Sunday, October 3, 2010

Apologia Biology, Module 3, Kingdom Protista, Part B

Quizlet Vocabulary Game, M3 
M3 Recap Blog Post at Sahm-I-Am
Module 3, Part A.

Resources for Review:
Protists powerpoint - click thru the images
Protists online practice quiz - click the correct answer; see your score at the bottom.  Do as many times as you like.
Protists crossword - print

Kingdom Protista:  Subkingdom Algae

p. 69-70
Subkingdom Algae is divided into five phyla (pl. of phylum).
Each of the phyla for subkingdom Algae has one or more examples in the genus category given in the text.

Kingdom, Phylum, Class, Order, Family, Genus, species

The division for Algae is based on these three things:  
  1. habitat - they can live in marine (salt) water, or in fresh water.
  2. organization (single or multicellular) - Many algae exist as individual cells, but most form simple colonies, although a few colonies are quite complex.  Either way, their cells are all eukaryotic (having organelles, each with their own type of job).
  3. type of cell wall - what it is made of.

(1) p. 84-85, Subkingdom Algae
The members of subkingdom Algae can produce their own food by photosynthesis.
So why aren't they plants?  
According to an email from Apologia:
"When it comes to classification, there is no single rule that applies, and not every biologist agrees.  You probably remember that they don't even agree on how many kingdoms there are.  Algae, even multicellular algae, lack any of the structures of a plant.  They don't have true leaves, stems, or roots.  The blades in a kelp for instance have no veins to distribute nutrients, and both sides of a kelp blade are identical. The stipe on a kelp, while it looks like a stem, does not contain any of the vascular structures (xylem or phloem) to carry nutrients from the soil, and the holdfast just anchors the organism to the sea floor and does not have roots to draw nutrients.
In addition, some of the unicellular algae (like dinoflagellates), while photosynthetic, have flagella for movement more like an animal.
The sum of all of these distinctions is why algae and plants are considered to be parts of different kingdoms."
So that is why.  =D

Algae can live in warm or cold marine water (salt water) and in fresh water.   
This is the habitat category.
Algae is a type of plankton.  There are two groups - zooplankton and phytoplankton.
  • Zooplankton are tiny floating organisms that are either small animals or protozoa.
  • Phytoplankton are tiny floating photosynthetic organisms, primarily algae.
Based on these definitions, what we studied in the first half of Module 3 has mostly been zooplankton.
Now we will learn about phytoplankton.

We know that grass, trees, and other green plants produce the by-product oxygen during the process of photosynthesis.  (To the plant, it is a by-product; they produce it, but don't need it.)
But did you know that the majority of photosynthesis done on earth is not done by green plants, but is done by phytoplankton!?!  Phytoplankton (which is mainly algae) produce about three-fourths of all the oxygen on earth!
So I don't really think we'll run out of oxygen if someone cuts down a tree.  =)

Algae are also a major food source for many aquatic (water-living) organisms.
Humans have also found quite a few uses for algae.  Some algae is used as food in some parts of the world, and some is used as food additives.  One substance in a type of algae is used to thicken things like ice cream, pudding, and dressings.  There are other products made from algae as well:  iodine, vitamins, minerals, paper, floor polish, cosmetics, toothpaste, and more.

Many algae exist as individual cells, but most form simple colonies, although a few colonies are quite complex.
This is the organization category.
A colony is sometimes called a thallus (pl. is thalli) - the body of a plant-like organism that is not divided into leaves, roots, or stems.

When algae reproduce so rapidly that they essentially take over their habitat, the water appears to be the same color as the algae themselves.  This is called an algal bloom.

