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A Survey of Life in the Sea - Introduction The Linnaeus Classification System Prokaryotes – Small Yet Vital Eukaryotes – Diversity of Body Forms Chromalveolates – Dinoflagellates, Coccolithophores, Diatoms and Brown Algae Marine Plants: Red Algae, Green Algae, Seagrasses and Mangroves

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  1. A Survey of Life in the Sea - Introduction The Linnaeus Classification System Prokaryotes – Small Yet Vital Eukaryotes – Diversity of Body Forms Chromalveolates – Dinoflagellates, Coccolithophores, Diatoms and Brown Algae Marine Plants: Red Algae, Green Algae, Seagrasses and Mangroves Rhizaria: Foraminiferans and Radiolarians Choose to view chapter section with a click on the section heading. Chapter Topic Menu

  2. Survey of Life in the Sea - Introduction Survey of Life in the Sea - Introduction Chapter 5 Pages 5-3 to 5-5

  3. A Survey of Life in the Sea - Introduction • Chapter’s 5, 6 and 7 survey life in the sea. • Chapter 5 overviews the classification system, prokaryotes, eukaryotes chromalveolates, marine plants and rhizaria. • Chapter 6 overviews invertebrates - animals without backbones. • Chapter 7 overviews vertebrates - animals with backbones. Survey of Life in the Sea - Introduction Chapter 5 Pages 5-3 to 5-5

  4. A Survey of Life in the Sea - Introduction • Few people realize how diverse life is on planet Earth. • Scientists have classified about 2 million species. • It is estimated that there are between 5 to 100 million possible species on Earth. • New species are discovered with regularity. • What is the importance of any one species? Survey of Life in the Sea - Introduction Chapter 5 Pages 5-3 to 5-5

  5. Imagine Classifying theVariety of Organisms Survey of Life in the Sea - Introduction Chapter 5 Pages 5-3 to 5-5

  6. The Linnaeus Classification System -Putting Life in Its Place The Linnaeus Classification System Chapter 5 Pages 5-5 to 5-15

  7. The Need for Classification • Three reasons for classifying organisms: • It helps identify the relationships between organisms. • It requires scientists to clearly identify key characteristics of each organism. • It avoids confusion. Common names differwith cultures. Scientists in the US and Japan can identify exactly what they are both talking about by using the species’ Latin name. Common names areavoided in science. The Linnaeus Classification System Chapter 5 Pages 5-5 to 5-6

  8. The Need for Classification • The same common namemay apply to two differentorganisms. • Scientists avoid the problems with common names by assigning every species its own Latin name. • These photos are different animals. The common name for both is “Dolphin.” But, it’s a Dolphin “fish” and a Dolphin “mammal.” The Linnaeus Classification System Chapter 5 Pages 5-5 to 5-6 Coryphaena hippurus Tursiops truncatus

  9. Classification Taxa • In 1758, Carolus Linnaeus laid the framework for the classification system we use today. • Linnaeus used Latin for organism’s names since that was the common language of science at the time. Latin is used for two main reasons: • Tradition • It’s a neutral language - no one culture need feel slighted because scientific names are in another scientist’s native language. The Linnaeus Classification System Chapter 5 Pages 5-7 to 5-9

  10. Classification Taxa • An organism’s scientific name represents two taxa. They are: • Species – is the most specific of the taxa. Species is usually considered to be a group of organisms that can reproduce together. • Genus – is the taxon above species. Genus grouped species are considered to be closely related. Example, there are 34 species of reef shark belonging to genus Carcharhinus. The Linnaeus Classification System Chapter 5 Pages 5-7 to 5-9 Arctic KrillEuphausia superba

  11. Classification Taxa • Scientists identify each species by referring to both the genus and the species. The genus is capitalized and the species name in lower case. You also italicize or underline scientific names. The Linnaeus Classification System Chapter 5 Pages 5-7 to 5-9 Bull SharkCarcharhinus leucas Gray Reef SharkCarcharhinus amblyrhynchos

  12. Classification Taxa • A scientific name is a binomial name - from Latin bis meaning twice and nomen meaning name. • Each organism has a unique scientific name. The Linnaeus Classification System Chapter 5 Pages 5-7 to 5-9 Pilot WhaleGlobicephala melas

