Unit 2 L2 Protista & Fungi PDF

**What are some characteristics of protists?** The kingdom Protista is a group of eukaryotic organisms that cannot be classified as fungi, plants, or animals. Members of the kingdom Protista are called protists. Protists are a very diverse group of organisms. Many members of this kingdom are not cl...

**What are some characteristics of protists?** The kingdom Protista is a group of eukaryotic organisms that cannot be classified as fungi, plants, or animals. Members of the kingdom Protista are called protists. Protists are a very diverse group of organisms. Many members of this kingdom are not closely related to each other and some are more closely related to members of other kingdoms. As a result, classification of protists is likely to change. So are there traits that are shared by all protists? As eukaryotes, they all have a nucleus and membrane-bound organelles. A. **They Have One or Many Cells:** Most protists are single-celled organisms. These protists cannot be seen without a microscope. Diatoms are single-celled protists that have cell walls with unusual shapes. Some protists have many cells. Brown algae are multicellular protists that grow many meters long. Other protists live in colonies. Volvox, a kind of green algae, has cells that form spherical colonies. These colonies can have thousands of cells that all work together. B. **They Have Membrane-Bound Organelles:** Like all eukaryotes, protists have membrane- bound organelles. Organelles are structures that carry out jobs inside a cell. For example, some protists have chloroplasts that make food from the sun\'s energy. Many protists have contractile vacuoles that remove excess water from the cell. Some protists have organelles that sense light. C. **They Have Complex Structures for Movement:** Some protists have structures for movement. Most protists that move do so in order to find food. Some protists use cilia to move. Cilia are hairlike structures that beat rapidly back and forth. Other protists use a flagellum or many flagella to move. A flagellum is a whiplike structure that propels the cell forward. Amoebas are protists that move by stretching their bodies. This forms a pseudopod (SOO-duh-pahd) or "false foot." When cytoplasm flows into the pseudopod, the rest of the cell follows. **How can protists reproduce?** Some protists reproduce only asexually. Others reproduce asexually at one stage in their life cycle and sexually at another stage. For some protists, the type of reproduction alternates by generation. For example, a parent reproduces asexually, and its offspring reproduce sexually. Then the cycle starts again. Other protists reproduce asexually until environmental conditions become stressful. A lack of food or water can trigger these protists to reproduce sexually until conditions improve. **A) By Asexual Reproduction:** Most protists can reproduce asexually. In asexual reproduction, the offspring come from just one parent. So every organism can produce offspring on its own. These offspring are genetically identical to the parent. When environmental conditions are favorable and there is plenty of food and water, asexual reproduction produces many offspring very quickly. Protists can reproduce asexually in different ways. These include binary fission and fragmentation. During binary fission, a single-celled protist copies its DNA. The protist then divides into two cells. Each new cell has a copy of the DNA. The paramecium shown above is splitting through binary fission. Fragmentation is a process in which a piece breaks off of an organism and develops into a new individual. Many multicellular protists can reproduce by fragmentation. **B) By Sexual Reproduction:** Some protists reproduce sexually. In sexual reproduction, two cells, called gametes, join together. Each gamete contains a single copy of the genes for the organism. A cell with only one copy of genetic material is described as being haploid. A cell with two copies is diploid. Each gamete comes from a different parent. When the haploid gametes join, the diploid offspring have a unique combination of genetic material. Genetic diversity increases a species\' chance of survival when the environment changes. In some protists, generations alternate between using sexual or asexual reproduction. The haploid generation adults are called gametophytes (guh-MEET-uh-fyts). The diploid generation adults are called sporophytes (SPOHR-uh-fyts). Diploid adults undergo meiosis to make haploid spores. Spores are reproductive cells that are resistant to stressful environmental conditions. These spores develop into haploid adults. The haploid adults undergo mitosis to form haploid gametes. Two gametes join to form a diploid zygote. The zygote then grows into a diploid adult. This continuing cycle is called alternation of generations. **What are different kinds of protists?** Because protists are so diverse, grouping them can be difficult. One useful way to group protists is by how they get food. Some capture food, like animals do. Some absorb nutrients, like fungi do. Some make food, like plants do. A. **Animal-like Protists:** Animal-like protists cannot make their own food. Instead, they get nutrients by ingesting other organisms. Many animal-like protists eat small organisms such as bacteria, yeast, or other protists. Most animal-like protists can move around their environment. This allows them to search for food in the environment. Sometimes, the same structures that aid movement can also help protists get food. For example, cilia sweep food toward a paramecium\'s food passageway. Amoebas use their pseudopodia to engulf their food. B. **Fungus-like Protists:** Usually, fungus-like protists cannot move on their own. So capturing live organisms would be hard for these protists. Since they cannot make their own food, how do they get nutrients? Fungus-like protists absorb nutrients from the environment. Many fungus-like protists absorb nutrients from living or dead organisms. Fungus-like protists produce spores that are used in reproduction. The