EVE12 Week 2 Notes
EVE12 Week 2 Notes EVE12
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Date Created: 04/06/16
EVE Week 2 Notes Sex in the Sea (Reproduction is a defining characteristic of life) 1. nudibranchs mating (naked-respitory mollusks) GOALS: (Explore modes of reproduction in the sea, simple vs. complex life histories, broadcast spawning, brooding, hermaphroditism (simultaneous, sequential), Understand reproductive challenges imposed by sea, Understand costs and benefits of different reproductive modes) LECTURE 1. Sponges (Porifera) a. Asexual: without mating (budding, cloning) i. Can fragment its tissue, which then becomes another sponge ii. Allows them to be stationary, sex can be brutal and costly so asexual reproduction can produce many copies without the cost of sex b. Sexual (gametes) i. Broadcast spawning: throws out larva and leaves it to change, no parental care, are dispersed to different habitats and might actually give the offspring a better habitat ii. Hermaphrodite (sponges have both male and female parts, they “double down” and can self fertilize, basically doubles the chance of successful fertilization) 2. Sea Stars, Sea Urchins, Sea Cucumbers (Echinodermata) a. Larvae themselves can spontaneously clone, doubles the number of offspring, sister larva has same genetic code as the first b. Discovered in 2003 c. Increased probability of surviving in the plankton 3. Coral Reproduction Mass Spawning a. Simultaneous hermaphrodites b. Complex life histories (planula larva) c. Internal fertilization larva released d. External fertilization parents release eggs/sperm packets, packets split up and can fertilize each other or fertilize other packets e. Simultaneous release of gametes type of broadcast spawning, up to 32 species in a single night, all release within the same time frame to ensure fertilization 4. Costs of Internal Fertilization (Komodo dragon mating, Varanus komodoensis) a. Territorial fights, mating can be brutal b. Usually vertebrates c. A lot of energy expended in the mating, female dragon gets clawed up and bleeds as a result of the courtship 5. Sex in the Sea risky business a. Barnacles (crustacea) hermaphrodites, sessile (immobile, attached to bottom) i. They each have a penis capable of fertilizing their neighbors eggs, penis is twice the length of the body ii. Females hold the larva until phytoplankton levels are abundant b. Dark abyss reproductive challenges, deep sea angler fish, male parasitizes female i. Females: sexual dimorphism, male and female don’t look alike ii. Female is 60x longer and ½ million x heavier 6. Sexual vs. Complex Life Histories (what happens to the organism between birth and death) a. Simple: no metamorphosis, no larval forms i. Humans, turtles, sharks, fucus (rockweed) brown seaweed b. Complex life histories: common in the sea i. Larvae (microscopic plankton stages) cast adrift ii. Metamorphosis iii. Settlement into adult habitat (recruitment) iv. 4 stages in the blue crab life history (zooea and megalops) v. stages might be in different habitats, might help avoid some of the risks of the other habitats c. Many seaweeds have complex life histories i. Kelp have a complex life history with two stages, each with a different morphology ii. The sporophyte produces spores that settle into microscopic gametophytes that look like microscopic kelp, which produce gametes iii. Red (Rhodophyta) seaweed, three stages, 2 produce spores, 1 stage produces gametes d. Seaweed perfume sperm attractant kelp and other brown seaweeds i. The female seaweed produces volatile compounds that attract sperm ii. Pheromones are small organic compounds that direct behavior iii. Some organic pollutants might interfere with sexual reproduction of important brown seaweeds 7. Brooding caring for offspring (opposite of broadcast spawning) a. Pre spawning aggregation (pseudocopulation: no actual mating going on) i. Leptasterias (sea star) ii. Male deposits sperm on rock iii. Female pinwheels over sperm, releases eggs, broods them b. Brooding by male seahorses i. Simple life history ii. Courtship, very elaborate, no internal fertilization during this iii. Eggs extruded and mixed with sperm iv. Mixture enters brood pouch 8. Quality vs. quantity a. Large investment brooding=fewer, larger offspring b. Small investment broadcasting= numerous offspring that are smaller 9. Sequential hermaphroditism gender switch during life history a. Anemonefishes= members of the damselfish family i. Fishanemone commensalism, born as males, strict dominance hierarchy within anemone (one dominant breeding female, nest guarding by male ii. Female dies, one of the males, usually the largest, becomes a female and takes over b. Clownfish (In Class Assignment) i. False clownfish: amphiprion ocellaris ii. Clark’s anemonefish: Amphiprion clarkii iii. Tomato