Taxonomy and Diversity of Life PDF

8/27/24, 8:23 PM Platform | Study Fetch Taxonomy and Diversity of Life Taxonomy (00:00:25 - 00:00:52) What is Taxonomy? Taxonomy is the practice of classifying organisms based on similar characteristics There are many lev...

8/27/24, 8:23 PM Platform | Study Fetch Taxonomy and Diversity of Life Taxonomy (00:00:25 - 00:00:52) What is Taxonomy? Taxonomy is the practice of classifying organisms based on similar characteristics There are many levels of organization in taxonomy The Six Kingdoms of Life and Three Domains The six kingdoms of life are: Archaea Bacteria Protista Fungi Plantae Animalia The three domains of life are: Archaea Bacteria Eukarya Taxonomy Hierarchy Mnemonic "King Philip Came Over For Good Soup" This mnemonic represents the taxonomy hierarchy: Kingdom Phylum Class Order Family Genus Species Prokaryotes (00:01:15 - 00:01:42) Characteristics of Prokaryotes Prokaryotes include the kingdoms Archaea and Bacteria Bacteria have a cell wall made of peptidoglycan The cell wall includes ester-linked lipids Bacterial DNA does not have introns or histones Archaea have a cell wall not made of peptidoglycan The cell wall lipids are ether-linked Archaea DNA does have histones https://www.studyfetch.com/platform/studyset/66cd116dd279f5220d947c66/material/66ce6bd78ab287f54e41f2ac/document?go=note 1/7 8/27/24, 8:23 PM Platform | Study Fetch Gram Positive vs. Gram Negative Bacteria (00:01:42 - 00:02:26) Gram Staining Gram staining is an older method of classifying bacteria It depends on whether the bacteria take up a specific type of stain Gram positive bacteria have a thick outer layer of peptidoglycan Gram negative bacteria have a thinner peptidoglycan layer Eukaryotes (00:02:26 - ) Characteristics of Eukaryotes Eukaryotes have a true nucleus and membrane-bound organelles Examples of eukaryotes include protists, fungi, plants, and animals Eukaryotic cells are generally larger and more complex than prokaryotic cells Eukaryotic Cell Structure Eukaryotic cells have a true nucleus with a nuclear envelope They contain membrane-bound organelles like mitochondria, chloroplasts, endoplasmic reticulum, Golgi apparatus, etc. Eukaryotic DNA is linear and found in chromosomes, with introns and histones Eukaryotic Diversity Major eukaryotic groups include protists, fungi, plants, and animals These groups show a wide diversity of cellular structures, life cycles, and ecological roles Gram-Positive vs. Gram-Negative Bacteria (00:02:26 - 00:02:41) Gram-negative bacteria have an outer membrane, with a peptidoglycan layer sandwiched between the outer membrane and the cytoplasmic membrane. The characteristics of the outer cell membrane and peptidoglycan layer are different between gram-positive and gram-negative bacteria, which can help determine the antibiotics used to treat infections. (00:02:41 - 00:02:56) Some antibiotics are active on the outer layer of gram-negative bacteria. It's important to consider whether bacteria are gram-positive or gram-negative when thinking about treatment. (00:02:56 - 00:03:07) The cell wall of gram-positive bacteria is a smooth, single layer, while gram-negative bacteria have a double layer. The peptidoglycan layer is thick in gram-positive bacteria and thin in gram-negative bacteria. https://www.studyfetch.com/platform/studyset/66cd116dd279f5220d947c66/material/66ce6bd78ab287f54e41f2ac/document?go=note 2/7 8/27/24, 8:23 PM Platform | Study Fetch (00:03:07 - 00:03:18) Gram-positive bacteria have teichoic acids, while gram-negative bacteria do not. Gram-positive bacteria do not have an outer membrane, but gram-negative bacteria do. (00:03:18 - 00:03:29) The lipid content is lower in gram-positive bacteria compared to gram-negative bacteria. The toxin makeup and antibiotic resistance are different between the two groups. (00:03:29 - 00:03:41) Knowing whether a bacterium is gram-positive or gram-negative is important for determining the appropriate antibiotics to use clinically. Eukaryotes (00:03:41 - 00:04:07) Eukaryotes include protists, fungi, and animals. Eukaryotic cells have true nuclei. Fungi and some protists (like slime molds) have flagella or cilia. Protists that are not fungi do not have a chitinous cell wall. (00:04:07 - 00:04:18) Protists that are not fungi are saprophytic, meaning they ingest decaying material through phagocytosis. (00:04:18 - 00:04:34) Plant-like protists are photosynthetic and include dinoflagellates, diatoms, and euglenoids. These plant-like protists can have flagella and be heterotrophic. Autotrophs and Heterotrophs (00:04:34 - 00:04:47) Both autotrophs and heterotrophs can undergo photosynthesis and uptake food from their environment Heterotrophs have membrane-bound vacuoles, which are food vacuoles that store the food they've taken up from their environment Examples of heterotrophs include amoeba and paramecium Amoeba and Paramecium (00:04:47 - 00:04:58) Amoeba and paramecium are examples of heterotrophs Amoeba can consume things by engulfing them and storing the