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Single Celled Organisms
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Objective 7. L.1:
Understand the processes, structures and functions of living
organisms that enable them tosurvive, reproduce and carry out
the basic functions of life.
Clarifying Objective:• 7.L.1.1 Compare the structures
and life functions of single-celled organisms that carry out all of the basic functions of life including: Euglena; Amoeba; Paramecium; Volvox.
Language Objective: 7.L.1.1 Students Will Be Able To:
Define and explain the following terms:
-Euglena -Amoeba-Paramecium -Volvox-Protists -Flagellum
-Cytoplasmic streaming-Cilia -Chlorophyll
(You)
Language Function• 7.L.1.1 SWBAT DESCRIBE AND
COMPARE the structures and functions of single celled organisms. (Euglena, Amoeba, Paramecium, and Volvox)
Language Skills7.L.1.1 SWBAT DISCUSS how single celled organisms are similar and how they vary, based on their structures and functions.
Language Structures7.L.1.1 SWBAT USE CORRECT SENTENCE FORMATION to describe the similarities and differences between single celled organisms. (Euglena, Amoeba, Paramecium, and Volvox)
Lesson Tasks7.L.1.1 SWBAT DRAW PICTURES of single celled organisms and DRAFT SENTENCES about their life functions. (Foldables)
Essential Question: What are the characteristics of the
following single-celled organisms?
EuglenaAmoeba
ParameciumVolvox
Comparisons of Single-celled Organisms
The cell is the basic structural and functional unit of all known living organisms. It is the smallest unit of life that is classified as a living thing (except virus, which consists only from DNA/RNA covered by protein and lipids), and is often called the building block of life
Euglena
• Found in calm fresh and salt water• Used as a model organism in the lab• Contain chloroplasts (Chloroplasts are organelles found in plant cells and other
eukaryotic organisms that conduct photosynthesis.)
• Autotrophs – get energy via photosynthesis• Can also get nourishment heterotrophically like
animals (heterotrophically is an organism that cannot synthesize its own food and is dependent on complex organic substances for nutrition.)
Euglena
• Have features of both plants and animals > Kingdom Protista
• Heterotrophic feeding – surrounds particle of food• Autotrophic feeding produces sugars via
photosynthesis where sufficient sunlight is present• Possess a red eyespot which filters sunlight and
allows the Euglena to find and move towards light
Euglena
• Does not contain a cell wall• May form a protective barrier and become
dormant until environmental conditions are more favorable
• Moves by use of a flagella
• http://www.youtube.com/playlist?list=PLMWvLl-qJ8mb1maLoPUtppQJkUCFl9FA7
Amoeba
• Can change its shape• Live in fresh and salt water, in soil, and as
parasites in moist body parts of animals• Heterotroph• One large pseudopod on back end, and
several smaller ones branching to the sides
Amoeba• Eukaryotic – contains one or more nuclei• Dines on bacteria, algae, and other protozoa• Food is enveloped, stored, and digested in
vacuoles• Reproduce asexually (mitosis and cytokinesis)
(Mitosis is the process by which a eukaryotic cell separates the chromosomes in its cell nucleus into two identical sets, in two separate nuclei.) {During Cytokinesis, the cytoplasm (the liquid center of the cell that holds the organelles into place.) splits into two equal halves, a cleavage point appears and the cell becomes two daughter cells.}
• Can survive being forcibly divided – the part with the nucleus survives, other part dies
Amoeba• May become dormant by forming into a ball and
secreting a protective membrane to survive harsh environments
• Moves using pseudopod (false foot into which the body then flows) or by changing shape
• Feed on plankton and diatoms by engulfing them with a pseudopod, it is then enveloped, stored, and digested in vacuoles
• http://www.youtube.com/playlist?list=PLMWvLl-qJ8mYt7rgFNpzZhXm8pim1zjxW
Paramecium
• Moves via cilia and spirals through the water• Can move about 12 body lengths per second• Shape resembles a shoe’s sole• Uses an oral groove to draw food inside• Feed on bacteria and other small cells• Heterotrophic • Relatively large
Paramecium
• Very common in scums and other calm freshwater environments
• Stiff elastic membrane gives it a definite shape
• Outer membrane is covered in cilia
Paramecium• Contain two nuclae (macro and micro)• Feed on micro-organisms like bacteria, algae,
and yeasts• Uses cilia to sweep food into the cell mouth
after falling into the oral groove to eventually be enveloped in a food vacolue (A vacuole is a membrane-bound sac that plays roles in intracellular digestion and the release of cellular waste products.)
• http://www.youtube.com/playlist?list=PLMWvLl-qJ8mbRm9VWx_h5mgj8hFF5teCT
Volvox
• Type of green algae• Forms spherical colonies of up to 50,000 cells• Live in lots of freshwater habitats – ponds,
ditches, puddles, lagoons• Colonies have flagellate cells for swimming
Volvox
• Cells have eyespots which enable the colony to swim towards light
• Make food via photosynthesis• Heterotrophs• Act like one multicellular organism• Reproduce sexually or asexually
Volvox• Asexual colonies:
– Daughter colonies are held within the parent colony and have flagella directed inward
– Parent eventually disintegrates and the daughter colonies invert
• Sexually reproducing colonies:– Two gametes are produced– Male colonies release sperm– Female colonies grow a single oogamete or egg
• http://www.youtube.com/playlist?list=PLMWvLl-qJ8mbaKi29FtoRsT0zKKJbGHeP