anemonefish: amphiprion frenatus: the most territorial c. Serial hermaphroditism and harems parrotfishes (runs around with a group of females) i. Juvenile female to permanent male ii. Sequential hermaphroditism 1. Slipper shell, fornicating slipper shell, (crepidula fornicata) 2. They stack up, female on the bottom, mate with the one underneath 10. Coastal fishes show abnormal sex reversal a. Seine: a net that is dragged through the water b. Feminization of males, disruption of the normal sex hormones (endocrine disruption) i. Pharmaeceuticals and personal care products ii. Sewage effluent iii. Industrial chemicals iv. Pesticdies v. Many unidentified chemicals 11. Life history changes in color, behavior many spotted sweetlips, Plectorhinchus chaetodonoides a. Nuptial coloration: green chromis (chromis viridis: damselfish) b. When they mate they become yellow and black, and then change back to blue 12. Summary a. Risks b. Adaptations to reduce risks c. Successful reproduction is achieved in highly diverse ways i. Cloning (non sexual) ii. Interval vs. external fertilization iii. Broadcast spawning vs. brooding iv. Hermaphrotidism d. Complex life histories are common 13. Prep for Next Class (Phytoplankton and Seaweeds) a. phytoplankton vs. seaweeds: unicellular algae are not seaweeds but all seaweed is algae i. Phytoplankton are single celled or simple chains of cells and are not attached to anything (kelps and seaweeds are) ii. Phytoplankton float in the epipelagic zone iii. Both use photosynthesis and are the primary producers of the ocean b. Upwelling: surface waters are replaced by cold, nutrient rich water that “wells up” from below, leads to productivity and biodiversity of the habitat c. Harmful algal bloom (HAB): algal blooms composed of phytoplankton known to naturally produce biotoxins, occur when certain types of microscopic algae grow quickly in the water and form visible patches that may harm the health of the environment, plants and animals Studying for Exams Reviews (1sr slide in every lecture) Thought/study questions at the end of lecture Understand goals of lecture Mating Behavior, sexual dimorphism of mandarinfish (synchriopus slendidus) Phytoplankton and Seaweed 1. Review a. Ocean environment imposes constraints on sea life (cold, dark, high pressure, viscous) b. Fluid motion (disperses reproductive particles and chemicals, imposes forces like drag) c. Natural variation in ocean environment (El Nino) d. Unprecedented variation in ocean environment (The Blob) 2. Goals a. Introduce major marine algae b. Describe diverse groups composing phytoplankton and seaweeds c. Introduce marine food webs d. Compare a phytoplankton to a seaweed based food web e. Understand ecology of phytoplankton and seaweeds 3. Terms a.Common names for diverse groups of marine photosynthetic organisms b. Photosynthesis: light energy us used to produce organic matter (sugar) c.Primary producers i. Produce organic matter ii. Food for herbivores iii. Are at the base of many marine food webs d. Algae: describes photosynthetic aquatic organisms that lack true leaves and roots and do not flower to reproduce e.Phytoplankton: microscopic single celled algae that float in the pelagic zone f.Seaweed: multi celled marine alga that live in the coastal intertidal and subtidal zone, typically attached to bottom g. Primary production: the transformation of inorganic molecules like carbon dioxide and water into organic molecules like sugars i. Provides the energy and matter for food webs 4. Global Ocean Primary Production a. 55% of total primary production on earth occurs in the ocean b. upwelling regions are the most productive ocean environments but cover little area of the ocean i. high nutrient concentrations in cold waters fertilize phytoplankton, satellite chlorophyll sensors show more phytoplankton, higher chlorophyll levels and higher primary production c. CA Coastal upwelling ecosystem i. One of four on earth ii. Highly productive iii. Fertilizes phytoplankton iv. Satellite chlorophyll sensors have sensed more phytoplankton, higher chlorophyll levels and higher primary production d. Upwelling: cold, nutrient rich water rises from the deep to replace surface waters, winds and rotation of the earth pull surface waters away from land e. Mapping surface currents with coastal radar, UCD’s marine lab operates one as part of is ocean observing system (BOON) f. Major surface current off of our coast moves south 5. Phytoplankton a. A mixed species pelagic community, including diatoms and photosynthetic protozoan’s (flagellated) b. Live in mixed communities of many different species c. Float in the surface waters (epipelagic zone) d. Microscopic size e. Phytoplankton photosynthesis supports food webs f. Adaptations to avoid sinking below the photic zone i. Gas bubbles for buoyancy