8. What phylums and kingdom do all these creatures belong to?

 

What is new! ( Comparing Protists to Bacteria and Virus)

1. Protists are eukaryotes and so have

• distinct nucleus
• membrane bound cell organelles
• unique flagella
• are single celled
• have cytoplasmic streaming

 

1. Protist can live in a variety of environments, but are now larger so they need to regulate water balance and store and/or make food.

 

2. Protist are more diverse in how they move, using flagellums, pseudopods and cilia and intermediate hosts.

 

3. Some protists can change their body shape or cell membrane during their life cycle.

 

4. Some protists can reproduce using sexual reproduction.

 

5. Some protist, are parasitic they are called protozoans and cause diseases.

 

6. Some protist have a silicone membranes and can glow in the dark!

 

7. Tiny protists are the major food choice of some of the worlds largest animals.

 

General Protist Notes:

 

Where are they may found?…

• Usually single cell creatures found in pond water
• Over 50,000 living species
• other locations and points of interest include:

used as a means to clean sewage

found in intestines of termites for digestion of cellulose

may be an infectious diseases such as

plasmodium…          which is malaria

trympanosoma….    which is called sleeping sickness

• protist move in response to several stimuli. This movement is called Protist can respond both to light and chemical stimuli, positive phototropism allows organisms to be attracted to light. Negative tropism allows organisms to avoid harmful stimuli such as predators, low oxygen, lower temperatures and other possible harmful chemical or physical stimuli. This response ( to move away from a stimuli) is called an avoidance response.

 

On a historic note:

 

By jove! Forminifera (type of diatom) has hard shell which are used for dating early forms of life. Protozoans also show shell like deposits, an example is the White Cliffs of Dover in England.

 

 

Form and Function:

protists are Eukaryotes so…

 

• usually unicellular, so no tissues yet….
• have a nucleus with a membrane
• can be motile
• can be (animal like) heterotrophic or ( plant like) autotrophic
• have complex arrary cell organelles

 

 

Classification:

Note:  All protist belong to Kingdom Protista, which has four phylums.

 

• Mostly Autotrophs called Phytoplankton

 

1. Phylum Euglenophyta                         example        Euglena

• autotrophic, chlorphyll
• no cell wall
• move about with flagella
• found in fresh water and soil
• attracted to light ( positive phototropic)

 

1. Phylum Chrysophyta: example        Diatoms

• autotrophic, chlorophyll and yellow pigment ( golden algae)
• silica shell in cell wall form symetric shapes
• found in oceans
• positive phototropism
• silicas used in commercial product such as pool filters, silver polish and            toothpaste

 

1. Phylum Pyrrophyta: example        Dinoflagellates

• autotrophic, chlorophyll, have red pigment which makes “red tide”
• heavy rigid cell wall
• two (dino) flagella
• found in oceans
• some species glow in dark ( bioluminescence: phenomenon of living      things giving off light, have protein which converts chemical energy to         ight energy.

 

• Mostly Heterotrophs called Zooplankton:

 

1. Phylum Protozoa ( classified by how they move)

• usually heterotrophic
• no cell walls, usually moveable cell membrane
• can move about or live as parasite

 

Protozoan classification

class Sarcodinia    Amoeba

class Flagellata       trympanosoma and in termites

class Ciliophora      Paramecium

class Sporozoa       parasitic

 

 

Types of Locomotion:

flagella                                   found in Euglena

pseudo pod                          found in Amoeba

(cytoplasmic streaming)

            cilia                                         found in Paramecium

 

A quick comparison of three protist: ( note highlighted vocabulary)

 

Euglena:

1. for movement it uses a flagellum, which makes the Euglena                                                                         very fast.

 

2. for storing genetic material it has a nucleus and a nucleolus

which regulates protein sythesis and cell                                                                      control, it is asexual in reproductive behaviour

 

3. for energy Euglena are autotrophs and have a chlorplast,                                                                        with chlorophyll which allows for                                                                          photosythesis

 

4. for storing energy pyrenoids and parmylum store starch which                                                               is a product of photosythesis

 

5. for protection and water it has a pellicle which maintains shape and

balance                                            allows for diffusion across cell membrane.

 

6. Response to stimuli Euglena are attracted to light, this is call                                                                        phototropism

 

Amoeba

• for locomotions it has extensions of cytoplasm which are                                                                      called pseudopod ( false foot), so an                                                                                   amoeba will move very slow. Ectoplasm ( layer                                                      closest to cell membrane) is water like next to                                                                        internal gel like endoplasm

 

• for genetic material it has only one nucleus and is asexual

 

• for energy it has food vacuoles which digest food                                                                          with enzymes and move nutrients to

 

• to balance water it has contractile vacuoles, in a variety                                                              of positions within cytoplasm

.

• to maintain shape it has an inner membrane, endoplasm

and an outer membrane, ectoplasm,                                                                             these two layers are needed since it is                                                                          constantly changing shape.

 

• stimuli amoebas are attracted to food and                                                                                 some chemicals but move away from                                                                          harmful chemicals and light. (negative                                                                     tropism)

 

Paramecium

• for locomotion it has cilia surrounding whole body so it                                                                        moves very fast.

 

• for genetic information there is a micronucleus to controls                                                                                sexual reproduction, ( it divides during                                                                              conjugation)and a macronucleus to                                                                         control cell functions.

 

• for feeding it has a “mouth” called an oral groove                                                                           and a mouth pore

 

• for digestion it has a gullet which is like a stomach,                                                                           which forms food vacuoles

 

• for removal of food waste there is an anal pore

 

• for water balance there is a contractile vacuole

 

• for shape there is a distinct cell membrane, a                                                                                rigid pellicle which holds cells shape.

 

• for stimuli there are small “spears” call trichocyst                                                                                    which serve as a form of protection or                                                                               hunting for food.

 

 

 

1. Ways to compare Zooplankton:

 

Function or Structure	Euglena	Amoeba	Paramecium
Locomotion (structure)	Flagellum	Pseudopod	Cilia
Speed of locomotion	Moderately Fast	Very Slow	Very fast
Nutrition or digestion	autotroph manufactures own food with chlorphyll	heterotroph engulfs food at any point of cell membrane. Digests via food vacuoles	heterotroph uses oral groove or gullet to suck in food (cyclosis)
Respiration or gas exchange	Diffusion through cell membrane	Same	Same
Excretion of liquids and water balance	Contractile vacuole in definite position	contractile vacuole may vary in position	two contractile vacuoles in definite position
Excretion of solids	Through reservoir	Pushed through membrane at any point	Has an anal pore
Excretion of gaseous wastes	Diffuse through cell membrane or through contractile vacuole if dissolved in fluid	same	same
Reproduction	asexual via binnary fission	asexual by binnary fission may form cysts	asexual binary fission sexual via conjugation
Shape	definite shape
Behaviour	responds to light, called phototrophic	+ to food and chemicals – to light	+ to food and chemicals – to trichocysts

 

 

The Amoeba

has

a nucleus

granular cytoplasm

vacuoles

semi-permeable membrane

engulfs food by using pseudopod

 

Other species

Forminifera

Radiolaria

Bacillaria

 

The Paramecium

member of class called the ciliates

has

cilia for locomotion

feeds through funnel like gullet

has 2 nuclei, reproduction through binary fission

for every single cell, 8 new ones are created

contractile vacuole controls water balance

sexual reproduction by conjugation

 

Protist are:

single cell

complex

can be in colonies ( example: Volvox..has up to 5000 cells in it