  13. Classification Taxa • There are eight main taxa into which scientists classify organisms (from the general to specific): • Domain - Fundamental groups of living organisms based on the genetic and physical structure of individual cells. • Kingdom - (or supergroups) a group of similar phyla. • Phylum - (or division) - a group of Classes. • Classes - are groups of related Orders. • Orders - groups of related Families. • Families - groups of Genera that share characteristics. • Genus - (plural Genera) groups species that are closely related. • Species - the Latin name for an individual organism. The Linnaeus Classification System Chapter 5 Pages 5-7 to 5-9

  14. Classification Taxa The Linnaeus Classification System Chapter 5 Pages 5-7 to 5-9

  15. Classification Taxa The Linnaeus Classification System Chapter 5 Pages 5-7 to 5-9

  16. Determining Taxa • How organisms are classified: • Originally by using anatomical features. • The prevailing view now is that taxonomy generally reflects theoretical evolutionary relationships. • Classifying by anatomical features remains an important classification method. However, the study of genetics has become more important. The Linnaeus Classification System Chapter 5 Pages 5-10 to 5-12

  17. Determining Taxa • A common problem taxonomists have in classifying organisms is that some organisms don’t fit neatly into defined classifications. An organism can have characteristics that fit in one and others that separate it from that same classification. • The answer is to insert intermediate classification levels. • By assigning super or sub levels to create new higher or lower divisions within a classification. • Intermediate classifications may sometimes have two names. For example, one taxonomist may use the division subphylum, while another uses the division superclass. The Linnaeus Classification System Chapter 5 Pages 5-10 to 5-12

  18. Determining Taxa The Linnaeus Classification System Chapter 5 Pages 5-10 to 5-12

  19. The Three Domain System of Classification • Taxonomic studies have lead to the development of a system of classification. • They divided all life-forms (except viruses) into several kingdoms. • Division into kingdoms is still argued among scientists. • Today, most taxonomists divide all life on Earth into three domains - Archaea, Bacteria, and Eukarya. The Linnaeus Classification System Chapter 5 Pages 5-13

  20. Viruses - The Tiniest Fragments of Life • The smallest forms of what could be considered marine life are viruses. • Unlike other organisms, viruses have no metabolism or cell structure of any kind. • Viruses are simply strands of DNA or RNA in a protective coat. • Despite their small size, it has been calculated that the ocean contain hundreds of millions of tons of viruses. • The biomass of marine viruses may be greater than that of all marine mammals. • They are the most common biological agent in the sea. The Linnaeus Classification System Chapter 5 Pages 5-13

  21. Phylogenetic Tree of Life • The tree is a visual representation of how organisms fit with one another. • It shows the theorized evolutionary relationships among various species that are thought to have a common ancestor. The Linnaeus Classification System Chapter 5 Pages 5-14

  22. Prokaryotes - Small Yet Vital Prokaryotes – Small yet Vital Chapter 5 Pages 5-16 to 5-20

  23. Old and Simple • Most life in the ocean exists as microbes and minute organisms. • The prokaryotes(from the Latin, pro meaning before and the Greek, karyon meaning kernal, nucleus) are important oceanic micorbes. • In the world’s ocean they numbermore than 3 x1028. This is analmost unimaginable number –more than 100 million times asgreat as the number of starsin the visible universe. Prokaryotes – Small yet Vital Chapter 5 Pages 5-16 to 5-17

  24. Old and Simple • Domain Bacteria and Archaea are classified as prokaryotes because they’re structurally far simpler than the cells found in the organisms of the domain Eukarya. • They: • Lack chromosomes or a nucleus. • Do not have mitochondria. • Lack chloroplasts, but accomplishphotosynthesis. • Photosynthesis by prokaryotes isaccomplished by having chlorophyllmolecules in its membranes. • They are the smallest organisms. Prokaryotes – Small yet Vital Chapter 5 Pages 5-16 to 5-17

  25. Old and Simple • It is theorized that the process of photosynthesis evolved with these early prokaryotes. • It is thought that prokaryote cells had a endosymbiotic relationship within other cells. • Some prokaryotes are extremophiles– organisms that live in environments fatal to most forms of life. Prokaryotes – Small yet Vital Chapter 5 Pages 5-16 to 5-17