ii. Increase surface area 1. Long processes (spines) 2. Formation of chains or colonies 6. Planktonic Food Web Trophic Web a. Apex/top predators including humans b. One or more levels of predators (secondary consumers) c. Herbivores (grazers or primary consumers) like zooplankton and krill d. Primary producers like phytoplankton 7. Zooplankton decline in CA Upwelling system a. Plankton: community of organisms that drift in the sea b. Zooplankton: animals in the plankton c. Temperature has risen, decrease in zooplankton population (due to decline in phytoplankton) 8. Sea Life Responses to ocean temperature variation a. Tufted puffins are major top predators, chick survival declines above 9.5 degrees C b. Harfmful Algal Bloom: disrupted food web and poisoned every level c. Dead sea birds d. 8090 species of phytoplankton are toxic 9. HAB’s Red Tides a. Caused by toxic dinoflagellates with reddish pigments that reproduce so rapidly that they color the sea b. Produce toxins as an antiherbivore defense, a lot of them don’t produce the toxin c. Dinoflagellates can cause Paralytic Shellfish Poisoning 10. Seaweeds: The large marine algae a. Blade/fronds b. Thallus c. Stipe d. Holdfast e. Seaweeds are limited to shallow waters: because they are thicker they need more light to survive and grow f. Seaweed diversity i. Identified based on their photosynthetic pigments 1. Green (chlorophyta) 2. Brown (Phaeophyta) 3. Red (Rhodophyta) ii. Divisions also differ in cell wall structure, storage compounds and reproduction iii. Green tropical seaweeds are the only seaweeds that grow in soft sediments iv. Brown seaweeds can be very small but they include the largest (kelps) v. Red seaweeds are beautiful and inspire art g. Life histories (diverse and often complex) i. Kelp: complex life history with 2 stages in which each has a different morphology, the sporophyte produces spores that settle into microscopic gametophytes which produce gametes ii. Females that produce eggs also produce attractants iii. Red seaweed: 3 phases 11. Seaweed values a. Food b. Cell wall compounds extracted for cosmetics c. Health supplements 12. Kelp Forests a. Cool waters along rocky coasts b. 20m tall c. grow fast, 1cm/day d. highly prodctive e. provide habitat f. support a seaweed based food web g. sea otters eat sea urchins which eat kelp h. effect of sea otters on biodiversity in a kelp forest i. the sea urchin kelp interaction is an example of top down control of marine biodiversity, predators keep dominant organisms in check and prevent them from outcompeting other species, top down control=trophic cascade j. the loss of top predators can result in loss of marine biodiversity 13. Abalone a. Mollusk with a single shell (gastropod) b. Eats kelp detritus c. Large muscular foot (edible) d. Several species all of different color e. Threatened with extinction f. White abalone is endangered g. Live in kelp beds, eaten by sea otters and humans, herbivore (live red algae), detritivore (kelp detritus), broadcast spawning h. Abalone larvae prefer to settle on red seaweeds, their habitat and food source i. Gamma amino butyric acid is a neurotransmitter compound and induces settlement of abalone, red algae release a chemical mimic of GABA j. Abalone withering foot syndrome: in addition to overharvesting, abalone are decimated by disease 14. Summary a. Upwelling ecosystems are v ery productive due to a rich supply of nutrients from deep water b. CA coastal upwelling ecosystem is one of 4 on earth c. Diverse groups of marine algae d. Phytoplanktonpelagic primary producers (HABS) e. Seaweeds are benthic primary producers, many examples of complex life histories f. Foundation of marine foodwebs i. CA coastal upwelling ecosystem is phytoplankton based and kelp beds are benthic seaweed based g. Top down control of marine food webs, a predator controls the food webs from the top (sea otter urchin kelp) h. Overharvesting and disease can decimate marine populations 15. Study Questions a. Techniques used by scientists to study the ocean b. Draw and label a planktonic and a benthic food web, differences? c. Most productive regions of the ocean and why 16. Preview for Next Lecture a. Benthic and pelagic b. Rhizome c. Prop root and which type of marine flowering plankts have them EVE 12 Quiz 1 Study Guide Species/Terms 1. xenoturbella- purple socks flatworm, 4 new species were discovered in 2016 at a hydrothermal vent in the Gulf of California a. they had mollusk DNA in them because they eat mollusks b. they have bilateral symmetry, no anus, kidney, nervous or circulatory systems 2. Riftia- vent tube/lipstick worms a. Have symbiotic sulfur bacteria that are red due to hemoglobin that binds to the sulfur b. They grow fast and tall c. They have no mouth or digestive tract 3. hydrothermal vents a. undersea volcanoes where molten