protists release the spores into the environment, and the spores can survive through periods of harsh conditions. When the spores land on a good source of nutrients, they develop into an adult. C. **Plant-like Protists:** Plant-like protists are producers. This means they use the sun\'s energy to make food through photosynthesis. Single-celled, free-floating, plant-like protists are a main part of the ocean\'s phytoplankton. Phytoplankton are tiny, floating organisms that provide food for many larger organisms. They also produce much of the world\'s oxygen. Multicellular plant-like protists are called (algae). All algae have the green pigment chlorophyll in their cells. Many also have other pigments. Algae are grouped by color. The three main groups of algae are brown algae, red algae, and green algae. The pigment color determines what wavelengths of light the algae can absorb. **What are some characteristics of fungi?** Fungi (FUHN-jy; singular, fungus) are spore-producing organisms that absorb nutrients from the environment. Fungi are so different from other organisms that they are placed in their own kingdom. Fungi are consumers, which means they cannot make their own food. Also, fungi cannot move. This means they cannot catch organisms to ingest as food. Fungi get nutrients by secreting digestive juices onto a food source. Then, they absorb nutrients from the dissolved food. Many fungi are decomposers. Decomposers get nutrients from dead matter. All fungi are made of eukaryotic cells that have nuclei. Fungi are unique because their cell walls contain chitin. Chitin is a hard substance that strengthens the cell walls. Some fungi are single- celled. Most are made up of many cells that form chains. These chains are threadlike fungal filaments called hyphae (HY-fee; singular, hypha). We can only see a small part of many fungi. That\'s because most of the organism is underground or woven into its food source. Most hyphae in a fungus form a twisted mass called a mycelium (mie-SEE-lee-uhm). The hidden mycelium makes up the major part of the body of a fungus. Just a small part of a fungus is visible. The visible part of a mushroom includes a stalk, a cap, and gills that release spores. **How can fungi reproduce?** Fungi reproduce both asexually and sexually. In asexual reproduction, offspring are genetically identical to the parent. In sexual reproduction, offspring are genetically unique. A. **By Asexual Reproduction:** Asexual reproduction in fungi occurs in three ways. In fragmentation, hyphae break apart, and each piece becomes a new fungus. In budding, a small portion of a parent cell pinches off to become a new individual. In asexual reproduction by spores, hyphae produce a long stalk called a sporangium (spuh·RAN·jee·uhm). Here, spores develop through mitosis. Spores are light and easily spread by wind. So spores can travel long distances even though fungi cannot move on their own. When conditions are favorable, a spore develops into a new fungus. B. **By Sexual Reproduction:** In most fungi, sexual reproduction occurs when hyphae from two individuals join together. The fused hyphae produce a special reproductive structure, such as a mushroom. Genetic material from both individuals fuse to form diploid cells. Then the cells undergo meiosis to become haploid again. The spores are then released. These spores are much like asexual spores. Both can spread easily through the environment and survive until favorable conditions arise. **What are some kinds of fungi?** Fungi are classified based on their shape and the way they reproduce. Many species of fungi fit into three main groups. These groups are zygote fungi, sac fungi, and club fungi. A. **Sac Fungi:** Sac fungi are the largest group of fungi. Sac fungi include yeasts, powdery mildews, morels, and bird\'s-nest fungi. Sac fungi reproduce asexually and sexually. Sexually produced spores develop within a microscopic sac that then opens to release the spores. This structure gives sac fungi their name. Most sac fungi are multicellular. Yeasts are typically single-celled sac fungi that usually reproduce asexually by budding. Budding occurs when a new cell pinches off from an existing cell. Under certain conditions a yeast will reproduce sexually and form spores in sacs. Yeasts are used to make bread and alcohol. Other sac fungi make antibiotics and vitamins. B. **Zygote Fungi:** Zygote fungi are named for sexual reproductive structures that produce zygotes inside a tough capsule. Most of the fungi in this group live in the soil and are decomposers. Some zygote fungi are used to process foods like soybeans. Other types of zygote fungi are used to fight bacterial infections. However, some zygote fungi can cause problems for people. Have you ever seen moldy bread? A mold is a fast-growing, fuzzy fungus that reproduces asexually. Bread mold and molds that rot fruits and vegetables are examples of this asexual stage of a zygote fungus life cycle. Some molds also have a stage during which they reproduce sexually. C. **Club Fungi:** Mushrooms, bracket fungi, puffballs, smuts, and rusts are club fungi. Club fungi are named for the microscopic structures in which the spores develop. Only the spore-producing part of a club fungus is visible. These structures usually grow at the edges of the mycelium. A fungal mycelium can be incredibly large. One of the world\'s largest living organisms is a honey mushroom in Oregon whose mycelium spans almost 9 km². Club fungi are very important decomposers of wood. Without fungi, the nutrients in wood could not be recycled. Smuts and rusts are plant parasites. They often attack crops such as corn and wheat. **How do fungi form partnerships?