Biology- Mr.Willets
Protist Kingdom - Algae
Kingdom Protista includes protozoans and algae. The algae were once part of the Plant Kingdom. They are unicellular or colonial (although some of the larger algae seem multicellular and are sometimes put into the plant kingdom). All algae are autotrophic. These and other characteristics are outlined below.
1) Algae are autotrophic- they make food using photosynthesis.
2)Algae are mostly aquatic- some live in very moist soil.
3) Algae are unicellular or colonial. Many colonial forms have the cells attached end to end to form filaments. Colonial organisms are made of many cells but the cells do not work together. In multicellular organisms, the cells work together and depend on each other. Some larger algae (seaweeds) are close to being multicellular.
4) Algae are the primary producers of food in aquatic environments-
5) Since most of the earth is water, the algae are very abundant. When algae photosynthesize, they release large quantities of oxygen into the atmosphere. You rely on this.
6) Many algae float in the water. These are called phytoplankton. "Phyto" means plant (or in this case, plant-like: they make their own food), "plankton" means drifter.
7) Many algae are part of a symbiotic relationship. One type of algae live inside coral. Another alga lives inside a type of ciliate. When algae and fungus live together, we call it lichen. In all these cases, the algae supplies food while the other member provides protection and nutrients needed for photosynthesis.
8) Reproduction- Most algae cells reproduce by binary fission. There is usually some form of sexual reproduction also. This can involve actual gametes or can simply be a method of genetic recombination usually called conjugation.
9) There are 6 phyla of algae based on color (notice all the phylum names end in "phyta" which means plants. This is because they were once considered to be plants)
a) Phylum Chlorophyta- Green algae- These are the probable ancestors of today's plants
b) Phylum Chrysophyta- Golden brown algae- most of these are unicellular with a two-part protective shell: they are called diatoms. When these die, the shells becomes a powder called diatomaceous earth. This powder is used in pool filters (DE) and as a polishing abrasive. Diatoms are the most numerous algae in the ocean.
c) Phylum Pyrrophyta- the fire algae or dinoflagellates- many of these are bioluminescent- they have a reddish glow seen at night. Some species, when eaten by clams, can make the clams poisonous to us although the algae do not harm the clam. The algae that do this are commonly called the Red Tide.
d) Phylum Phaeophyta- Brown algae- these are the large seaweeds- these could be an important source of food for the future.
e) Phylum Rhodophyta- Red Algae- smaller seaweeds- these can also be used for food. Agar is made from one of these. Carrageenan is made from a red algae and is used in foods and cosmetics. Look for this on the ingredients label of ice cream.
f) Phylum Euglenophyta- these are photosynthetic organisms that have flagella like some protozoans. In light, they make food. In darkness, they absorb food.
Biology-Mr. Willets
Questions- Algae
1) Why are algae so important to any aquatic ecosystem? ___________________________________
2) Why are algae important to all living things? _________________________________________
3) Many algae are phytoplankton. What does this word tell you about these algae? __________________
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4) Why is it incorrect to call lichen an organism? ________________________________________
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5) Two different organisms that live together are in what kind of relationship? _____________________
When algae are involved, what do they supply? __________________ What does the other organism supply? ___________________________
6) Since many algae are unicellular, they reproduce by _______________________ Some algae use conjugation for what purpose? __________________________
7) Some algae have actual sexual reproduction which involves ____________________
8) Algae are put into phylums based on what trait? ___________________________
9) Which phylum of algae has members with two part shells? ______________________________ What is the common name for these organisms? _________________ How are they useful to us?
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10) Phylum Rhodophyta and Phaeophyta contain organisms commonly called _______________________ These are now used in some places as ______________ What lab product is made from these? _________
What ingredient in our foods is made from these? _____________________________
11) The "fire algae" are in what phylum? __________________________ They are called this because many _____________ with a __________________ color. What word describes an organism that gives off light? ____________________________ In what way does the phylum name tell you about these algae? ________________________________________
12) What problem does the "red tide" algae cause when they grow in large amounts in the ocean?
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13) The members of Phylum Euglenophyta have a _____________________to move and can _______________food in darkness. This makes them like what protozoans.?______________________ They are included with the algae because they can ________________________
14) The phylum names for the algae all end in what suffix? ________________ What does this suffix mean? _______________ Is this an accurate name for algae? ________ Why were they given these names originally? ________________________
15) Algae are ______________________ or colonial. A colonial organism is made of many _________ but they do not __________ together and they do not _________________ on each other.