rocks are released from the Earth’s mantle b. life is abundant due to chemosynthesis: bacteria use H2S and other inorganic molecules to make organic matter that supports food webs 4. biodiversity a. species richness: the number of species in a community b. dominance: one species is very abundant (species with low abundance could go extinct and therefore biodiversity would go down) c. evenness: all species have relatively the same abundance Properties of Sea Water 1. chemical composition a. salinity: the total amount of dissolved salts, 96.5% water and 3.5% salts 2. constant composition a. ratios of major ions are constant in the ocean whereas lakes each have different compositions, the ratios in the ocean create a very stable environment for organisms 3. water is a good solvent a. lowers freezing point, well buffered (stable pH) 4. light a. most of visible light is absorbed in the photic zone (200ft deep) 5. temperature a. thermocline: sharp change in temperature with ocean depth, most of the ocean is between 0 and 3 degrees C and 17 degrees at the surface 6. density a. many marine organisms collapse under the force of gravity when on land, our skeletal systems are adaptations to survive the force of gravity but the ocean harbors many invertebrates 7. viscosity a. the tendency for a fluid to be sticky or to resist flow b. 55x more viscous than air, currents are 29x as strong as wind c. drag: the force of a flowing fluid on an organism i. kelp’s holdfasts at their base to resist drag ii. elasticity of organisms to be able to stretch and bend iii. streamline shape of many organisms 8. fluid flow a. transport of food, waste, reproductive particles b. chemical signaling c. boundary layers: regions of very slow flow close to a surface that provide protection from fluid flow 9. major ocean currents a. driven by heating and cooling of the earth, salinity and density b. have transported debris across the globe (2011 Japanese tsunami debris) c. concern because radiation as well as invasive species can travel this way 10. thermohaline circulation a. the conveyor belt global circulation of ocean water between the surface and deep water layers, transfers heat to the benthos, if this circulation slows down at all we will see drastic and abrupt climate change b. caused by differences in water density 11. El Nino Southern Oscillation (ENSO), a Pacific phenomenon a. Is a normal ocean climate cycle that begins with higher than average surface temperatures and after 7 years is followed by colder than average temperatures b. Typically a 9 degree difference from normal in either case c. Is caused by the slowing of trade winds Sea Life Responses to Ocean Variation 1. tropical species show up in CA during El Nino 2. coral bleaching: coral release their symbiotic brown algae (zooxanthellae) when stressed (currently very high predictions for this occurring this summer) Week 2 Lectures 1. reproduction a. asexual reproduction: occurs without mating i. budding or cloning: a piece that breaks off of an individual can grow into a new individual ii. can produce many copies without the risks of sex b. sexual (gametes) i. broadcast spawning: throw out larva and leave it to change, no parental care, larva are dispersed to other habitats, which in some cases turn out to be better or less risky habitats than the original ii. hermaphrodite: have both male and female parts, leads to doubling down which doubles the chances of successful fertilization iii. internal fertilization: can be costly in terms of energy, must be mobile, partners can harm each other (the case of the Komodo dragon) iv. release of egg/sperm packets, split apart and mix with other sperm/egg packets c. brooding: caring for offspring 2. adaptations a. barnacles have penis’s twice the length of their body so they can inseminate their neighbors b. deep sea angler fish males parasitize females to ensure fertilization 3. life history a. simple: no metamorphosis, no larval forms (humans, turtles, sharks, brown seaweed) b. complex: common in the sea i. larval stage, sometimes several larval stages ii. metamorphic stage iii. settlement into adulthood (recruitment) iv. stages may occur in different habitats, which might help avoid some of the risks of certain habitats 4. quality vs. quanitity a. large investment brooding means fewer, larger offspring b. small investment brooding means many, smaller offspring 5. hermaphroditism a. sequential: gender switch during lifetime b. anemonefish (damselfish family) i. one female who dominates anemone territory, males guard the territory, when the female dies usually the biggest male becomes the new female ii. in class assignment compared the Clark’s, false and tomato anemonefish (tomato was the most aggressive in terms of defending territory)
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