MICROORGANISMS

Micro = Tiny Organism = Living Thing

AMOEBA

AMOEBA

• One-celled protozoan

• Look for tiny gray blobs on the slide

• Reproduction - gets too large -> divides in half

• Nucleus splits in half as well

• Size 600 μm (micrometers)

• Two amoebas would almost fit in 1 mm

AMOEBA - MOVEMENT

• Moves with pseudopods (“false feet”).

• Extends a “foot” of cytoplasm in one direction

• Rest of the body flows into that area.

AMOEBA - FEEDING

• Surrounds another live organism with its pseudopods and takes it into a food vacuole.

QUESTIONS

IS THE AMOEBA ALIVE? HOW DO YOU KNOW?

HOW IS AN AMOEBA LIKE AN ANIMAL?

EUGLENA

EUGLENA

• One-celled algae

• Look for tiny green organisms moving on the slide

• Size - 35 μm

EUGLENA - MOVEMENT

• Moves by whipping its flagellum around like a helicopter propeller.

EUGLENA - FEEDING

• Has chloroplasts that contain chlorophyll

• When light is available, the euglena makes it own food like a plant

• When there is not enough light for photosynthesis, the euglena acts like an animal and captures food.

EUGLENA - REPRODUCTION

• When a euglena gets too large, it divides in half.

• The nucleus splits, too.

QUESTIONS

HOW MANY EUGLENAS WOULD FIT END TO END IN ONE MILLIMETER?

HOW DOES A EUGLENA FIND LIGHT?

PARAM

ECIU

M

PARAMECIUM

• One-celled protozoan.

• Look for organisms that are shaped like the sole of a shoe.

• 180 to 300 μm (Three to five paramecia would fit in 1 mm.)

PARAMECIUM - MOVEMENT

• Moves like a bumper car

• Covered with cilia that beat back and forth to move the cell

PARAMECIUM - FEEDING

• Feeds on bacteria and other tiny organisms

• Cilia push the food into an opening called the oral groove.

PARAMECIUM - REPRODUCTION

• When a paramecium gets too large, it divides in half.

• The nucleus splits, too.

QUESTIONS

WATER ENTERS THE PARAMECIUM WITH ITS FOOD. WHICH STRUCTURE LETS THE PARAMECIUM GET RID OF EXTRA WATER?

WHAT MIGHT HAPPEN TO THE PARAMECIUM IF IT DIDN’T HAVE THAT STRUCTURE?

STENTO

R

STENTOR

• One-celled protozoans

• Can retract its body into a ball to hide

• Look for a blue-green ball or a trumpet shape.

• Reproduction - gets too large -> divides in half

• Size - 1 to 2 mm (one of the largest protists)

STENTOR – MOVEMENT

• Moves by beating the cilia that cover its body.

STENTOR – FEEDING

• Waves the cilia around its mouth and sweeps in food

QUESTION

GREEN PHOTOSYNTHETIC ALGAE OFTEN LIVE INSIDE STENTORS.

HOW COULD THIS HELP A STENTOR?

SPIROSTO

MUM

SPIROSTOMUM

• One-celled protozoan with a central digestive tube

• Look for a long cylinder-shaped cell.

• Reproduction – gets too big -> divides in half

• Size - 1 to 2 mm (one of the largest protists)

SPIROSTOMUM - MOVEMENT

• Body has spiral rows of cilia

• Cilia beat back and forth to move the organism

• Snake-like wiggling motion.

SPIROSTOMUM - FEEDING

• Beating cilia sweep small organisms into the spirostomum’s mouth.

QUESTIONS

CAN A SPIROSTOMUM MAKE ITS OWN FOOD? EXPLAIN

VOLVOX

VOLVOX

• One-celled algae that live together in a colony

• Colony is a hollow ball with 500 to 20,000 individual cells

• Look for rolling green balls on the slide

• Size - 350 to 500 μm (Two or three volvox cells would fit in 1 mm.)

VOLVOX - MOVEMENT

• Each volvox cell has two flagella.

• Flagella beat together to roll the ball through the water.

VOLVOX - FEEDING

• Cells have chlorophyll

• Make their own food by photosynthesis.

VOLVOX - REPRODUCTION

• Daughter colonies are small, dark green balls inside the volvox colony.

• When the daughter colonies mature, the parent ball bursts open and releases the daughter colonies.

QUESTION

VOLVOX CELLS HAVE EYESPOTS THAT SENSE LIGHT.

HOW DO THE EYESPOTS HELP VOLVOX SURVIVE?

HYDRA

HYDRA

• Many-celled animal

• Cells in two layers

• Inside is hollow

• Look for white stringy objects attached to the sides and bottom of the jar

• Size - 10 mm

HYDRA - MOVEMENT

• Can stay in one place, glide on its base, or somersault using its tentacles

HYDRA - FEEDING

• Stuns small organisms by shooting out stinging cells on its tentacles

• Tentacles grab the food and stuff it into the mouth.

HYDRA - REPRODUCTION

• Grows a bud of cells on the outside of its body

• Bud develops into a small hydra with tentacles

• Falls off and swims away

QUESTION

WHERE DO YOU THINK A HYDRA DIGESTS ITS FOOD?

VINEGAR E

ELS

VINEGAR EELS

• many-celled animal

• also called nematodes or roundworms

• easy to find wiggling in the vinegar culture jar because they are always moving

• Size - 2 mm or larger

VINEGAR EELS - MOVEMENT

• Moves with a whip-like motion

• Muscles that run along the sides of the worm make the body whip back and forth.

VINEGAR EELS - FEEDING

• Feed on the acid-loving bacteria that make vinegar from fermented apple juice

• Adapted to living in acid

VINEGAR EELS - REPRODUCTION

• Male - produces sperm

• Female - produces eggs

• Sperm and an egg combine and grow into a new vinegar eel

QUESTION

WHAT IS THE PATH OF FOOD IN A VINEGAR EEL?

THE E

ND