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(2) p. 85-86, Phylum Chlorophyta
Phylum: Chlorophyta
Habitat:  mostly fresh water
Organization:  single cells
Cell Wall:  cellulose
examples: genus Cosmarium or Desmid (same picture for both in the textbook), Chloroella, and Spirogyra

If you will remember the name of this phylum, Chlorophyta, it may help you remember that the most visible feature of these algae is that they contain the pigment chlorophyll, which is green.  Therefore they are referred to as green algae, even though most of them appear yellowish green because of other yellowish pigments present called carotenoids (kuh rot' en oydz).
Like Euglena, members of this phylum store the chlorophyll in organelles called chloroplasts.
Other main features of this phylum are that its members live mostly in fresh water, so you likely won't find them in the ocean.
And they have cell walls made of celulose (sel' yoo lohs), which is composed of certain types of sugar to feed the organism.

The following are green algae from three different genera (pl. of genus) from the phylum Chlorophyta.

phylum Chlorophyta, genus Chloroella.  
(see images)
These single-celled organisms clump together, but are not really in colonies.  
This has been made into vitamins.

phylum Chlorophyta, genus Cosmarium or Desmid.
(see images here and here)
These single-celled organisms sometimes form simple colonies, but mostly exist as individual cells.
They are characterized by the "pinched" look in the middle.  

phylum Chlorophyta, genus Spirogyra. 
(see images)
These single-celled organisms form colonies, called filaments, that can reach up to two feet long.

Green Algae
I don't think they "communicate" w/ one another. I believe it is a God-given instinct that they know exactly what to do.

phylum Chlorophyta, genus Desmid or Cosmarium

phylum Chlorophyta, genus Spirogyra form thread-like colonies

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(3) p. 87-88, Phylum Chrysophyta
Phylum: Chrysophyta
Habitat:  marine and fresh water
Organization:  single cells, some colonies
Cell Wall:  silicon dioxide
examples: genus Diatom, Dynobryon

This phylum Chrysophyta has more than 1,000 different species which are collectively called diatoms.
These algae are found in both marine and fresh water.
They are a unique type of algae, mostly because their cell walls are composed of silicon dioxide, which is the main component of glass.  This makes their cell wall very hard and protective.  This is why it remains hard long after the diatom dies.  When these remains are clumped together, they form a crumbly, abrasive substance called diatomaceous earth (die' uh tuh may' shus), or diatomite.

There are huge deposits of diatomaceous earth in most regions of the world.  Creation scientists think this may have happened at the time of the Flood.  (Genesis 6-9)  Scientists who do not believe the Bible have a hard time explaining these deposits of diatomaceous earth.

Diatomaceous earth is quite useful.  It is used for filtering liquids, or as an abrasive. (for example, in toothpaste.)  Insects can be killed by crawling over a thin coating of jagged diatomaceous earth.

Phylum Chrysophyta, genus Diatom
At The Microscopic Museum, see The Diatom Display 
These are beautiful!


See the diatoms that the kids in Michelle's class saw.

phylum Chrysophyta, genus Dynobryon
Another genus, Dynobryon (see images), is also a member of phylum Chrysophyta.  These contain algae that form colonies.  They usually contain a few cells called holdfasts, which can anchor them to objects in the water, like rocks.  These holdfasts form long strands so that the organism can stay in one place.

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(4) p. 88-89, Phylum Pyrrophyta
Phylum: Pyrrophyta
Habitat:  marine
Organization:  single cells
Cell Wall:  cellulose or atypical
examples: genus Peridinium (pehr' uh din' ee uhm), and  
genus/species Gymnodinium brevis (also called Karenia brevis)
Phylum Pyrrophyta is made up of a group of single-celled creatures often called dinoflagellates (see images), because most species have two flagella, one of which is in a groove that encircles the cell.  
These organisms are found in marine waters.
Some dinoflagellates are heterotrophic, obtaining their food from other sources, and some are photosynthetic, making their own food.

