CLASSIFICATION & THE TREE OF LIFE

Transcription

1 CLASSIFICATION & THE TREE OF LIFE

2 WHAT ARE THE CHALLENGES TO LIVING IN THE SEA? Maintaining Homeostasis through - Salinity Diffusion & Osmosis moving from an area of high concentration to an area of low concentration Active Transport- moving from an area of low concentration to an area of high concentration Regulating Salt & Water Balance Osmoconformer: internal concentrations change as the salinity of the water changes; many organisms can only live in a narrow range of salinity; there are a few others that can tolerate relatively large changes in salinity These organisms have limits & experience osmotic problems outside their range of tolerance Since many of these organisms live out in the open ocean, there aren t many issues

3 WHAT ARE THE CHALLENGES TO LIVING IN THE SEA? Osmoregulators: control their internal concentrations to avoid problems; these organisms still have limits but can adapt better than others they adjust the concentrations of solutes in their body fluids so that the concentration of their fluids match their environment It DOES NOT matter if there are the same dissolved chemicals as long as the TOTAL AMOUNT of dissolved materials is the same Sometimes its only ONE chemical that they change Example: Sharks typically only change the amount of urea in their bodies

4 WHAT ARE THE CHALLENGES TO LIVING IN THE SEA? Temperature Organisms are greatly affected by temperature; metabolic reactions speed up in higher temperatures & slow down drastically as it gets cold Most reactions occur 2x as fast with a 10 o C rise in temperature; at extreme temps, most enzymes will cease to function; most organisms are adapted for living within a particular temp range

5 WHAT ARE THE CHALLENGES TO LIVING IN THE SEA? Organisms are classified based on their metabolic reaction rate Ectotherms - cold-blooded organisms; heat is quickly lost to the environment & doesn t change the body temperature Poikilotherms - body temperature & metabolic rates change with the temperature of the surroundings (includes some endotherms - shark & tuna); these organisms slow down as temperature decreases Endotherms - warm-blooded organisms; metabolic heat is retained & raises the body temperature above the surroundings (mammals, birds, some large fish (tuna & sharks) Homeotherms - organisms with the ability to regulate their internal temperature so that it stays even with the external temperature; retain heat & control their metabolism by burning fats & energy-rich molecules; they remain highly active regardless of water temperature - eat more that poikilotherms; most have blubber, feathers, or hair though to help insulate and reduce this amount

6 WHAT ARE THE CHALLENGES TO LIVING IN THE SEA? Surface to Volume Ratio Amount of surface area relative to the total volume of an organism Determines how rapidly heat & materials (nutrients, waste products, & gases) flow through the organism, typically across the surface of the organism Size is the main determining factor - as organisms grow larger, their volume increases faster than their surface area Small organisms have a larger S/V ratio, which means they can rely on simple diffusion across their surfaces to exchange materials Larger organisms have a smaller S/V ratio & must develop supplementary mechanisms, like respiratory & excretory systems

7 WHAT ARE THE CHALLENGES TO LIVING IN THE SEA? Reproductive Strategies Some species release millions of eggs & sperm into the water, where fertilization occurs & have no further interaction with their offspring - known as BROADCAST SPAWNING (corals) Some species only have a few offspring & invest a lot of time & effort into them (whales) Some species develop from larval stages & look differently from egg to adult (jellyfish) Can be asexually or sexually Sexually reproducers can be male/female in separate individuals or hermaphroditic

8 TREE OF LIFE Charles Darwin s version

9 The New Tree of Life (updated 4/11/2016)

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12 PROKARYOTES Smallest & structurally simple organisms Carryout nearly ALL chemical processes that eukaryotes do plus those that are unique to prokaryotes Enclosed by a cell wall Single-celled Lack nucleus & membrane-bound organelles Contain circular DNA The Usual Suspects: Domain Bacteria [Eubacteria] Domain Archaea [Archaeabacteria]

13 FEEDING PROKARYOTES Autotrophs Self-feeders Make their own organic compounds Photosynthetic/Photoautotrophic - contain chlorophyll to trap light energy (no chloroplasts); account for the majority of the primary production in the ocean; some even use the glow of hydrothermal vents; some produce S instead of O 2 Chemosynthetic/Chemoautotrophic - derive energy from chemical compounds like H 2 S, S, N, & Fe (hydrothermal vent smoke) Classified as Primary Producers

