Protist Powerpoint

Biologist ______Date ______

Protist PowerPoint

The First Eukaryotes Protists are ______that are not members of the plant, animal, or fungi kingdoms. Although most protists are ______, quite a few are not.

The “Protist” Dilemma Biologists have discovered that “protists” display a far greater degree of ______than any other eukaryotic kingdom. ______, brown algae, diatoms, and slime molds are examples of protists. Biologists also found that many “protists” are far more closely related to members of ______eukaryotic kingdoms than they are to other “protists.”

What “Protist” Means Today Even though the biologist building the Tree of Life prefer a ______classification, the word “protist” remains in common usage, even among scientists. Bear in mind that “protists” are not a single kingdom but a ______of organisms that includes several distinct clades.

Protists—Ancestors and Descendants The split between Archaea and Eukarya may have come as early as ______years ago. Since that time, protists have diversified into as many as 300,000 species. The roots of all eukaryotic diversity, from plants to animals, are found among the ______of protists.

Amoeboid Movement Many unicellular protists move by changing their shape, a process that makes use of cytoplasmic projections known as ______. Amoeboid movement is powered by a cytoskeletal protein called ______. Actin also plays a role in the muscle contractions of animals.

Cilia and Flagella Many protists move by means of cilia and flagella, structures supported by ______. ______are short and numerous, and they move somewhat like oars on a boat. ______are relatively long and usually number only one or two per cell. Some flagella spin like tiny propellers, but most produce a wavelike motion from base to tip.

Passive Movement Some protists are ______—they depend on air or water currents and other organisms to carry them around. These protists form reproductive cells called ______that can enter the cells of other organisms and live as parasites.

Conjugation Paramecia and most ciliates reproduce asexually by ______cell division. However, under stress, paramecia can remake themselves through conjugation—a process in which two organisms ______genetic material. Paramecium has ______types of nuclei: a macronucleus and one or more smaller micronuclei. The ______holds a “reserve copy” of every gene in the cell. The ______has multiple copies of the genes the cell uses in its day-to-day activities.

Sexual Reproduction Many protists have complex sexual life cycles in which they alternate between a diploid and a haploid phase, a process known as alternation of ______. Water molds reproduce asexually by producing spores in a structure called a ______. The male and female structures produce haploid nuclei that fuse during ______, forming a zygote that begins a new life cycle.