food in food vacuoles Kingdom Fungi (00:04:58 - 00:05:19) Fungi can be divided into two main groups: filamentous fungi (molds) and non-filamentous fungi (yeasts) Filamentous fungi are multicellular and form hyphae Examples of filamentous fungi that can infect humans include Candida and Aspergillus https://www.studyfetch.com/platform/studyset/66cd116dd279f5220d947c66/material/66ce6bd78ab287f54e41f2ac/document?go=note 3/7 8/27/24, 8:23 PM Platform | Study Fetch Non-filamentous fungi, or yeasts, are unicellular and reproduce asexually by budding Fungal Hyphae (00:05:34 - 00:06:00)Types of Fungal Hyphae: Septate Hyphae: Hyphae with septa (walls) that separate them into different units Coenocytic Hyphae: Hyphae with no septa, forming a continuous unit of multinucleated cytoplasm Fungal Reproduction (00:06:00 - 00:06:26) Fungi have both asexual and sexual reproduction Asexual reproduction: Mycelium undergoes mitosis to create spores Spores germinate to form more mycelium Sexual reproduction: Two different mycelia fuse to form a diploid zygote The zygote then forms spores that can germinate Fungal Life Cycle (00:06:26 - 00:06:50) The fungal life cycle involves both asexual and sexual reproduction Asexual reproduction: Mycelium undergoes mitosis to form haploid spores Spores germinate to form more mycelium Sexual reproduction: Two different haploid mycelia fuse to form a diploid zygote The zygote then forms spores that can germinate Fungi Reproduction and Animal Phyla Fungal Reproduction (00:06:50 - 00:07:00) Fungi can reproduce in two main ways: 1. Mycelium Fusion: Two different mycelia (fungal networks) can fuse together. 2. Spore Production: The mycelium can produce spores that then grow into new fungi. https://www.studyfetch.com/platform/studyset/66cd116dd279f5220d947c66/material/66ce6bd78ab287f54e41f2ac/document?go=note 4/7 8/27/24, 8:23 PM Platform | Study Fetch Animal Phyla (00:07:00 - 00:07:13) There are many different animal phyla, including: Porifera (sponges) Cnidaria (jellyfish, corals, sea anemones) Nematoda (roundworms) Rotifera (rotifers) Mollusca (snails, squid, clams) Remembering Animal Phyla (00:07:13 - 00:07:27) Mnemonic to remember the animal phyla: "Privileged Children Play Nicely Respectfully And Maturely. Arthropods Ensure Cooperation, Porifera, Cnidaria, Nematoda, Rotifera, Annelida, Mollusca, Arthropoda, Echinodermata, Chordata." Animal Phyla Characteristics (00:07:27 - 00:08:54) Phylum Characteristics Porifera (Sponges) - Asymmetrical - No body cavity - Not segmented - Examples: sea sponges Cnidaria - Radial symmetry - No segmentation - Mouth but no anus - Examples: jellyfish, coral, sea anemones Platyhelminthes - Bilateral symmetry - Flattened body - Mouth but no anus - Examples: tapeworms, planaria Nematoda - Segmented - Mouth and anus - Bilateral symmetry - Examples: roundworms, earthworms, leeches Mollusca - Mouth and anus - Mantle and foot - Not segmented https://www.studyfetch.com/platform/studyset/66cd116dd279f5220d947c66/material/66ce6bd78ab287f54e41f2ac/document?go=note 5/7 8/27/24, 8:23 PM Platform | Study Fetch - May have a shell - Bilateral symmetry - Examples: snails, squid, clams Chordates: Diversity and Characteristics Introduction to Chordates (00:09:06 - 00:09:19) Chordates include a variety of animals, such as: Clams or oysters Octopus Arthropods (insects, spiders, crustaceans) Arthropods are segmented animals with a hard exoskeleton and a body divided into a head, thorax, and abdomen. Chordate Diversity (00:09:19 - 00:09:34) Chordates are further divided into the following groups: Lancelets Tunicates Jawless fish Cartilaginous fish Bony fish Amphibians Mammals (monotremes, marsupials, placental) Reptiles Birds Characteristics of Chordates (00:09:48 - 00:10:22) Four key characteristics of chordates: 1. Notochord: A cartilaginous rod that runs between the nerve cord and the digestive tract. In humans, it becomes the central column of the spine. 2. Dorsal nerve cord: The nerve fibers that connect the brain and muscles to organs. 3. Post-anal tail: An extension of the body beyond the anus. 4. Pharyngeal slits: Openings that connect the mouth and throat. Chordate Taxonomy https://www.studyfetch.com/platform/studyset/66cd116dd279f5220d947c66/material/66ce6bd78ab287f54e41f2ac/document?go=note 6/7 8/27/24, 8:23 PM Platform | Study Fetch (00:10:22 - 00:10:39) Chordates are divided into the following major groups: Lancelets Tunicates Jawless fish Cartilaginous fish Bony fish Amphibians Reptiles Birds Mammals (monotremes, marsupials, placental) Mastering Chordate Diversity (00:10:39 - 00:11:05) Memorizing the defining features of each chordate group is key to understanding their diversity. While the taxonomy may seem daunting at first, with practice, the differences between the groups will become more apparent. Mastering this knowledge will help you answer questions about the diversity of life accurately. https://www.studyfetch.com/platform/studyset/66cd116dd279f5220d947c66/material/66ce6bd78ab287f54e41f2ac/document?go=note 7/7