14 FEEDING PROKARYOTES Heterotrophs Different -feeders Obtain energy through cellular respiration Cannot make their own food, must obtain it from other organisms Many are decomposers Nitrogen-Fixers Convert gaseous N2 into ammonium to be used as a nitrogen source for primary producers Many are bottom-dwelling & planktonic cyanobacteria

15 DOMAIN BACTERIA [EUBACTERIA] Branched early; very distinct from the other 2 branches Abundant in ALL parts of the ocean Stiff or slimy coverings on the cell wall (thick) to allow them to attach to surfaces or act as a protector Can range in size Very Small - 250,000 can fit on a period. Larger (0.02 in) found in intestines of coral reef fish In larger numbers they can appear as white hairs on rotting seaweed or pink patches in stagnant mudflats or saltmarshes

16 DOMAIN BACTERIA [EUBACTERIA] Grow in extremely high numbers in favorable environments Example - Detrius (dead organic matter) Decay bacteria breakdown wastes & detritus then release nutrients back into the environment; this is vital to life on Earth to ensure the recycling of essential nutrients Most abundant form of life on Earth = Pelagibacter ubique (found in open ocean waters) Can reproduce quickly, some in 20 minutes (binary fission, a type of asexual reproduction)

17 DOMAIN BACTERIA [EUBACTERIA] BACILLI SPIRILLA Types/Forms Some play a vital role to feed bottom-dwelling animals Some degrade oil & toxic pollutants that enter the environment Some cause disease in marine animals & humans COCCI Cyanobacteria (blue-green algae) is a group of photosynthetic bacteria (can also appear red) 1 st photosynthetic organisms on Earth Thought to play an important role in the accumulation of O2 in the atmosphere Can live in hairs of polar bears, in calcareous rocks & coral skeletons, and along rocky coasts Planktonic species reproduce rapidly & change color of water - create red tides Epiphytes live ON algae or marine plants, while Endophytes live INSIDE algae

18 DOMAIN BACTERIA [EUBACTERIA] Major Forms: Nostoc Spirulina Oscillatoria Fisherella

19 DOMAIN ARCHAEA [ARCHAEABACTERIA] Simplest, most primitive life forms Look similar to the oldest fossils Estimated to be 3.8 billion years old Important role in early evolution of life More closely related to eukaryotes than bacteria

20 DOMAIN ARCHAEA [ARCHAEABACTERIA] Found in extreme environments - hot sulfur springs, saline lakes, & highly acidic/alkaline environments Named extremophiles or lovers of extremes - but it is not true of all species Survive pressures of 300 to 800 atmospheres Types/Forms Some live at hydrothermal vents Some live in coastal salt plains or deep ocean basins, where it s extremely salty

21 EUKARYOTES Can be either unicellular or multicellular Contain a nucleus & membrane-bound organelles DNA is within nucleus & contains chromosomes Cellular Respiration occurs in mitochondria Respiration is the breakdown of organic molecules into energy Many contain cilia or flagella For movement To push water or particles into or over bodies

22 DOMAIN EUKARYA [PROTISTA] General term of this group is ALGAE Mostly aquatic & photosynthetic, but unicellular Color is a result of pigments & their concentration Lack flowers, true leaves, stems, & roots; have simple reproductive systems Multicellular seaweeds technically fall under this group since they lack the specialized tissues of plants Not considered to be it s own Kingdom anymore since so many of it s characteristics are shared Examples: Diatoms Dinoflagellates Silicoflagellates Coccolithiophorids Cryptopyhtes

23 DIATOMS [PHYLUM HETEROKONTOPHYTA] Unicellular, but form aggregate into chains or star-like groups Enclosed by cell walls made of silica, a glass-like material Glassy shell is called a frustule, which is similar to two tightly fitting halves (like a box) Has perforations & ornaments (spines or ribs), that allow light to pass through for photosynthesis and dissolved gases & nutrients to enter & exit Store food as oil instead of starch

24 DIATOMS [PHYLUM HETEROKONTOPHYTA] Color is a yellowish-brown, due to carotenoid pigments in chlorophyll a & c (called golden algae ) Important open-water primary producers in temperate & polar regions The large number of diatom cells in the ocean accounts for a large share of the organic carbon & oxygen produced on Earth Over half of the estimated 12,000 species are marine, most of which are planktonic Reproduce through cell division

