Chapter 5 Marine Prokaryotes, Protists, Fungi and

Plants

Simple Life

 Prokaryotes, in the kingdom Monera are among the simplest and most primitive forms of life.

Bacteria   Bacteria are microscopic, single celled and simple in

structure. A typical bacterial cell is rod shaped and bound by a rigid, protective cell wall. These cells lack membrane bound organelles. They are the smallest living creatures on Earth. About 250,000 will fit on the period in this sentence but others can be seen without a microscope.

  Although they are small, they can carry out almost all of the chemical reactions as a more complex form of life.

Heterotrophic Bacteria

  Most bacteria are herterotrophs and obtain their food by decomposing dead organic matter. These are essential on Earth because the help recycle essential nutrients. They are found everywhere, even in the water and help feed countless bottom dwelling animals.

Autotrophic Bacteria

  These bacteria make their own food and contain chlorophyll that converts light energy into organic material. Other autotrophic bacteria called chemoautotrophic which release energy stored in chemical compounds such as hydrogen sulfide, ammonia or methane.

Cyanobacteria   Groups of primitive, plant like organisms that have

chlorophyll and a bluish pigment called phycocyanin. Most marine cyanobacteria have a reddish pigment called phycoerythrin. The photosynthesis takes place on the folded membranes within the cell rather than in the chloroplasts.

  Cynobacteria are believed to be the first photosynthetic organisms on Earth and may have provided much of the original oxygen in our atmosphere.

Stromatolites   Cynobacteria can live in a wide range of salinity and

temperature areas. They can live in warm areas, polluted areas as well as in the fur of polar bears. Sometimes the algae can blooms into a harmful red tide.

  Many cyanobacteria carry out nitrogen fixation, converting gaseous nitrogen into nitrogen compounds. Some live on other plants and they are called epiphytes.

Unicellular Algae

  Algae are mostly aquatic, photosynthetic eukaryotic organisms. The color of the algae is a result of the different pigments and their concentration. These are different from land plants in that they do not flower, have roots or leaves and have a simple reproductive system.

  Some algae are free swimming using their flagella and move like animals. These are usually called Protists.

Diatoms   Diatoms are single

celled organisms enclosed by a cell wall made of silica, a glass like material. The glassy shell called a frustule, consisting of two tightly fitting halves. The frustule is usually clear to allow light to penetrate and has many spines or ribs.

Diatoms

 The minute perforations allow dissolved gasses and nutrients to enter and exit and the oil sac and spines help the diatom stay afloat. The yellow brown pigment is called carotenoid. Diatoms are photosynthesis factories and are responsible for most of the oxygen produced on planet Earth.

Diatoms Reproduction

 Diatoms reproduce asexually by cell division. The overlapping halves of the frustule separate and each produces a smaller half. If the conditions are right, reproduction is fast and a bloom occurs. The diatoms get smaller and smaller during the bloom because they use up the dissolved silica in the water.

Diatoms Divide   To regain full size, the diatom develops a resting stage

called an auxospore. Some are produced as a result of sexual reproduction.

Dinoflagellates

 Another large group of planktonic, unicellular organism that possess 2 unequal flagella. One is wrapped around a grove in the middle of the cell and the other is trailing free. The flagella direct the movement of water and the cell wall is armored with plates made of cellulose.

Where are Dinoflagellates Found?

 They are found primarily in warm water and are considered among the most important planktonic primary producers.

Actual Dinoflagellates

Dangerous Blooms

 They reproduce primarily by cell division and can also form blooms. The color of the water may turn a reddish brown called a “red tide” and may be poisonous to some marine animals. The seafood collected during this period could also be poisonous.

Red Tide

Bioluminescence

 Other dinoflagellates are noted for the production of light, known as bioluminescence. This can only be observed at night and is usually sparked by a passing boat or the waves crashing on the shore.

Bioluminescene

Protozoans

 These organisms are sometimes considered “animal like” in that they ingest food and are eukaryotic, but contain chlorophyll and photosynthesis like plants. Most are single celled and microscopic.

Cilia and Flagella

Foraminiferans�

  Better known as forams, typically having a shell or test made of calcium carbonate with several chambers. They possess pseudopodia which extend out and trap smaller diatoms. Most live on the bottom either free or attached and if they do not possess a shell, they will use sand or other materials to help protect them.

  Few live in the plankton and they have thinner shells and have spines to aid in their floatation.

Calcium Shell/Pseudopodia

Foraminiferans

 Few live in the plankton and they have thinner shells and have spines to aid in their floatation.

Radiolarians

 Planktonic marine protozoans that secrete delicate shells made of glass.

 Most are microscopic, but some strange sausage-shaped colonies reach 3 m in length.

Single or Colony

Ciliates •  They have many hair-like cilia that are

used in locomotion and feeding. Most are freshwater but the marine ciliates are found on the bottom, in the gills of clams, on the skin of fish or in the intestines of sea urchins. Some will build their own vase like cases and drift in water.