** Fungi form two very important partnerships. Some fungi grow on or in the roots of plants. These plants provide nutrients to the fungus. In return, the fungus usually helps the roots absorb minerals. This partnership is called a mycorrhiza (my.kuh.RY.zuh). A lichen is a partnership between a fungus and a green alga or cyanobacterium. They are so inseparable that scientists give lichens their own scientific names. The alga or cyanobacterium uses photosynthesis to make food. The fungus gives protection, water, and minerals. Lichens provide food for animals in polar climates. Also, because lichens are very sensitive to pollution, the presence of lichens indicates that an environment has clean air. \*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\* - This moth has been infected by a fungus. When the fungus sprouts, the moth dies. The fungus then bursts open, and its spores disperse. - The photo below shows a protist you might be familiar with---seaweed. Write a caption for the photo that describes this protist. - The two organisms shown below look very different. Why do scientists classify both as protists? - The brown algae shown here is a multicellular protist. - The paramecium shown here is a consumer that uses cilia to move and to capture food. - The diatom shown here is a microscopic single-celled protist. - How can structures for movement help protists to survive? - Draw Each protist shown below is missing the structures it uses for movement. Draw the missing parts for each individual. - The euglena is a producer that uses light to make food. It uses its flagellum to move toward light and to escape from predators. - What are the benefits of asexual reproduction and the benefits of sexual reproduction. - Both protists and bacteria can reproduce asexually using binary fission. Research to find out how protist fission differs from bacterial fission. - A paramecium can reproduce asexually by binary fission. First, it copies the DNA. Then, the paramecium divides in half. - Ulva, or sea lettuce, is an algae that reproduces by alternation of generations. - Use the terms diploid, haploid, and adult to fill in the blanks describing how Ulva reproduces with alternating generations of diploid and haploid cells. - how each kind of protist gets its food. - Amoebas capture their food by surrounding it with a pseudopod. - This water mold absorbs nutrients from the body of a fish. - Some brown algae can grow to be many meters long. - This green algae lives in shallow tide pools. - For each kind of protist on the chart below, list three characteristics: (Animal-like Protists, Fungus-like Protists, Plant-like Protists). - Because plant-like protists make their own food from sunlight, in what kind of environment would they not be able to survive? Why? - Red algae live in tropical water. - Fungi come in all shapes and sizes. Draw an organism that is a mushroom with all the parts shown in the image at left but that is shaped according to your imagination. Label each part of the mushroom. - Thread-like strands called hyphae make up the body of this mushroom. Most of the hyphae are underground. - Describe the role of spores in both asexual and sexual fungus reproduction. - Why is it important for spores to spread easily to other locations? - This bread mold sporangium will release spores to spread through the environment. - This collared earthstar fungus releases its spores by shooting them into the air. - What are the characteristics that define each kind of fungus. - This bread mold is a fuzzy example of a zygote fungus. - Morels are an edible type of sac fungus that grow at the base of trees. - These red Amanita are highly toxic, yet beautiful, club fungi. - These mushrooms are club fungi. - Lichens can grow on rocks. They release acids that break down rock over time to make soil. - Suppose that the number of kinds of lichens at a city park is decreasing each year. What might explain this disappearance? - Protists are eukaryotes that don\'t fit in other classification groups. - A \_\_\_\_\_\_\_\_\_\_\_\_\_ is a haploid reproductive cell used in sexual reproduction. - Fungi absorb nutrients and have chitinous cell walls. - Fungi are \_\_\_\_\_\_\_\_\_\_\_\_\_\_ because they have a nucleus and other membrane-bound organelles. - Protists can be grouped as fungus-like, plant-like, and animal-like protists. - \_\_\_\_\_\_\_\_\_\_\_\_\_\_ -like protists can produce their own food from the sun\'s energy. - Fungi can partner with other organisms. - \_\_\_\_\_\_\_\_\_\_\_\_\_\_ can indicate levels of air pollution. - This lesson groups protists informally by the way they get food. Think of another way to categorize the different kinds of protists and describe your system below. 1 fungi A reproductive cell that resists harsh environmental conditions. --- ---------- -- ------------------------------------------------------------------- 2 protists extremely diverse group of eukaryotic organisms; some have cilia. 3 spore reproductive cell that unites with another reproductive cell. 4 gamete spore-producing organisms that absorb nutrients. - Why are protists discussed in groups such as animal-like, plant-like, and fungus-like protists? - Write the three major types of fungi and an example of each. - What are two ways that protists can reproduce asexually? - What are two ways in which fungi reproduce? - Use this image to answer the following question. Do you think this protist can make its own food? Explain. - In humans, infections by fungi and protists are usually more difficult to treat than bacterial infections. Suggest an explanation that is based on cell structure. - Suppose that when crops developed a fungal infection, a farmer decided to spray the soil with a fungicide. Just after spraying, the plants looked healthier, but soon they showed signs of mineral deficiency. What might explain this response? - Mushrooms belong to the kingdom Plantae (True / False). - Algae use sunlight to make food through photosynthesis (True / False). - Spores are important in fixing atmospheric nitrogen (True / False). - Protists can reproduce both asexually and sexually (True / False). - Many English words have their roots in other languages. Use the Greek words below to make an educated guess about the meaning of the words spores and hyphae. (spora) = seed, sowing / (huphe) = web, Example sentence: Fungi reproduce asexually by means of spores. Mushrooms are made up of tangled hyphae.