25 DIATOMS [PHYLUM HETEROKONTOPHYTA] Favorable environmental conditions (adequate nutrients & light) trigger periods of rapid reproduction, known as blooms Most get significantly smaller in size, due to cell division & a depletion in the silicate from water the growing population Glassy frustules of dead diatoms settle to the bottom of the ocean & form thick deposits of siliceous material (biogenous sediments) that is known as diatomaceous ooze This material is found fossilized in various parts of the world, known as diatomaceous earth and is mined & used in products such as pool filters, temperature & sound insulators, & mild abrasives in toothpaste and bathroom cleaners

26 Stands for Fire Algae DINOFLAGELLATES [PHYLUM PYRROPHYTA] Plant-like, microscopic algae Contain 2 flagella, thick cell wall plates of cellulose(can have spines or pores) Most are photosynthetic, but can ingest food particles Some have a light sensitive pigment spot, that acts as a crude eye There are over 1,200 marine species Ceratium

27 DINOFLAGELLATES [PHYLUM PYRROPHYTA] Important planktonic primary producer in warm waters Reproduce by simple cell division Sometimes will form blooms that color the water red, reddish-brown, yellow, or other colors Some (especially the red forms) release toxic substances that taint the seafood collected during that time and make it poisonous Others are noted for their ability to bioluminesce This is only seen at night along the sea surface They are especially bright if the water is disturbed by a boat or when waves crash on shore

28 DINOFLAGELLATES [PHYLUM PYRROPHYTA] Symbiotic Relationships Mutualism - Zooxanthellae live within sponges, coral reefs, sea anemones, & giant clams; they fix CO2 by photosynthesis, release organic matter used by the coral, & help in the formation of the coral skeleton Parasitism - Pfiesteria or phantom dinoflagellates reside as cysts in sediments; blooms are triggered by coastal pollution which causes deadly open sores on fish, crabs, oysters, & clams Major issue in the Chesapeake Bay area Noctiluca (Seasparkle)

29 RED TIDES

30 COCCOLITHOPHORIDS [PHYLUM HETEROKONTOPHYTA] Another form of golden algae (like diatoms) Flagellated, spherical shells covered with button-like structures called coccoliths (made of calcium carbonate) Make up a large part of calcareous deposits in sediments of warm waters

31 DOMAIN EUKARYA [PROTISTA/PROTOZOAN] Animal-like protists, most are unicellular; classified by movement First animals ; considered zooplankton Enormous diversity in structure, function, & lifestyle; 50,000 estimated species Heterotrophic (eat like animals - engulf food) Inhabit freshwater, saltwater, & the water inside other organisms Found in sediments, surface of seaweeds, guts of animals, & plankton samples Examples: Foraminiferans Radiolarians Ciliates

32 RADIOLARIAN [PHYLUM SARCODINA] Planktonic marine protozoans with shells made of silica; are spherical in shape with radiating spines Thin, needle-like pseudopodia capture food Remains of their shells settle to the bottom of deep water areas because their shells are more resistant to dissolving under pressure

33 FORAMINIFERAN [PHYLUM SARCODINA] Marine protozoans with a shell made of calclium carbonate Have long, thin, retractable pseudopodia; used to trap diatoms & other organisms suspended in water Most species are known as microfossils - they can use the distribution of these to determine past water temperatures, where to look for oil, & tell the age of sediments

34 CILIATES [PHYLUM CILOPHORA] Largest group of protozoans Use cilia to move & feed Many are found creeping over seaweeds & in sediments Others live on the gills of clams, in the intestines of sea urchins, & on the skin of fish Important to the open-water food web (microbial loop)

35 DOMAIN EUKARYA [FUNGI] Mostly multicellular, with cell walls & cell membranes Heterotrophic 500 known species of marine fungi Mostly microscopic Types/Forms Most are decomposers & saprophytes (live on dead organisms) Some are parasites of fish & plants, like seagrass or borers in mollusk shells Some live in symbiotic relationships with algae or cyanobacteria to form lichens on rocky intertidal zones

36 DOMAIN EUKARYA [PLANTAE] Primary producers Majority composed of seaweed (multicellular algae), Seagrass, Kelps, & Mangroves

37 DOMAIN EUKARYA [THE SEAWEEDS] Multicellular algae Known as macrophytes or macroalgae rather than seaweed Eukaryotic, but lack highly specialized structures & reproductive mechanisms; some people don t classify them as plants, but as protists Types are based on colors

