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--- name: Genes Protein and Variation route: /2018/fall/bi360/week1/1 menu: BI 360 order: 2 --- ## Terrestrial vs. Marine ### Terrestrial Habitats #### Terrestrial Habitats - Air not dense - Easily move through not dense air. - But, organims are size limited - Too big => can't overcome gravity #### Marine Habitats - Water is denser than air - second - third Amount of energy you'd have to expend just to hold yourself up on land with gravity would be too much. Limits your size. ## The Earth is an ocean planet. The ocean regulates climate. - 2013-2015 "Ridiculously Resilient Ridge" of hot air *heat blob* - Like coffee with the lid on the cup - At its worse, 3.5 million square miles from MX to AK. - Temp increased by 7 degrees climate. - Tropical animals moved to PNW waters. - Massive toxic algal blooms. - Trophic webs crashed. *Look up "trophic web"?* - Hot summers in PNW. ## 80% of water occurs at depths > 200m - Avg depth of ocean is about 4300m / 14,000 ft - Deepend point is almost 11,000m / 36,000 ft ## The ocean is full o flife at all depths, forom Artic to Antartctic ## The ocean comprises many Habitats - Marine realm: a relatively open system of interconnected water - What dictates where an organism can live? - *Covered in sections (2-2, 2-4, 2-5, 2-6)* ## Life in a fluid medium ### Movement - Polar nature of water makes it thick ### Obtaining information / nutrients - Organisms are constantly bathed in a mix of chemical cues, nutrients,toxins, waste, etc. ## What dictates where an organism lives? - Optimal range / habitat = where physiological stress is minimized. - Ability to tolerate flucutaitons outside of this range ## Habitat Range and Homeostasis ## What helps define the optimaal range? 1. Abiotic Factors - The physical and chemical characteristics of an environment. - Sunlight, temp, salinity, pressure, metabolic requirements, waste removal - Deviating from the "norm" creates stress - Influence distribution - Can only move as far as they are physically able 2. ## Abiotic Factors - Light Where is the primary producer? Light is essential to this in most environments. - Seawater absorbs light quickly. - Light level / wavelength changes dramatically with depth. - Vision - Many organisms rely on vision to feed, communicate, find mates, avoid predators - Powers photosynthesis - Phytoplankton dominant primary producer of ocean food web - seaweeds, plants are also important - Influences distribution - solar energy can support high rates of Ps (photic zone) - distribution of primary producers correlates to where light leveles are higher - Also changes seasonally with light - 70% ocean water is outside visible light range - Photosynthetic organisms remain in the upper layers - **Primary production at surface fuels the dark deep sea** ## Temperature - Presence of H bonds restricts water molecule movement. - Takes more energy to raise 1 g of water 1 degree celcius than other liquid = **high heat capacity** - Ocean is relatively stable temp - Deep water = cold - Near shore and shallow water have higher fluctuation. - Has significant impact on metabolism - cold water = more sluggish - too hot = death - most live between 5 and 30 deggrees celcius - Many invertebrates are ectotherms - rely on environment for heat - Mammals and birds are endotherms - metabolism generates sufficient internal heat - endotherms can occupy a larger habitat because they can regulate temp better. ## Salinity - Salt is important because water is constantly moving back and forth between membranes. - Organisms deal with change in salinity by either being an: 1. Osmoconformer - Salt contents inside cell = salte conent of sea water outside cell - "Isotonic Solution" - "body is same saltiness as the water" 2. Osmoregulator - Marine vertabrates - Most fish have salinity that is about half that of the sea water - Live in a hypertonic Solution - Body is less salty than the water, so water is rushing out of body to match the salte - The body is shrinking - "hypertonic solution" - constantly fighting water loss ## Pressure - Water is much denser than air ## Metabolic Requirements - Organisms obtain all nutrients from water - require organic and inorganic materials to metabolize, grow, and reproduce. - Limited Materials: - CaCO3, Nitrogen, Phosphorous, etc. - How much or how little of these things are available, pushes stress and can influence survival rate. ## The Carbon Cycle - Closed system - Carbon is continuously cycled in didfferent forms. - CO2 is produced in respiration, decomp. - Absorbed into water from atmosphere. - Primary producers utilize CO2. ## What happens when additional carbon is introduced into a closed system? - Buring fossil fuel releases CO2 - Excess CO2 = **Ocean Acidification** - Less calcium carbonate - binds to CO3, making it so that animals can't make CaCO3. - Animals need CaCO3 for things (shells, etc.) - impacts corals, oysters, snails, etc. -- any animal with a calcium based shells ## Ocean Acidification - Carbonate in water is going away ## Nitrogen Cycle - Plants and other primary produces require nitrogen for protein synthesis. - Too much nitrogen = overgrow (lots of plant growth) = plants use up everything = deadzone = overfertilize the oceans - happens in places with a lot of run off Limiting nutrients need to be limiting. Too much CO2 is bad. Too much N2 is bad also. ## What helps define the optimal range? 2. Biological interactions - biological interactions within / across individuals / species ## Biological Interactions Interactions within the same species Interactions within different species (community) - usually predator / prey dynamic Biological interactions + physical conditions help define an organisms niche. There can be a wide range of niches. ## Niche partitioning (section 2-4) - Niche: the role an organism has in its environment, e.g. - keystone species - top tier predator - filter feeder - primary producer - Niche influenced by both biological and physeical Factors - Abiotic: fundamental niche - biotic: realized niche. ## How abiotic and biotic factors drie niche partitioning Barnacles are filter feeding crustaceans. Competition and predation create a "realized" niche. - Mussels - Capable of inhabiting a wide intertidal range - good at competing for space - prefer to be closer to ther water - maintain a reduced niche space due to predation by sea stars "Realized Niche" - somethign could live somewhere well, but things like predation push it to live in a certain way / place.