Presentation on theme: "Biology. Protist characteristics Protists are organisms that do not fit into any other kingdom. They can either by uni-celled or simple multicellular."— Presentation transcript:
Protist characteristics Protists are organisms that do not fit into any other kingdom. They can either by uni-celled or simple multicellular. They can be animal-like, plant-like, or fungus-like. Protists are made up of eukaryotic cells, each containing a nucleus and other organelles.
Protist characteristics A hypothesis for how eukaryotic cells arose: From prokaryotes that obtained organelles via endosymbiosis. Protists are often classified: By how the resemble fungi, plants, or animals Most protists are unicellular such as an amoeba. Some of these unicellular protists form colonies in which several cells are joined into a larger body, such as Volvox.
Protist characteristics A few protists are multicellular, such as Brown algae. They have specialized regions for reproduction, photosynthesis, and attachment to the ocean floor, but lack true tissues and organs.
Protist characteristics Two ways in which protists obtain energy: Autotrophy Heterotrophy
Protist characteristics Protists move via Flagella Cilia Pseudopodia
Protist characteristics Protists reproduce: Asexually either binary or multiple fission Sexually conjugation
Animal-Like Protists Phylum Protozoa Single-celled protists that can move independently without cilia or flagella Have pseudopodia which are large, rounded cytoplasmic extensions that function both in movement and feeding. They engulf small organisms. Move by amoeboid movement, which is a form of cytoplasmic streaming. An example of a Protozo is an Amoeba Harmful to humans in that some can live in human intestines and attack the lining, and may cause disease
Animal-Like Protists Phylum Ciliophora They share one key feature: they have cilia which are: short, hair like cytoplasmic projections that line the cell membrane. Cilia make it possible for these protists to move. An example of Ciliophora is Paramecia. The process in which two Paramecia come together after meiosis to exchange parts of their genetic material is called conjugation.
Plant-like Protists Algae Many plant-like protists are known as algae. Algae are autotrophic protists and have chloroplasts and produce their own carbohydrates by photosynthesis, as plants do. They do not have true roots, stems, or leaves.
Plant and Animal-like Protists Phylum Euglenophyta Phylum Euglenophyta contain flagellated unicellular algae called euglenoids, which are both plant-like and animal-like. How are they like plants? Autotrophic, contain chlorophyll Have contractile vacuole and chloroplast How are they like animals? Lack a cell wall and are highly motile If raised in dark, do not form chloroplast and become heterotrophs
Plant and Animal-like Protists Where do you find Euglena? In fresh water, especially water polluted by excess nutrients How do they move? Long flagellum
Fungus-like Protists Slime mold- can either be: *mobile, amoeba-like feeding *sessile, reproductive spore- bearing form Water mold- composed of branching filaments of cells
Protists and Humans Environmental roles of protist producers: Produce oxygen Form the foundation of food webs Recycle materials
Protists and Humans Protists symbiosis: Corral, fungi, and termites
Protists and Humans Protists for food: Seaweeds are eaten directly Byproducts are used to make cheeses, ice cream, salad dressing, and bakery items.
Protists and Humans People use: Alginate is used in cosmetics Carageenan is used in gelatin capsules Agar is used to culture microbes
Protists and Humans What is Giardiasis? Caused by Giardia lamblia Reults in diarrhea and cramps
Protists and Humans What is Cryptosporidiosis? Caused by Cryptosporidium paruum Characterized by diarrhea
Protists and Humans What is Trichomoniasis? Caused by Trichomona vaginalis An STD that causes discolored discharge and genital itching.