  26. Archaea and Bacteria • Genetic work has clearly separated bacteria and archaea into two different domains - although both are prokaryotes. • Archaea (from the Greek archaio meaning old) are extremely common in the ocean – they dominate the life of many deep-sea open ocean areas. • Archaea includes many extremophiles. Archaea live near deep hydrothermal vents, in highsalinity pools, in highly acidicenvironments, in sulfur pools,and even close to volcanoes. Prokaryotes – Small yet Vital Chapter 5 Pages 5-18 to 5-20

  27. Archaea and Bacteria • Scientists continue to find new and diverse bacteria. • Bacteria are extremely adaptable and capable of processes that no other organisms can accomplish. • One important example is a species of bacteria that creates organic nitrogen compounds by fixing inorganic nitrogen from the air. These organic nitrogen compounds are essential to most forms of life. Prokaryotes – Small yet Vital Chapter 5 Pages 5-18 to 5-20

  28. Archaea and Bacteria • There are hundreds of thousands of bacteria species, one important group are Cyanobacteria (from the Greek kyan meaning dark blue). • Cyanobacteria are: • Crucial to life - important to nitrogen cycle and are primary producers. • Cyanobacteria areextremely abundant.Perhaps the mostplentiful species onEarth. Prokaryotes – Small yet Vital Chapter 5 Pages 5-18 to 5-20

  29. Eukaryotes - Diversity of Body Forms Eukaryotes – Diversity of Body Forms Chapter 5 Pages 5-21 to 5-22

  30. Domain Eukarya – Major Groups • Domain Eukarya includes protists (mostly microbial eukaryotes, including those eukaryotes that aren’t a plant, animal or fungus), fungi, plants and animals. • Eukaryotes are all organisms with cells organized into complex structures enclosed within membranes. • All organisms in this domain have cells that have a nucleus. It is the presence of a nucleus that defines the members of domain Eukarya. • “Eukarya” comes from the Greek eu, meaning good or true, and karyon meaning kernal, nucleus. Eukaryotes – Diversity of Body Forms Chapter 5 Pages 5-21 to 5-22

  31. Domain Eukarya – Major Groups • Eukaryotic cells are typically larger than prokaryote cells. • Besides having a distinct nucleus, eukaryotic cells also have a variety of complex internal membranes and structures that prokaryotes do not. • Eukaryotic animal and plant cells also differ from each other. • Plant eukaryotic cells have a cell wall for rigid structural support and protection. Many have chlorplasts allowing them to perform photosynthesis. Animal Eukaryote cells do not have these structures. Eukaryotes – Diversity of Body Forms Chapter 5 Pages 5-21 to 5-22

  32. Domain Eukarya – Major Groups EukaryoteAnimal Cell Eukaryotes – Diversity of Body Forms Chapter 5 Pages 5-21 to 5-22

  33. Domain Eukarya – Major Groups MajorEukaryote Groups Eukaryotes – Diversity of Body Forms Chapter 5 Pages 5-21 to 5-22

  34. Chromalveolates - Dinofagellates, Coccolithophores, Diatomsand Brown Algae Chromalveolates Chapter 5 Pages 5-23 to 5-30

  35. Chromalveolates - Dinofagellates, Coccolithophores, Diatomsand Brown Algae Chromalveolates Chapter 5 Pages 5-23

  36. Dinoflagellates • Dinoflagellates are the second most productive group of primary producers, after diatoms. • Dinoflagellates are: • Mostly marine and unicellular. • Have a flagella for swimming. • Microplankton. • Both autotophic and heterotrophic. • Some species are bioluminescent. • Some species can causeHarmful Algal Blooms (HABs). Chromalveolates Chapter 5 Pages 5-23 to 5-25

  37. Dinoflagellates • Some are symbiotic organisms called zooxanthellate. • These species live in the tissues of corals, anemones, giant clams and some species of sponges. • Without these symbiotic species of dinoflagellates, most hard corals could not exist as we know it. • They provide their hosts food via photosynthesis. • The hosts provide the dinoflagellates with nitrogenous wastes. Chromalveolates Chapter 5 Pages 5-23 to 5-25