The most important thing about dinoflagellates is that certain species frequently bloom in nutrient-rich waters.  The species Gymnodinium brevis (see images) (also called Karenia brevis by some scientists) are reddish-brown in color, and their bloom turns the water red.
These algal blooms are called red tides. (see images)
These red tides are deadly to most to marine life, but mollusks, clams, and oysters are immune.  However, the toxin emitted by the dinoflagellate does build up in their bodies.  Eating clams, oysters, or mollusks that have been exposed to red tide can be poisonous.  Not only to humans, but other marine life that eat them.
Seafood restaurants do not serve these dishes when a red tide occurs in the area from where they get their supplies.
These tides are harmful to humans to even be around! It can cause burning eyes and respiratory problems.

►Read how one family was affected by a red tide

Red Tide in late 2007

Red Tide in Cocoa Beach, Fl, in late 2007
She says, "Look at all those single-celled, microscopic, dinoflagellate Karenia brevis."
What a mouthful.  =) (Remember, this is the same as Gymnodinium brevis.)

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We have learned that kingdom Protista includes eukaryotic organisms made up of a single cell, or simple association of single-celled organisms.
But we have also seen that every classification rule has its exceptions.  We often see the words "usually" or "most" as we learn about biology.
The following two phyla are made up of multi-celled organisms instead of single-celled.

(5) p. 89-90, Phylum Phaeophyta
Phylum: Phaeophyta
Habitat:  cold marine waters
Organization:  multiple cells
Cell Wall:  cellulose and alginic acid
examples: genus Macrocystis (mah' kroh sis' tus), genus Fū'cus 

Phylum Phaeophyta is made up of about 1,500 species of multicellular organisms that live in the cold ocean waters.
A multicellular organism is not the same as a colony of single-celled organisms.
►Single-celled organisms, although they may sometimes live in colonies, are not dependent on one another.  They can live on their own if separated from the colony.
►Multicellular organisms have individual cells that are designed for a specific task.  The cells work together, each performing the task for which it was designed.  They need each other to survive.  A single cell that is separated from a multicellular creature usually cannot exist on its own.

Members of phylum Phaeophyta, also called brown algae, look a lot like plants.
Species within the genus Macrocystis are commonly called kelp or seaweed. (see images) 
Kelp and most other members of phylum Phaeophyta form holdfasts (see image) to anchor themselves to rocks at the bottom of the ocean.  Some kelp can grow as long as 100 meters, growing as fast as 2 feet per day under ideal conditions.

If you enjoy ice cream, pudding, dressings, etc, you can be thankful that God made the members of this phylum.  One of their unique characteristics is that their cell walls contain alginic acid, commonly called algin.  This is extracted from brown algae and used to make a thickening agent in these kinds of foods.
Algin is used in other products as well.
Kelp is harvested in many parts of the world for food.

Another kind of seaweed nicknamed Turkish Washcloth (see imagesis known for being rich in carrageenan, which is another thickening agent.

Phylum Phaeophyta, genus Fū'cus (see images) has species that are often called rockweed.  These algae are thick and feel leathery.  They live in shallow water along the shore, and are about one to two feet long.  On these alga (singular of algae) you can see air bladders, which fill with air to allow the organism to float on top of the water.

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(6) p. 91-92, Phylum Rhodphyta
Phylum: Rhodophyta
Habitat:  warm marine waters
Organization:  multiple cells
Cell Wall:  cellulose
example: genus Corallina (kor' uh lee' nuh), genus Hildenbrandia 

The last major phylum in subkingdom Algae is phylum Rhodophyta.
These are found in warm marine (salt) waters.
Members of this phylum are often called red algae because of their striking red color.  (Do not confuse this with the dinoflagellates that cause red tides.)

Phylum Rhodophyta, Genus/species Corallina officinalis (see images) is often called "coral weed."  It looks and feels a lot like coral.

From Phylum Rhodophyta, the genus Hildenbrandia (see images) are thin algae that grow in clumps (the red splotches) on underwater surfaces.

At The Microscopic Museum, see The Algae Exhibit.  He always has such awesome pictures.
See diatoms, phytoplankton, phaeocystis, and more.

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