Protozoa PDF - Biology Study Guide

# The Kingdom of Protoctists The kingdom of protoctists includes **protozoa** and **algae**, which are simple eukaryotic organisms. ## Protozoa ### What are protozoa? Protozoa are **eukaryotic**, **unicellular**, and **heterotrophic** organisms. They live in aquatic environments, in damp places, or...

# The Kingdom of Protoctists The kingdom of protoctists includes **protozoa** and **algae**, which are simple eukaryotic organisms. ## Protozoa ### What are protozoa? Protozoa are **eukaryotic**, **unicellular**, and **heterotrophic** organisms. They live in aquatic environments, in damp places, or inside other living organisms. ### Types of protozoa * **Ciliated protozoa**: Have small movable hairs called **cilia** on their surface. * **Flagellated protozoa**: Have a single hair-like structure called a **flagellum** that helps them move. * **Rhizopod protozoa**: Move and capture food using extensions of their cytoplasm called **pseudopods**. * **Sporozoan protozoa**: Parasitic protozoa with simple structures that lack methods of movement. They form resistant structures called **spores**. ### Examples of protozoa * **Paramecium**: Uses its cilia to move. * **Vorticella**: Uses its cilia to capture food and attaches to substrates using a stalk. * **Amoeba**: Moves with pseudopods, also known as "false feet". * **Flagellated protozoa**: Have one or more flagella that they use for movement. ## The Vital Functions of Protozoa ### Nutrition Protozoa are **heterotrophic**. Some **parasitic** protozoa obtain nutrition from other living organisms, which can cause disease. Others are **free-living**, feeding on organic material, bacteria, or other protoctists. ### Relationships Protozoa can move to pursue food, escape danger, or avoid light. Some are **immobile**. ### Reproduction Protozoa typically reproduce **asexually**, but some can undergo **sexual reproduction** using **gametes**. During asexual reproduction, the cell duplicates its DNA and divides into two daughter cells. ## Asexual Reproduction in Protozoa Protozoa reproduce asexually through different methods depending on the specific type: - **Ciliates**: Divide into two daughter cells. - **Flagellates**: Divide into two daughter cells. - **Rhizopods**: Divide into two daughter cells. - **Sporozoans**: Divide into multiple daughter cells. ## The Importance of Protozoa ### Beneficial Protozoa: * **Wastewater treatment**: Protozoa help break down bacteria in sewage. * **Food chain**: Protozoa are part of plankton, serving as food sources for other aquatic organisms. ### Harmful Protozoa: * **Parasitic protozoa**: Cause diseases such as **malaria** (transmitted by mosquitos) and **amebiasis** (transmitted through contaminated water or food). ## Important points to remember about protozoa: * Protozoa are heterotrophic. * Not all protozoa are free-living. * Protozoa can move. * Protozoa reproduce asexually and sometimes sexually. * Protozoa play important roles in ecosystems and can cause diseases.