  38. Coccolithophores • Coccolithophores all live in the upper layers of the ocean. • Coccolithophores are: • Unicellular. • Autotrophic. • Surrounded by extremely tinyplates made of calcium carbonatefor protection - called coccoliths. • Are numerous in some waters. • A leading calcium carbonateproducer in the ocean. Chromalveolates Chapter 5 Pages 5-25 to 5-26

  39. Diatoms • Diatoms are: • In the phylum Heterokontophyta that also includes brown algae. • Single celled algae. • The most productive phytoplankton. • Basically dormant during wintermonths - in the spring theyreproduce rapidly. • Known for their cellular beautyand have a two-part silicon shell. • A cause of Harmful AlgalBlooms (HABs). Chromalveolates Chapter 5 Pages 5-26 to 5-27

  40. Brown Algae • Brown algae: • Are in the same group as diatoms, but are structurally complex. • Are multicellular. • Range in size, with some individuals being gigantic. • Have adapted to a variety of habitats. • Can be found in tidepools and deep, near-shore waters. • Prefer predominately cold water with lots of nutrients. Chromalveolates Chapter 5 Pages 5-28 to 5-30

  41. Brown Algae • Many brown algae species have • Holdfasts – anchor the algae to the bottom. • Leathery stipes – provide supportlike plant stems, but withno vascular system. • Blades – equivalent of leaves. • Pneumatocysts – gas filled floatstructures that lift the algaeoff the bottom and keep the blades close to the surface and sun. Chromalveolates Chapter 5 Pages 5-28 to 5-30

  42. Brown Algae • Gets its distinctive olive-green/brown color from the pigment fucoxanthin. • Kelp is the largest of the brown algae. • Kelp is important because it is the foundationformany temperate coastal ecosystems. Chromalveolates Chapter 5 Pages 5-28 to 5-30

  43. Brown Algae • Sargassum, another brown algae can be found drifting in North Atlantic currents. Early mariners feared that sargassum could ensnare their ships, though such dense concentrations are rare. • The Sargasso Sea exists in a relatively currentless portion of the Atlantic. Chromalveolates Chapter 5 Pages 5-28 to 5-30

  44. Marine Plants - Red Algae, Green Algae, Seagrasses and Mangroves Marine Plants Chapter 5 Pages 5-31 to 5-38

  45. Marine Plants – Red Algae, Green Algae, Seagrasses and Mangroves Marine Plants Chapter 5 Pages 5-31

  46. Phylum Rhodophyta – Red Algae • Red algae: • Are in the Phylum Rhodophyta. • Consists of freshwater and marine algae. • Are multicellular macro algae. • Have chlorophyll a, but not b. • Has red pigments called phycoerythrins - they allow some red algae to live much deeper than any other algae. Marine Plants Chapter 5 Pages 5-32 to 5-33

  47. Phylum Rhodophyta – Red Algae • Red algae species that live on coral reefs secrete a calcium carbonate shell. • Their secretions bond coral colonies and debristogether which in turn holds the reef together. Marine Plants Chapter 5 Pages 5-32 to 5-33

  48. Phylum Chlorophyta – Green Algae • Green algae: • Is in the Phylum Chlorophyta. • Is made up of the macro algae. • Shares the same green color as land plants. • Has Chlorophyll a – a pigment directly involvedwith photosynthesis. • Has Chlorophyll b – assists chlorophyll a in capturing lightfor use in photosynthesis. • Consists of approximately 7,000 species. Marine Plants Chapter 5 Pages 5-33 to 5-34

  49. Phylum Chlorophyta – Green Algae • Scientists think the presence of chlorophyll a and b has evolutionary significance. It may indicate that land plants evolved from green algae. • Green algae and land plants also have other pigments in common and have cell walls made of cellulose. Marine Plants Chapter 5 Pages 5-33 to 5-34 Sea Lettuce

  50. Marine Flowering Plants - Underwater Meadows and Shallow Nurseries • Few flowering plant species live in the marine environment - only about 200 species. • These marine flowering plants play a surprisingly important role in the health of the ocean. Marine Plants Chapter 5 Pages 5-34

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