38 DOMAIN EUKARYA [THE SEAWEEDS] Structure - Lack leaves, stems, & roots Body is known as a thallus Leaf-like flattened portions are blades; large surface area, where photosynthesis occurs (no veins) Pneumatocysts (CO air-filled sacs) keep blades close to the water surface Some blades originate from a stipe; a stem-like structure that provides support) Holdfast, a structure that resembles roots, attaches to the thallus (kelps) No roots or soft-bottom anchors; water & nutrients are picked-up directly across the surface of the thallus (no need for roots)

39 DOMAIN EUKARYA [THE SEAWEEDS]

40 DOMAIN EUKARYA [PHYLUM CHLOROPHYTA] Green Algae Freshwater & terrestrial environments 10% of the 7000 species are marine (mostly unicellular) Wide variety in bays, estuaries, & isolated tide pools on rocky coasts Believed that land plants originated from these Bright green thallus Sometimes flourish in polluted areas Enteromorpha Ulva or Sea Lettuce

41 DOMAIN EUKARYA [PHYLUM HETEROKONTOPHYTA, CLASS PHAEOPHYTA] Brown Algae Color varies from olive green to dark brown (due to pigment fucoxanthin) Almost all 1500 species are marine Include the largest & most complex seaweeds (kelps) Many can withstand exposure to air This variety is used as a food source

42 DOMAIN EUKARYA [PHYLUM HETEROKONTOPHYTA, CLASS PHAEOPHYTA] Brown Algae Types - Rockweeds are found on Atlantic & Pacific coasts Knotted seaweed is found on Atlantic coasts Sargasso Weed (think baby sea turtles floating around) is found in the Gulf of Mexico Have air bladders to keep it afloat Most species grow on rocks, but two species float in large masses at sea Kelp are found below low tide levels; provide food & shelter for many Many form fast growing intertwined stripes that are very dense & productive; known as Kelp Beds or Kelp Forests in the Pacific

43 DOMAIN EUKARYA [PHYLUM RHODOPHYTA] Gelidium Red Algae More species than green & brown combined Phycobilins (red filaments) mask chlorophyll Most are red, but color can vary depending on exposure to light Majority of the 4000 species are marine Inhabit mostly shallow water environments Rhodymenia Gigartina

44 ECONOMIC IMPORTANCE OF SEAWEEDS Food Source (red & brown) Mariculture - farming of seaweed in China, Japan, & Korea Gelatinous Chemicals - phycocolloids (valuable due to their ability to form viscous suspensions or gels Algin (from giant kelp) is used as a stabilizer in making ice cream & cheese; prevents icing from drying out; aids in emulsifying shampoo, shaving cream, plastic, & pesticides; used in making rubber, paint, paper, & cosmetics Carrageenan (from red algae) is a jelly-like substance used to protect ham, fish, & other meats during shipping; used in laxatives & cosmetics; to grow bacteria

45 DOMAIN EUKARYA [PLANTAE] True leaves, stems, & roots Specialized tissue to transport water & nutrients Found living submerged in seawater environments (seagrass) or in estuaries & along shores (mangroves & salt-marsh grasses),

46 DOMAIN EUKARYA [ORDER ALISMATALES] Seagrasses Only truly marine plant - often live submerged in seawater, rarely exposed at low tide Resemble grass, but are not actually grasses (closest relatives are lilies) Flowers are small & inconspicuous; pollen is carried (in strands) by water currents

47 DOMAIN EUKARYA [ORDER ALISMATALES] Types Eelgrass is the mostly widely distributed variety (of the 60 known species) Temperate & tropical regions of the world Found in shallow, well-protected coastal waters (estuaries & bays) Common in oxygen-poor sediments Zostera Highly productive; provide shelter & food for many organisms Surf Grass Inhabits rocky coats, that are exposed to significant wave action Found along the Pacific coasts

48 DOMAIN EUKARYA [FAMILY POACEAE: SALT MARSH GRASSES] Cordgrass (Spartina sp.) True members of the grass family; not marine species, but adapted to living in salt Do not tolerate total submergence in seawater Live throughout temperate regions Highly productive & provide habitat and breeding grounds for many fish species Offer protection against erosion & provide natural water purification Leaves are always partially exposed to air; salt glands in the leaves excrete excess salt

49 DOMAIN EUKARYA [FAMILY RHIZOPHORACEAE] Mangroves Trees & shrubs adapted to living along tropical & subtropical shores Land plants that can tolerate salt (like salt-marsh grasses) Flourish along muddy or sandy shores, that are protected from waves Adaptations allow it to live in areas where water loss from leaves is high & sediments are soft and poor in oxygen Thick leaves to prevent water loss Seeds germinate while still attached to the tree