There is a secret within every drop of water in a lake, pond, or stream. Pond Water Video

Prokaryotes vs. Eukaryotes Prokaryotes: a single-celled organism that lacks a membrane-bound nucleus. -DNA is in cytoplasm -Ex: bacteria Eukaryotes: any organism whose cells contain a membrane-bound nucleus, which contains its DNA. -Ex: Plants, Animals, Protists

Kingdom Protista (Protists) PROTISTS: any member of the kingdom Protista, a group of eukaryotic, mostly unicellular microscopic organisms. “Trash can” kingdom (not plants, animals, or fungi) Very diverse group

Characteristics of ALL Protists All protists have a membrane-bound nucleus (“control center” within the cell). All protists contain other organelles (membrane- bound structures within a cell that perform specific jobs)

Characteristics of MOST Protists -Most live in wet places (oceans, lakes, swamps, damp soils.) -Most are unicellular (made of one cell). -Most have structures that help them move.

How do protists get energy? Autotrophs = get energy from the sun through photosynthesis. Heterotrophs = get energy by eating other organisms or by decomposing material. Mixotrophs = can get energy from the sun AND by eating other organisms (“mixing it up”). How do you think this green Volvox gets its energy?

AMOEBA -Microscopic (small), unicellular (one cell) protozoa (animal-like protist) -Live in fresh water, salt water, in soil, and as parasites in moist body parts of animals.

Structures of an Amoeba -Plasma membrane: surrounds cell, allows substances to pass in/out -Nucleus: membrane-bound control center -Food vacuole: digests food -Cytoplasm: jelly-like substance within cell -Contractile vacuole: pumps water out of cell

Amoeba Movement & Feeding Pseudopodia: extensions of the cytoplasm that allows amoebas to move and detect food; “false feet.” Also called cytoplasmic streaming. Amoeba Eats!

Amoeba Reproduction Amoebas reproduce by a type of asexual reproduction (1 parent) called binary fission. = DNA is replicated and cytoplasm pinches in half to produce 2 identical daughter cells.

PARAMECIUM Paramecium is a microscopic (very small), unicellular (one cell) protozoa (animal-like protist). It is plentiful in freshwater ponds.

STRUCTURES OF A PARAMECIUM Pellicle: Thick membrane that gives the paramecium its shape Nucleus: “control center” Cytoplasm: jelly-like substance that hold all the organelles Cilia: hair-like projections that help it move STRUCTURES OF A PARAMECIUM

5. Contractile vacuole: Remove excess water out of the cell; works like a pump. Cilia Pellicle Macronucleus Micronucleus 6. Oral groove: takes in food Contractile vacuole 8. Food vacuole: digests food Oral groove Food vacuole Anal pore 9. Anal pore: Removes waste Trichocyst 10. Trichocyst: Protection or defense against predators

Paramecium Movement The outer surface of the cell is covered with many hundreds of tiny hair-like structures called cilia. Act like “microscopic oars” Can swim backwards, forwards, or rotate using the cilia. Moves so quickly that we have to add a thickening agent or quieting solution to the slide to slow it down to study it.

Paramecium Feeding The paramecium rotates on its axis as it moves through the water. Small particles of debris and food are collected and swept into the oral groove (6) and down the funnel-shaped gullet (7) by the cilia that also helps it move. Eats small organisms such as bacteria, yeasts, algae and even other smaller protozoa.

Paramecium Reproduction Paramecium reproduce by conjugation and binary fission. Conjugation: 2 paramecia exchange nuclear material and then separate. Binary fission: cell replicates its DNA, cytoplasm pinches in half, and 2 new daughter cells are formed (cell then grows in size and makes structures).

Paramecium Excretion Food waste left in a food vacuole is excreted through the anal pore (the vacuole and pore fuse. Other wastes left over from cellular activity (metabolic waste) simply diffuse through the pellicle. Excess water and some metabolic wastes are excreted through the contractile vacuole.

“One scientist calculated that if all the progeny of a single Paramecium survived, assuming a division rate of once a day, then after 113 days, the mass of paramecia would equal the volume of the Earth! “